Dose-Dependent Association of Adolescent Breakfast Consumption with Mental Health and Changes Over Time: an International Observational Study

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Methods Data were obtained from five rounds (2002, 2006, 2010, 2014, and 2018) of a multi-country cross-national survey of school students: Health Behavior in School-aged Children (HBSC). Mental health was measured using a list of eight items for psychosomatic health complaints, combined into a composite score from 0 to 32. Breakfast consumption frequency was measured by the days per week. A multilevel generalized additive model was applied to evaluate the dose-dependent association of adolescent breakfast consumption with mental health. Results This study included 918,564 adolescents, with a mean (SD) age of 13.59 (1.64) years, of whom 473,633 (51.6%) were girls. In the final multivariate-adjusted model, breakfast consumption frequency was negatively associated with mental health, compared with daily breakfast consumption, adolescents with breakfast skipping had significantly higher psychosomatic complaints (β: 2.93, 95% CI: 2.84–3.02, P < 0.001). This significant non-linear association was consistent across different survey years ( P < 0.001), gender ( P < 0.001), and school grade ( P < 0.001), indicating a broad relevance to adolescent mental health. The association of breakfast consumption on mental health was more pronounced in females ( P for interaction < 0.001) and in higher school grade ( P for interaction < 0.001). Conclusions Breakfast consumption frequency was negatively associated with mental health, and this dose-dependent association exhibited a non-linear pattern. Over time, the association of breakfast consumption on mental health was more pronounced, and this trend particularly was pronounced in recent years. Furthermore, girls and adolescents in higher grades are more likely to experience worse mental health. Mental health Breakfast consumption Adolescent Figures Figure 1 Figure 2 Figure 3 Introduction Adolescence is considered a crucial phase for the development of mental health problems 1 , and is also a period during which young people are most vulnerable to experiences of mental ill-health and the onset of mental disorders 2 , 3 . Globally, approximately 14% of young people aged 10 to 19 are affected by mental health problems, which rank among the leading causes of illness and disability and account for 22.9% of the total global years lived with disability 4 . The proportion of adolescents with poor mental health has continued to grow in recent years, which brings significant adverse impacts on individual, family, and society 5 . The consequences of failing to address adolescent mental health conditions extend to adulthood, impairing both physical and mental health. Therefore, protecting adolescents from adversity and promoting psychological well-being are critical for their health and well-being during adolescence and adulthood. The causes of mental disorders are complex and involve multiple factors. Adopting healthy dietary patterns may serve as a cost-effective and safe approach to reduce the short- and long-term burden associated with mental health conditions. Breakfast is generally accepted to be the most important meal of the day 6 , and breakfast consumption may be the most important modifiable indicator of dietary habits and behaviors in general 7 . A growing body of research has identified links between breakfast consumption and various health benefits, such as improved overall diet quality, reduced cholesterol levels, lower obesity prevalence, and enhanced cognitive performance in adolescents 8 , 9 . However, evidence regarding the relationship between breakfast consumption and adolescent mental health remains limited and inconclusive. For example, a recent systematic review that included 9 observational studies on breakfast consumption and mental health in adolescents reported mixed results 10 . In addition, most of the studies in this systematic review had small sample sizes, and no dose-dependent analysis was conducted to assess the relationship between breakfast consumption and mental health. Considering that adolescence is recognized as a critical period for behavioral change, including eating behaviors, and that the transition from adolescence to adulthood represents an optimal window for encouraging healthy eating and facilitating the formation of lasting habits 11 , 12 , comprehensive research is warranted to better understand the association between breakfast consumption and mental health in adolescents. In this context, based on a large-scale multi-country sample of adolescents from 45 countries and regions in Europe, Central Asia, and North America, the primary objectives of this study were to identify the association between breakfast consumption frequency and mental health in adolescents. The second objective was to investigate the dose-dependent breakfast consumption-mental health association in this key demographic. Methods Data Source and Participants The data used in this population-based cross-sectional study were derived from the international Health Behavior in School-aged Children (HBSC) study. The HBSC study is a World Health Organization Collaborative Cross-National Survey which has been conducted every 4 years since 1983 across Europe, North America, and the Middle East. HBSC collects data on the health and well-being, living environments, social relationships, and health behaviors of 11-, 13-, and 15-year-old boys and girls, including socio-economic environment, alcohol and drug use, sexual health, health habits, body image, and family and peer relationships 13 . Anonymity was maintained during data collection, and appropriate confidentiality measures were implemented. Comprehensive information on the HBSC sampling design and data collection methods is available in prior publications 14 . Prior to data collection, study procedures received ethical approval from the institutional ethics committee or other relevant board at the country or regional level and were endorsed by the World Health Organization to ensure compliance with ethical research standards. All countries participating in the study follow a standardized protocol. The protocol describes the methods for conducting the survey, the rules to be followed, and the coding procedures for the collected data 14 , 15 . The present study used the most recent five waves of HBSC data collected in 2002, 2006, 2010, 2014, and 2018, which are publicly accessible. After excluding records with missing data on primary exposures and outcomes concerning the evaluation of breakfast consumption frequency and mental health, the final sample analyzed in this study consisted of 918,564 adolescents. Supplementary Figure S1 provides the flowchart of participants. Measurement of breakfast consumption Breakfast consumption was measured by the number of days per week. Participants were asked to indicate how many days they usually consumed breakfast (defined as having more than a glass of milk or fruit juice) during the week and weekends, respectively. The categories of responses were: “I never have breakfast on weekdays”, “One day”, “Two days”, “Three days”, “Four days”, “Five days” for weekdays. In addition, for weekend: “I never eat breakfast on the weekend”, “I usually eat breakfast on only one day of the weekend”, “I usually eat breakfast on both Saturday and Sunday”. The responses were summed to reflect the weekly frequency of breakfast consumption, with possible scores ranging from 0 (breakfast skipping) to 7 (daily breakfast consumption). Measurement of mental health Mental health was measured via an 8-item scale assessing the frequency of experiencing the following eight psychosomatic health complaints (feeling low, irritability or bad temper, feeling nervous, difficulty sleeping, dizziness, headache, stomachache, and backache) over the past 6 months. The response options for each question ranged from “daily”, “more than once a week”, “about every week”, “about every month”, to “rarely or never”. After reverse coding each item on a 0–4 scale, responses were aggregated to create a total score ranging from 0 to 32, where higher values indicated more frequent psychosomatic complaints. Cronbach’s alpha in our sample was 0.835, indicating that the items had a high internal consistency. The psychosomatic complaints score has demonstrated good validity and reliability in adolescent populations and has been widely applied in previous research 16 , 17 . Covariates Covariate selection was informed by data availability and prior literature. Sociodemographic variables included age, sex, school grade, and socioeconomic status. Socioeconomic status was assessed using the Family Affluence Scale (FAS), a validated composite indicator widely employed in the HBSC study to reflect objective socioeconomic status 18 . The FAS consists of four items: family car ownership, bedroom occupancy, frequency of family holidays, and computer ownership. A total FAS score ranging from 0 to 9 was calculated by summing the responses to each item 18 . Body mass index (BMI) was derived from self-reported height and weight. The validity of self-reported data for estimating BMI in child and adolescent populations has been supported by previous research 19 . Physical activity was assessed through the item: “Over the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day?”, with response options ranging from 0 to 7 days. Academic pressure was measured using a single item: “How pressured do you feel by the schoolwork you have to do?”, with responses ranging from “Not at all” to “A lot”. Experience of bullying was measured with the question: “How often have you been bullied at school in the past couple of months?”, with response options including “Never”, “Once or twice”, “2–3 times per month”, “Once a week”, and “Several times a week” 20 . Statistical Analysis Summary statistics are presented stratified by different survey year. Categorical variables were presented as numbers and percentages, while continuous variables were presented as means and standard deviations. Baseline characteristics across different survey years were compared using ANOVA for continuous variables and Chi-square tests for categorical variables. A multilevel generalized additive model (GAM) was applied to estimate the association between breakfast consumption frequency and mental health, adjusted for age, gender, school grade, physical activity, BMI, FAS, academic pressure, the experience of being bullied, and survey year (only for overall participants). Among them, age and BMI were represented as smoothing splines. Considering the multilevel structure of the data, where students are nested within schools, schools within countries, and countries within survey rounds, a multilevel framework was applied to account for clustering. The dose-dependent association of breakfast consumption frequency with mental health was examined through multilevel GAM analysis, with the same covariates. Subgroup analyses were performed to identify possible effect modifications of gender and school grade by adding an interaction term (breakfast consumption frequency × survey year, breakfast consumption frequency × survey year × gender, breakfast consumption frequency × survey year × school grade) to the model, and the modification was evaluated using P -interaction by likelihood ratio test. Sensitivity analysis was conducted using five-fold cross-validation, where the dataset was partitioned into five subsets, and the model was refitted on each fold to assess the stability of coefficient estimates. All analyses were performed using R Statistical Software (version 4.4.3), with statistical significance set at a two-sided P value of < 0.05. Results Table 1 presents the descriptive statistics for adolescents across survey years. From 2002 to 2018 HBSC data, a total of 918,564 adolescents (mean age: 13.59 ± 1.64) were included, of whom 473,633 (51.6%) were girls (Table 1 ). Among them, 247,921 (32.9%) adolescents were in grade 5, the mean (SD) of BMI was 19.49 (3.50), and 41,189 (4.6%) adolescents reported no physical activity. In addition, 104,947 (11.6%) adolescents felt a lot of academic pressure, and 616,492 (70.5%) adolescents reported no experience of bullying. Across survey years from 2002 to 2018, psychosomatic complaint scores gradually increased from a mean (SD) of 7.77 (6.14) in 2002 to 8.63 (6.72) in 2018 ( P < 0.001). In parallel, the proportion of breakfast skipping increased from 2.7–4.1% ( P < 0.001). Table 1 Baseline characteristics of study participants Variable Overall 2002 2006 2010 2014 2018 P Total participants 918564 141347 184448 194443 186311 212015 Age 13.59 (1.64) 13.57 (1.66) 13.63 (1.64) 13.59 (1.64) 13.61 (1.63) 13.54 (1.63) < 0.001 Gender Male 444931 (48.4) 68071 (48.2) 89211 (48.4) 94329 (48.5) 90390 (48.5) 102930 (48.5) 0.095 Female 473633 (51.6) 73276 (51.8) 95237 (51.6) 100114 (51.5) 95921 (51.5) 109085 (51.5) School grade Grade 5 247921 (32.9) 47304 (33.5) 58513 (31.9) 48425 (33.6) 41378 (32.3) 52301 (33.4) < 0.001 Grade 7 257256 (34.1) 48521 (34.3) 62850 (34.3) 47829 (33.2) 43968 (34.4) 54088 (34.5) Grade 9 248487 (33.0) 45522 (32.2) 62097 (33.8) 47837 (33.2) 42615 (33.3) 50416 (32.2) Physical activity No Physical activity 41189 (4.6) 6146 (4.6) 8498 (4.7) 8932 (4.7) 7386 (4.0) 10227 (4.9) < 0.001 1 days 67958 (7.6) 12291 (9.2) 13847 (7.7) 14418 (7.5) 12471 (6.8) 14931 (7.2) 2 days 120389 (13.4) 21017 (15.6) 24332 (13.5) 25906 (13.6) 23317 (12.7) 25817 (12.4) 3 days 149810 (16.7) 23988 (17.9) 29660 (16.4) 31757 (16.6) 29975 (16.4) 34430 (16.5) 4 days 136790 (15.2) 19769 (14.7) 26772 (14.8) 29687 (15.5) 27888 (15.2) 32674 (15.7) 5 days 129531 (14.4) 17418 (13.0) 25375 (14.1) 27545 (14.4) 27566 (15.1) 31627 (15.2) 6 days 83612 (9.3) 10766 (8.0) 16070 (8.9) 18149 (9.5) 18202 (9.9) 20425 (9.8) 7 days 168078 (18.7) 22932 (17.1) 36002 (19.9) 34732 (18.2) 36229 (19.8) 38183 (18.3) BMI 19.49 (3.50) 19.19 (3.30) 19.43 (3.39) 19.62 (3.52) 19.58 (3.58) 19.55 (3.64) < 0.001 Family Affluence Scale 0 8769 (1.0) 2116 (1.5) 2485 (1.4) 1244 (0.7) 1159 (0.7) 1765 (0.9) < 0.001 1 22908 (2.6) 5523 (4.0) 5451 (3.0) 3370 (1.8) 3655 (2.1) 4909 (2.4) 2 45341 (5.1) 10239 (7.4) 10343 (5.8) 7275 (3.9) 7895 (4.5) 9589 (4.7) 3 77555 (8.8) 16705 (12.1) 18086 (10.1) 13596 (7.3) 13848 (8.0) 15320 (7.5) 4 115996 (13.1) 24140 (17.4) 26815 (15.0) 22109 (11.8) 20644 (11.9) 22288 (10.9) 5 147134 (16.7) 26502 (19.1) 32059 (17.9) 30020 (16.1) 28109 (16.1) 30444 (14.9) 6 163204 (18.5) 24081 (17.4) 32191 (18.0) 35653 (19.1) 34027 (19.5) 37252 (18.2) 7 140248 (15.9) 17070 (12.3) 26008 (14.5) 33165 (17.7) 29342 (16.9) 34663 (17.0) 8 97926 (11.1) 8481 (6.1) 16460 (9.2) 24787 (13.3) 21027 (12.1) 27171 (13.3) 9 64043 (7.3) 3565 (2.6) 9260 (5.2) 15784 (8.4) 14348 (8.2) 21086 (10.3) Academic pressure Not at all 185115 (20.4) 28120 (20.1) 35165 (19.3) 39482 (20.5) 39417 (21.5) 42931 (20.5) < 0.001 A little 398606 (44.0) 62386 (44.6) 80713 (44.4) 85830 (44.7) 80942 (44.2) 88735 (42.4) Some 217380 (24.0) 34326 (24.6) 46217 (25.4) 45927 (23.9) 41535 (22.7) 49375 (23.6) A lot 104947 (11.6) 14953 (10.7) 19888 (10.9) 20896 (10.9) 21176 (11.6) 28034 (13.4) Experienced bullying Never 616492 (70.5) 93568 (66.8) 118831 (68.2) 132182 (71.1) 126826 (72.2) 145085 (72.9) < 0.001 Once or twice 158947 (18.2) 28954 (20.7) 33915 (19.5) 33266 (17.9) 30292 (17.3) 32520 (16.3) 2–3 times per month 39280 (4.5) 6494 (4.6) 8340 (4.8) 8271 (4.5) 7531 (4.3) 8644 (4.3) Once/week 25472 (2.9) 4358 (3.1) 5608 (3.2) 5266 (2.8) 4785 (2.7) 5455 (2.7) Several times/week 34534 (3.9) 6800 (4.9) 7428 (4.3) 6876 (3.7) 6142 (3.5) 7288 (3.7) Psychosomatic complaints 8.19 (6.55) 7.77 (6.14) 8.05 (6.42) 8.13 (6.52) 8.19 (6.80) 8.63 (6.72) < 0.001 Breakfast days 0 days 29525 (3.2) 3772 (2.7) 5329 (2.9) 5673 (2.9) 5982 (3.2) 8769 (4.1) < 0.001 1 days 39460 (4.3) 5674 (4.0) 7502 (4.1) 8203 (4.2) 7428 (4.0) 10653 (5.0) 2 days 102115 (11.1) 15293 (10.8) 21275 (11.5) 21318 (11.0) 19994 (10.7) 24235 (11.4) 3 days 40159 (4.4) 5506 (3.9) 7743 (4.2) 8563 (4.4) 7706 (4.1) 10641 (5.0) 4 days 47015 (5.1) 6356 (4.5) 9202 (5.0) 10127 (5.2) 9331 (5.0) 11999 (5.7) 5 days 72534 (7.9) 9915 (7.0) 14409 (7.8) 15963 (8.2) 14643 (7.9) 17604 (8.3) 6 days 83356 (9.1) 11927 (8.4) 16147 (8.8) 18307 (9.4) 17058 (9.2) 19917 (9.4) 7 days 504400 (54.9) 82904 (58.7) 102841 (55.8) 106289 (54.7) 104169 (55.9) 108197 (51.0) Abbreviations: BMI, body mass index. Data presented as means (standard deviation) for continuous variables and numbers (percentages) for categorical variables. Examining differences among different survey years based on t test (for continuous variables) and χ 2 test (for categorical variables). Table 2 shows the associations between breakfast consumption frequency and mental health among overall adolescents and across different survey years. Among overall adolescents, those with fewer breakfast consumption days had significantly higher psychosomatic complaints ( P -trend < 0.001), compared with daily breakfast consumption (7 days), the fully adjusted β for the breakfast skipping was 2.93 (95% CI 2.84–3.02). Furthermore, this association was consistent across different survey years. In 2002, compared with daily breakfast consumption, those with breakfast skipping had significantly higher psychosomatic complaints (β: 2.60, 95% CI: 2.39–2.81, P < 0.001), and this relationship strengthened over time, reaching 3.10 (95% CI: 2.91–3.29) in 2018. Table 2 Associations of Total Breakfast Days Categories with Psychosomatic Complaints Total Breakfast days Overall Survey 2002 Survey 2006 Survey 2010 Survey 2014 Survey 2018 β(95% CI) P β(95% CI) P β(95% CI) P β(95% CI) P β(95% CI) P β(95% CI) P 0 days 2.93 (2.84–3.02) < 0.001 2.60 (2.39–2.81) < 0.001 2.87 (2.68–3.05) < 0.001 2.69 (2.48–2.90) < 0.001 3.05 (2.82–3.28) < 0.001 3.10 (2.91–3.29) < 0.001 1 days 2.70 (2.62–2.78) < 0.001 2.32 (2.15–2.49) < 0.001 2.46 (2.30–2.62) < 0.001 2.64 (2.46–2.81) < 0.001 2.74 (2.53–2.94) < 0.001 3.11 (2.95–3.28) < 0.001 2 days 1.58 (1.53–1.63) < 0.001 1.41 (1.30–1.52) < 0.001 1.56 (1.46–1.65) < 0.001 1.52 (1.41–1.64) < 0.001 1.56 (1.44–1.69) < 0.001 1.71 (1.60–1.82) < 0.001 3 days 1.62 (1.54–1.69) < 0.001 1.38 (1.20–1.55) < 0.001 1.65 (1.50–1.80) < 0.001 1.77 (1.59–1.94) < 0.001 1.68 (1.48–1.88) < 0.001 1.49 (1.33–1.65) < 0.001 4 days 1.50 (1.43–1.57) < 0.001 1.26 (1.10–1.42) < 0.001 1.51 (1.37–1.66) < 0.001 1.42 (1.26–1.58) < 0.001 1.71 (1.53–1.88) < 0.001 1.48 (1.33–1.63) < 0.001 5 days 1.25 (1.20–1.31) < 0.001 1.11 (0.98–1.24) < 0.001 1.34 (1.22–1.45) < 0.001 1.18 (1.05–1.31) < 0.001 1.28 (1.14–1.43) < 0.001 1.24 (1.11–1.37) < 0.001 6 days 0.95 (0.90–1.01) < 0.001 0.78 (0.66–0.90) < 0.001 0.96 (0.85–1.07) < 0.001 1.10 (0.98–1.22) < 0.001 0.97 (0.83–1.11) < 0.001 0.88 (0.76-1.00) < 0.001 7 days Ref. Ref. Ref. Ref. Ref. Ref. Abbreviations: CI, confidence interval; Ref, reference. The βs and 95% CIs were extracted from multilevel generalized additive model, with psychosomatic complaints as the outcome and variable of total breakfast days categories as the exposure, as well as controlling for survey year (only for overall participants), gender, school grade, physical activity, Family Affluence Scale, academic pressure, having experienced bullying, and smooth term of age and BMI. Figure 1 illustrates the dose-dependent associations between breakfast consumption and psychosomatic complaints across different survey years. A significant non-linear relationship was identified between breakfast consumption frequency and psychosomatic complaints scores (Fig. 1 ). Overall, higher breakfast consumption frequency was consistently associated with lower psychosomatic complaints scores across all survey years ( P < 0.001). The psychosomatic complaints score showed a decreasing trend as total breakfast days per week increased, with a more pronounced decline observed from 0 to 4 days per week, followed by a plateau between approximately 3 and 5 days, and then a further decrease toward daily breakfast consumption. In addition, the overall inverse association remained stable across different survey years. Figure 2 shows subgroup-specific dose-dependent associations of breakfast consumption with psychosomatic complaints, stratified by gender. In both males and females, a significant non-linear association was observed, with psychosomatic complaints scores progressively decreasing as breakfast consumption frequency increased ( P < 0.001). The association between breakfast consumption and psychosomatic complaints stratified by gender was evaluated using GAM, with the results shown in Supplementary Table S1 . In both the male and female subgroups, breakfast consumption was negatively correlated with psychosomatic complaints. The association between breakfast consumption and mental health outcomes was stronger in females than males (Supplementary Table S1 ), with a significant interaction observed between gender and breakfast consumption in relation to psychosomatic complaints across different survey years ( P for interaction < 0.001). Figure 3 shows subgroup-specific dose-dependent associations of breakfast consumption with psychosomatic complaints, stratified by school grade. Among different school grades, a significant non-linear association was observed, with psychosomatic complaints scores progressively decreasing as breakfast consumption frequency increased ( P < 0.001). The association between breakfast consumption and psychosomatic complaints stratified by school grade was evaluated using GAM, with the results shown in Supplementary Table S2. Among different school grade subgroups, breakfast consumption was negatively correlated with psychosomatic complaints. The effects of breakfast consumption on mental health were more pronounced in higher school grade than those in lower school grade (Supplementary Table S2). There was a significant interaction in the school grade subgroup for breakfast consumption and psychosomatic complaints across different survey years ( P for interaction < 0.001). We conducted a sensitivity analysis to examine the robustness of findings and presented the additional details in Supplementary Table S3. The same pattern of results was observed in the sensitivity analysis using 5-fold cross-validation (Supplementary Table S3). Discussion To the best of our knowledge, this is the largest study to date providing evidence of the association between adolescents’ breakfast consumption and mental health. It also provides an up-to-date insight into the dose-dependent relationship, an area that has not been extensively studied. Based on this multinational survey study with nearly one million adolescents, we found that breakfast consumption frequency was negatively associated with mental health. Adolescents who skipped breakfast entirely exhibited more severe psychosomatic complaints compared to those with daily breakfast consumption. Notably, this negative association has become more pronounced over time, and this trend was particularly pronounced in recent years. Furthermore, girls and adolescents in higher grades are more likely to experience worse mental health. In recent years, the prevalence of breakfast skipping among adolescents has increased, a trend that may continue due to ongoing social transitions and decreasing breakfast portion sizes. Findings from the current HBSC dataset indicate that the proportion of adolescents who regularly skipped breakfast rose from 2.7% in 2002 to 4.1% in 2018. This upward trend raises public health concerns, as breakfast consumption is recognized as a key health-supportive behavior. Prior evidence suggests that regular breakfast intake is associated with reduced risks of obesity and cardio-metabolic disorders 21 . Multiple factors may underlie breakfast skipping among adolescents, including limited self-efficacy, perceived obstacles, pre-existing habits such as staying up late or having unstructured mornings, and the tension between competing demands and individual preferences 22 . Indeed, research on the relationship of breakfast consumption with mental health is rare. In this study, our findings revealed an inverse association between breakfast consumption and mental health, which is consistent with prior studies conducted in children and adolescents. For example, one study among secondary school students found that those who frequently skipped breakfast were more likely to experience anxiety and depression 23 . Similarly, Milajerdi et al. reported that breakfast consumption was associated with lower odds of depression and psychological distress 24 . Collectively, the conclusion about the potential link between regular breakfast consumption and improved mental health outcomes is convincing. However, further information is required to shed light on the relationship between breakfast consumption and psychological disorders. Furthermore, our study identified that female adolescents and those in higher grades exhibited a greater likelihood of experiencing poorer mental health. Previous studies showed stronger associations between breakfast skipping and unhealthy behaviors in girls than in boys 25 . Although the current data did not demonstrate a significant sex difference in this association, a gender-specific effect was anticipated given that girls are more likely to engage in dieting behaviors, and female dieters are three times more likely to skip breakfast than non-dieters. Furthermore, the tendency among girls to simultaneously restrict food intake and increase physical activity for weight management may further complicate the interplay between these behaviors 26 . Breakfast skipping has been linked to irregular eating patterns and unhealthy weight control behaviors (such as restrictive dieting), particularly among adolescents with higher school grades, which may lead to psychological stress and mood instability 27 , 28 . The mechanisms underlying the association between breakfast consumption and mental health remain insufficiently understood. One of the underlying mechanisms is that adolescents who regularly consume breakfast tend to have more balanced macro- and micronutrient intakes—characterized by higher levels of dietary fiber and carbohydrates, and lower intake of total fats 29 . Some nutrients provided at breakfast, such as B vitamins, magnesium, and other trace elements, are essential for neurotransmitter synthesis and emotional regulation, potentially influencing mood and depressive symptoms 29 . In addition, breakfast consumption has been shown to reduce hypothalamic-pituitary-adrenal (HPA) axis activity, thereby lowering cortisol levels 30 . Elevated cortisol can suppress immune function (e.g., T cell and natural killer cell activity) and has been linked to mood disturbances and stress-related psychological disorders 31 , 32 . Further research is needed to elucidate the specific mechanisms through which breakfast skipping may contribute to the development of poor mental health. To the best of our knowledge, this is the largest study to date to demonstrate the association between adolescents’ breakfast consumption and mental health, while also providing up-to-date evidence on the dose-dependent relationship. The main advantages of this study include a large, nationally representative sample of more than 900,000 adolescents from multiple countries, which provides sufficient statistical power and enhances the generalizability of the results. The research’s extended time frame, covering data from 2002 to 2018, allows for the examination of temporal patterns in breakfast consumption and mental health among adolescents. In addition, stratified analyses by sex and grade level enabled the identification of subgroup-specific associations, which provided a useful basis for informing future research and intervention efforts. The present study also has some limitations. First, since this was a cross-sectional study with no temporal relationship, it is impossible to infer causality. Second, if the association between breakfast consumption and mental health is indeed valid, it is reasonable to assume that the composition and nutritional quality of breakfast may also play a role. However, the present study lacked data on the type and quality of breakfast, daily energy intake and expenditure, as well as other dietary behaviors such as lunch and dinner consumption, limiting further exploration of these factors. Therefore, additional studies are necessary to determine the association between breakfast composition and mental health. Third, there is currently no universally accepted definition of breakfast, and the operational definition adopted in this study may differ from those used in other research, potentially limiting the comparability of findings across studies. Fourth, another potential limitation may be reporting bias due to the use of self-reported questionnaires. Fifth, although a series of potential confounders was controlled for in the analysis, the possibility of residual confounding due to unmeasured or unknown variables cannot be entirely excluded. Finally, the majority of participants came from multiple European and North American countries, enhancing the generalizability of our findings within these regions. However, this may limit the applicability of the results to predominantly low-income populations, and the generalization of these findings should therefore be interpreted with caution. Conducting further country-specific analyses highlights a key area for future research. Conclusions In summary, based on this large HBSC study of more than 900,000 adolescents, we found that breakfast consumption frequency was negatively associated with mental health, and this dose-dependent association exhibited a non-linear pattern. Notably, there was a strengthening relationship of breakfast consumption with mental health over time, particularly among girls and adolescents in higher grades. These findings may offer valuable guidance for public health and school-based interventions, emphasizing the importance of promoting regular breakfast consumption and fostering healthy dietary habits for adolescents’ mental well-being. Declarations Ethical approval and consent to participate This study analyzed the five most recent waves of HBSC, which are publicly available and contain only de-identified secondary data. As such, this research is exempt from institutional review board oversight. All procedures involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committees and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Each HBSC survey received ethical approval from relevant national or regional ethics committees, and informed consent was obtained from all participants and their parents or legal guardians in each participating country. Consent for publication Not applicable. Competing interests The authors declare no competing interests Funding None. Author Contribution Yuzhong Duan and Dankang Li: conception and design of the study; drafting the manuscript; generation, collection, assembly, analysis data. Jiao Yang and Dankang Li: conception and design of the study; approval of the final version of the manuscript. Acknowledgement HBSC is an international study done in collaboration with the WHO Regional Office for Europe. The HBSC Data Management Centre is based at the Department of Health Promotion and Development in the University of Bergen, Norway. Prof Oddrun Samdal is the Data Manager of the HBSC study. We thank the wider international HBSC network for developing the study, generating the data, and making them available for analyses. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Data availability The data are publicly available and can be accessed here ( https://hbsc.org/data/ ). References Blakemore SJ. Adolescence and mental health. Lancet. 2019;393:2030–1. 10.1016/S0140-6736(19)31013-X . Caspi A, et al. Longitudinal Assessment of Mental Health Disorders and Comorbidities Across 4 Decades Among Participants in the Dunedin Birth Cohort Study. JAMA Netw Open. 2020;3:e203221. 10.1001/jamanetworkopen.2020.3221 . Solmi M, et al. Age at onset of mental disorders worldwide: large-scale meta-analysis of 192 epidemiological studies. Mol Psychiatry. 2022;27:281–95. 10.1038/s41380-021-01161-7 . WHO. https://www.who.int/news-room/fact-sheets/detail/adolescent-mental-health Schmidt-Persson J, et al. Screen Media Use and Mental Health of Children and Adolescents: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open. 2024;7:e2419881. 10.1001/jamanetworkopen.2024.19881 . Arenaza L et al. Association of Breakfast Quality and Energy Density with Cardiometabolic Risk Factors in Overweight/Obese Children: Role of Physical Activity. Nutrients 10. 10.3390/nu10081066 (2018). Baumert PW Jr., Henderson JM, Thompson NJ. Health risk behaviors of adolescent participants in organized sports. J Adolesc Health. 1998;22:460–5. 10.1016/s1054-139x(97)00242-5 . Liu J, Hwang WT, Dickerman B, Compher C. Regular breakfast consumption is associated with increased IQ in kindergarten children. Early Hum Dev. 2013;89:257–62. 10.1016/j.earlhumdev.2013.01.006 . Raaijmakers LG, Bessems KM, Kremers SP, van Assema P. Breakfast consumption among children and adolescents in the Netherlands. Eur J Public Health. 2010;20:318–24. 10.1093/eurpub/ckp191 . Zahedi H, et al. Breakfast consumption and mental health: a systematic review and meta-analysis of observational studies. Nutr Neurosci. 2022;25:1250–64. 10.1080/1028415X.2020.1853411 . Koehn S, Gillison F, Standage M, Bailey J. Life transitions and relevance of healthy living in late adolescence. J Health Psychol. 2016;21:1085–95. 10.1177/1359105314546340 . Fielding-Singh P. You're worth what you eat: Adolescent beliefs about healthy eating, morality and socioeconomic status. Soc Sci Med. 2019;220:41–8. 10.1016/j.socscimed.2018.10.022 . Inchley JC, Stevens G, Samdal O, Currie DB. Enhancing Understanding of Adolescent Health and Well-Being: The Health Behaviour in School-aged Children Study. J Adolesc Health. 2020;66:S3–5. 10.1016/j.jadohealth.2020.03.014 . Roberts C, et al. The Health Behaviour in School-aged Children (HBSC) study: methodological developments and current tensions. Int J Public Health. 2009;54(2):140–50. 10.1007/s00038-009-5405-9 . Currie C et al. Social determinants of health and well-being among young people. Health Behaviour in School-aged Children (HBSC) study: international report from the 2009/2010 survey. (2012). Chen S, et al. Dose-Dependent Association Between Body Mass Index and Mental Health and Changes Over Time. JAMA Psychiatry. 2024;81:797–806. 10.1001/jamapsychiatry.2024.0921 . Khan A, Lee EY, Rosenbaum S, Khan SR, Tremblay MS. Dose-dependent and joint associations between screen time, physical activity, and mental wellbeing in adolescents: an international observational study. Lancet Child Adolesc Health. 2021;5:729–38. 10.1016/S2352-4642(21)00200-5 . Currie C, et al. Researching health inequalities in adolescents: the development of the Health Behaviour in School-Aged Children (HBSC) family affluence scale. Soc Sci Med. 2008;66:1429–36. 10.1016/j.socscimed.2007.11.024 . Ferrer-Cascales R et al. Higher Adherence to the Mediterranean Diet is Related to More Subjective Happiness in Adolescents: The Role of Health-Related Quality of Life. Nutrients 11. 10.3390/nu11030698 (2019). Fischer SM, Bilz L, Germany HSG. Traditional bullying and cyberbullying at schools in Germany: Results of the HBSC study 2022 and trends from 2009/10 to 2022. J Health Monit. 2024;9:42–61. 10.25646/11872 . Huang CJ, Hu HT, Fan YC, Liao YM, Tsai PS. Associations of breakfast skipping with obesity and health-related quality of life: evidence from a national survey in Taiwan. Int J Obes (Lond). 2010;34:720–5. 10.1038/ijo.2009.285 . Dehdari T, Rahimi T, Aryaeian N, Gohari MR, Esfeh JM. Developing and testing a measurement tool for assessing predictors of breakfast consumption based on a health promotion model. J Nutr Educ Behav. 2014;46:250–8. 10.1016/j.jneb.2013.12.007 . Richards G, Smith AP. Breakfast and Energy Drink Consumption in Secondary School Children: Breakfast Omission, in Isolation or in Combination with Frequent Energy Drink Use, is Associated with Stress, Anxiety, and Depression Cross-Sectionally, but not at 6-Month Follow-Up. Front Psychol. 2016;7:106. 10.3389/fpsyg.2016.00106 . Milajerdi A, et al. Breakfast consumption in relation to lowered risk of psychological disorders among Iranian adults. Public Health. 2019;167:152–8. 10.1016/j.puhe.2018.05.020 . Peprah P, Oduro MS, Boakye PA, Morgan AK. Association between breakfast skipping and psychosomatic symptoms among Canadian adolescents. Eur J Pediatr. 2024;183:1607–17. 10.1007/s00431-023-05392-4 . Quiles-Marcos Y, et al. Eating habits, physical activity, consumption of substances and eating disorders in adolescents. Span J Psychol. 2011;14:712–23. 10.5209/rev_sjop.2011.v14.n2.19 . Maridakis V, Herring MP, O'Connor PJ. Sensitivity to change in cognitive performance and mood measures of energy and fatigue in response to differing doses of caffeine or breakfast. Int J Neurosci. 2009;119:975–94. 10.1080/00207450802333995 . Kaneita Y, et al. Insomnia among Japanese adolescents: a nationwide representative survey. Sleep. 2006;29:1543–50. 10.1093/sleep/29.12.1543 . Ciardullo S, et al. Trend in Breakfast Consumption among Primary School Children in Italy. Nutrients. 2023;15. 10.3390/nu15214632 . Smith AP. Stress, breakfast cereal consumption and cortisol. Nutr Neurosci. 2002;5:141–4. 10.1080/10284150290018946 . Li Q, et al. Healthy lifestyles are associated with higher levels of perforin, granulysin and granzymes A/B-expressing cells in peripheral blood lymphocytes. Prev Med. 2007;44:117–23. 10.1016/j.ypmed.2006.08.017 . Segerstrom SC, Miller GE. Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry. Psychol Bull. 2004;130:601–30. 10.1037/0033-2909.130.4.601 . Additional Declarations No competing interests reported. Supplementary Files SupplementaryResults.docx Cite Share Download PDF Status: Published Journal Publication published 10 Apr, 2026 Read the published version in Archives of Public Health → Version 1 posted Editorial decision: Revision requested 06 Oct, 2025 Reviews received at journal 01 Sep, 2025 Reviewers agreed at journal 28 Aug, 2025 Reviewers agreed at journal 20 Aug, 2025 Reviews received at journal 20 Aug, 2025 Reviewers agreed at journal 20 Aug, 2025 Reviewers agreed at journal 20 Aug, 2025 Reviewers invited by journal 20 Aug, 2025 Editor assigned by journal 11 Aug, 2025 Submission checks completed at journal 11 Aug, 2025 First submitted to journal 09 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7331364","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":504340566,"identity":"61d891b5-ba26-4ab8-8233-cc88fd3ffd3a","order_by":0,"name":"Yuzhong Duan","email":"","orcid":"","institution":"Chinese PLA General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuzhong","middleName":"","lastName":"Duan","suffix":""},{"id":504340567,"identity":"2f1b9977-c213-4ea0-a94a-b0b6c315b52e","order_by":1,"name":"Jiao Yang","email":"","orcid":"","institution":"China National Academy of Educational Sciences","correspondingAuthor":false,"prefix":"","firstName":"Jiao","middleName":"","lastName":"Yang","suffix":""},{"id":504340568,"identity":"7df5f7cd-1d82-4f2e-925e-727bb3559495","order_by":2,"name":"Dankang Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYBACPoY0hgMfKmx4+NkbGx9+IEYLG0Ma48EZZ9LkJHsONxtLEKmF+TBv22FjgxvpbQI8RGlhT0sAamFOnDnzYRuDBIOdnG4DIS08zw4cnHOOLbFfOrHtQQFDsrHZAUJaJNIbDrwp40mcOTux3UCC4UDiNqK08LBJJG64ebBNgoc4LWkHDvK0GQC9z0isFp5nCcBATgAGciIwkA2I8As/e5rxhw8V/4FRefzhww8VdnIEtaABA9KUj4JRMApGwSjAAQCL4Ee40mom6wAAAABJRU5ErkJggg==","orcid":"","institution":"Jianghan University","correspondingAuthor":true,"prefix":"","firstName":"Dankang","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2025-08-09 05:08:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7331364/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7331364/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13690-026-01914-2","type":"published","date":"2026-04-10T15:58:20+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":90307725,"identity":"dec69f94-3005-482d-b385-6d8c65507cf4","added_by":"auto","created_at":"2025-09-01 09:33:42","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":83051,"visible":true,"origin":"","legend":"\u003cp\u003eGeneralized Additive Models of Psychosomatic Complaints as a Function of Total Breakfast Days by Survey Year\u003c/p\u003e\n\u003cp\u003eThe shaded area presents 95% CIs of fitting on the function of total breakfast days. The \u003cem\u003eP\u003c/em\u003e value was extracted from the multilevel generalized additive model, with psychosomatic complaints as the outcome and smooth term of total breakfast days as the exposure, controlling for gender, school grade, physical activity, Family Affluence Scale, academic pressure, having experienced bullying, and smooth term of age and BMI. Psychosomatic complaints scores were measured using an 8-item instrument assessing feeling low, irritability, nervousness, sleep difficulties, dizziness, headache, stomachache, and backache.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7331364/v1/78680753e1f3dcdf20dc11cc.jpeg"},{"id":90305999,"identity":"1689b633-e1e7-45fc-93e3-cc4fa10d3607","added_by":"auto","created_at":"2025-09-01 09:25:42","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":61348,"visible":true,"origin":"","legend":"\u003cp\u003eGeneralized Additive Models of Psychosomatic Complaints as a Function of Total Breakfast Days, by Survey Year and Sex\u003c/p\u003e\n\u003cp\u003eThe shaded area presents 95% CIs of fitting on the function of total breakfast days. The \u003cem\u003eP\u003c/em\u003evalue was extracted from the multilevel generalized additive model, with psychosomatic complaints as the outcome and smooth term of total breakfast days as the exposure, controlling for school grade, physical activity, Family Affluence Scale, academic pressure, having experienced bullying, and smooth term of age and BMI. Psychosomatic complaints scores were measured using an 8-item instrument assessing feeling low, irritability, nervousness, sleep difficulties, dizziness, headache, stomachache, and backache.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7331364/v1/e2f68e8d3454eb06144aaa5b.jpeg"},{"id":90307724,"identity":"4bc340e0-a057-4795-93b6-aa242da1b4cd","added_by":"auto","created_at":"2025-09-01 09:33:42","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":66160,"visible":true,"origin":"","legend":"\u003cp\u003eGeneralized Additive Models of Psychosomatic Complaints as a Function of Total Breakfast Days, by Survey Year and School Grade\u003c/p\u003e\n\u003cp\u003eThe shaded area presents 95% CIs of fitting on the function of total breakfast days. The \u003cem\u003eP\u003c/em\u003e value was extracted from the multilevel generalized additive model, with psychosomatic complaints as the outcome and smooth term of total breakfast days as the exposure, controlling for gender, physical activity, Family Affluence Scale, academic pressure, having experienced bullying, and smooth term of age and BMI. Psychosomatic complaints scores were measured using an 8-item instrument assessing feeling low, irritability, nervousness, sleep difficulties, dizziness, headache, stomachache, and backache.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7331364/v1/dad773a099f96a0d44aad6f3.jpeg"},{"id":106809197,"identity":"f1f2d315-2f2d-4269-8d88-85ca6c108131","added_by":"auto","created_at":"2026-04-13 16:08:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1172675,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7331364/v1/2aa0b76c-f57f-439d-b516-2cffd27e2999.pdf"},{"id":90306001,"identity":"c73949ed-c864-4b30-a60d-0d0ac93c1d0a","added_by":"auto","created_at":"2025-09-01 09:25:42","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":269748,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryResults.docx","url":"https://assets-eu.researchsquare.com/files/rs-7331364/v1/8485e63d8133a821ebc6f48e.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dose-Dependent Association of Adolescent Breakfast Consumption with Mental Health and Changes Over Time: an International Observational Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAdolescence is considered a crucial phase for the development of mental health problems\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, and is also a period during which young people are most vulnerable to experiences of mental ill-health and the onset of mental disorders\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Globally, approximately 14% of young people aged 10 to 19 are affected by mental health problems, which rank among the leading causes of illness and disability and account for 22.9% of the total global years lived with disability\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. The proportion of adolescents with poor mental health has continued to grow in recent years, which brings significant adverse impacts on individual, family, and society\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. The consequences of failing to address adolescent mental health conditions extend to adulthood, impairing both physical and mental health. Therefore, protecting adolescents from adversity and promoting psychological well-being are critical for their health and well-being during adolescence and adulthood.\u003c/p\u003e\u003cp\u003eThe causes of mental disorders are complex and involve multiple factors. Adopting healthy dietary patterns may serve as a cost-effective and safe approach to reduce the short- and long-term burden associated with mental health conditions. Breakfast is generally accepted to be the most important meal of the day\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, and breakfast consumption may be the most important modifiable indicator of dietary habits and behaviors in general\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. A growing body of research has identified links between breakfast consumption and various health benefits, such as improved overall diet quality, reduced cholesterol levels, lower obesity prevalence, and enhanced cognitive performance in adolescents\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. However, evidence regarding the relationship between breakfast consumption and adolescent mental health remains limited and inconclusive. For example, a recent systematic review that included 9 observational studies on breakfast consumption and mental health in adolescents reported mixed results\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In addition, most of the studies in this systematic review had small sample sizes, and no dose-dependent analysis was conducted to assess the relationship between breakfast consumption and mental health.\u003c/p\u003e\u003cp\u003eConsidering that adolescence is recognized as a critical period for behavioral change, including eating behaviors, and that the transition from adolescence to adulthood represents an optimal window for encouraging healthy eating and facilitating the formation of lasting habits\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, comprehensive research is warranted to better understand the association between breakfast consumption and mental health in adolescents.\u003c/p\u003e\u003cp\u003eIn this context, based on a large-scale multi-country sample of adolescents from 45 countries and regions in Europe, Central Asia, and North America, the primary objectives of this study were to identify the association between breakfast consumption frequency and mental health in adolescents. The second objective was to investigate the dose-dependent breakfast consumption-mental health association in this key demographic.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eData Source and Participants\u003c/h2\u003e\u003cp\u003eThe data used in this population-based cross-sectional study were derived from the international Health Behavior in School-aged Children (HBSC) study. The HBSC study is a World Health Organization Collaborative Cross-National Survey which has been conducted every 4 years since 1983 across Europe, North America, and the Middle East. HBSC collects data on the health and well-being, living environments, social relationships, and health behaviors of 11-, 13-, and 15-year-old boys and girls, including socio-economic environment, alcohol and drug use, sexual health, health habits, body image, and family and peer relationships\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Anonymity was maintained during data collection, and appropriate confidentiality measures were implemented. Comprehensive information on the HBSC sampling design and data collection methods is available in prior publications\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Prior to data collection, study procedures received ethical approval from the institutional ethics committee or other relevant board at the country or regional level and were endorsed by the World Health Organization to ensure compliance with ethical research standards. All countries participating in the study follow a standardized protocol. The protocol describes the methods for conducting the survey, the rules to be followed, and the coding procedures for the collected data\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe present study used the most recent five waves of HBSC data collected in 2002, 2006, 2010, 2014, and 2018, which are publicly accessible. After excluding records with missing data on primary exposures and outcomes concerning the evaluation of breakfast consumption frequency and mental health, the final sample analyzed in this study consisted of 918,564 adolescents. Supplementary Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e provides the flowchart of participants.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eMeasurement of breakfast consumption\u003c/h3\u003e\n\u003cp\u003eBreakfast consumption was measured by the number of days per week. Participants were asked to indicate how many days they usually consumed breakfast (defined as having more than a glass of milk or fruit juice) during the week and weekends, respectively. The categories of responses were: \u0026ldquo;I never have breakfast on weekdays\u0026rdquo;, \u0026ldquo;One day\u0026rdquo;, \u0026ldquo;Two days\u0026rdquo;, \u0026ldquo;Three days\u0026rdquo;, \u0026ldquo;Four days\u0026rdquo;, \u0026ldquo;Five days\u0026rdquo; for weekdays. In addition, for weekend: \u0026ldquo;I never eat breakfast on the weekend\u0026rdquo;, \u0026ldquo;I usually eat breakfast on only one day of the weekend\u0026rdquo;, \u0026ldquo;I usually eat breakfast on both Saturday and Sunday\u0026rdquo;. The responses were summed to reflect the weekly frequency of breakfast consumption, with possible scores ranging from 0 (breakfast skipping) to 7 (daily breakfast consumption).\u003c/p\u003e\n\u003ch3\u003eMeasurement of mental health\u003c/h3\u003e\n\u003cp\u003eMental health was measured via an 8-item scale assessing the frequency of experiencing the following eight psychosomatic health complaints (feeling low, irritability or bad temper, feeling nervous, difficulty sleeping, dizziness, headache, stomachache, and backache) over the past 6 months. The response options for each question ranged from \u0026ldquo;daily\u0026rdquo;, \u0026ldquo;more than once a week\u0026rdquo;, \u0026ldquo;about every week\u0026rdquo;, \u0026ldquo;about every month\u0026rdquo;, to \u0026ldquo;rarely or never\u0026rdquo;. After reverse coding each item on a 0\u0026ndash;4 scale, responses were aggregated to create a total score ranging from 0 to 32, where higher values indicated more frequent psychosomatic complaints. Cronbach\u0026rsquo;s alpha in our sample was 0.835, indicating that the items had a high internal consistency. The psychosomatic complaints score has demonstrated good validity and reliability in adolescent populations and has been widely applied in previous research\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003ch3\u003eCovariates\u003c/h3\u003e\n\u003cp\u003eCovariate selection was informed by data availability and prior literature. Sociodemographic variables included age, sex, school grade, and socioeconomic status. Socioeconomic status was assessed using the Family Affluence Scale (FAS), a validated composite indicator widely employed in the HBSC study to reflect objective socioeconomic status\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The FAS consists of four items: family car ownership, bedroom occupancy, frequency of family holidays, and computer ownership. A total FAS score ranging from 0 to 9 was calculated by summing the responses to each item\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Body mass index (BMI) was derived from self-reported height and weight. The validity of self-reported data for estimating BMI in child and adolescent populations has been supported by previous research\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Physical activity was assessed through the item: \u0026ldquo;Over the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day?\u0026rdquo;, with response options ranging from 0 to 7 days. Academic pressure was measured using a single item: \u0026ldquo;How pressured do you feel by the schoolwork you have to do?\u0026rdquo;, with responses ranging from \u0026ldquo;Not at all\u0026rdquo; to \u0026ldquo;A lot\u0026rdquo;. Experience of bullying was measured with the question: \u0026ldquo;How often have you been bullied at school in the past couple of months?\u0026rdquo;, with response options including \u0026ldquo;Never\u0026rdquo;, \u0026ldquo;Once or twice\u0026rdquo;, \u0026ldquo;2\u0026ndash;3 times per month\u0026rdquo;, \u0026ldquo;Once a week\u0026rdquo;, and \u0026ldquo;Several times a week\u0026rdquo;\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eSummary statistics are presented stratified by different survey year. Categorical variables were presented as numbers and percentages, while continuous variables were presented as means and standard deviations. Baseline characteristics across different survey years were compared using ANOVA for continuous variables and Chi-square tests for categorical variables.\u003c/p\u003e\u003cp\u003eA multilevel generalized additive model (GAM) was applied to estimate the association between breakfast consumption frequency and mental health, adjusted for age, gender, school grade, physical activity, BMI, FAS, academic pressure, the experience of being bullied, and survey year (only for overall participants). Among them, age and BMI were represented as smoothing splines. Considering the multilevel structure of the data, where students are nested within schools, schools within countries, and countries within survey rounds, a multilevel framework was applied to account for clustering.\u003c/p\u003e\u003cp\u003eThe dose-dependent association of breakfast consumption frequency with mental health was examined through multilevel GAM analysis, with the same covariates. Subgroup analyses were performed to identify possible effect modifications of gender and school grade by adding an interaction term (breakfast consumption frequency \u0026times; survey year, breakfast consumption frequency \u0026times; survey year \u0026times; gender, breakfast consumption frequency \u0026times; survey year \u0026times; school grade) to the model, and the modification was evaluated using \u003cem\u003eP\u003c/em\u003e-interaction by likelihood ratio test. Sensitivity analysis was conducted using five-fold cross-validation, where the dataset was partitioned into five subsets, and the model was refitted on each fold to assess the stability of coefficient estimates.\u003c/p\u003e\u003cp\u003eAll analyses were performed using R Statistical Software (version 4.4.3), with statistical significance set at a two-sided \u003cem\u003eP\u003c/em\u003e value of \u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the descriptive statistics for adolescents across survey years. From 2002 to 2018 HBSC data, a total of 918,564 adolescents (mean age: 13.59\u0026thinsp;\u0026plusmn;\u0026thinsp;1.64) were included, of whom 473,633 (51.6%) were girls (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Among them, 247,921 (32.9%) adolescents were in grade 5, the mean (SD) of BMI was 19.49 (3.50), and 41,189 (4.6%) adolescents reported no physical activity. In addition, 104,947 (11.6%) adolescents felt a lot of academic pressure, and 616,492 (70.5%) adolescents reported no experience of bullying. Across survey years from 2002 to 2018, psychosomatic complaint scores gradually increased from a mean (SD) of 7.77 (6.14) in 2002 to 8.63 (6.72) in 2018 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In parallel, the proportion of breakfast skipping increased from 2.7\u0026ndash;4.1% (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBaseline characteristics of study participants\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOverall\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2002\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2006\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2010\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2014\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2018\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal participants\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e918564\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e141347\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e184448\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e194443\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e186311\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e212015\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13.59 (1.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.57 (1.66)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13.63 (1.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13.59 (1.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13.61 (1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e13.54 (1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e444931 (48.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e68071 (48.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e89211 (48.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e94329 (48.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e90390 (48.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e102930 (48.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.095\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e473633 (51.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73276 (51.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95237 (51.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e100114 (51.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e95921 (51.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e109085 (51.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSchool grade\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGrade 5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e247921 (32.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47304 (33.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e58513 (31.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e48425 (33.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e41378 (32.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e52301 (33.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGrade 7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e257256 (34.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e48521 (34.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e62850 (34.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e47829 (33.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43968 (34.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e54088 (34.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGrade 9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e248487 (33.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45522 (32.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e62097 (33.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e47837 (33.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e42615 (33.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e50416 (32.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePhysical activity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo Physical activity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e41189 (4.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6146 (4.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8498 (4.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8932 (4.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7386 (4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e10227 (4.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e67958 (7.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12291 (9.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e13847 (7.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e14418 (7.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e12471 (6.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e14931 (7.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e120389 (13.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21017 (15.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e24332 (13.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25906 (13.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e23317 (12.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e25817 (12.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e149810 (16.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23988 (17.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29660 (16.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e31757 (16.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e29975 (16.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e34430 (16.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e136790 (15.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19769 (14.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e26772 (14.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e29687 (15.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e27888 (15.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e32674 (15.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e129531 (14.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17418 (13.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e25375 (14.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e27545 (14.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e27566 (15.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e31627 (15.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83612 (9.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10766 (8.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16070 (8.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e18149 (9.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e18202 (9.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e20425 (9.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e168078 (18.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22932 (17.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36002 (19.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e34732 (18.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e36229 (19.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e38183 (18.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19.49 (3.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19.19 (3.30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19.43 (3.39)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e19.62 (3.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e19.58 (3.58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e19.55 (3.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFamily Affluence Scale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8769 (1.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2116 (1.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2485 (1.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1244 (0.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1159 (0.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1765 (0.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22908 (2.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5523 (4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5451 (3.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3370 (1.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3655 (2.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e4909 (2.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e45341 (5.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10239 (7.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10343 (5.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7275 (3.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7895 (4.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e9589 (4.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e77555 (8.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16705 (12.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e18086 (10.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13596 (7.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13848 (8.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e15320 (7.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e115996 (13.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24140 (17.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e26815 (15.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e22109 (11.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e20644 (11.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e22288 (10.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e147134 (16.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26502 (19.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32059 (17.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e30020 (16.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e28109 (16.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e30444 (14.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e163204 (18.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24081 (17.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32191 (18.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e35653 (19.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e34027 (19.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e37252 (18.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e140248 (15.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17070 (12.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e26008 (14.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33165 (17.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e29342 (16.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e34663 (17.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e97926 (11.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8481 (6.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16460 (9.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e24787 (13.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21027 (12.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e27171 (13.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e64043 (7.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3565 (2.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e9260 (5.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15784 (8.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14348 (8.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e21086 (10.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAcademic pressure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot at all\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e185115 (20.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28120 (20.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e35165 (19.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e39482 (20.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e39417 (21.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e42931 (20.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eA little\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e398606 (44.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e62386 (44.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e80713 (44.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e85830 (44.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e80942 (44.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e88735 (42.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSome\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e217380 (24.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e34326 (24.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e46217 (25.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e45927 (23.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e41535 (22.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e49375 (23.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eA lot\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e104947 (11.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14953 (10.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19888 (10.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e20896 (10.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21176 (11.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e28034 (13.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExperienced bullying\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNever\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e616492 (70.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e93568 (66.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e118831 (68.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e132182 (71.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e126826 (72.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e145085 (72.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOnce or twice\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e158947 (18.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28954 (20.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e33915 (19.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33266 (17.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30292 (17.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e32520 (16.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u0026ndash;3 times per month\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e39280 (4.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6494 (4.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8340 (4.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8271 (4.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7531 (4.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e8644 (4.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOnce/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25472 (2.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4358 (3.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5608 (3.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5266 (2.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4785 (2.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e5455 (2.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSeveral times/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e34534 (3.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6800 (4.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7428 (4.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6876 (3.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6142 (3.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e7288 (3.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePsychosomatic complaints\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8.19 (6.55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.77 (6.14)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8.05 (6.42)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8.13 (6.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.19 (6.80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e8.63 (6.72)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBreakfast days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e29525 (3.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3772 (2.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5329 (2.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5673 (2.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5982 (3.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e8769 (4.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e39460 (4.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5674 (4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7502 (4.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8203 (4.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7428 (4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e10653 (5.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e102115 (11.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15293 (10.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e21275 (11.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e21318 (11.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e19994 (10.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e24235 (11.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e40159 (4.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5506 (3.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7743 (4.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8563 (4.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7706 (4.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e10641 (5.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e47015 (5.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6356 (4.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e9202 (5.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10127 (5.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9331 (5.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e11999 (5.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e72534 (7.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9915 (7.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14409 (7.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15963 (8.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14643 (7.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e17604 (8.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e83356 (9.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11927 (8.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16147 (8.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e18307 (9.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e17058 (9.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e19917 (9.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e504400 (54.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e82904 (58.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e102841 (55.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e106289 (54.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e104169 (55.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e108197 (51.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eAbbreviations: BMI, body mass index.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eData presented as means (standard deviation) for continuous variables and numbers (percentages) for categorical variables. Examining differences among different survey years based on \u003cem\u003et\u003c/em\u003e test (for continuous variables) and \u003cem\u003eχ\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/em\u003e\u003c/sup\u003e test (for categorical variables).\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the associations between breakfast consumption frequency and mental health among overall adolescents and across different survey years. Among overall adolescents, those with fewer breakfast consumption days had significantly higher psychosomatic complaints (\u003cem\u003eP\u003c/em\u003e-trend\u0026thinsp;\u0026lt;\u0026thinsp;0.001), compared with daily breakfast consumption (7 days), the fully adjusted β for the breakfast skipping was 2.93 (95% CI 2.84\u0026ndash;3.02). Furthermore, this association was consistent across different survey years. In 2002, compared with daily breakfast consumption, those with breakfast skipping had significantly higher psychosomatic complaints (β: 2.60, 95% CI: 2.39\u0026ndash;2.81, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and this relationship strengthened over time, reaching 3.10 (95% CI: 2.91\u0026ndash;3.29) in 2018.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eAssociations of Total Breakfast Days Categories with Psychosomatic Complaints\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"13\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eTotal Breakfast days\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eOverall\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eSurvey 2002\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003eSurvey 2006\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003eSurvey 2010\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u003cp\u003eSurvey 2014\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u003cp\u003eSurvey 2018\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c12\"\u003e\u003cp\u003eβ(95% CI)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c13\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.93 (2.84\u0026ndash;3.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.60 (2.39\u0026ndash;2.81)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.87 (2.68\u0026ndash;3.05)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2.69 (2.48\u0026ndash;2.90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.05 (2.82\u0026ndash;3.28)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e3.10 (2.91\u0026ndash;3.29)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.70 (2.62\u0026ndash;2.78)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.32 (2.15\u0026ndash;2.49)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.46 (2.30\u0026ndash;2.62)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2.64 (2.46\u0026ndash;2.81)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e2.74 (2.53\u0026ndash;2.94)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e3.11 (2.95\u0026ndash;3.28)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.58 (1.53\u0026ndash;1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.41 (1.30\u0026ndash;1.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.56 (1.46\u0026ndash;1.65)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.52 (1.41\u0026ndash;1.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e1.56 (1.44\u0026ndash;1.69)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1.71 (1.60\u0026ndash;1.82)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.62 (1.54\u0026ndash;1.69)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.38 (1.20\u0026ndash;1.55)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.65 (1.50\u0026ndash;1.80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.77 (1.59\u0026ndash;1.94)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e1.68 (1.48\u0026ndash;1.88)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1.49 (1.33\u0026ndash;1.65)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.50 (1.43\u0026ndash;1.57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.26 (1.10\u0026ndash;1.42)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.51 (1.37\u0026ndash;1.66)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.42 (1.26\u0026ndash;1.58)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e1.71 (1.53\u0026ndash;1.88)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1.48 (1.33\u0026ndash;1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.25 (1.20\u0026ndash;1.31)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.11 (0.98\u0026ndash;1.24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.34 (1.22\u0026ndash;1.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.18 (1.05\u0026ndash;1.31)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e1.28 (1.14\u0026ndash;1.43)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1.24 (1.11\u0026ndash;1.37)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.95 (0.90\u0026ndash;1.01)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78 (0.66\u0026ndash;0.90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96 (0.85\u0026ndash;1.07)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.10 (0.98\u0026ndash;1.22)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.97 (0.83\u0026ndash;1.11)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e0.88 (0.76-1.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7 days\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"13\"\u003eAbbreviations: CI, confidence interval; Ref, reference.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"13\"\u003eThe βs and 95% CIs were extracted from multilevel generalized additive model, with psychosomatic complaints as the outcome and variable of total breakfast days categories as the exposure, as well as controlling for survey year (only for overall participants), gender, school grade, physical activity, Family Affluence Scale, academic pressure, having experienced bullying, and smooth term of age and BMI.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates the dose-dependent associations between breakfast consumption and psychosomatic complaints across different survey years. A significant non-linear relationship was identified between breakfast consumption frequency and psychosomatic complaints scores (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Overall, higher breakfast consumption frequency was consistently associated with lower psychosomatic complaints scores across all survey years (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The psychosomatic complaints score showed a decreasing trend as total breakfast days per week increased, with a more pronounced decline observed from 0 to 4 days per week, followed by a plateau between approximately 3 and 5 days, and then a further decrease toward daily breakfast consumption. In addition, the overall inverse association remained stable across different survey years.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows subgroup-specific dose-dependent associations of breakfast consumption with psychosomatic complaints, stratified by gender. In both males and females, a significant non-linear association was observed, with psychosomatic complaints scores progressively decreasing as breakfast consumption frequency increased (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The association between breakfast consumption and psychosomatic complaints stratified by gender was evaluated using GAM, with the results shown in Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e. In both the male and female subgroups, breakfast consumption was negatively correlated with psychosomatic complaints. The association between breakfast consumption and mental health outcomes was stronger in females than males (Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e), with a significant interaction observed between gender and breakfast consumption in relation to psychosomatic complaints across different survey years (\u003cem\u003eP\u003c/em\u003e for interaction\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows subgroup-specific dose-dependent associations of breakfast consumption with psychosomatic complaints, stratified by school grade. Among different school grades, a significant non-linear association was observed, with psychosomatic complaints scores progressively decreasing as breakfast consumption frequency increased (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The association between breakfast consumption and psychosomatic complaints stratified by school grade was evaluated using GAM, with the results shown in Supplementary Table S2. Among different school grade subgroups, breakfast consumption was negatively correlated with psychosomatic complaints. The effects of breakfast consumption on mental health were more pronounced in higher school grade than those in lower school grade (Supplementary Table S2). There was a significant interaction in the school grade subgroup for breakfast consumption and psychosomatic complaints across different survey years (\u003cem\u003eP\u003c/em\u003e for interaction\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWe conducted a sensitivity analysis to examine the robustness of findings and presented the additional details in Supplementary Table S3. The same pattern of results was observed in the sensitivity analysis using 5-fold cross-validation (Supplementary Table S3).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo the best of our knowledge, this is the largest study to date providing evidence of the association between adolescents\u0026rsquo; breakfast consumption and mental health. It also provides an up-to-date insight into the dose-dependent relationship, an area that has not been extensively studied. Based on this multinational survey study with nearly one million adolescents, we found that breakfast consumption frequency was negatively associated with mental health. Adolescents who skipped breakfast entirely exhibited more severe psychosomatic complaints compared to those with daily breakfast consumption. Notably, this negative association has become more pronounced over time, and this trend was particularly pronounced in recent years. Furthermore, girls and adolescents in higher grades are more likely to experience worse mental health.\u003c/p\u003e\u003cp\u003eIn recent years, the prevalence of breakfast skipping among adolescents has increased, a trend that may continue due to ongoing social transitions and decreasing breakfast portion sizes. Findings from the current HBSC dataset indicate that the proportion of adolescents who regularly skipped breakfast rose from 2.7% in 2002 to 4.1% in 2018. This upward trend raises public health concerns, as breakfast consumption is recognized as a key health-supportive behavior. Prior evidence suggests that regular breakfast intake is associated with reduced risks of obesity and cardio-metabolic disorders\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Multiple factors may underlie breakfast skipping among adolescents, including limited self-efficacy, perceived obstacles, pre-existing habits such as staying up late or having unstructured mornings, and the tension between competing demands and individual preferences\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Indeed, research on the relationship of breakfast consumption with mental health is rare. In this study, our findings revealed an inverse association between breakfast consumption and mental health, which is consistent with prior studies conducted in children and adolescents. For example, one study among secondary school students found that those who frequently skipped breakfast were more likely to experience anxiety and depression\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Similarly, Milajerdi et al. reported that breakfast consumption was associated with lower odds of depression and psychological distress\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. Collectively, the conclusion about the potential link between regular breakfast consumption and improved mental health outcomes is convincing. However, further information is required to shed light on the relationship between breakfast consumption and psychological disorders.\u003c/p\u003e\u003cp\u003eFurthermore, our study identified that female adolescents and those in higher grades exhibited a greater likelihood of experiencing poorer mental health. Previous studies showed stronger associations between breakfast skipping and unhealthy behaviors in girls than in boys\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Although the current data did not demonstrate a significant sex difference in this association, a gender-specific effect was anticipated given that girls are more likely to engage in dieting behaviors, and female dieters are three times more likely to skip breakfast than non-dieters. Furthermore, the tendency among girls to simultaneously restrict food intake and increase physical activity for weight management may further complicate the interplay between these behaviors\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Breakfast skipping has been linked to irregular eating patterns and unhealthy weight control behaviors (such as restrictive dieting), particularly among adolescents with higher school grades, which may lead to psychological stress and mood instability\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe mechanisms underlying the association between breakfast consumption and mental health remain insufficiently understood. One of the underlying mechanisms is that adolescents who regularly consume breakfast tend to have more balanced macro- and micronutrient intakes\u0026mdash;characterized by higher levels of dietary fiber and carbohydrates, and lower intake of total fats\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. Some nutrients provided at breakfast, such as B vitamins, magnesium, and other trace elements, are essential for neurotransmitter synthesis and emotional regulation, potentially influencing mood and depressive symptoms\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. In addition, breakfast consumption has been shown to reduce hypothalamic-pituitary-adrenal (HPA) axis activity, thereby lowering cortisol levels\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Elevated cortisol can suppress immune function (e.g., T cell and natural killer cell activity) and has been linked to mood disturbances and stress-related psychological disorders\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Further research is needed to elucidate the specific mechanisms through which breakfast skipping may contribute to the development of poor mental health.\u003c/p\u003e\u003cp\u003eTo the best of our knowledge, this is the largest study to date to demonstrate the association between adolescents\u0026rsquo; breakfast consumption and mental health, while also providing up-to-date evidence on the dose-dependent relationship. The main advantages of this study include a large, nationally representative sample of more than 900,000 adolescents from multiple countries, which provides sufficient statistical power and enhances the generalizability of the results. The research\u0026rsquo;s extended time frame, covering data from 2002 to 2018, allows for the examination of temporal patterns in breakfast consumption and mental health among adolescents. In addition, stratified analyses by sex and grade level enabled the identification of subgroup-specific associations, which provided a useful basis for informing future research and intervention efforts. The present study also has some limitations. First, since this was a cross-sectional study with no temporal relationship, it is impossible to infer causality. Second, if the association between breakfast consumption and mental health is indeed valid, it is reasonable to assume that the composition and nutritional quality of breakfast may also play a role. However, the present study lacked data on the type and quality of breakfast, daily energy intake and expenditure, as well as other dietary behaviors such as lunch and dinner consumption, limiting further exploration of these factors. Therefore, additional studies are necessary to determine the association between breakfast composition and mental health. Third, there is currently no universally accepted definition of breakfast, and the operational definition adopted in this study may differ from those used in other research, potentially limiting the comparability of findings across studies. Fourth, another potential limitation may be reporting bias due to the use of self-reported questionnaires. Fifth, although a series of potential confounders was controlled for in the analysis, the possibility of residual confounding due to unmeasured or unknown variables cannot be entirely excluded. Finally, the majority of participants came from multiple European and North American countries, enhancing the generalizability of our findings within these regions. However, this may limit the applicability of the results to predominantly low-income populations, and the generalization of these findings should therefore be interpreted with caution. Conducting further country-specific analyses highlights a key area for future research.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn summary, based on this large HBSC study of more than 900,000 adolescents, we found that breakfast consumption frequency was negatively associated with mental health, and this dose-dependent association exhibited a non-linear pattern. Notably, there was a strengthening relationship of breakfast consumption with mental health over time, particularly among girls and adolescents in higher grades. These findings may offer valuable guidance for public health and school-based interventions, emphasizing the importance of promoting regular breakfast consumption and fostering healthy dietary habits for adolescents\u0026rsquo; mental well-being.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003cp\u003eThis study analyzed the five most recent waves of HBSC, which are publicly available and contain only de-identified secondary data. As such, this research is exempt from institutional review board oversight. All procedures involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committees and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Each HBSC survey received ethical approval from relevant national or regional ethics committees, and informed consent was obtained from all participants and their parents or legal guardians in each participating country.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003cp\u003eThe authors declare no competing interests\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eNone.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eYuzhong Duan and Dankang Li: conception and design of the study; drafting the manuscript; generation, collection, assembly, analysis data. Jiao Yang and Dankang Li: conception and design of the study; approval of the final version of the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eHBSC is an international study done in collaboration with the WHO Regional Office for Europe. The HBSC Data Management Centre is based at the Department of Health Promotion and Development in the University of Bergen, Norway. Prof Oddrun Samdal is the Data Manager of the HBSC study. We thank the wider international HBSC network for developing the study, generating the data, and making them available for analyses. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e\u003cp\u003eThe data are publicly available and can be accessed here (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://hbsc.org/data/\u003c/span\u003e\u003cspan address=\"https://hbsc.org/data/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBlakemore SJ. Adolescence and mental health. Lancet. 2019;393:2030\u0026ndash;1. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0140-6736(19)31013-X\u003c/span\u003e\u003cspan address=\"10.1016/S0140-6736(19)31013-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCaspi A, et al. 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Psychol Bull. 2004;130:601\u0026ndash;30. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1037/0033-2909.130.4.601\u003c/span\u003e\u003cspan address=\"10.1037/0033-2909.130.4.601\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aoph","sideBox":"Learn more about [Archives of Public Health](http://archpublichealth.biomedcentral.com/)","snPcode":"13690","submissionUrl":"https://submission.nature.com/new-submission/13690/3","title":"Archives of Public Health","twitterHandle":"@Archpubhealth","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Mental health, Breakfast consumption, Adolescent","lastPublishedDoi":"10.21203/rs.3.rs-7331364/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7331364/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eWe aimed to examine the dose-dependent association between breakfast consumption and mental health, and how this relationship has changed over time.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eData were obtained from five rounds (2002, 2006, 2010, 2014, and 2018) of a multi-country cross-national survey of school students: Health Behavior in School-aged Children (HBSC). Mental health was measured using a list of eight items for psychosomatic health complaints, combined into a composite score from 0 to 32. Breakfast consumption frequency was measured by the days per week. A multilevel generalized additive model was applied to evaluate the dose-dependent association of adolescent breakfast consumption with mental health.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThis study included 918,564 adolescents, with a mean (SD) age of 13.59 (1.64) years, of whom 473,633 (51.6%) were girls. In the final multivariate-adjusted model, breakfast consumption frequency was negatively associated with mental health, compared with daily breakfast consumption, adolescents with breakfast skipping had significantly higher psychosomatic complaints (β: 2.93, 95% CI: 2.84\u0026ndash;3.02, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This significant non-linear association was consistent across different survey years (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), gender (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and school grade (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating a broad relevance to adolescent mental health. The association of breakfast consumption on mental health was more pronounced in females (\u003cem\u003eP\u003c/em\u003e for interaction\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and in higher school grade (\u003cem\u003eP\u003c/em\u003e for interaction\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eBreakfast consumption frequency was negatively associated with mental health, and this dose-dependent association exhibited a non-linear pattern. Over time, the association of breakfast consumption on mental health was more pronounced, and this trend particularly was pronounced in recent years. Furthermore, girls and adolescents in higher grades are more likely to experience worse mental health.\u003c/p\u003e","manuscriptTitle":"Dose-Dependent Association of Adolescent Breakfast Consumption with Mental Health and Changes Over Time: an International Observational Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-01 09:25:37","doi":"10.21203/rs.3.rs-7331364/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-06T16:41:11+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-01T11:50:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"217881723724203199300141968616809563962","date":"2025-08-28T05:59:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"321378670155407433249895426149074512607","date":"2025-08-20T10:36:44+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-20T09:57:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"201963633665431993857224809495820691520","date":"2025-08-20T08:13:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"223469038247740834988601321425172572289","date":"2025-08-20T06:20:08+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-20T05:10:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-12T02:46:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-12T02:45:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Public Health","date":"2025-08-09T04:59:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aoph","sideBox":"Learn more about [Archives of Public Health](http://archpublichealth.biomedcentral.com/)","snPcode":"13690","submissionUrl":"https://submission.nature.com/new-submission/13690/3","title":"Archives of Public Health","twitterHandle":"@Archpubhealth","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"21f269c6-65b0-48aa-a0df-228650002277","owner":[],"postedDate":"September 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-13T16:04:21+00:00","versionOfRecord":{"articleIdentity":"rs-7331364","link":"https://doi.org/10.1186/s13690-026-01914-2","journal":{"identity":"archives-of-public-health","isVorOnly":false,"title":"Archives of Public Health"},"publishedOn":"2026-04-10 15:58:20","publishedOnDateReadable":"April 10th, 2026"},"versionCreatedAt":"2025-09-01 09:25:37","video":"","vorDoi":"10.1186/s13690-026-01914-2","vorDoiUrl":"https://doi.org/10.1186/s13690-026-01914-2","workflowStages":[]},"version":"v1","identity":"rs-7331364","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7331364","identity":"rs-7331364","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}