Potential social-environmental factors affecting ADHD symptoms of 55528 children from Longhua district, Shenzhen, China

Potential social-environmental factors affecting ADHD symptoms of 55528 children from Longhua district, Shenzhen, China | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Potential social-environmental factors affecting ADHD symptoms of 55528 children from Longhua district, Shenzhen, China Jianhui Chen, Xiao-nan Yang, Yan-ni Yang, Rong Li, Xiao-xiao Zhang, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4135215/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 06 Dec, 2025 Read the published version in BMC Public Health → Version 1 posted 4 You are reading this latest preprint version Abstract Objective: Attention-deficit hyperactivity disorder (ADHD) is a common childhood behavioral disorder which often persists into adulthood and is correlated with a broad range of other mental or behavioral problems. Some researches have indicated that social-environmental factors could be influential on children with ADHD, but none has a large sample size and most of them lack of data of social-environmental factors from early childhood. Therefore, we aimed to assess the frequency and duration of outdoor activities of preschool-age children at their age of 0–1 and 1–3 and to explore their association with ADHD symptoms. Methods We conducted a retrospective study. We distributed questionnaires to a 59,600 sample of parents of children enrolled in 250 kindergartens in Longhua District, Shenzhen, China. We collected data on sociodemographic characteristics, outdoor activities frequency and duration. We assessed ADHD symptoms with the Strengths and Difficulties Questionnaire (SDQ). Results 55528 valid questionnaires were finally included in the study. The prevalence of ADHD symptoms was 6.9%, with a higher score in boys (3.76 ± 1.96 vs. 3.42 ± 1.87, P < 0.001). There was a significant difference in ADHD symptoms between high level of household monthly income and low level of household monthly income ( F = 261.478, P < 0.001). There was a significant association between higher frequency and duration of outdoor activitiesand lower ADHD symptoms scores ( P < 0.001). Conclusion Higher frequency and duration of outdoor activities in early childhood may reduce the ADHD symptoms in children. More participation in outdoor activities should be encouraged to manage ADHD symptoms. Continued research should be conducted to better understand the mechanisms behind this association and to tailor interventions to the diverse needs of children with ADHD. Background Attention-deficit hyperactivity disorder (ADHD) is a common childhood behavioral disorder, estimated to affect around 3–5% of children [ 1 ]. ADHD often persists into adulthood and is correlated with a broad range of other mental or behavioral problems such as sleep disorder, depression, anxiety[ 2 ], eating disorder[ 3 ], autism[ 4 ], gaming disorder[ 5 ], internet addiction[ 6 ], as well as multiple adverse social outcomes including lower levels of emotional support and an increased likelihood of being NEET (Not in Education, Employment or Training) and of receiving state benefits (a proxy measure of socio-economic disadvantage)[ 7 ]. ADHD symptoms are the main clinical manifestations of ADHD, exerting long-term economic burden upon families and the entire country[ 8 , 9 ]. Moreover, ADHD symptoms may also bring about a lifetime dysfunction without effective treatment or prevention[ 10 ]. Given these negative result, it’s of vital significance to discover the influence factors of ADHD in childhood for the psychological well-being development towards children. Outdoor activity frequency and duration could be the protective factors that may have the potential to improve children’s mental health and physical well-being including ADHD. For instance, a study investigating whether time spent in natural settings affects the inattentive symptoms of attention deficit disorder showed that children’s activities taking place in natural settings were more likely to be mentioned as helpful in reducing their inattentive symptoms. In addition, as tree cover increased, symptoms of attention deficit disorder decreased in severity[ 11 ]. A nationwide study published in 2004 facing to parents of children who had been diagnosed with ADHD examined whether “green” settings reduced symptoms of ADHD. The result demonstrated that natural outdoor activities reduced ADHD symptoms significantly more than activities conducted in built outdoor settings or indoor settings[ 12 ]. ADHD-diagnosed children from another study were guided through a 20mins walk in 3 different environments: a city park, an urban area, and a residential area. Before each of the walks, children completed a series of puzzles that were selected to cause a degree of mental fatigue. After the walks, tests of concentration and impulse control were conducted on the participants. Concentration was significantly better after a walk in a city park than the other two setting[ 13 ]. Although the existing research suggested the connection of outdoor activity frequency and duration with ADHD symptoms, there were still limitations of them. On one hand, there is low external validity of these study due to small sample size. On the other hand, most research subjects were in the late childhood which will eventuate in a lack of data on the relationship between early childhood outdoor activity and ADHD symptoms. For this reason, we conducted a large-scale sample size study aiming at children in Longhua district, Shenzhen, China in order to add more evidence of early childhood outdoor activities frequency and duration effect on ADHD symptoms. Methods Study design and participants This study was conducted in accordance with the Declaration of Helsinki. The data for this project were from the 2021 survey of the Longhua Children’s Cohort Study (LCCS). The LCCS was a large-scale epidemiological survey conducted in Longhua District, Shenzhen, China, which aims to assess the impact of children's lifestyle habits on early psychological and behavioral development of preschoolers. The research project was carried out in 250 kindergartens in Longhua District of Shenzhen in 2021. From October to November 2021, the research project was publicized to parents of kindergarten children, who were mobilized to participate in the project. After obtaining the consent of the children's parents, the informed consent form was signed by the parents and a questionnaire survey was conducted. A total of 59,600 questionnaires were distributed and 56740 questionnaires were returned, with a recovery rate of 95.2%. After excluding 1212 questionnaires with incomplete information, the final sample size was 55528. This study was approved by the Ethics Committee of Longhua Maternal and Child Health Hospital (Ethics approval No. 2016102501). Data collection The questionnaire collected information on family demographic characteristics, outdoor activity frequency and duration at the age of 0–1 and 1–3 for children, and the severity of ADHD symptoms in preschoolers(measured using the Strengths and Difficulties Questionnaire, SDQ). All the participants had signed the Human Ethics and Consent to Participate declarations and agreed to be involved in this study. Measurement of frequency and duration of outdoor activities (major exposure variables) “Outdoor activity” were defined as outdoor activity occurring during the day only. The frequency and duration of outdoor activity were reported by the children’s parents. We divided into two groups (group aged 0 to 1 and group aged 1 to 3) to collect information on the frequency and duration of outdoor activities for the reason that children at the age of 0–1 cannot walk independently, so their outdoor activity frequency and duration are dependent on their parents' activity, while those at the age of 1–3 can walk on their own and actively engage in outdoor activity. Following previous research[ 14 ], we conducted a categorized survey on the frequency and duration of outdoor activity (Table 1 ). Table 1 Questions and options regarding the frequency and duration of outdoor activities for infants and toddlers. No. Questions Options Q1.1 How often do you conduct the outdoor activities of your child/children before he/she is 1 year old༟ 1=<1 times/week 2 = 1–2 times/week 3 = 3-6times/week 4 = ≥ 7 times/week Q1.2 How long do you conduct the outdoor activities of your child/children before he/she is 1 year old༟ 1 = < 30 min/time 2 = 30–59 min/time 3 = 60–89 min/time 4 = 90–119 min/time 5 = ≥ 120 min/time Q2.1 How often do you conduct the outdoor activities of your child/children at his/her age of 1 to 3༟ 1=<1 times/week 2 = 1–2 times/week 3 = 3-6times/week 4 = ≥ 7 times/week Q2.2 How long do you conduct the outdoor activities of your child/children at his/her age of 1 to 3༟ 1 = < 30 min/time 2 = 30–59 min/time 3 = 60–89 min/time 4 = 90–119 min/time 5 = ≥ 120 min/time Measurement of ADHD symptoms In this study, SDQ was used to assess the severity of ADHD symptoms of children. SDQ was compiled by Goodman, an American psychologist, in 1997 and is a concise behavior screening scale[ 15 ]. In 2005, China studied the norm belonging to Chinese people[ 16 ]. The scale had 25 items, including 5 dimensions: emotional symptoms, conduct problems, ADHD symptoms, peer problems and prosocial behavior. Items on the SDQ scale are rated on a scale between 0 and 2, with 0 indicating no agreement, 1 indicating somewhat agreement, and 2 indicating perfect agreement. The total score of ADHD symptoms from 0 to 5 is normal, 6 is borderline level, and 7 to 10 is abnormal, with higher scores indicating severer ADHD symptoms. The scale had good reliability, and the Cronbach α coefficient was 0.749[ 17 ]. Covariates The following confounding covariates were included in the analysis: child’s gender, single-child status, parents’ education level, household monthly income, and parental marital status. Statistical analysis The participants’ descriptive statistics were used to characterize the study population. Mean ± standard deviation (SD) and sample number (percentage) were presented for continuous and categorical variables, respectively. Pearson correlation test was used to examine the correlation between continuous variables and ADHD symptoms score. T-tests were used to compare gender, single child status and parental marital status differences among ADHD symptoms score. Analysis of Variance (ANOVA) was used to compare parents’ education level and monthly family income differences among ADHD symptoms score. Multiple Linear Regression analysis was used to explorer the association between frequency and duration of outdoor activity and ADHD symptoms. Results Participants sociodemographic characteristics and adherence to ADHD symptoms Participants’ SDQ score and category was presented in Table 1 . In the total sample, we found that 6.9% of the participants were at the abnormal levels (defined as a score 7–10) of ADHD symptoms. 8.4% of the participants were on the brink of ADHD symptoms (defined as a score of 6). The prevalence of ADHD symptoms was 6.9%. Participants’ demographics and characteristics are summarized in Table 2 . 55528 children (29608 boys [53.3%] and 25920 girls [46.7%]; mean [SD] age, 5.15 ± 0.67 years old) completed the questionnaire information. Sample’s average score of ADHD symptoms was 3.60 ± 1.93. Age was statistically significantly negatively correlated with ADHD symptoms score. Boys’ symptoms are severer than girls’ (3.76 ± 1.96 vs. 3.42 ± 1.87, P < 0.001). Participants who are singletons and have lower household monthly income have severer ADHD symptoms ( P < 0.001). Participants whose parents are higher education attainment and married have less severer ADHD symptoms ( P < 0.001, Table 3 ). Table 2 Scores and category of the Strengths and Difficulties Questionnaire (SDQ) Category Mean ± SD n(%) Total 3.60 ± 1.93 55528(100.0) Normal 3.04 ± 1.46 47001(84.6) Edge value 6.00 ± 0.00 4678(8.4) Abnormal 7.59 ± 0.84 3849(6.9) Mean ± SD was presented for continuous variables. N(%) was presented for categorical variables. Table 3 Sociodemographic characteristics and ADHD symptoms Characteristics Total ADHD score r/t/F P -value Age 5.15 ± 0.67 3.60 ± 1.93 -0.017 < 0.001 Gender Male 29608(53.3) 3.76 ± 1.96 21.258 < 0.001 Female 25920(46.7) 3.42 ± 1.87 Single child status Yes 16959(30.5) 3.83 ± 1.96 18.638 < 0.001 No 38569(69.5) 3.50 ± 1.90 Maternal education attainment Junior high school and below 8543(15.4) 4.04 ± 1.87 373.156 < 0.001 High school or technical secondary school 11760(21.2) 3.84 ± 1.91 Junior college 33508(60.3) 3.44 ± 1.92 Undergraduate and above 1717(3.1) 2.89 ± 1.88 Paternal education attainment Junior high school and below 7844(14.1) 4.05 ± 1.89 382.915 < 0.001 High school or technical secondary school 11877(21.4) 3.86 ± 1.91 Junior college 33140(59.7) 3.46 ± 1.91 Undergraduate and above 2667(4.8) 2.93 ± 1.88 Household monthly income <¥10,000 9488(17.1) 3.96 ± 1.91 261.478 < 0.001 ¥10,000–20,000 19161(34.5) 3.77 ± 1.90 ¥20,000–30,000 11610(20.9) 3.50 ± 1.91 ¥30,000–40,000 6312(11.4) 3.29 ± 1.89 ≥¥40,000 8957(16.1) 3.22 ± 1.93 Parental marital status Married 53251(95.9) 3.59 ± 1.92 -6.447 < 0.001 Remarried/Divorced/Widowed 2277(4.1) 3.86 ± 1.98 Mean ± SD was presented for continuous variables. N(%) was presented for categorical variables. Abbreviation: r , coefficient of Pearson correlation. t , t-values of Independent t-test. F , F-values of ANOVA. Relationship between frequency and duration of outdoor activity and ADHD symptoms We performed Multiple Linear Regression analysis to explore the associations between frequency and duration of outdoor activity and ADHD symptoms(Table 3 & Table 4 & Table 5 ). Same statistically significantly negative associations with ADHD symptoms were observed in every category of outdoor activity frequency and duration when the participants were 0 to 1 years old or 1 to 3 years old ( P -0.445 > -0.598; β 1−3 years old : -0.300 > -0.495 > -0.699), as well as duration of outdoor activity ( β 0−1 years old : -0.110 > -0.201 > -0.302 > -0.381; β 1−3 years old : -0.304 > -0.408 > -0.532 > -0.657). Table 4 Relationship between frequency and duration of outdoor activity in 0–1 year old children and ADHD symptoms(n = 55528) Outdoor activity Total β(95%CI) P -value Frequency 55528 < 1 time/week 2826(5.1) Ref. 1 ~ 2 times/week 11111(20.0) -0.233(-0.310~-0.156) < 0.001 3–6 times/week 14794(26.6) -0.445(-0.520~-0.369) < 0.001 ≥ 7 times/week 26797(48.3) -0.589(-0.662~-0.516) < 0.001 Duration < 30 mins/time 5104(9.2) Ref. 30 ~ 59 mins/time 20159(36.3) -0.110(-0.168~-0.052) < 0.001 60 ~ 89 mins/time 12272(22.1) -0.201(-0.263~-0.139) < 0.001 90 ~ 119 mins/time 8426(15.2) -0.302(-0.368~-0.237) < 0.001 ≥ 120 mins/time 9567(17.2) -0.381(-0.445~-0.317) < 0.001 Frequency and duration of outdoor activity were transferred into dummy variables. Abbreviation: β , coefficient of Multiple Linear Regression Analysis. β with adjustment for age, gender, single child status, maternal and paternal education level, household monthly income and parental marital status. 95%CI, 95% confidence interval of Multiple Linear Regression Analysis. Table 5 Relationship between frequency and duration of outdoor activity in 1–3 year old children and ADHD symptoms(n = 55528) Outdoor activity Total β(95%CI) P -value Frequency 55528 < 1 time/week 3491(6.3) Ref. 1 ~ 2 times/week 13702(24.7) -0.300(-0.371~-0.229) < 0.001 3–6 times/week 14542(26.1) -0.495(-0.566~-0.424) < 0.001 ≥ 7 times/week 23793(42.9) -0.699(-0.767~-0.631) < 0.001 Duration < 30 mins/time 2559(4.6) Ref. 30 ~ 59 mins/time 16745(30.2) -0.304(-0.383~-0.224) < 0.001 60 ~ 89 mins/time 14949(26.9) -0.408(-0.489~-0.328) < 0.001 90 ~ 119 mins/time 10655(19.2) -0.532(-0.615~-0.449) < 0.001 ≥ 120 mins/time 10620(19.1) -0.657(-0.740~-0.574) < 0.001 Discussion Outdoor activity has been proved to be effective in facilitating healthy child development and a disconnect with nature presents potential health risks[ 18 ]. However, the connection between outdoor activity with Chinese ADHD symptoms was not fully explored, until our research[ 19 ]. In our research, it involved 55528 Chinese’s children at the age from 0 to 3 locating at Longhua district of Shenzhen city, which was large scaled, persuasive, and clinically significant. Meanwhile, in our study, the prevalence of ADHD symptoms was evaluated, and it was 6.9%. It was consistent with the previous literature, which influential and aggregated 102 studies (and then an additional 41 studies) involving community samples of children and adolescents from 35 countries in six continents worldwide and estimated the prevalence of ADHD as 5·29% (95% CI 5·01–5·56)[ 20 , 21 ]. It implied there might be no significant racial difference in ADHA’s prevalence. Moreover, several sociodemographic characteristics evaluated in our study were proved to have significant effect on ADHD symptoms, including age, gender, single child status, maternal education attainment, paternal education attainment, household monthly income, and parental marital status. Interestingly, in our study, the higher household income, the lower ADHD scores. However, in Frances E. Kuo et al.’s research examining the impact of relatively “green” settings on ADHD symptoms, 120 ADHD children were involved with their household income over 75000 $ , while only 9 ADHD children were involved with their household income below 10000 $ [ 22 ]. In our study, it was proved that children ,who conducted more often and spent more time on outdoor activities at the age of 0 to 3, had lower ADHD symptoms scores. This result is supported by several key arguments. First, outdoor activities often involve physical exercise, which has been shown to have a positive effect on cognitive function and behavior in children with ADHD[ 23 ]. Exercise is believed to improve executive functions[ 24 ], reduce impulsivity, and enhance attention[ 25 ], partly through the release of endorphins and the improvement of dopamine[ 26 , 27 ], neurotransmitters known to be beneficial in individuals with ADHD[ 28 , 29 ]. Second, the natural environment itself may play a therapeutic role. The Attention Restoration Theory (ART) suggests that natural settings, through their restorative effects, can help reduce mental fatigue and improve concentration and attention[ 30 ]. This is particularly relevant for children with ADHD, who often experience difficulty in sustaining attention and resisting distractions. Third, engaging in outdoor activities provides opportunities for social interaction and the development of social skills, which are often areas of difficulty for children with ADHD[ 31 ]. Through play and organized activities, children can learn to cooperate, follow rules, and interact more effectively with peers, potentially mitigating some of the social and behavioral challenges associated with ADHD. However, it is also important to acknowledge the limitations and variability in this research. While several studies support the beneficial effects of outdoor activities for children with ADHD, results can vary based on factors such as the type of activity, the specific needs and characteristics of the child, and the presence of other interventions. Moreover, the nature of the association – whether causal or correlational – is not yet fully understood, necessitating further research in this area. Conclusion The relationship between frequency and duration of outdoor activities and ADHD symptoms in children presents a promising area for intervention. Encouraging regular participation in outdoor activities may serve as a valuable component of a multi-faceted approach to managing ADHD symptoms. Nonetheless, this should be complemented by continued research to better understand the mechanisms behind this association and to tailor interventions to the diverse needs of children with ADHD. Declarations Ethics approval and consent to participate The study protocol was approved by the ethics committee of Longhua Maternal and Child Health Hospital, and the study was performed in accordance with the tenets of the Declaration of Helsinki and relevant policies in China. Informed consent was obtained from all subjects and their legal guardian(s) before data collection and their personal information was maintained anonymously. Consent for publication Not applicable. Data availability Data are available from the corresponding author upon reasonable request. Competing interests The authors declare no competing interests. Funding Longhua District Medical And Health Institutions Regional Scientific Research Project (2022086). Guangzhou Aier Eye Hospital Science Foundation for Youths (GA2023003). Longhua District Medical And Health Institutions Regional Scientific Research Project (2021043). Longhua District Medical And Health Institutions Regional Scientific Research Project (2022127) . Medical Key Discipline Construction Fund of Longhua District. Author Contributions Conceptualization: Jian-Bo Wu and Jianhui Chen. Data curation: Jianhui Chen, Xiaonan Yang and Jian-Bo Wu. Formal analysis: Jian-Bo Wu and Jianhui Chen. Funding acquisition: Jianhui Chen and Jian-Bo Wu. Investigation: Jianhui Chen, Xiaonan Yang and Jian-Bo Wu. Methodology:Yanni Yang and Xiaoxiao Zhang. Project administration: Jian-Bo Wu, Rong Li and Jianhui Chen. Resources: Jian-Bo Wu and Jianhui Chen. Software: Jianhui Chen. Supervision: Jian-Bo Wu. Validation: Jian-Bo Wu. Visualization: Jianhui Chen. Writing–original draft: Jianhui Chen, Xiaonan Yang and Jian-Bo Wu. Writing–review and editing: Jianhui Chen, Xiaonan Yang and Jian-Bo Wu. Acknowledgments The authors would like to show their gratitude to the families who participated in the study, the doctors from Longhua Maternal and Child Healthcare Center, and the kindergarten teachers who took part in the investigation. Disclosure statement Data is provided within the manuscript or supplementary in formation files. No potential conflict of interest was reported by the authors. References Sayal K, Prasad V, Daley D, Ford T, Coghill D. ADHD in children and young people: prevalence, care pathways, and service provision. Lancet Psychiatry. 2018;5(2):175–86. Loram G, Ling M, Silk T, Sciberras E, Associations Between ADHD. Sleep Problems, and Mental Health Symptoms in Adolescents. J Atten Disord. 2023;27(6):635–42. Tan EJ, Raut T, Le LK, Hay P, Ananthapavan J, Lee YY, Mihalopoulos C. 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Cite Share Download PDF Status: Published Journal Publication published 06 Dec, 2025 Read the published version in BMC Public Health → Version 1 posted Editorial decision: Revision requested 17 Apr, 2024 Editor assigned by journal 17 Apr, 2024 Submission checks completed at journal 01 Apr, 2024 First submitted to journal 20 Mar, 2024 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4135215","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":292352250,"identity":"db8683c2-1389-4f0b-8242-adf13df630d9","order_by":0,"name":"Jianhui Chen","email":"","orcid":"","institution":"Guangzhou Aier Eye Hospital Affiliated to Jinan University","correspondingAuthor":false,"prefix":"","firstName":"Jianhui","middleName":"","lastName":"Chen","suffix":""},{"id":292352251,"identity":"fbcc400e-b040-4f1a-974f-f17bb4201e6d","order_by":1,"name":"Xiao-nan Yang","email":"","orcid":"","institution":"First Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"prefix":"","firstName":"Xiao-nan","middleName":"","lastName":"Yang","suffix":""},{"id":292352252,"identity":"13f7fe05-df64-4974-9690-8c3cafa23348","order_by":2,"name":"Yan-ni Yang","email":"","orcid":"","institution":"ShenZhen PingShan XinHe Experimental School","correspondingAuthor":false,"prefix":"","firstName":"Yan-ni","middleName":"","lastName":"Yang","suffix":""},{"id":292352253,"identity":"998af226-203a-4aed-ba0c-08349dbe3b8c","order_by":3,"name":"Rong Li","email":"","orcid":"","institution":"Guangzhou Aier Eye Hospital Affiliated to Jinan University","correspondingAuthor":false,"prefix":"","firstName":"Rong","middleName":"","lastName":"Li","suffix":""},{"id":292352254,"identity":"bae2887f-4b8f-4aa9-ab51-b48d3b3cef39","order_by":4,"name":"Xiao-xiao Zhang","email":"","orcid":"","institution":"Guangzhou Aier Eye Hospital Affiliated to Jinan University","correspondingAuthor":false,"prefix":"","firstName":"Xiao-xiao","middleName":"","lastName":"Zhang","suffix":""},{"id":292352255,"identity":"5fc363e6-56f4-47fe-9d08-e067995c2f7a","order_by":5,"name":"Jian-Bo Wu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAt0lEQVRIiWNgGAWjYBACNmbmww8+GNjY8bM3HyBOCx87W5rhjIq0ZMmeYwnEaZHj5zGQ5jhzmHHDjRwDYh3GlmDM2HaYWbLnzMcbbxjs5HQbCGphPvC4sC2dj5+9d7PlHIZkY7MDxNgys80aaMvZbdI8DAcStxHWAvQLbxszyC/PSNDCc8YZpIWNWC2IQDa2nGNAhF/k+w/Do/LhjTcVdnIEtaAACR4iowZZC6k6RsEoGAWjYEQAAMw9P63PWZ78AAAAAElFTkSuQmCC","orcid":"","institution":"Shenzhen Longhua Maternity and Child Healthcare Hospital","correspondingAuthor":true,"prefix":"","firstName":"Jian-Bo","middleName":"","lastName":"Wu","suffix":""}],"badges":[],"createdAt":"2024-03-20 08:02:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4135215/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4135215/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12889-025-25865-5","type":"published","date":"2025-12-06T15:58:07+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":97723934,"identity":"4b77e380-5898-435f-a7da-6e1c16084500","added_by":"auto","created_at":"2025-12-08 16:09:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":954068,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4135215/v1/84cfcd2f-d6c0-4518-9049-09fc53c9999b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Potential social-environmental factors affecting ADHD symptoms of 55528 children from Longhua district, Shenzhen, China","fulltext":[{"header":"Background","content":"\u003cp\u003eAttention-deficit hyperactivity disorder (ADHD) is a common childhood behavioral disorder, estimated to affect around 3\u0026ndash;5% of children [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. ADHD often persists into adulthood and is correlated with a broad range of other mental or behavioral problems such as sleep disorder, depression, anxiety[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], eating disorder[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], autism[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], gaming disorder[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], internet addiction[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], as well as multiple adverse social outcomes including lower levels of emotional support and an increased likelihood of being NEET (Not in Education, Employment or Training) and of receiving state benefits (a proxy measure of socio-economic disadvantage)[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. ADHD symptoms are the main clinical manifestations of ADHD, exerting long-term economic burden upon families and the entire country[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Moreover, ADHD symptoms may also bring about a lifetime dysfunction without effective treatment or prevention[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Given these negative result, it\u0026rsquo;s of vital significance to discover the influence factors of ADHD in childhood for the psychological well-being development towards children.\u003c/p\u003e \u003cp\u003eOutdoor activity frequency and duration could be the protective factors that may have the potential to improve children\u0026rsquo;s mental health and physical well-being including ADHD. For instance, a study investigating whether time spent in natural settings affects the inattentive symptoms of attention deficit disorder showed that children\u0026rsquo;s activities taking place in natural settings were more likely to be mentioned as helpful in reducing their inattentive symptoms. In addition, as tree cover increased, symptoms of attention deficit disorder decreased in severity[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. A nationwide study published in 2004 facing to parents of children who had been diagnosed with ADHD examined whether \u0026ldquo;green\u0026rdquo; settings reduced symptoms of ADHD. The result demonstrated that natural outdoor activities reduced ADHD symptoms significantly more than activities conducted in built outdoor settings or indoor settings[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. ADHD-diagnosed children from another study were guided through a 20mins walk in 3 different environments: a city park, an urban area, and a residential area. Before each of the walks, children completed a series of puzzles that were selected to cause a degree of mental fatigue. After the walks, tests of concentration and impulse control were conducted on the participants. Concentration was significantly better after a walk in a city park than the other two setting[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough the existing research suggested the connection of outdoor activity frequency and duration with ADHD symptoms, there were still limitations of them. On one hand, there is low external validity of these study due to small sample size. On the other hand, most research subjects were in the late childhood which will eventuate in a lack of data on the relationship between early childhood outdoor activity and ADHD symptoms. For this reason, we conducted a large-scale sample size study aiming at children in Longhua district, Shenzhen, China in order to add more evidence of early childhood outdoor activities frequency and duration effect on ADHD symptoms.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and participants\u003c/h2\u003e \u003cp\u003e This study was conducted in accordance with the Declaration of Helsinki. The data for this project were from the 2021 survey of the Longhua Children\u0026rsquo;s Cohort Study (LCCS). The LCCS was a large-scale epidemiological survey conducted in Longhua District, Shenzhen, China, which aims to assess the impact of children's lifestyle habits on early psychological and behavioral development of preschoolers.\u003c/p\u003e \u003cp\u003eThe research project was carried out in 250 kindergartens in Longhua District of Shenzhen in 2021. From October to November 2021, the research project was publicized to parents of kindergarten children, who were mobilized to participate in the project. After obtaining the consent of the children's parents, the informed consent form was signed by the parents and a questionnaire survey was conducted. A total of 59,600 questionnaires were distributed and 56740 questionnaires were returned, with a recovery rate of 95.2%. After excluding 1212 questionnaires with incomplete information, the final sample size was 55528. This study was approved by the Ethics Committee of Longhua Maternal and Child Health Hospital (Ethics approval No. 2016102501).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData collection\u003c/h2\u003e \u003cp\u003eThe questionnaire collected information on family demographic characteristics, outdoor activity frequency and duration at the age of 0\u0026ndash;1 and 1\u0026ndash;3 for children, and the severity of ADHD symptoms in preschoolers(measured using the Strengths and Difficulties Questionnaire, SDQ). All the participants had signed the Human Ethics and Consent to Participate declarations and agreed to be involved in this study.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003eMeasurement of frequency and duration of outdoor activities (major exposure variables)\u003c/h2\u003e \u003cp\u003e\u0026ldquo;Outdoor activity\u0026rdquo; were defined as outdoor activity occurring during the day only. The frequency and duration of outdoor activity were reported by the children\u0026rsquo;s parents. We divided into two groups (group aged 0 to 1 and group aged 1 to 3) to collect information on the frequency and duration of outdoor activities for the reason that children at the age of 0\u0026ndash;1 cannot walk independently, so their outdoor activity frequency and duration are dependent on their parents' activity, while those at the age of 1\u0026ndash;3 can walk on their own and actively engage in outdoor activity. Following previous research[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], we conducted a categorized survey on the frequency and duration of outdoor activity (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\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\u003eQuestions and options regarding the frequency and duration of outdoor activities for infants and toddlers.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQuestions\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOptions\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQ1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHow often do you conduct the outdoor activities of your child/children before he/she is 1 year old༟\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1=\u0026lt;1 times/week\u003c/p\u003e \u003cp\u003e2\u0026thinsp;=\u0026thinsp;1\u0026ndash;2 times/week\u003c/p\u003e \u003cp\u003e3\u0026thinsp;=\u0026thinsp;3-6times/week\u003c/p\u003e \u003cp\u003e4\u0026thinsp;=\u0026thinsp;\u0026ge;\u0026thinsp;7 times/week\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQ1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHow long do you conduct the outdoor activities of your child/children before he/she is 1 year old༟\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u0026thinsp;=\u0026thinsp;\u0026lt;\u0026thinsp;30 min/time\u003c/p\u003e \u003cp\u003e2\u0026thinsp;=\u0026thinsp;30\u0026ndash;59 min/time\u003c/p\u003e \u003cp\u003e3\u0026thinsp;=\u0026thinsp;60\u0026ndash;89 min/time\u003c/p\u003e \u003cp\u003e4\u0026thinsp;=\u0026thinsp;90\u0026ndash;119 min/time\u003c/p\u003e \u003cp\u003e5\u0026thinsp;=\u0026thinsp;\u0026ge;\u0026thinsp;120 min/time\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQ2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHow often do you conduct the outdoor activities of your child/children at his/her age of 1 to 3༟\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1=\u0026lt;1 times/week\u003c/p\u003e \u003cp\u003e2\u0026thinsp;=\u0026thinsp;1\u0026ndash;2 times/week\u003c/p\u003e \u003cp\u003e3\u0026thinsp;=\u0026thinsp;3-6times/week\u003c/p\u003e \u003cp\u003e4\u0026thinsp;=\u0026thinsp;\u0026ge;\u0026thinsp;7 times/week\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQ2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHow long do you conduct the outdoor activities of your child/children at his/her age of 1 to 3༟\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u0026thinsp;=\u0026thinsp;\u0026lt;\u0026thinsp;30 min/time\u003c/p\u003e \u003cp\u003e2\u0026thinsp;=\u0026thinsp;30\u0026ndash;59 min/time\u003c/p\u003e \u003cp\u003e3\u0026thinsp;=\u0026thinsp;60\u0026ndash;89 min/time\u003c/p\u003e \u003cp\u003e4\u0026thinsp;=\u0026thinsp;90\u0026ndash;119 min/time\u003c/p\u003e \u003cp\u003e5\u0026thinsp;=\u0026thinsp;\u0026ge;\u0026thinsp;120 min/time\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eMeasurement of ADHD symptoms\u003c/h2\u003e \u003cp\u003eIn this study, SDQ was used to assess the severity of ADHD symptoms of children. SDQ was compiled by Goodman, an American psychologist, in 1997 and is a concise behavior screening scale[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In 2005, China studied the norm belonging to Chinese people[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The scale had 25 items, including 5 dimensions: emotional symptoms, conduct problems, ADHD symptoms, peer problems and prosocial behavior. Items on the SDQ scale are rated on a scale between 0 and 2, with 0 indicating no agreement, 1 indicating somewhat agreement, and 2 indicating perfect agreement. The total score of ADHD symptoms from 0 to 5 is normal, 6 is borderline level, and 7 to 10 is abnormal, with higher scores indicating severer ADHD symptoms. The scale had good reliability, and the Cronbach α coefficient was 0.749[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eCovariates\u003c/h2\u003e \u003cp\u003eThe following confounding covariates were included in the analysis: child\u0026rsquo;s gender, single-child status, parents\u0026rsquo; education level, household monthly income, and parental marital status.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe participants\u0026rsquo; descriptive statistics were used to characterize the study population. Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) and sample number (percentage) were presented for continuous and categorical variables, respectively. Pearson correlation test was used to examine the correlation between continuous variables and ADHD symptoms score. T-tests were used to compare gender, single child status and parental marital status differences among ADHD symptoms score. Analysis of Variance (ANOVA) was used to compare parents\u0026rsquo; education level and monthly family income differences among ADHD symptoms score. Multiple Linear Regression analysis was used to explorer the association between frequency and duration of outdoor activity and ADHD symptoms.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eParticipants sociodemographic characteristics and adherence to ADHD symptoms\u003c/h2\u003e \u003cp\u003eParticipants\u0026rsquo; SDQ score and category was presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. In the total sample, we found that 6.9% of the participants were at the abnormal levels (defined as a score 7\u0026ndash;10) of ADHD symptoms. 8.4% of the participants were on the brink of ADHD symptoms (defined as a score of 6). The prevalence of ADHD symptoms was 6.9%.\u003c/p\u003e \u003cp\u003eParticipants\u0026rsquo; demographics and characteristics are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. 55528 children (29608 boys [53.3%] and 25920 girls [46.7%]; mean [SD] age, 5.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67 years old) completed the questionnaire information. Sample\u0026rsquo;s average score of ADHD symptoms was 3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93. Age was statistically significantly negatively correlated with ADHD symptoms score. Boys\u0026rsquo; symptoms are severer than girls\u0026rsquo; (3.76\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96 vs. 3.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Participants who are singletons and have lower household monthly income have severer ADHD symptoms (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Participants whose parents are higher education attainment and married have less severer ADHD symptoms (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\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\u003eScores and category of the Strengths and Difficulties Questionnaire (SDQ)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003en(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e55528(100.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNormal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e3.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47001(84.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEdge value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e6.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4678(8.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAbnormal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e7.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3849(6.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD was presented for continuous variables. N(%) was presented for categorical variables.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSociodemographic characteristics and ADHD symptoms\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eADHD score\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003er/t/F\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGender\u003c/b\u003e\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 \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\u003e29608(53.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.76\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e21.258\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\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\u003e25920(46.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSingle child status\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16959(30.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e18.638\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38569(69.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.50\u0026thinsp;\u0026plusmn;\u0026thinsp;1.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaternal education attainment\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJunior high school and below\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8543(15.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e4.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e373.156\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh school or technical secondary school\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11760(21.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.84\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJunior college\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33508(60.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.92\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndergraduate and above\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1717(3.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e2.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePaternal education attainment\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJunior high school and below\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7844(14.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e4.05\u0026thinsp;\u0026plusmn;\u0026thinsp;1.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e382.915\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh school or technical secondary school\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11877(21.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJunior college\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33140(59.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.46\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndergraduate and above\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2667(4.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e2.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHousehold monthly income\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026yen;10,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9488(17.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e261.478\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026yen;10,000\u0026ndash;20,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19161(34.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026yen;20,000\u0026ndash;30,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11610(20.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.50\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026yen;30,000\u0026ndash;40,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6312(11.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026yen;40,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8957(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.22\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eParental\u0026nbsp;marital\u0026nbsp;status\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarried\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53251(95.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.59\u0026thinsp;\u0026plusmn;\u0026thinsp;1.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-6.447\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRemarried/Divorced/Widowed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2277(4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e3.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD was presented for continuous variables. N(%) was presented for categorical variables. Abbreviation: \u003cem\u003er\u003c/em\u003e,\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003ecoefficient of Pearson correlation. \u003cem\u003et\u003c/em\u003e, t-values of Independent t-test. \u003cem\u003eF\u003c/em\u003e, F-values of ANOVA.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eRelationship between frequency and duration of outdoor activity and ADHD symptoms\u003c/h2\u003e \u003cp\u003eWe performed Multiple Linear Regression analysis to explore the associations between frequency and duration of outdoor activity and ADHD symptoms(Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u0026amp; Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e \u0026amp; Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Same statistically significantly negative associations with ADHD symptoms were observed in every category of outdoor activity frequency and duration when the participants were 0 to 1 years old or 1 to 3 years old (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Besides, as the frequency of outdoor activity increasing, the coefficients were also rising (\u003cem\u003eβ\u003c/em\u003e\u003csub\u003e0\u0026minus;1 years old\u003c/sub\u003e: -0.233 \u0026gt; -0.445 \u0026gt; -0.598; \u003cem\u003eβ\u003c/em\u003e\u003csub\u003e1\u0026minus;3 years old\u003c/sub\u003e: -0.300 \u0026gt; -0.495 \u0026gt; -0.699), as well as duration of outdoor activity (\u003cem\u003eβ\u003c/em\u003e\u003csub\u003e0\u0026minus;1 years old\u003c/sub\u003e: -0.110 \u0026gt; -0.201 \u0026gt; -0.302 \u0026gt; -0.381; \u003cem\u003eβ\u003c/em\u003e\u003csub\u003e1\u0026minus;3 years old\u003c/sub\u003e: -0.304 \u0026gt; -0.408 \u0026gt; -0.532 \u0026gt; -0.657).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship between frequency and duration of outdoor activity in 0\u0026ndash;1 year old children and ADHD symptoms(n\u0026thinsp;=\u0026thinsp;55528)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutdoor activity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eβ(95%CI)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFrequency\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55528\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 time/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2826(5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eRef.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u0026thinsp;~\u0026thinsp;2 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11111(20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.233(-0.310~-0.156)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14794(26.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.445(-0.520~-0.369)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26797(48.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.589(-0.662~-0.516)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDuration\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;30 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5104(9.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eRef.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026thinsp;~\u0026thinsp;59 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20159(36.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.110(-0.168~-0.052)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e60\u0026thinsp;~\u0026thinsp;89 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12272(22.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.201(-0.263~-0.139)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e90\u0026thinsp;~\u0026thinsp;119 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8426(15.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.302(-0.368~-0.237)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;120 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9567(17.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.381(-0.445~-0.317)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFrequency and duration of outdoor activity were transferred into dummy variables. Abbreviation: \u003cem\u003eβ\u003c/em\u003e, coefficient of Multiple Linear Regression Analysis. \u003cem\u003eβ\u003c/em\u003e with adjustment for age, gender, single child status, maternal and paternal education level, household monthly income and parental marital status. 95%CI, 95% confidence interval of Multiple Linear Regression Analysis.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship between frequency and duration of outdoor activity in 1\u0026ndash;3 year old children and ADHD symptoms(n\u0026thinsp;=\u0026thinsp;55528)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutdoor activity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eβ(95%CI)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFrequency\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55528\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 time/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3491(6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eRef.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u0026thinsp;~\u0026thinsp;2 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13702(24.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.300(-0.371~-0.229)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u0026ndash;6 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14542(26.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.495(-0.566~-0.424)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;7 times/week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23793(42.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.699(-0.767~-0.631)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDuration\u003c/b\u003e\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;30 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2559(4.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eRef.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026thinsp;~\u0026thinsp;59 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16745(30.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.304(-0.383~-0.224)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e60\u0026thinsp;~\u0026thinsp;89 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14949(26.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.408(-0.489~-0.328)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e90\u0026thinsp;~\u0026thinsp;119 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10655(19.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.532(-0.615~-0.449)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;120 mins/time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10620(19.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.657(-0.740~-0.574)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eOutdoor activity has been proved to be effective in facilitating healthy child development and a disconnect with nature presents potential health risks[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. However, the connection between outdoor activity with Chinese ADHD symptoms was not fully explored, until our research[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In our research, it involved 55528 Chinese\u0026rsquo;s children at the age from 0 to 3 locating at Longhua district of Shenzhen city, which was large scaled, persuasive, and clinically significant. Meanwhile, in our study, the prevalence of ADHD symptoms was evaluated, and it was 6.9%. It was consistent with the previous literature, which influential and aggregated 102 studies (and then an additional 41 studies) involving community samples of children and adolescents from 35 countries in six continents worldwide and estimated the prevalence of ADHD as 5\u0026middot;29% (95% CI 5\u0026middot;01\u0026ndash;5\u0026middot;56)[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. It implied there might be no significant racial difference in ADHA\u0026rsquo;s prevalence.\u003c/p\u003e \u003cp\u003eMoreover, several sociodemographic characteristics evaluated in our study were proved to have significant effect on ADHD symptoms, including age, gender, single child status, maternal education attainment, paternal education attainment, household monthly income, and parental marital status. Interestingly, in our study, the higher household income, the lower ADHD scores. However, in Frances E. Kuo et al.\u0026rsquo;s research examining the impact of relatively \u0026ldquo;green\u0026rdquo; settings on ADHD symptoms, 120 ADHD children were involved with their household income over 75000 \u003cspan\u003e$\u003c/span\u003e, while only 9 ADHD children were involved with their household income below 10000 \u003cspan\u003e$\u003c/span\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our study, it was proved that children ,who conducted more often and spent more time on outdoor activities at the age of 0 to 3, had lower ADHD symptoms scores. This result is supported by several key arguments.\u003c/p\u003e \u003cp\u003eFirst, outdoor activities often involve physical exercise, which has been shown to have a positive effect on cognitive function and behavior in children with ADHD[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Exercise is believed to improve executive functions[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], reduce impulsivity, and enhance attention[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], partly through the release of endorphins and the improvement of dopamine[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], neurotransmitters known to be beneficial in individuals with ADHD[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSecond, the natural environment itself may play a therapeutic role. The Attention Restoration Theory (ART) suggests that natural settings, through their restorative effects, can help reduce mental fatigue and improve concentration and attention[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. This is particularly relevant for children with ADHD, who often experience difficulty in sustaining attention and resisting distractions.\u003c/p\u003e \u003cp\u003eThird, engaging in outdoor activities provides opportunities for social interaction and the development of social skills, which are often areas of difficulty for children with ADHD[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Through play and organized activities, children can learn to cooperate, follow rules, and interact more effectively with peers, potentially mitigating some of the social and behavioral challenges associated with ADHD.\u003c/p\u003e \u003cp\u003eHowever, it is also important to acknowledge the limitations and variability in this research. While several studies support the beneficial effects of outdoor activities for children with ADHD, results can vary based on factors such as the type of activity, the specific needs and characteristics of the child, and the presence of other interventions. Moreover, the nature of the association \u0026ndash; whether causal or correlational \u0026ndash; is not yet fully understood, necessitating further research in this area.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe relationship between frequency and duration of outdoor activities and ADHD symptoms in children presents a promising area for intervention. Encouraging regular participation in outdoor activities may serve as a valuable component of a multi-faceted approach to managing ADHD symptoms. Nonetheless, this should be complemented by continued research to better understand the mechanisms behind this association and to tailor interventions to the diverse needs of children with ADHD.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the ethics committee of\u0026nbsp;Longhua Maternal and Child Health Hospital, and the study was performed in accordance with the tenets of the Declaration of Helsinki and relevant policies in China. Informed consent was obtained from all subjects and their legal guardian(s) before data collection and their personal information was maintained anonymously.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eLonghua District Medical And Health Institutions Regional Scientific Research Project (2022086).\u003c/li\u003e\n \u003cli\u003eGuangzhou Aier Eye Hospital Science Foundation for Youths (GA2023003).\u003c/li\u003e\n \u003cli\u003eLonghua District Medical And Health Institutions Regional Scientific Research Project (2021043).\u003c/li\u003e\n \u003cli\u003eLonghua District Medical And Health Institutions Regional Scientific Research Project (2022127)\u0026nbsp;.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eMedical Key Discipline Construction Fund of Longhua District.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization:\u0026nbsp;Jian-Bo Wu\u0026nbsp;and Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eData curation: Jianhui\u0026nbsp;Chen, Xiaonan Yang\u0026nbsp;and\u0026nbsp;Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eFormal analysis: Jian-Bo Wu\u0026nbsp;and\u0026nbsp;Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eFunding acquisition: Jianhui\u0026nbsp;Chen\u0026nbsp;and\u0026nbsp;Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eInvestigation:\u0026nbsp;Jianhui\u0026nbsp;Chen, Xiaonan Yang\u0026nbsp;and\u0026nbsp;Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eMethodology:Yanni Yang\u0026nbsp;and\u0026nbsp;Xiaoxiao Zhang.\u003c/p\u003e\n\u003cp\u003eProject administration: Jian-Bo Wu, Rong Li\u0026nbsp;and\u0026nbsp;Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eResources: Jian-Bo Wu\u0026nbsp;and\u0026nbsp;Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eSoftware: Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eSupervision: Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eValidation: Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eVisualization: Jianhui\u0026nbsp;Chen.\u003c/p\u003e\n\u003cp\u003eWriting\u0026ndash;original draft:\u0026nbsp;Jianhui\u0026nbsp;Chen, Xiaonan Yang\u0026nbsp;and Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003eWriting\u0026ndash;review and editing: Jianhui\u0026nbsp;Chen, Xiaonan Yang\u0026nbsp;and Jian-Bo Wu.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to show their gratitude to the families who participated in the study, the doctors from Longhua Maternal and Child Healthcare Center, and the kindergarten teachers who took part in the investigation.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisclosure statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData is provided within the manuscript or supplementary in formation files. No potential conflict of interest was reported by the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSayal K, Prasad V, Daley D, Ford T, Coghill D. ADHD in children and young people: prevalence, care pathways, and service provision. Lancet Psychiatry. 2018;5(2):175\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLoram G, Ling M, Silk T, Sciberras E, Associations Between ADHD. Sleep Problems, and Mental Health Symptoms in Adolescents. J Atten Disord. 2023;27(6):635\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTan EJ, Raut T, Le LK, Hay P, Ananthapavan J, Lee YY, Mihalopoulos C. The association between eating disorders and mental health: an umbrella review. J Eat Disord. 2023;11(1):51.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarcha J, Smith AP. Associations between Autistic and ADHD Traits and the Well-Being and Mental Health of University Students. 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The roles of dopamine and noradrenaline in the pathophysiology and treatment of attention-deficit/hyperactivity disorder. Biol Psychiatry. 2011;69(12):e145\u0026ndash;57.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOhly H, White MP, Wheeler BW, Bethel A, Ukoumunne OC, Nikolaou V, Garside R. Attention Restoration Theory: A systematic review of the attention restoration potential of exposure to natural environments. J Toxicol Environ Health B Crit Rev. 2016;19(7):305\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSalley B, Gabrielli J, Smith CM, Braun M. Do communication and social interaction skills differ across youth diagnosed with autism spectrum disorder, attention-deficit/hyperactivity disorder, or dual diagnosis? Res Autism Spectr Disord. 2015;20:58\u0026ndash;66.\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":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4135215/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4135215/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective:\u003c/h2\u003e \u003cp\u003eAttention-deficit hyperactivity disorder (ADHD) is a common childhood behavioral disorder which often persists into adulthood and is correlated with a broad range of other mental or behavioral problems. Some researches have indicated that social-environmental factors could be influential on children with ADHD, but none has a large sample size and most of them lack of data of social-environmental factors from early childhood. Therefore, we aimed to assess the frequency and duration of outdoor activities of preschool-age children at their age of 0\u0026ndash;1 and 1\u0026ndash;3 and to explore their association with ADHD symptoms.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe conducted a retrospective study. We distributed questionnaires to a 59,600 sample of parents of children enrolled in 250 kindergartens in Longhua District, Shenzhen, China. We collected data on sociodemographic characteristics, outdoor activities frequency and duration. We assessed ADHD symptoms with the Strengths and Difficulties Questionnaire (SDQ).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003e55528 valid questionnaires were finally included in the study. The prevalence of ADHD symptoms was 6.9%, with a higher score in boys (3.76\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96 vs. 3.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.87, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was a significant difference in ADHD symptoms between high level of household monthly income and low level of household monthly income (\u003cem\u003eF\u003c/em\u003e\u0026thinsp;=\u0026thinsp;261.478, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was a significant association between higher frequency and duration of outdoor activitiesand lower ADHD symptoms scores (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eHigher frequency and duration of outdoor activities in early childhood may reduce the ADHD symptoms in children. More participation in outdoor activities should be encouraged to manage ADHD symptoms. Continued research should be conducted to better understand the mechanisms behind this association and to tailor interventions to the diverse needs of children with ADHD.\u003c/p\u003e","manuscriptTitle":"Potential social-environmental factors affecting ADHD symptoms of 55528 children from Longhua district, Shenzhen, China","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-18 03:33:25","doi":"10.21203/rs.3.rs-4135215/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-04-17T13:04:05+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-04-17T12:46:14+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-04-01T07:07:42+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Public Health","date":"2024-03-20T08:00:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"70a0ebec-ca3d-4a17-9aff-65df98bab5e8","owner":[],"postedDate":"April 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-08T16:03:11+00:00","versionOfRecord":{"articleIdentity":"rs-4135215","link":"https://doi.org/10.1186/s12889-025-25865-5","journal":{"identity":"bmc-public-health","isVorOnly":false,"title":"BMC Public Health"},"publishedOn":"2025-12-06 15:58:07","publishedOnDateReadable":"December 6th, 2025"},"versionCreatedAt":"2024-04-18 03:33:25","video":"","vorDoi":"10.1186/s12889-025-25865-5","vorDoiUrl":"https://doi.org/10.1186/s12889-025-25865-5","workflowStages":[]},"version":"v1","identity":"rs-4135215","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4135215","identity":"rs-4135215","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}