Association between nutritional level, menstrual-related symptoms, and mental health in female medical students.

Many medical students experience depression and suicidal ideation [ 1 ] because they are under a high level of stress associated with the immense volume of information to learn, time constraints, examinations, competition, and challenging curricular factors [ 2 – 4 ]. A recent systematic review has reported that the prevalence of depression or depressive symptoms among medical students was 27.2% compared to 9.5% in the general population of 19- to 25-year-olds [ 1 ]. Furthermore, there is a significant gender difference in the prevalence of these problematic depressive conditions. Depression and depressive symptoms are twice as more prevalent in women than in men [ 5 – 7 ]. These findings suggest that it is important to identify the factors related to depression and depressive symptoms in female medical students. Several reasons have been suggested for the increased prevalence of depression in young female medical students; one is menstrual symptoms, and the other is nutritional status. Menstrual-related symptoms, including premenstrual syndrome and menstrual pain have been reported to be associated with mental disorders and depression, particularly in young women [ 8 – 11 ]. Furthermore, lower serum levels of albumin and high-density lipoprotein cholesterol (HDL-C) have been observed in patients with depression compared to healthy controls [ 12 ]. Reports also suggest that anemia and lower hemoglobin (Hb) levels are associated with depression [ 13 , 14 ]. However, the association between nutritional status and depression is still unknown due to inconsistent results [ 12 , 15 , 16 ]. Additionally, although gender differences in the rate of major depression and depressive symptoms peak in adolescence [ 7 ], these aforementioned studies regarding nutritional status have focused on middle-aged and elderly participants. To date, little is known about the effects of menstrual symptoms and nutritional status on the mental health of young female medical students. Therefore, this study aimed to examine the association between menstrual symptoms, nutritional parameters, and psychological distress in Japanese young female medical students.

In total, 326 Japanese female medical students were included in this study ( Fig 1 ). The characteristics of the study population are summarized in Table 1 . Red blood cell count, Hb, hematocrit, and serum albumin levels in the high GHQ group were significantly lower than those in the low GHQ group. There was no significant difference between the low and high GHQ groups with respect to BMI, ferritin, and lipid metabolites (TG, HDL-C, and LDL-C). For menstrual-related symptoms, presence of PMS and the total MDQ score were significantly higher in the high GHQ group compared to the low GHQ group. Participant characteristics. GHQ, General Health Questionnaire; BMI, body mass index; BPs, blood pressure systolic; BPd, blood pressure diastolic; WBC, white blood cell; RBC, red blood cell; Hb, hemoglobin; Ht, hemocrit; Plt, platelet; Alb, albumin, AST, aspartate aminotransferase; ALT, alanine aminotransferase; TG, triglycerides; LDL-C, low density lipid cholesterol; HDL-C, high density lipid cholesterol; MDQ, Menstrual Distress Questionnaire a Reported as mean (standard deviation) b Reported as % (numbers) c Reported as median (25 th percentile, 75 th percentile) The crude analysis revealed that lower levels of Hb and albumin, presence of PMS, and higher MDS-scores were associated with high levels of psychological distress. After making adjustments considering participation in sporting activities as a physical activity factor, age, and school grades as sociodemographic factors (model 2), a lower level of albumin was significantly associated with high levels of psychological distress, whereas Hb, ferritin, LDL-C, HDL-C, and TG were not. In model 3, which included the menstrual symptoms in addition to the factors considered in model 2, the presence of PMS and higher total MDQ-scores were associated with high levels of psychological distress ( Table 2 ). In addition, lower levels of albumin were independently associated with high levels of psychological distress ( Table 2 ). Model 1, unadjusted; model 2 is adjusted for BMI, participation in sporting activities as a physical activity factor, age, and school grades as sociodemographic factors, and Hb, ferritin, albumin, LDL-C, HDL-C, and TG as nutritional factors; model 3 includes all model 2 variables plus the presence of PMS and MDQ-score as menstrual-related symptoms. The levels of albumin are standardized. ORs are computed per standard deviation increment. CI, confidence interval; OR, odds ratio; BMI; body mass index, LDL-C; low density lipoprotein-cholesterol, HDL-C, high density lipoprotein-cholesterol; TG, triglycerides; PMS; premenstrual syndrome; MDQ, Menstrual Distress Questionnaire; TG, triglycerides; Hb, hemoglobin With regard to the statistical power in model 1, the calculated statistical power of Hb, albumin, the presence of PMS, and MDS-scores were 0.057, 0.999, 0.970, and 0.999, respectively. Moreover, in model 2, the calculated statistical power of Hb and albumin were 0.059, 0.999. Finally, in model 3, those of Hb, albumin, the presence of PMS, and MDS-scores were 0.054, 0.996, 0.850, and 0.996, respectively.

The levels of psychological distress in female medical students may be associated with nutritional markers such as albumin, and with menstrual-related symptoms. It is important to improve dietary habits and control menstrual-related symptoms in female medical students to improve mental health. School doctors and nurses can play a role in ameliorating mental health in young female medical students by encouraging a healthy diet and checking for the presence of menstrual symptoms.

The participants in this cross-sectional study were students of Tokyo Women’s Medical University. There were 673 medical students who attended a medical check-up at the university between April and July in 2018. At the medical check-up, blood samples were collected from the first-, third-, and sixth-grade students, according to the prescribed university protocol. The exclusion criteria were as follows: (i) presence of chronic diseases such as collagen disease, ulcerous colitis, as well as others, and (ii) insufficient questionnaire data. This study was approved by the Medical Ethics Committee of the School of Medicine, Tokyo Women’s Medical University, Tokyo, Japan (approval no. 5002), and all participants provided written informed consent. The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki and its later amendments. All data and samples were collected during the medical check-up. Data on demographics and lifestyle factors, including medical history and participation in sporting activities, were collected through a self-administered questionnaire. Height and weight were measured with the participant wearing light clothing. Body mass index (BMI) was calculated as weight (in kilograms) divided by the square of height (in metres). Blood samples were collected in the morning (after the students had fasted overnight). Plasma albumin levels were measured using the bromocresol purple method. The serum levels of triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C) were measured using enzymatic methods. Low-density lipoprotein cholesterol (LDL-C) level was measured using the direct methods. The levels of psychological distress were assessed using the Japanese version of the General Health Questionnaire (J-GHQ-30) [ 17 , 18 ]. The J-GHQ-30 comprises 30 items, and each item has four subsequently dichotomized response categories, providing a total score of between 0 and 30. The participants were characterized according to their mental state within the last few weeks, including depressive mood, sleeping problems, anxiety, social functioning, well-being, and coping abilities. A high GHQ score was defined as ≥7 of the entire score on J-GHQ-30 [ 17 , 18 ]. The premenstrual phase was defined as the 10 days before the first day of menstrual bleeding, while the menstrual phase was defined as the period from the first to the last day of menstruation. Premenstrual symptoms were measured using the Premenstrual Symptoms Questionnaire [ 19 , 20 ]. This questionnaire was developed and translated into Japanese by Takeda et al. and consists of DSM-IV criteria assessed on a rating scale with degrees of severity. The Premenstrual Symptoms Questionnaire is identical to the Premenstrual Symptoms Screening Tool. The questionnaire asks participants to rate the severity of premenstrual symptoms as ‘not at all’, ‘mild’, ‘moderate’, or ‘severe’. We defined moderate or severe premenstrual symptoms as premenstrual syndrome (PMS). In addition, menstrual symptoms were appraised by the Japanese version of the Menstrual Distress Questionnaire (MDQ) [ 21 ]. In this questionnaire, menstrual symptoms were assessed by assigning a score of 1 (no symptoms), 2 (minimal), 3 (mild), 4 (moderate), 5 (strong), or 6 (severe) to each of the 35 items across six of the eight categories (pain, concentration, behaviour change, autonomic reaction, water retention, and negative effect). These scores were summed, and we used the total score (MDQ-score) as the assessment of menstrual symptoms. A higher MDQ-score indicated that the participant was suffering from menstrual symptoms. Using the Q-Q plot, we checked whether the continuous variables were normally distributed or not. Continuous variables were presented as mean (standard deviation [SD]), or as median (25 th percentile, 75 th percentile), and categorical variables were presented as frequency and percentage. Continuous variables were compared between the participants with low and high GHQ scores using a student t-test or Mann-Whitney U test. Categorical variables were compared using a Chi-square test. Logistic regression was used to perform univariable and multivariable analyses for the factors influencing psychological distress. The dependent variables were dichotomized as the high or low of the entire J-GHQ-30 score at ≥7 or less; a crude analysis has been presented in model 1. For multiple logistic regression analyses, we made adjustments considering participation in sporting activities as a physical activity factor, age, and school grades as sociodemographic factors and Hb, ferritin, albumin, LDL-C, HDL-C, and TG levels as the nutritional factors in model 2. Model 3 included all model 2 variables plus the presence of PMS and MDQ-scores for menstrual-related symptoms. For analysis, the MDQ-scores were divided into four groups using the 25 th , 50 th , and 75 th percentiles as cut-off points. All statistical analyses were performed using SPSS version 19.0 (IBM Corp., Armonk, NY, USA). The post-hoc power of the study was estimated using G*Power software (version 3.1) with an α-error of 0.05. The significance level was set at p <0.05, and all statistical tests were two-tailed.