ABSTRACT
[Background] Students in early adolescence have a high incidence of mental health problems. Studies have found an association between physical activity and mental health in adults, but the association among children and adolescents is not clear. [Objective] This study investigates the relationship between mental health and physical activity among students in early adolescence, aiming to provide evidence for the prevention and control of mental problems among students in this stage. [Methods] By using stratified cluster random sampling method, a questionnaire survey was conducted among 859 fourth grade students from 12 elementary schools in 3 urban and 3 suburban areas in Shanghai. The survey included students' general information, the total and mental health problems, and physical activity time, and calculated the total and dimensional (emotional symptoms, conduct problems, hyperactivity, peer problems, and prosocial behaviors) positive rates of mental health and the daily moderate-to-vigorous-intensity physical activity time. Chi-square test was used to compare the differences in mental health status among students with different family economic, educational backgrounds and family relationships. Logistic regression models were used to analyze the associations between mental health problems and physical activity. [Results] The total positive rate of mental health problems among the participants was 10.7%, and the rate of boys was higher than that of girls (13.4% vs. 8.0%, X 2=6.58, P < 0.05). The dimensional positive rates from high to low were peer problems (22.9%), hyperactivity (15.8%), emotional symptoms (9.0%), conduct problems (7.6%), and social impairment (5.2%). The median time[M (P25, P75)] of daily moderate-tovigorous-intensity physical activity of the students was 76.9 (8.4, 107.1) min;48.7% of the students spent less than 60 min on moderateto-vigorous-intensity physical activities per day, and the proportion in boys (52.2%) was higher than that in girls (45.1%) (X 2=4.36, P < 0.05). The rank-sum test results showed that the daily time of moderate-to-vigorous-intensity physical activity was correlated with the positive rate of emotional symptoms, conduct problems, hyperactivity, peer problems, and total mental health problems (P < 0.05). The chi-square test results showed that the factors such as mother's education level, father's and mother's monthly income, and family relationships were related to the positive rate of total mental health problems (P < 0.05). The logistic regression analysis results showed that spending less than 60 min on moderate-to-vigorous-intensity physical activities per day was associated to reporting hyperactivity, total mental health problems, and social impairment, and the ORs (95%CI) were 1.633 (1.095-2.436), 2.811 (1.676-4.714), and 2.307 (1.153-4.618) respectively. [Conclusion] Among the fourth grade students in Shanghai, the positive rate of boys' mental health problems is higher than that of girls', and the overall rate of peer problems is high. Nearly half of the students spend less than 60 min on moderate-to-vigorous-intensity physical activities per day. Doing moderate-to-vigorous-intensity physical activity for less than 60 min per day is possibly associated to the positive rate of students' mental health problems.
ABSTRACT
BACKGROUND: Since December 2019, the coronavirus disease 2019 (COVID-19) has become a global pandemic. Currently, the COVID-19 pandemic is still ongoing. What changes have taken place in the obesity and obesity-related lifestyle behaviours of adolescents during the first year of the COVID-19 pandemic? OBJECTIVE: This study aims at analysing the changes in obesity and lifestyle behaviours of Chinese adolescents before and 1 year after the outbreak of the COVID-19 pandemic, providing evidence for the global strategies to respond to the impact of the COVID-19 pandemic on adolescent obesity. METHODS: Physical examinations and student health and influencing factors questionnaires were conducted among 6047 adolescents aged 11-16 years by health professionals in Shanghai, China, before the COVID-19 pandemic (September-November of 2019) and 1 year after the outbreak of the COVID-19 pandemic (September-November of 2020). Paired χ2 tests, paired t-tests or Wilcoxon signed-rank test was used to evaluate the changes in the obesity prevalence, BMI and lifestyle behaviours from 2019 to 2020. RESULTS: 1 year after the outbreak of the COVID-19 pandemic, the obesity prevalence of Chinese adolescents rose from 14.2% to 15.4% (p < 0.01), mainly because of the increase in boys. And the average BMI increased from 20.3 to 21.2 kg/m2 (p < 0.01). Their lifestyle behaviours have also significantly changed. The mobile screen time increased from 0.25-1.50 h/day to 0.33-2.00 h/day (p < 0.01). The proportion of adolescents who participated in MVPA for ≥60 min/day on all 7 days during the past week dropped from 14.4% to 11.7% (p < 0.01). The generalized estimation equation analysis indicated that adolescents who participated in MVPA for ≥60 min/day on all 7 days had a lower likelihood of having obesity. Boys with computer time ≥2 h/day and girls with mobile screen time ≥2 h/day or TV time ≥2 h/day had a higher likelihood of having obesity. CONCLUSION: This study found that 1 year after the outbreak of the COVID-19 pandemic, the BMI and obesity prevalence of Chinese adolescents increased and obesity-related lifestyle behaviours have also changed.