Objective: The study was aimed at exploring the latent classes and factors influencing middle school students health risk behaviors in Beijing, so as to provide a scientific basis for determining key intervention targets and formulating relevant intervention measures. Methods: A questionnaire survey was conducted among 17 730 junior middle school, senior high school and vocational high school students in 16 districts of Beijing from October to December 2022. Six types of health risk behaviors were assessed with latent class analysis, including unhealthy diet, lack of exercise, unintentional harm, intentional harm, substance abuse and Internet addiction behavior. Results: The latent classes of health risk behavior among middle school students in Beijing were divided into three classes:high risk behavior (961 participants, 5.42%), low lack of exercise/high intentional injury (1 099 participants, 6.20%), and low risk behavior (15 670 participants, 88.38%). Disordered multiple Logistic regression analysis indicated that middle school students who were male ( OR =1.45), in high school ( OR =2.00), had other family types ( OR =1.90), possibly had depressed feelings ( OR =2.27), had depressed feelings ( OR =6.18), or were absent from school because of illness in the past year ( OR =1.79) were more likely to be in the high risk than the low risk behavior group. Moreover, middle school students who were male ( OR =2.30), had an extended family ( OR =1.18), had a reorganized family ( OR =1.70), had other family types ( OR =1.94), possibly had depressed feelings ( OR =3.10), had depressed feelings ( OR =4.91), had taken sick leave in the prior 2 weeks ( OR =1.54), or had absence from school because of illness in the past year ( OR =1.71) were relatively more likely to be in the low lack of exercise or high intentional injury group ( P <0.05). Conclusion Clear latent classes of health risk behaviors among middle school students are found to be present in differing proportions in Beijing. Relevant departments should take targeted intervention measures in a timely manner to reduce the occurrence of health risk behaviors among middle school students.

Objective: To analyze the current status and related factors of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing, so as to provide a basis for comprehensive public health interventions for common diseases. Methods: Through stratified cluster random sampling in October 2022, a total of 11 262 junior high school, senior high school, and vocational high school students in 16 districts of Beijing were surveyed with self administered questionnaires, physical examinations and visual acuity examinations. The χ 2 test and binary Logistic regression model were used to analyze group differences in the comorbidity of myopia, obesity and depression symptoms and factors influencing the comorbidity. Stratified analysis was applied to analyze the associations between health risk behaviors and the comorbidity. Results: The detection rate of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing was 3.35%, the comorbidity rate among vocational high school students (4.61%) was higher than that in junior high school students (2.80%) and senior high school students (3.41%). The comorbidity rate was higher among students in suburban areas (3.66%) than that in urban areas (2.92%), and the differences was statistically significant ( χ 2=15.02, 4.63, P <0.05). Binary Logistic regression analyses indicated that middle school students with poor dietary behaviors ( OR =1.59) and excessive screen time ( OR =1.70) were associated with elevated risk of comorbidity of myopia, obesity, and depression symptoms. Both boys and girls with poor dietary behaviors ( OR =1.63, 1.69) and excessive screen time ( OR =1.45, 2.23) had elevated likelihood of comorbidity of myopia, obesity and depression symptoms. Students in junior high school and senior high school with poor dietary behaviors ( OR =2.16, 1.47) and excessive screen time ( OR =2.20, 1.63 ) had elevated likelihood of comorbidity of myopia, obesity, and depression symptoms ( P <0.05). Conclusions The current status of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing is concerning. Schools and parents should work together to guide students to develop healthy behaviors such as balanced diet and moderate video, in order to achieve the goal of controlling myopia, obesity and depression symptoms.