Abstract: Objective To investigate the prevalence of comorbid myopia and overweight/obesity among primary and secondary school students, explore its influencing factors, and thereby provide a scientific basis for establishing a "co-morbidity, shared etiology, shared prevention" mechanism for common diseases in children and adolescents. Methods In 2023, a multi-stage stratified cluster sampling method was used to select 217 393 students from fourth grade in primary school to third grade in high school in 18 cities in Sichuan Province. These students underwent height and weight measurements, myopia screenings, and questionnaire surveys. Differences between groups were tested using the χ² test, and factors influencing the comorbidity of myopia and overweight/obesity were analyzed using a multivariate logistic regression model. Results A total of 213 609 primary and secondary school students were included, the myopia rate was 65.82% (140 593 cases), the overweight/obesity rate was 23.47% (50 132 cases), and the comorbidity rate of both conditions was 15.26% (32 596 cases). Fully meeting the 24-hour movement guideline was a protective factor for comorbid myopia and overweight/obesity (OR=0.858). Additionally, gender, ethnicity, school grade, economic region, and family structure also had significant impacts on the occurrence of comorbidity (all P<0.01). Conclusions The prevalence rates of myopia, overweight/obesity, and their comorbidity are relatively high among primary and secondary school students in Sichuan Province. Targeted interventions should be implemented based on gender, ethnicity, school grade, economic region, and family structure. Fully meeting the 24-hour movement guideline can reduce the incidence of comorbid myopia and overweight/obesity.

Key words: Myopia, Overweight, Obesity, Comorbidity, Students, Influencing factors