Abstract
OBJECTIVES: This study aimed to assess the association between various types of outdoor activities and myopia among school-aged children. DESIGN: A cross-sectional study. SETTING: Fengyang County, Chuzhou City, Anhui Province. PARTICIPANTS: A total of 2123 students aged 9-19 years (mean 14.60±2.04 years) were recruited from two primary schools, four junior high schools and eight high schools between October and December 2023. 2066 students were included in the final analysis, comprising 1151 boys and 915 girls. MAIN OUTCOME MEASURES: Daily time for various types of outdoor activities and eye parameters. RESULTS: Of the 2066 students enrolled, 85.04% (1757) were diagnosed with myopia. On adjustment for confounding variables, both the total (OR=0.82, 95% CI: 0.73 to 0.92, p=0.001) and low-intensity outdoor activities (OR=0.73, 95% CI: 0.58 to 0.92, p=0.008) exhibited significant associations with the presence of myopia. A gender-based subgroup analysis revealed that daily total outdoor activity hours emerged as a protective factor against myopia in male students (OR=0.83, 95% CI: 0.72 to 0.96, p=0.014), whereas for females, daily medium-intensity outdoor activities were identified as a protective factor (OR=0.44, 95% CI: 0.20 to 0.96, p=0.040). Stratified by educational level, our findings indicated that both daily total outdoor activity (OR=0.59; 95% CI: 0.46 to 0.77, p<0.001) and high-intensity outdoor activities (OR=0.44; 95% CI: 0.21 to 0.91, p=0.026) were beneficial in preventing myopia among students in primary grades 4 to 6. Conversely, for high school students, only daily low-intensity outdoor activities demonstrated a protective effect against myopia (OR=0.69; 95% CI: 0.50 to 0.94, p=0.020). CONCLUSIONS: Outdoor activities, particularly those of low intensity, may offer a protective effect against the development of myopia in school-aged children.