Association of sleep duration with different degrees of myopia in Chinese students: a cross-sectional study

Abstract

Abstract Background: At present, there are many studies on the relationship between sleep duration and myopia, but the results are not consistent. The aim of this study was to evaluate the association between sleep duration and the degree of myopia among Chinese primary students in grade 1 to grade 5. Materials and methods: This study was a cross-sectional study. From March to June2023, a total of 30653 students in grade 1 to grade 5 from 18 primary schools in Zhengzhou completed the questionnaire survey. The refractive error is divided into four grades: No-myopia (spherical equivalents (SE)＞-0.50 dioptres (D)), mild myopia (-3.00D＜SE≤-0.50D), moderate myopia (-6.00D＜SE≤-3.00D) and high myopia (≤-6.00D). Nighttime sleep duration was divided into two categories (＜8 h/d, ≥8 h/d). To evaluate the effect of sleep duration on myopia severity, stratified analyses were performed by sex and grades, with sleep duration ≥8 h/d as the reference for each stratum, and using ordinal logistic regression. Results: There are differences in age, gender, class, and sleep duration among primary school students with different degrees of myopia (all P＜0.001). Among boys, the risk of one degree increase in myopia with sleep duration＜8h/d is 12.291 (95%CI:11.280, 13.393) times higher than that with sleep duration ≥8h/d. Among girls, the risk of one degree increase in myopia with sleep duration＜8h/d is 12.709 (95%CI:11.611, 13.912) times higher than that with sleep duration ≥8h/d. In different grades, in grade 1, the risk of myopia increased by one grade with sleep duration ＜8h/d was 5.197 (95%CI:4.520, 5.975) times that with sleep duration ≥8h/d. In grade 2, the risk of myopia grade one increased with sleep duration ＜8h/d was 8.783 (95%CI:7.642, 10.094) times that with sleep duration ≥8h/d. In grade 3, the risk of myopia with sleep duration ＜8h/d was 11.834 (95%CI:10.278, 13.625) times that with sleep duration ≥8h/d. In grade 4, the risk of myopia grade one increased with sleep duration ＜8h/d was 13.567 (95%CI:11.793, 15.608) times that with sleep duration ≥8h/d. In grade 5, the risk of myopia grade one increased with sleep duration ＜8h/d was 16.280 (95%CI:13.981, 18.957) times that with sleep duration ≥8h/d. Conclusions: Our results suggest that sleep duration has a significant impact on the degree of myopia in Chinese primary school students. Students with sleep duration ＜8h/d had a faster decline in SE than those with sleep duration ≥8h/d, and the risk of high myopia was higher.