Association of sedentary behaviors with visual acuity among primary school students: a cohort study

Objective To examine the association of sedentary behaviors with visual acuity among primary school children, and to provide a reference basis for the prevention and control of poor vision. Methods Using stratified random cluster sampling method, a total of 4 969 students in grade 1–4 were selected from 5 primary schools in Guangzhou in 2017, and then were followed up in 2019. A validated questionnaire was used to collect data on children’s sedentary behaviors, including doing homework, watching TV, playing computer/video games, and taking the bus/car between home and school. Visual acuity was measured in the baseline and the follow-up using a 5 m standard logarithmic visual acuity chart. Multiple linear regression and Logistic regression were conducted to analyze the relationship between sedentary behaviors and visual changes. Results The two-year cumulative incidence of poor vision was 48.74%. Homework time was inversely associated with visual acuity of left eye ( β = −0. 012, 95% CI = −0.023–−0.002). Homework time was positively correlated with poor vision ( OR = 1.16, 95% CI = 1.05–1.27). However, total sedentary time, screen time and bus/car time were not statistically associated with changes in visual acuity ( P>0.05). Conclusion Increased homework time was associated with poorer vision in primary school students. Interventions to reduce the academic burden should be taken. 【摘要】 目的 探究小学生静态行为与视力变化的关联性, 为学生视力不良防控工作提供参考依据。 方法 采用分层整群随机抽样的方法, 于 2017 年抽取广州市 5 所小学, 纳入一至四年级学生 4 969 名, 并于 2 年后进行随访。采用经信、效度检验的《广州市小学生体质健康监测系统问卷》收集小学生基线放学后做作业、看电视、用电脑/玩游戏、往返交通等静态行为时间。使用 5 m 标准对数视力表分别测量基线和随访的视力。分别采用多重线性回归和 Logistic 回归分析小学生静态行为与视力变化值以及视力不良的关联性。 结果 2 年期间, 一至四年级学生视力不良的累积发病率为 48.74%。放学后做作业时间与左眼视力变化值呈负相关 ( β = −0.012, 95% CI = −0.023~−0.002)。放学后做作业时长与视力不良的发生正性相关 ( OR = 1.16, 95% CI =1.05~1.27)。静态行为总时长、视屏时间、往返交通时间与视力变化相关均无统计学意义 ( P 值均>0.05)。 结论 静态行为中的放学后做作业时间增加与小学生视力降低相关, 合理减轻课业负担有利于视力保护。