Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Guangdong Provincial Engineering Technology Research Center of Environmental and Health risk Assessment, Department of Occupational and Environmental Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
Environ Health Perspect. 2021 Oct;129(10):107006. doi: 10.1289/EHP8429. Epub 2021 Oct 27.
Evidence concerning the effects of greenness on childhood visual impairment is scarce.
We aimed to assess whether greenness surrounding schools was associated with visual impairment prevalence and visual acuity levels in Chinese schoolchildren and whether the associations might be explained by reduced air pollution.
In September 2013, we recruited 61,995 children and adolescents 6-18 years of age from 94 schools in seven provinces/municipalities in China. Greenness exposure was assessed using the normalized difference vegetation index (NDVI) and the soil-adjusted vegetation index (SAVI) from July to August 2013. Visual impairment was defined as at least one visual acuity level (dimensionless) lower than 4.9 (Snellen 5/6 equivalent). Three-year annual averages of particulate matter (PM) with an aerodynamic diameter of () and nitrogen dioxide () at each school were assessed using machine learning methods. We used generalized linear mixed models to estimate the associations between greenness and prevalent visual impairment and visual acuity levels and used mediation analyses to explore the potential mediating role of air pollution.
In the adjusted model, an interquartile range increase in was associated with lower odds of prevalent visual impairment [; 95% confidence interval (CI): 0.93, 0.97]. The same increase in was also associated with (95% CI: 0.008, 0.015) and (95% CI: 0.007, 0.015) increases in visual acuity levels for left- and right-eye, respectively. Our results also suggested that and significantly mediated the association between and visual impairment. Similar effect estimates were observed for , and our estimates were generally robust in several sensitivity analyses.
These findings suggest higher greenness surrounding schools might reduce the risk of visual impairment, possibly owing in part to lower and in vegetated areas. Further longitudinal studies with more precise greenness assessment are warranted to confirm these findings. https://doi.org/10.1289/EHP8429.
关于绿化对儿童视力损害影响的证据很少。
我们旨在评估学校周围的绿化是否与中国学童的视力损害患病率和视力水平有关，以及这些关联是否可以通过减少空气污染来解释。
2013 年 9 月，我们从中国七个省/直辖市的 94 所学校招募了 61995 名 6-18 岁的儿童和青少年。使用归一化差异植被指数（NDVI）和土壤调整植被指数（SAVI）从 2013 年 7 月到 8 月评估绿化暴露情况。视力损害定义为至少有一个视力水平（无维度）低于 4.9（与 Snellen 5/6 等效）。使用机器学习方法评估了每所学校的三年年平均颗粒物（PM）和二氧化氮（）。我们使用广义线性混合模型来估计绿化与普遍视力损害和视力水平之间的关联，并使用中介分析来探讨空气污染的潜在中介作用。
在调整后的模型中，与较高的绿色植被相比，每增加一个四分位间距的 与较低的普遍视力损害几率相关[比值比（OR）：0.93，95%置信区间（CI）：0.97]。同样，每增加一个四分位间距的 与左眼和右眼的视力水平分别增加 0.008（95%CI：0.007，0.015）和 0.015（95%CI：0.007，0.015）有关。我们的结果还表明，和 显著介导了与视觉障碍之间的关联。对于 和 ，我们也观察到了类似的效应估计值，并且我们的估计值在几项敏感性分析中基本稳健。
这些发现表明，学校周围较高的绿化水平可能会降低视力损害的风险，这可能部分归因于绿化区域中较低的 和 。需要进一步进行具有更精确绿化评估的纵向研究来证实这些发现。
