Impact of Ambient Air Pollution on Reduced Visual Acuity Among Children and Adolescents

Previous studies have assessed the impact of air pollution on myopia from the individual level, while none of them have explored the role of air pollution in visual health disparities between different regions from the area level. This ecological study aimed to investigate the impact of ambient air pollution on reduced visual acuity (VA).

The data were derived from the Chinese National Survey on Students' Constitution and Health (CNSSCH) conducted in 2014 and 2019, which involved 261,833 and 267,106 students respectively. The participants were 7-22 years old randomly selected from 30 mainland provinces in China. Locally weighted scatterplot smoothing (LOESS) regression models and fixed-effects panel regression models were used to explore the associations of provincial-level prevalence of reduced VA with air quality index (AQI), fine particulate matter ;(PM2.5), PM10, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) concentrations.

There were nearly linear positive dose-response relationships between AQI, air pollutant concentrations and the prevalence of reduced VA. After adjusting for covariates, an interquartile range increase in PM2.5 exposure was significantly associated with a 5.0% (95% confidence interval, 0.7%-9.3%) increase in the prevalence of reduced VA, whereas no significant associations were observed between AQI, the other five pollutants and the prevalence of reduced VA.

Regions with more polluted air tend to have a higher prevalence of reduced VA. Exposure to PM2.5 might be an important risk factor for myopia among children and adolescents.