Long-Term Exposure to Ambient PM2.5 and Age-Related Cataracts among Chinese Middle-Aged and Older Adults: Evidence from Two National Cohort Studies

Cataract is one key cause of visual disability and blindness. Ambient particulate matter is more likely to increase cataract risk due to eye continuous exposure to the environment. However, less is known about whether long-term exposure to particulate matter 2.5 (PM_2.5) is related to age-related cataracts. We conducted a population-based study among 22,298 adults from two multicenter cohort studies [China Family Panel Studies (CFPS) and Chinese Longitudinal Healthy Longevity Survey (CLHLS)]. The associations between PM_2.5 and age-related cataracts were analyzed by Cox proportional hazard regression models, which were also stratified according to demographic characteristics. The restricted cubic spline (RCS) model was used to explore the dose-response relationships between PM_2.5 and age-related cataracts. The population attributable fraction (PAF) was calculated to assess the burden of age-related cataracts that can be attributed to PM_2.5. In the final analysis, 1897 participants reported age-related cataracts during follow-up. Long-term exposure to PM_2.5 was associated with age-related cataracts, with HRs of 1.165 (1.130, 1.201), 1.138 (1.103, 1.173), and 1.091 (1.057, 1.126) for per 10 μg/m³ increase at one-, two-, and three-year before the end of follow-up, respectively. Furthermore, associations between PM_2.5 and age-related cataracts were also demonstrated in RCS models. The PAF of age-related cataracts to PM_2.5 in the total participants was 24.63%. Our research found that long-term exposure to PM_2.5 may increase the risk of age-related cataracts, and age-related cataracts should be considered as an important public health issue due to air pollution.