# Association of Air Pollution Exposure with Incident Cataract Surgery and Neovascular Age-Related Macular Degeneration in 2 French Nationwide Cohorts

## TL;DR

This study finds that air pollution, especially in urban areas, is linked to a higher risk of cataract surgery and a type of macular degeneration.

## Contribution

The study reveals distinct effects of air pollution on eye diseases in urban versus rural populations in France.

## Key findings

- Urban participants exposed to high NO2 levels had an 8% higher risk of cataract surgery.
- High BC exposure in the Constances cohort was linked to an 88% increased risk of nAMD.
- No significant association was found between BC and nAMD in the combined population.

## Abstract

Age-related macular degeneration (AMD) and cataracts are part of the leading causes of blindness globally, with oxidative stress being a key factor in their development. Air pollution, known to exacerbate oxidative stress, may contribute to the progression of these diseases. This study aims at investigating the association between ambient air pollution exposure and the incidence of cataract surgery and neovascular AMD (nAMD).

Two nationwide prospective French cohorts.

The study involved 36 140 participants, including 17 911 Electricité de France-Gaz de France employees from the Gazel cohort and 18 229 individuals from the general French population in the Constances cohort, all aged over 53 years at inclusion and followed up for 10 years.

Cataract surgery and nAMD cases were identified using the French National Health Data System (SNDS), which provided medical procedures and prescriptions. Air pollution exposure to nitrogen dioxide (NO2), fine particulate matter, and black carbon (BC) were estimated using land-use regression models. Cox proportional hazards models adjusted for age, sex, and education were used to assess associations. Analyses were stratified by area of residence (urban vs. rural), because of significant interactions.

Neovascular AMD was identified through intravitreal anti-VEGF injections, and cataract surgery by the first surgery date, both extracted from SNDS data.

Among the 36 140 participants included (39% women, mean age 60.2 years), 5543 incident cataract surgery and 266 nAMD cases were identified. In the combined Constances and Gazel populations, urban individuals exposed to more than 34.8 μg/m3 of NO2 had an 8% higher risk of cataract surgery (HR = 1.08, 95% confidence interval [CI]: 1.01–1.16, P = 0.017), while no significant effect was observed among rural participants. Additionally, in the Constances cohort, participants exposed to the fourth quartile (≥2.33 10-5/m) of BC had an 88% increased risk of nAMD compared to those exposed to the first quartile (HR = 1.88, 95% CI: 1.03–3.45, P = 0.041). No significant association with BC was observed in the combined Constances and Gazel populations.

This study provides new insights into the impact of air pollution on ocular aging at a national level, highlighting the distinct effects observed between urban and rural populations.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.