Climate change and ocular health: temperature-pollution synergies amplify uveitis burden.

Background: Uveitis, an inflammatory eye disease, exhibits seasonal patterns, which suggest environmental influences. This study examines the link between average temperature and uveitis outpatient visits, considering air pollution's modifying effects.

Methods: We analyzed uveitis outpatient data ( = 8,090) from a major hospital in Shanghai between 2017 and 2023, along with meteorological and air pollutant data. A distributed lag non-linear model (DLNM) was used to assess the associations between temperature and outpatient visits, adjusting for humidity, pollutants, and temporal factors.

Results: A non-linear relationship exists between temperature and uveitis visits. Lower temperatures increased visits, with peak relative risk at -4°C lagged by 1 day (RR = 1.351, 95%CI: 1.069-1.706). Significant associations were found at lags 0-1 and 12-14, with the highest risk at lag 14 (-4°C, RR = 1.257, 95%CI: 1.113-1.420). Stratified analyses showed stronger associations in males and individuals under 60 years. High humidity and elevated PM levels strengthened the cold temperature association, while extremely high temperatures (33-34°C) increased visits under low humidity (RR = 2.625, 95%CI: 1.034-6.668 at 34°C).

Conclusion: Temperature extremes are linked to increased uveitis outpatient visits in Shanghai, particularly with cold temperatures in high-humidity and high-PM environments, and hot temperatures under low humidity.