Association between temperature changes and uveitis onset in mainland China.

Background: Some uveitis subtypes show seasonal patterns. Whether these patterns are caused by seasonally varying temperatures or by other climatic factors remains unknown. This ecological research aimed to quantify the association between climate variability and uveitis onset.

Methods: We combined data from the largest database of uveitis cases with surface climate data to construct panel data. We used choropleth maps to visually assess spatial uveitis variations.

Results: Among 12 721 reports of uveitis originating from 31 provinces of mainland China from 2006 to 2017, we found that a 1°C increase in monthly temperature was associated with a rise in approximately 2 uveitis reports per 1000 individuals (95% CI 0.00059 to 0.0029). This association was present across all provinces, ranging in effect size from 0.0011 to 0.072 (95% CI 0.00037 to 0.10). A clear 0-3 months of cumulative lagging effect was noted across all types of uveitis, with the strongest effect for non-infectious uveitis (0.0067, 95% CI 0.0041 to 0.013). Stratified by age and sex, we found that men and people aged 20-50 years were more affected by temperature variations. Our model predicts that China might experience an increase in uveitis cases due to future global warming.

Conclusion: Our study is the largest-ever investigation of the association between uveitis and climate and, for the first time, provides evidence that rising temperature can affect large-scale uveitis onset. These results may help promote and implement policies to mitigate future temperature increases and the burden of disease caused by global warming.