Genetic evidence supports the causal effects of exposure to ambient air pollution on autoimmune eye diseases

Previous observational studies have reported inconsistent associations between air pollution and autoimmune eye diseases (AEDs). The primary objective of this Mendelian randomization (MR) study was to investigate the causal link of air pollution with AEDs risk. The instrumental variables were selected based on genome-wide association study data. Univariable and multivariable MR analyses were conducted to disentangle the causality of air pollutants with AEDs. The estimates of univariable MR analysis revealed a suggestively causal link between NO2 or NOx exposure and diabetic retinopathy (OR=1.29, 95% CI=1.05-1.58, P=0.015; OR=1.33, 95% CI=1.05-1.69, P=0.019, respectively). A suggestive association was observed between PM2.5 exposure and age-related macular degeneration (OR=1.46, 95% CI=1.09-1.97, P=0.013). In addition, multivariable MR indicated that the observed association was remained consistent and robust. Rigorous sensitivity analyses confirmed the robustness and consistency of these findings. Our study firstly provided the genetic evidence linking air pollution, specially NO2, NOx and PM2.5, to AEDs susceptibility.