Greater exposure to PM_2.5 and PM₁₀ is associated with a higher BAD score: the Maastricht study

To investigate the associations between exposure to ambient air pollutants and the Belin/Ambrosio Enhanced Ectasia score (BAD score), a tomographic parameter for identifying corneas at risk for ectasia. This prospective cross-sectional study uses data from the Maastricht Study, a population-based cohort of adults aged 40-75 years living in and around Maastricht, the Netherlands. Participants underwent corneal tomography with a Pentacam HR. The BADD score was used to assess keratoconus risk. The annual average concentrations of air pollutants-PM2.5, PM10, nitrogen dioxide (NO₂), and soot-from the Geoscience and Health Cohort Consortium (GECCO) were used. Associations between standardized Z-scores of air pollutants and the BADD score were analysed via multiple linear regression models, adjusting for potential confounders, including age, sex, education, glucose metabolism status, smoking, and alcohol consumption. Data from 6343 eyes were included. Higher concentrations of PM2.5, PM10, and soot were significantly associated with higher BADD scores, indicating an increased risk of keratoconus [PM2.5: β = 0.03, 95% CI: 0.01-0.05; PM10: β = 0.03, 95% CI: 0.01-0.05; soot: β = 0.03, 95% CI: 0.00-0.04]. No significant association was found for NO₂ [stβ (95% CI): NO2 0.01 (-0.02; 0.03)] (p = 0.609). We found a significant influence of type 2 diabetes on the associations between PM2.5 or PM10 and the BADD score (p = 0.037 and p = 0.041, respectively). Our study revealed that exposure to relatively high levels of PM2.5, PM10, and soot are associated with relatively high BADD scores. Our results support the following hypotheses: air pollution is a risk factor for keratoconus, and T2DM may have a potential protective effect on the development of keratoconus.