Air Pollution and Meteorological Conditions Significantly Associated With Vernal Keratoconjunctivitis Exacerbations.

Purpose: Vernal keratoconjunctivitis (VKC) is a severe chronic allergic inflammation of the ocular surface with episodes of acute exacerbations, that primarily affects children and young adults. Although the etiology and pathogenesis of VKC remain unclear, studies have suggested that environmental factors may be involved. This study aims to investigate the association between exposure to meteorological and environmental factors and the incidence of VKC exacerbations. Methods: This study was conducted in southern Israel, which is a semi-arid, hot, and dry climate with frequent dust storms. Patients diagnosed with VKC were recruited for the study. VKC exacerbations were identified as the need for medical intervention. Pollutants measured included nitrogen dioxide (NO2), ozone (O3), particulate matter (PM10 and PM2.5), sulfur dioxide (SO2), relative humidity (RH), temperature, and solar radiation (SR). To assess the association between VKC exacerbations and exposure to different pollutants, a case-crossover analysis was conducted. We also stratified the analysis by sex, age, ethnicity, immigration status, and social state score. Results: Our results demonstrated that the pollutants NO2, O3, and PM10 were associated with VKC exacerbations with odds ratio (OR) = 2.17 (95% confidence interval [CI] =1.40 to 3.04), OR = 2.28 (95% CI = 1.30 to 3.39), and OR = 1.89 (95% CI = 1.06 to 2.74). Other pollutants PM2.5, temperature, and solar radiation were also independently associated with incidence of exacerbations with OR = 1.15 (95% CI = 0.87 to 1.50), OR = 1.75 (95% CI = 1.16 to 2.65), and OR = 1.37 (95% CI = 1.01 to 1.63) and had varying effects in different demographic strata. Conclusions: The environmental parameters, NO2, O3, PM10, PM2.5, temperature, and solar radiation were found to be significantly associated with VKC exacerbations, with NO2, O3, and PM10 showing the strongest associations. Our findings suggest that environmental factors should be considered when developing strategies to prevent and manage VKC exacerbations.