Association Between Air Pollution and Incidence of Psoriasis: A Nationwide Population-based Case-control Study

Abstract

Abstract Background Air pollutants may aggravate psoriasis. However, the association between air pollution and psoriasis incidence remains unclear. We aimed to identify the association between air pollution and psoriasis incidence.Methods This case-control study included patients with psoriasis and age-, sex-, urbanization level-, index date-, and comorbidities-matched controls from the National Health Insurance Research Database in Taiwan from January 1, 2012, to December 31, 2018. Exposure to air pollutants (sulfur dioxide, carbon monoxide, ozone, coarse particulate matter [PM10], fine particulate matter [PM2.5], and nitrogen dioxide [NO2]) was analyzed in the 5 years preceding psoriasis diagnosis and in controls.Results Overall, 45,093 patients with psoriasis and 180,372 controls were included. After adjusting for age, sex, urbanization level, index date, and comorbidities, our conditional logistic models showed that exposure to PM10 and PM2.5 was associated with a slightly increased psoriasis incidence. Estimating the effects of different air pollutants simultaneously, the adjustment model showed that PM10, PM2.5, and NO2 were associated with a slight increase in psoriasis incidence.Conclusion Although exposure to certain PM10, PM2.5, and NO2 levels was significantly associated with incident psoriasis, the increased risks were trivial, with no dose-response relationship.