Association of air pollution with incidence of late-onset seborrhoeic dermatitis: a prospective cohort study in UK Biobank

Abstract Background Late-onset seborrhoeic dermatitis seriously affects patients’ quality of life. Studies have shown an association between air pollution and other inflammatory skin diseases. However, associations between air pollution exposures and the incidence of late-onset seborrhoeic dermatitis have not been elucidated. Objectives To investigate air pollution’s role in the incidence of late-onset seborrhoeic dermatitis. Methods We engaged a prospective cohort analysis utilizing the UK Biobank database. Exposure data spanning various years for specific air pollutants, namely particulate matter [PM; with an aerodynamic diameter of ≤ 2.5 µm (PM2.5), between 2.5 and 10 μm (PM2.5–10), ≤ 10 μm (PM10)] along with nitrogen oxides (NO plus NO2, denoted NOx) and NO2, were incorporated. Through a composite air pollution score constructed from five pollutants and employing Cox proportional hazards models, the relationship between air pollution and seborrhoeic dermatitis was delineated. Results Our examination of 193 995 participants identified 3363 cases of seborrhoeic dermatitis. Higher concentrations of specific pollutants, particularly in the upper quartile (Q4), were significantly linked to an elevated risk of seborrhoeic dermatitis. Notably, PM2.5, PM10, NO2 and NOx exhibited hazard ratios of 1.11, 1.15, 1.22 and 1.15, respectively. The correlation was further solidified with a positive association between air pollution score increments and onset of seborrhoeic dermatitis. Intriguingly, this association was accentuated in certain demographics, including younger men, socioeconomically deprived people, smokers, daily alcohol consumers, and those engaging in regular physical activity. Conclusions Our findings revealed that air pollution exposures were associated with incidence of late-onset seborrhoeic dermatitis. These results emphasize the importance of preventing environmental air pollution exposures to mitigate the risk of developing the condition.