Air Pollution Increases Risk for Incident Atopic Dermatitis

Long-term exposure to air pollution may increase the risk for developing atopic dermatitis (AD), according to study findings published in the Journal of the American Academy of Dermatology.

This retrospective cohort study included an assessment of 209,168 people from Korea within the National Health Insurance Service–National Sample Cohort (NHIS-NSC) database who had not been diagnosed with AD from 2008 to 2013. Investigators calculated the long-term mean concentration of air pollutants before AD diagnosis for each individual. Specific pollutants measured in this study included ambient particulate matter (PM_2.5, PM₁₀) and gaseous air pollution (SO₂, NO₂, CO, and O₃).

A total of 3203 people in the overall study cohort developed AD. Significant associations were found in this population between incident AD and long-term average exposure to PM_2.5 (hazard ratio [HR], 1.420; 95% CI, 1.392-1.448), PM₁₀ (HR, 1.333; 95% CI, 1.325-1.341), SO₂ (HR, 1.626; 95% CI, 1.559-1.695), NO₂ (HR, 1.200; 95% CI, 1.187-1.212), and CO (HR, 1.005; 95% CI, 1.004-1.005).

In contrast, the investigators found a significant negative association between AD incidence and long-term average exposure to O₃ (HR, 0.814; 95% CI, 0.800-0.829).

The researchers found that long-term exposure to air pollutants above the average threshold concentrations of 24.78 for PM_2.5 and 48.93 μg/m³ for PM₁₀ were associated with the greatest increased risk for AD development.

A limitation of this study was the inability to adjust for exposure to other indoor air pollutants, such as benzene and toluene.

Although the biological mechanism underlying the association between air pollutant exposure and AD risk remains unclear, the study investigators suggest these “pollutants induce oxidative stress in the skin, leading to skin barrier dysfunction or immune dysregulation.”

Reference

Park SK, Kim JS, Seo HM. Exposure to air pollution and incidence of atopic dermatitis in the general population: A national population-based retrospective cohort study. Published online July 6, 2021. J Am Acad Dermatol. doi:10.1016/j.jaad.2021.05.061