Living near a major road with heavy vehicular traffic increases the risk of developing atopic dermatitis and the risk declined as the distance increased, according to a new study presented at the 2023 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI), which concluded yesterday in San Antonio, Texas.^1,2

In this study from the United States, researchers analysed data of atopic dermatitis patients, aged 0-18 years, being treated at a major respiratory hospital in Denver, Colorado. For this they selected 7384 patients and compared them to 7241 age- and sex-matched individuals without atopic dermatitis, who acted as controls. The distance of their residences from a major road, which had an annual daily traffic of more than 10,000 vehicles, was calculated. The objective of the study was to determine if exposure to traffic-related air pollution had an impact on atopic dermatitis (AD) in both urban and rural areas.

Retrospective analysis of 13 years of medical records of patients with atopic dermatitis showed that for every factor 10 increase in distance from a major road, the risk of atopic dermatitis decreased by 18.8%. Patients who resided more than one km from the nearest major road were as much as 26% less likely to have atopic dermatitis compared to patients who lived within 500 m from the nearest major road.

While association between asthma and air pollution has been well established, there is not much evidence linking air pollution and atopic dermatitis. The findings of this study add to the growing evidence about the association between air quality and pathogenesis of various diseases. However, this study only shows an association and does not conclusively suggest causation. “This is an early association study, so more work needs to be done to examine the pathophysiological mechanisms involved in the association,” Michael Nevid, the study lead author. Clinicians therefore should be aware of the association of atopic dermatitis with proximity to major roads and carefully and regularly screen their at-risk patients. The subclinical systemic inflammation induced by the air pollutants is hypothesized to play a role in the pathogenesis.

References

1. Nevid M, et al. Association of atopic dermatitis with proximity to major roads. J Allergy Clin Immunol. 2023 Feb.;151(2 Suppl): AB193. DOI:https://doi.org/10.1016/j.jaci.2022.12.604.
2. AAAAI Press release. Available at: https://www.aaaai.org/About/News/News/2023/road. February 3, 2023. Accessed on Feb. 27, 2023.