Date of Award

January 2024

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Jeffrey M. Cohen


A chronic inflammatory skin disease characterized by disruption of the epidermal barrier, eczema has increased in prevalence in tandem with industrialization. Ambient air pollution is a ubiquitous exposure resulting from industrial processes that includes fine particulate matter with aerodynamic diameter measuring less than 2.5 µm (PM2.5). Studies on the potential association between PM2.5 and eczema have produced conflicting results. The objective of this study was to determine the risk of eczema with exposure to PM2.5 in a diverse national cohort of American adults.

In this cross-sectional study, eczema cases were identified via electronic health records (EHR) in the All of Us Research Program and linked via three-digit zip code to average annual PM2.5 concentrations from the Center for Air, Climate, and Energy Solutions. Eczema diagnostic codes included SNOMED-43116000; ICD-10-CM L20, L30.0, and L30.1; and ICD-9-CM 691and 705.81; and excluded SNOMED-88996004 and ICD-9-CM 697 and 698.3. Eczema cases and controls were compared using Pearson’s χ2 test for categorical variables and one-way analysis of variance for continuous variables. Therelationship between PM2.5 and eczema was assessed via logistic regression adjusting for demographic factors, smoking, and atopic comorbidities.

Among 286,826 participants in All of Us with EHR and zip code data available, 12,695 were diagnosed with eczema (mean age, 58.45; standard deviation 16.80) and 274,127 were not diagnosed with eczema (mean age, 54.85; standard deviation 16.95). Individuals with eczema lived in areas with significantly higher PM2.5 concentrations than did individuals without eczema (0.83 x 10 µg/m3 v. 0.81 x 10 µg/m3, P < .001). PM2.5 concentration was significantly associated with eczema in univariable analysis (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.77-2.19, P < .001), as well as in multivariable analysis controlling for demographics and smoking status (OR 2.21, 95% CI 1.98-2.47, P < .001) and with the addition of atopic comorbidities (OR 2.37, 95% CI 2.12-2.66, P < .001).

Eczema was positively associated with PM2.5 concentration in this large, diverse, adult American cohort. This contributes to the increasing evidence that ambient air pollution is an environmental hazard that influences inflammatory skin disease.


This thesis is restricted to Yale network users only. It will be made publicly available on 04/30/2025