Supplementary Material for: Management and Genetics of Alopecia Areata Within the United States: A Cross-sectional Study of All of Us

Introduction: Alopecia areata (AA) is a difficult to treat and appearance altering disorder affecting up to 2% of people during their lifetime. Understanding current management trends will help in improving patient outcomes. The aim of this study was to determine the impact of comorbid disorders and demographic factors on the management of alopecia areata and determine the influence of previously discovered genetic factors in different ethnic groups. Methods: We used the All of Us controlled dataset (version 7) and examined electronic health record and genomic data from 206,173 participants in a retrospective cross-sectional study conducted in outpatients in the USA. Results: We found that AA patients with comorbid atopic dermatitis, psoriasis and vitiligo were more likely to have been prescribed topical corticosteroids. Patients that were not of European/Caucasian ancestry were less likely to be prescribed any type of corticosteroid. We also found that specific genetic variations (single nucleotide polymorphisms) that increased or decreased risk in European/Caucasian participants did not necessarily have the same effect in other ethnicities (Hispanics and Blacks). Conclusion: This work has helped to uncover the state of alopecia areata care within the United States and has identified access to healthcare inequities in different ethnic populations.