Atopic dermatitis (AD) is more common among African American children. Whether there are racial/ethnic difference among adults with AD and the causes for those disparities are unclear. We sought to examine the relationship between self-reported race/ethnicity and AD and determine whether African genetic ancestry is predictive of these outcomes among African American subjects. We analyzed data from 2 independent multiethnic longitudinal studies: 86,893 subjects aged 18 to 100 years from the Kaiser Permanente Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort and 5467 subjects aged 2 to 26 years from the national Pediatric Eczema Elective Registry (PEER) cohort. The primary outcomes were physician-diagnosed AD in GERA and repeated measures of self-reported disease control among patients with physician-diagnosed AD at 6-month intervals in PEER. We examined whether self-identified African American race/ethnicity was predictive of these outcomes and then tested whether a continuous measure of African genetic ancestry was associated with outcomes within the African American group. AD was more common among self-identified African American subjects than non-Hispanic white subjects in GERA (4.4% vs 2.1%; odds ratio, 2.06; 95% CI, 1.70-2.48) and less well-controlled in PEER subjects (odds of 1-level worse control, 1.91; 95% CI, 1.64-2.22). However, African genetic ancestry was not associated with AD risk or control among self-identified African American subjects in either cohort, nor did an AD polygenic risk score or genetic skin pigment score explain the AD disparities in patients with AD. Ancestry-related genetic effects do not explain increased AD prevalence or poorer disease control among African American subjects.
Genetic ancestry does not explain increased atopic dermatitis susceptibility or worse disease control among African American subjects in 2 large US cohorts
Authors: Abuabara K; You Y; Margolis DJ; Hoffmann TJ; Risch N; Jorgenson E
J Allergy Clin Immunol. 2020 01;145(1):192-198.e11. Epub 2019-07-29.