Atopic dermatitis is negatively associated with thyroid disorders among adults in Korean NHANES 2010-2023

Summary: A previous study using data from the US National Health and Nutrition Examination Survey (NHANES) reported a positive association between atopic dermatitis (AD) and thyroid disease. The purpose of this study was to replicate those findings using analogous data from the Korean NHANES (K-NHANES). We analyzed data from 45,831 adults aged 20-59 from the nationally representative K-NHANES dataset from 2010-2023. The exposure of interest was self-report of ever having AD, and the outcome of interest was selfreport of ever having thyroid disease. We used logistic regression to calculate odds ratios (OR), accounted for survey weights, and adjusted for age, sex, educational attainment, income, smoking status, diabetes, and body mass index. Contrary to previous literature, atopic dermatitis was overall found to be inversely associated with thyroid disease (adjusted OR: 0.46, 95%CI: 0.27-0.79). Stratified analysis by age showed a consistent inverse association among adults aged 20-39 (adjusted OR: 0.30, 95%CI: 0.14-0.68), but not among adults aged 40-59 (adjusted OR: 0.85, 95%CI: 0.41-1.77). There was also a consistent inverse association among females (adjusted OR: 0.46, 95%CI: 0.25-0.82), but not among males (adjusted OR: 0.52, 95%CI: 0.15-1.81). A closer review of NHANES survey wording revealed that while the Korean version specifically addresses AD, certain waves of the US version are not as specific, potentially impacting conclusions drawn about AD from the US data. Our findings highlight the importance of replication in different populations to assess the generalizability of conclusions from national cross-sectional surveys. Furthermore, using objective data on thyroid hormone levels and thyroid peroxidase autoantibody titers from the survey respondents, our future research will examine whether variations in screening and treatment practices or whether differences in Th1/Th17- vs Th2-predominant disease processes may explain these inverse associations. Richard Liang¹, Ryan M. Park², Gordon H. Bae³, Albert S. Chiou³, Jinwoo Lee³ 1. Epidemiology & Population Health, Stanford Medicine, Stanford, CA, United States. 2. Genetics, Stanford Medicine, Stanford, CA, United States. 3. Dermatology, Stanford Medicine, Stanford, CA, United States. Clinical Research: Epidemiology and Observational Research