Vitiligo and overt thyroid diseases: A nationwide population-based study in Korea

BackgroundAssociations between vitiligo and thyroid diseases have been reported repeatedly.ObjectiveWe investigated the associations between vitiligo and overt autoimmune thyroid diseases and thyroid cancer using the Korean National Health Insurance claims database.MethodsWe defined patients with vitiligo as those whose records showed ≥4 physician contacts between 2009 and 2013 in which vitiligo was the principal diagnosis. We also established an age- and sex-matched control group without vitiligo (2 per 1 vitiligo patient). The outcomes of interest were concurrent Graves disease and Hashimoto thyroiditis (the patients were taking relevant thyroid medications) and thyroid cancer.ResultsThe study enrolled 73,336 vitiligo patients and 146,672 controls. Patients with vitiligo were at increased risks of Graves disease (odds ratio [OR] 2.610 [95% confidence interval {CI} 2.319-02.938]), Hashimoto thyroiditis (OR 1.609 [95% CI 1.437-1.802]), and thyroid cancer (OR 1.127 [95% CI 1.022-1.242]), compared with the controls. The associations were consistently stronger in males and younger patients.LimitationsIndividual clinical information was not available, and the homogeneous population may limit the generalizability of the results.ConclusionVitiligo was significantly associated with overt autoimmune thyroid diseases and overt thyroid cancer.