Increased Incidence of Thyroid Disease in Patients with Alopecia Areata: A Systematic Review and Meta-Analysis

Background: Alopecia areata (AA) is a common, clinically heterogeneous, immune-mediated, nonscarring hair loss disease with a pathogenesis that is not fully understood. The prevalence of thyroid disease is likely increased among individuals with AA. However, this association remains controversial. Objective: To evaluate the risk of thyroid disease in patients with AA. Methods: We performed a systematic review by searching both English and Chinese literature databases. Random- or fixed-effects models were used to summarize the association between thyroid disease and AA. Results: In total, 17 articles were included in this meta-analysis, with 2,850 AA cases and 4,667 controls. Overall, the prevalence of thyroid disease in patients with AA was significantly increased compared with that in controls (odds ratios 3.66, 95% confidence intervals 2.90-4.61). Conclusions: The results suggest that AA patients should be screened for thyroid disease.