Risk of thyroid cancer among patients with vitiligo: A systematic review and meta-analysis

Background: Whether patients with vitiligo have an increased risk of thyroid cancer remained controversial. Objectives: To study the risk of developing thyroid cancer among vitiligo patients using meta-analysis. Methods: This meta-analysis was performed via a literature review of four databases (Web of Science, Embase, PubMed, and Cochrane Library) from their respective inception till February 17, 2023. Relevant reviews and the bibliographies of eligible studies were also scrutinized. During searching in databases, no filter was placed regarding the language or geography of the study. Only observational studies presenting with adjusted risk estimates were eligible for meta-analysis. The random-effects model was employed for performing this meta-analysis. Results: Four studies with 200,629 vitiligo patients and 404,124 nonvitiligo controls were included in this meta-analysis, and patients with vitiligo were found to have an elevated risk of thyroid cancer (pooled relative risk, 1.341; 95% confidence interval, 1.083-1.661). Conclusion: Our systematic review and meta-analysis found that vitiligo patients are at a slightly elevated risk of thyroid cancer, although the exact underlying mechanisms remain unclear. Even though the evidence is limited, clinicians should not ignore the possible susceptibility of developing thyroid malignancy among vitiligo patients.