The prevalence of thyroid disease in patients with vitiligo: a systematic review

Background Thyroid disease has been suggested to be associated with vitiligo. However, the outcomes of prevalence studies on thyroid disease in vitiligo vary widely. Objectives To summarize and critically appraise current evidence of the prevalence of thyroid diseases in vitiligo. Methods A systematic review was performed searching the electronic databases OVID MEDLINE, OVID EMBASE and PubMed. Guidelines for the critical appraisal of studies on prevalence of a health problem were adapted to evaluate the methodological quality of the included studies. Results were analysed in a meta-analysis with a risk ratio (RR). Results Forty-eight studies published between 1968 and 2012 met the inclusion criteria. Most of the studies (50%) were of fair methodological quality, whereas 18 studies (38%) were of poor quality and six studies (12%) were of good quality. Thyroid disease, autoimmune thyroid disease and presence of thyroid-specific autoantibodies showed a mean prevalence of, respectively, 15.1%, 14.3% and 20.8% in patients with vitiligo and an RR of, respectively, 1.9, 2.5 and 5.2 (all statistically significant). This review shows an increased prevalence and an increased risk of (autoimmune) thyroid disease in patients with vitiligo compared with nonvitiligo. This risk seems to increase with age. Conclusions Clinicians should be aware of this increased risk in patients with vitiligo and should be attentive for symptoms of thyroid disease. To make recommendations on screening for thyroid disease in patients with vitiligo future research of good methodological quality, including differentiation of vitiligo types and the use of standardized outcome measures, is needed.