Vitamin D Deficiency in Patients With Alopecia Areata: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis investigated the association between vitamin D deficiency and alopecia areata (AA), an autoimmune disease causing hair loss. The study included 11 studies with 456 patients with AA, revealing that these patients had a significantly higher prevalence of 25-hydroxyvitamin D deficiency and lower vitamin D levels compared to controls. Specifically, the odds ratio for vitamin D deficiency in AA patients was 4.86, and the standardized mean difference in vitamin D levels was -1.08. The findings suggested a potential link between vitamin D deficiency and AA, highlighting the need for further research to explore the mechanisms and potential benefits of vitamin D supplementation in treating AA. However, the study noted limitations due to heterogeneity in baseline characteristics and lack of detailed data on disease patterns and severity.