Dissertation_UdS_Brand

The dissertation conducted a systematic review and meta-analysis of observational studies to explore the relationship between Vitamin D status and Alopecia areata, an autoimmune disease causing hair loss. The analysis included 18 case-control studies and found that patients with Alopecia areata had, on average, a 9.3 ng/ml lower 25-Hydroxyvitamin-D serum level compared to controls, with a significantly higher risk of having serum levels below 20 ng/ml and 30 ng/ml. Despite the relatively high quality of the studies, the heterogeneity and small sample sizes were limitations. The evidence level was rated as 3b, indicating that while there is an association between Vitamin D deficiency and Alopecia areata, causality cannot be confirmed. Future large-scale, prospective, interventional studies are needed to establish a causal link.