Association Between Serum Trace Elements Level and Alopecia Areata: A Systematic Review and Meta-Analysis.

BACKGROUND: Alopecia areata (AA) is a prevalent autoimmune disorder in dermatology, impacting 0.5%-2% of the general population worldwide. More and more scholars are focusing on the important role of micronutrients in the occurrence and development of AA. AIMS: This research aimed to thoroughly and systematically assess the relationship between serum trace element levels and AA. METHODS: The PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched up to May 12, 2024. Two researchers independently screened and identified eligible studies. Depending on the heterogeneity assessed by the I2 statistic, either a random-effects model or a fixed-effects model was used to combine the effect estimates. RESULTS: 34 papers, including 4931 participants from 16 countries, were analyzed. The results of meta-analysis demonstrated patients with AA had a lower serum level of vitamin D (SMD = -0.93 ng/mL, 95% CI = 0.168-0.747, p < 0.05) and serum zinc (SMD = -0.69 μg/dL, 95% CI = -0.99 to -0.39, p < 0.05) than the healthy controls. Vitamin D deficiency was strongly associated to an elevated risk of AA (OR = 2.48, 95% CI = 1.47-4.17, p < 0.05). However, there is no significant difference in serum copper levels between AA patients and the control group. CONCLUSIONS: Our research provided evidence that the levels of serum VD and zinc were associated with the risk of AA. Supplementation with VD and zinc may become a potential treatment for AA.