Increased prevalence of vitamin D deficiency in patients with alopecia areata: a systematic review and meta-analysis

J Eur Acad Dermatol Venereol. 2018 Jul;32(7):1214-1221. doi: 10.1111/jdv.14987. Epub 2018 May 18.

Abstract

Background: Alopecia areata (AA) is a hair follicle-specific autoimmune disorder. Vitamin D deficiency has been associated with various autoimmune disorders for its immunomodulatory effects. However, in previous studies, there had been inconsistent association found between AA and vitamin D deficiency.

Objective: To demonstrate the differences of the mean serum 25-hydroxyvitamin D level and prevalence of vitamin D deficiency between AA patients and non-AA population.

Methods: A systematic review and meta-analysis of observational studies on AA and serum vitamin D levels and/or prevalence of vitamin D deficiency was performed searching MEDLINE, Cochrane, Web of Science and Google Scholar databases.

Results: In all, 14 studies including a total of 1255 AA subjects and 784 non-AA control were analysed. The mean serum 25-hydroxyvitamin D level was significantly lower in AA subjects (-8.52 ng/dL; 95% confidential interval; -5.50 to -11.53). The AA subjects had higher odds of vitamin D deficiency (odds ratio of 3.89; 2.02 to 7.49, mean prevalence of 73.8%; 59.1 to 84.6%). However, it was difficult to find clear correlation between serum 25-hydroxyvitamin D level and extent of hair loss in AA subjects.

Conclusion: The AA subjects had lower serum 25-hydroxyvitamin D level, and vitamin D deficiency was highly prevalent compared to non-AA controls. Hence, vitamin D deficiency should be assessed in AA patients. Furthermore, nutritional supplementation of vitamin D or topical vitamin D analogues can be considered for AA patients with vitamin D deficiency. The limitation of this study is the highly heterogeneity of the included studies.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Alopecia Areata / blood*
  • Alopecia Areata / epidemiology*
  • Humans
  • Observational Studies as Topic
  • Prevalence
  • Severity of Illness Index
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood*
  • Vitamin D Deficiency / epidemiology*

Substances

  • Vitamin D
  • 25-hydroxyvitamin D