Article summary by Wonder Edem | MD Candidate 2024 | University of California, Riverside School of Medicine
Vitamin D levels are important in regulating the growth of skin cells and hair follicles. A study completed by Conic et al. measured vitamin D levels in 358 patients with various types of hair loss seen at a specialist hair disorder center. The following types of alopecia were included: three non-scarring hair loss conditions – alopecia areata (AA), androgenic alopecia (AGA), telogen effluvium (TE); and two scarring hair disorders – central centrifugal scarring alopecia (CCCA), and lichen planopilaris (LPP). Vitamin D (25- hydroxyvitamin D) levels within 3 months from a new or recurring hair loss diagnosis were analyzed. In this study, vitamin D deficiency is defined as levels less than 30ng/mL and was categorized into mild (21-30 ng/mL), moderate (12-21 ng/mL) and severe (<12 ng/mL).
Out of all the patients with scarring and non-scarring alopecia, 65% were found to have vitamin D deficiency with 33% having mild, 18% with moderate, and 14% with severe deficiencies.
Among scarring hair loss conditions, LPP patients were found to have statistically 8.3 times higher odds of severe vitamin D deficiency (odds are the probability that the event e.g vitamin deficiency will occur compared to the chance that the event will not occur), in comparison to patients with AA.
Regarding difference in races, African Americans and Asians had 6.3 and 6.1 times greater odds of vitamin D deficiency respectively, compared to Caucasians.
These findings of vitamin D deficiency suggest a possible need for testing vitamin D levels in hair loss patients. Vitamin D changes the immune response and some studies have found autoimmune characteristics associated with it as well. Further research is needed for general guidance about vitamin D testing and supplements. While it is controversial, supplementation for people with vitamin D deficiency could be carefully considered depending on individual medical conditions and preference.
Note from writers: While this study did not make a direct comparison of vitamin D levels to the general population without hair loss disorders, vitamin D deficiency is relatively common. Approximately 42% of the U.S. population have vitamin D deficiency in research published in the National Institutes of Health database.1
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Reference: 1)Forrest KY, Stuhldreher WL. Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res. 2011 Jan;31(1):48-54. doi: 10.1016/j.nutres.2010.12.001. PMID: 21310306.