Effect of vitamin D3 on self-perceived fatigue A double-blind randomized placebo-controlled trial

Background: Vitamin D deficiency is frequent and has been associated with fatigue in uncontrolled trials. Methods: This is the first double-blind placebo-controlled clinical trial to investigate the efficacy of per os vitamin D3 (cholecalciferol) in treating fatigue among otherwise healthy persons with low serum 25-hydroxyvitamin D (25(OH)D) levels. We enrolled 120 individuals (mean age 29 +/- 6 years, 53% women) presenting with fatigue and vitamin D deficiency (serum 25(OH)D < 20 mu g/L). Participants were randomized to a single oral dose of 100,000 units of vitamin D or placebo. The primary endpoint was intra-individual change in the fatigue assessment scale (FAS) at 4 weeks after treatment. Result: The mean age of the participants was 29 +/- 6 years, 53% were women. Mean FAS decreased significantly more in the vitamin D group (-3.3 +/- 5.3; 95% confidence interval [CI] for change -14.1 to 4.1) compared with placebo (-0.8 +/- 5.3; 95% CI for change -9.0 to 8.7); (P = 0.01). Amelioration of fatigue was reported more frequently in vitamin D than in placebo group (42 [72%] vs. 31 [50%]; P = 0.01; odds ratio [OR] 2.63, 95% CI for OR 1.23-5.62). Among all participants, improvement in fatigue score correlated with the rise in 25(OH) D level (R = -0.22, P = 0.02). Conclusion: Vitamin D treatment significantly improved fatigue in otherwise healthy persons with vitamin D deficiency. This study was registered at the www.ClinicalTrials.gov Protocol ID NCT02022475.