Background
Vitamin D insufficiency is a risk factor for MS, and patients don’t always show the expected response to vitamin D supplementation.
Objective
To determine if vitamin D supplementation leads to a similar increase in serum 25-hydroxyvitamin-D (25(OH)D) levels in MS patients and healthy controls (HCs).
Methods
Participants in this open-label study were female, white, aged 18–60 years, had 25(OH)D levels ≤ 75 nmol/L at screening, and had RRMS or were HCs. Participants received 5,000 IU/day of vitamin D3 for 90 days. Utilizing generalized estimating equations we examined the relationship between the primary outcome (serum 25(OH)D level) and the primary (MS versus HC status) and secondary predictors.
Results
27 MS patients and 30 HCs were enrolled. There was no significant difference in baseline 25(OH)D level or demographics except for higher body mass index (BMI) in the MS group (25.3 vs 23.6 kg/m2, p=0.035). 24 MS subjects and 29 HCs completed the study. In a multivariate model accounting for BMI, medication adherence, and oral contraceptive use, MS patients had a 16.7 nmol/L (95%CI: 4.2, 29.2, p=0.008) lower increase in 25(OH)D levels compared to HCs.
Conclusions
MS patients had a lower increase in 25(OH)D levels with supplementation, even after accounting for putative confounders.