Vitamin D deficiency represents a significant risk factor for multiple sclerosis (MS), necessitating the need for greater public outreach and interventions to improve vitamin D levels in the population, according to a case-control study published in Neurology.
Investigators performed a prospective nested case-control study using patient data from the Finnish Maternity Cohort, in which approximately 1.8 million serum samples from 800,000 women were recorded. The researchers included 1092 women with MS who had at least 1 serum sample taken prior to their diagnosis. In 511 subjects, ≥2 samples were collected, and 3 controls (n=2123) were used to match each patient according to geographic residence and age.
There was a 39% reduced risk for MS when levels of 25-hydroxyvitamin D (25[OH]D) increased 50 nmol/L (relative risk [RR] 0.61; 95% CI, 0.44-0.85; P =.003). A 25(OH)D level <30 nmol/L was associated with a 43% greater risk for MS compared with levels that were ≥50 nmol/L (RR 1.43; 95% CI, 1.02-1.99, P =.04). In addition, a 25(OH)D level of <30 nmol/L vs ≥50 nmol/L was associated with a 2-fold greater risk for MS in women who had ≥2 serum samples (RR 2.02; 95% CI, 1.18-3.45, P =.01).
This study failed to adjust for MS risk factors such as body mass index, smoking, or the presence of the Epstein-Barr virus infection, which might have limited the findings. In addition, the Finnish Maternity Cohort included primarily white subjects, which may reduce the findings’ applicability to other races.
According to the investigators, “Our findings suggest that correcting vitamin D deficiency among reproductive age women may reduce their future risk of developing MS,” and that this risk “could be reduced by broad population-based programs to prevent vitamin D deficiency.”
Munger KL, Hongell K, Åivo J, et al. 25-hydroxyvitamin D deficiency and risk of MS among women in the Finnish Maternity Cohort [published online September 13, 2017]. Neurology. doi:10.1212/WNL.0000000000004489