Scientists conducted a prospective nested case-control study among women in the Finnish Maternity Cohort (FMC) to determine whether and to what extent vitamin D deficiency is associated with multiple sclerosis (MS).
The study, “25-Hydroxyvitamin D deficiency and risk of MS among women in the Finnish Maternity Cohort”, was published by the American Academy of Neurology in the journal Neurology.
The FMC has 1.8 million stored serum samples, which were taken during the pregnancies of more than 800,000 women at the time of the study. Through linkages with hospital and prescription registries, the team identified 1,092 women with MS diagnosed between 1983 and 2009 with at least one serum sample collected prior to date of MS diagnosis. Three controls were used to match each patient according to geographic residence and age.
According to the Office of Dietary Supplements (ODS), levels of vitamin D are measured by the 25-hydroxy level in nanomoles/liter (nmol/L) or nanograms/milliliter (ng/mL). Levels less than 30 nmol/L indicate a deficiency. Normal levels are between 50 and 125 nmol/L.
The results showed there was a 39% reduced risk of MS when levels of 25-Hydroxyvitamin D were increased to 50 nmol/L. In comparison, women having less than 30 nmol/L had a 43% higher MS risk. In women with two or more samples, MS risk was 2-fold higher when having less than 30 nmol/L 25-Hydroxyvitamin D when compared to women taking equal to or more than 50 nmol/L 25-Hydroxyvitamin D.
The scientists concluded that the results directly support vitamin D deficiency as a risk factor for MS and strengthens the rationale for broad public health interventions to improve vitamin D levels.