MS Risk Linked to Mothers with Vitamin D Deficiency in First Trimester of Pregnancy

Children whose mothers were vitamin D deficient during the early stages of pregnancy are at an elevated risk for developing multiple sclerosis (MS) in adulthood, according to a study published in the journal JAMA Neurology, titled “Vitamin D Status During Pregnancy and Risk of Multiple Sclerosis in Offspring of Women in the Finnish Maternity Cohort.”

Inadequate vitamin D nutrition has been identified as a risk factor for MS, a progressive, neurodegenerative disease of the central nervous system. Evidence from studies has shown that elevated serum levels of 25-hydroxyvitamin D (25[OH]D), a marker of vitamin D nutrition, in healthy adults is associated with a decreased MS risk. Other studies, however, have suggested that in utero vitamin D exposure may be a risk factor for MS in adulthood.

To examine whether serum 25[OH]D levels in early pregnancy (first trimester) are associated with a child’s risk of developing MS later in life, Kassandra L. Munger, ScD, at the Harvard T.H. Chan School of Public Health, Boston, and colleagues conducted a prospective, nested case-control study. They identified 193 people diagnosed with MS, whose mothers were in the Finnish Maternity Cohort and had an available serum sample taken at the time of their pregnancy with the affected child. The researchers matched 176 cases with 326 controls, date of child’s birth, date of mother’s birth, and date of collection of maternal serum samples.

Results revealed a 90 percent higher risk of MS as an adult in children whose mothers were considered vitamin-D deficient (25[OH]D levels less than 12.02 ng/mL), compared with children whose mothers were not vitamin-D deficient. These results indicated that insufficient maternal 25[OH]D during pregnancy may increase the risk of MS in the offspring.

The researchers mentioned a few limitations in their study, including that the levels of maternal 25[OH]D during pregnancy are not a straight measure of the levels to which the fetus is exposed.

According to a press release, the research team concluded “while our results suggest that vitamin D deficiency during pregnancy increases MS risk in the offspring, our study does not provide any information as to whether there is a dose-response effect with increasing levels of 25(OH)D sufficiency. Similar studies in populations with a wider distribution of 25(OH)D are needed.”

“The study was made possible by biobanking efforts in Finland as part of the Finnish Maternity Cohort (FMC). … When the FMC was established, it was not intended to create a resource for MS research, but its existence has created a powerful tool for understanding complex biology and disease,” wrote Benjamin M. Greenberg, MD, MHS, of the University of Texas Southwestern, Dallas, in a related editorial.