Can Maternal Vitamin D Level Increase MS Risk in Offspring?

Maternal vitamin D deficiency during pregnancy may be linked to a greater risk of multiple sclerosis (MS) in children, according to a study published in JAMA Neurology.

“There is growing evidence that exposures in early life may be associated with future MS risk. Studies looking at vitamin D status during pregnancy or early-life and risk of MS in the offspring have been mixed,” study author Kassandra Munger, ScD, of the Department of Nutrition at Harvard T.H. Chan School of Public Health in Boston, told Neurology Advisor.

Prospective studies have previously linked higher dietary intake of vitamin D with a lower risk of MS. However, there is little understanding of any potential relationship to maternal vitamin D levels and risk for MS in offspring.

Using data from the Finnish Maternal Cohort (FMC), Dr Munger and colleagues conducted a prospective, nested case study of patients with MS. Participants included those whose mothers had participated in the cohort study and had serum samples during pregnancy. The FMC included over 800,000 women with serum samples obtained at 10 to 14-weeks of pregnancy. In total, 176 offspring with MS were matched to 326 controls based on region, date of maternal sample, mother’s birth date, and participant’s birth date.

Children of mothers with 25(OH)D levels in quintiles 1 and 2 (12.62 ng/mL) had a 20% to 90% increased risk of MS compared to those with maternal 25(OH)D levels in the upper quintile (P trend=.09). Likewise, multivariate analysis found a nearly 2-fold increase in MS risk in children of mothers with 25(OH)D deficiency (12.02 ng/mL vs 12.02 to 20.03 ng/mL; RR: 1.90; 95% CI: 1.20-3.01; P=.006).

Unmatched analysis revealed a 43% reduction in MS risk for every 4.01 mg/mL increase in the mother’s 25(OH)D level (RR: 0.57; 95% CI: 0.28-1.18; P=.13). Further, vitamin D deficiency during pregnancy was associated with a 59% increased risk of MS in offspring in unmatched analysis (12.02 ng/mL vs 12.02 to 20.03 ng/mL; RR: 1.59; 95% CI: 1.04-2.42; P=.03).

“[Physicians] should monitor vitamin D levels in pregnant patients to ensure sufficiency, but it is too early to begin recommending pregnant women take vitamin D supplements for the purpose of reducing MS risk in their children,” Dr Munger said. “Our results need to be confirmed and more research in this area is needed.”

In an accompanying editorial, Benjamin Greenberg, MD, MHS, of the Department of Neurology at the University of Texas Southwestern in Dallas, highlighted several implications of a potential relationship of in utero vitamin D status and MS. “Determining if autoimmune tendencies could be set into motion at the time of birth would have large implications for the field,” he wrote.

Dr Greenberg continued, “Proving this hypothesis would change our screening for individuals at risk of the disease and perhaps offer opportunities for prevention.”

The study was funded by the National Institute of Neurological Disorders and Stroke. The authors reported several disclosures including relationships to pharmaceutical companies and the National Multiple Sclerosis Society.

Reference

1. Munger KL, Aivo J, Hongell K. Vitamin D Status During Pregnancy and Risk of Multiple Sclerosis in Offspring of Women in the Finnish Maternity Cohort. JAMA Neurol. 2016; doi:10.1001/jamaneurol.2015.4800.
2. Greenberg BM. Vitamin D During Pregnancy and Multiple Sclerosis:An Evolving Association. JAMA Neurol. 2016; doi:10.1001/jamaneurol.2016.0018.