Vitamin D exposure before birth may play an important role in the development of multiple sclerosis later in life, the Harvard Nurses' Mothers' Study suggests. The risk for multiple sclerosis is lower among women whose mothers had a high intake of either vitamin D during pregnancy.
Investigators studied more than 35,000 nurses whose biological mothers completed a questionnaire about their maternal milk intake, maternal dietary vitamin D intake, and predicted maternal serum 25-hydroxyvitamin D during pregnancy with their daughters' risk of developing multiple sclerosis. About 200 women were diagnosed with multiple sclerosis.
Investigators found that women born to mothers with a high vitamin D intake during pregnancy were less likely to have multiple sclerosis. The researchers report that the predicted vitamin D level in the pregnant mothers was inversely associated with the risk for multiple sclerosis in their daughters.
"It is important to realize that our results suggest, but certainly do not prove, an association. We agree with this critique, which can only be addressed by conducting an independent investigation, possibly using biomarkers of vitamin D status in pregnancy rather than self-reported diet. We are working on this." Still, researchers say, the findings will be of interest to women with multiple sclerosis and their physicians because of the higher-than-average risk for disease in their children.