Gestational Vitamin D and the Risk of Multiple Sclerosis in Offspring

Objective: Vitamin D may have a protective role in the etiology of multiple sclerosis (MS), but the effect of gestational vitamin D on adult onset MS has not been studied. Methods: In 2001, 35,794 mothers of participants of the Nurses' Health Study II completed a questionnaire inquiring about their experiences and diet during pregnancy with their nurse daughters. We studied the association of maternal milk intake, maternal dietary vitamin D intake, and predicted maternal serum 25-hydroxyvitamin D (25(OH) D) during pregnancy and their daughters' risk of developing MS. Results: MS was diagnosed in 199 women. The relative risk of MS was lower among women born to mothers with high milk or vitamin D intake during pregnancy. The multivariate adjusted rate ratio (RR) of MS was 0.62 (95% confidence interval [CI], 0.40-0.95; p trend = 0.001) for nurses whose mothers consumed 2 to 3 glasses of milk per day compared with those whose mothers consumed <3 glasses per month, and 0.57 (95% CI, 0.35-0.91; p trend = 0.002) for nurses with mothers in the highest quintile of dietary vitamin D intake compared with those in the lowest. The predicted 25(OH) D level in the pregnant mothers was also inversely associated with the risk of MS in their daughters. Comparing extreme quintiles, the adjusted RR was 0.59; (95% CI, 0.37-0.92; p trend = 0.002). Interpretation: Higher maternal milk and vitamin D intake during pregnancy may be associated with a lower risk of developing MS in offspring. ANN NEUROL 2011;70:30-40