Prenatal Vitamin Use and Vitamin D Status during Pregnancy, Differences by Race and Overweight Status

Abstract

Objective: We aimed to study whether prenatal vitamin (PNV) use protects against low 25(OH)D levels in all women and particularly in obese and black women who are both at risk of vitamin D deficiency and poor pregnancy outcomes. Study design We studied 1019 women enrolled in a prospective study at Brigham and Women’s Hospital in Boston, 2007–2009. We used multivariable logistic regression to analyze associations of PNV use and odds of vitamin D deficiency defined as 25(OH)D levels < 50 nmol/L. Results: 56% of black and 86% of white women reported pre- and/or post-conceptional PNV use. 75% of black and 19% of white women were vitamin D deficient in the first trimester. PNV use among black women was not associated with vitamin D deficiency (adjusted OR 1.0, 95%CI 0.4, 2.3) but was among white women (3.5, 95%CI 2.1, 5.8)(Interaction P<0.01). Conclusions: Ongoing trials of vitamin D supplementation during pregnancy should consider potential effect modification by race/ethnicity.