Association of Modifiable and Nonmodifiable Factors with Vitamin D Status in Pregnant Women and Neonates in Oakland, CA

Abstract There is little information on the contribution of modifiable vs nonmodifiable factors to maternal and neonatal vitamin D status in temperate regions of the United States. The purpose of this cross-sectional observation study conducted between December 2006 and February 2008 was to identify associations between observed and measured maternal characteristics and vitamin D status at term in pregnant women and their infants in a multiethnic community in Oakland, CA. Two hundred seventy-five pregnant women aged 18 to 45 years and carrying a singleton fetus were recruited and data from 210 mother-infant pairs were included in analyses. Analysis of covariance identified predictors of maternal and cord serum 25-hydroxyvitamin D [25(OH)D] in a multivariate model considering vitamin D intake, lifestyle factors, and skin pigmentation. Maternal serum 25(OH)D was significantly associated with season of delivery ( P =0.0002), average daily D intake ( P =0.0008), right upper inner arm pigmentation ( P =0.0035), and maternal pre- or early-pregnancy body mass index (calculated as kg/m 2 ) ( P =0.0207). The same factors were significant for cord serum 25(OH)D, which was highly correlated with maternal serum 25(OH)D ( r =0.79; P