Prepregnancy obesity predicts poor vitamin D status in mothers and their neonates

Lisa M Bodnar, Janet M Catov, James M Roberts, Hyagriv N Simhan, Lisa M Bodnar, Janet M Catov, James M Roberts, Hyagriv N Simhan

Abstract

Obesity is a risk factor for vitamin D deficiency, but this relation has not been studied among pregnant women, who must sustain their own vitamin D stores as well as those of their fetuses. Our objective was to assess the effect of prepregnancy BMI on maternal and newborn 25-hydroxyvitamin D [25(OH)D] concentrations. Serum 25(OH)D was measured at 4-21 wk gestation and predelivery in 200 white and 200 black pregnant women and in their neonates' cord blood. We used multivariable logistic regression models to assess the independent association between BMI and the odds of vitamin D deficiency [25(OH)D <50 nmol/L] after adjustment for race/ethnicity, season, gestational age, multivitamin use, physical activity, and maternal age. Compared with lean women (BMI <25), pregravid obese women (BMI >or=30) had lower adjusted mean serum 25(OH)D concentrations at 4-22 wk (56.5 vs. 62.7 nmol/L; P < 0.05) and a higher prevalence vitamin D deficiency (61 vs. 36%; P < 0.01). Vitamin D status of neonates born to obese mothers was poorer than neonates of lean mothers (adjusted mean, 50.1 vs. 56.3 nmol/L; P < 0.05). There was a dose-response trend between prepregnancy BMI and vitamin D deficiency. An increase in BMI from 22 to 34 was associated with 2-fold (95% CI: 1.2, 3.6) and 2.1-fold (1.2, 3.8) increases in the odds of mid-pregnancy and neonatal vitamin D deficiency, respectively. The rise in maternal obesity highlights that maternal and newborn vitamin D deficiency will continue to be a serious public health problem until steps are taken to identify and treat low 25(OH)D.

Figures

FIGURE 1
FIGURE 1
Plot of prepregnancy BMI vs. maternal serum 25(OH)D at 4–22 wk gestation. The solid line represents the best fit of this relation (r = −0.22; P < 0.0001).
FIGURE 2
FIGURE 2
Unadjusted association between maternal prepregnancy BMI and the probability of maternal vitamin D deficiency (A) and neonatal vitamin D deficiency (B). Vitamin D deficiency is defined as serum 25(OH)D < 50 nmol/L. Probabilities were predicted based on results from logistic regression models (BMI effect was significant at P < 0.05 in maternal model and P < 0.01 in neonatal model). The solid line represents the point estimate and the dashed lines represent the 95% confidence bands.

Source: PubMed

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