Early pregnancy vitamin D and patterns of antenatal inflammation in African–American women

• Pregnant African–American women had vitamin D and inflammatory cytokine measurement.
• Early pregnancy vitamin D is associated with second trimester inflammatory cytokines.
• Increased vitamin D is associated with lower inflammatory cytokine levels.
• Inverse vitamin D-inflammation link remained with principal component analysis.

Vitamin D is essential for the health of both mother and fetus during pregnancy. In the nonpregnant state, vitamin D demonstrates anti-inflammatory effects, but little is known about this relationship during pregnancy. African–American women are at a higher risk of vitamin D deficiency and for altered inflammatory responses during pregnancy. Therefore, we investigated the association of early pregnancy vitamin D nutrition, as assessed by serum 25-hydroxyvitamin D (25-OHD), with second-trimester inflammatory biomarkers (high-sensitivity C-reactive protein, IL-6, IL-10, IL-1β and TNF-α) in 178 pregnant African–American women. Mean serum 25-OHD was 13.4 ± 8.4 ng/ml, and most women (n = 147, 82.6%) had inadequate or deficient levels of 25-OHD (<20 ng/ml). Both serum 25-OHD and some inflammatory cytokines (IL-1β and TNF-α) demonstrated significant seasonal variation. In univariate models, log transformed 25-OHD was significantly and inversely associated with log transformed IL-1β (p = 0.002) and log transformed IL-6 (p = 0.032). After adjusting for covariates, including seasonality, only the inverse association with IL-1β remained statistically significant (p = 0.027). Early pregnancy vitamin D nutrition is associated with some inflammatory biomarkers in mid-pregnancy. Additional studies are needed to determine if low vitamin D nutrition is associated with birth outcomes via an inflammatory-mediated pathway.