Maternal vitamin D status during pregnancy may modulate fetal immune system development and infant susceptibility to infections. Vitamin D deficiency is common during pregnancy, particularly among African American (AA) women. Our objective was to compare maternal vitamin D status (plasma 25(OH)D concentration) during pregnancy and first-year infections in the offspring of African American (AA) and non-AA women. We used medical records to record frequency and type of infections during the first year of life of 220 term infants (69 AA, 151 non-AA) whose mothers participated in the Kansas University DHA Outcomes Study. AA and non-AA groups were compared for maternal 25(OH)D by Mann-Whitney U-test. Compared to non-AA women, AA women were more likely to be vitamin D deficient (<50 nmol/L; 84 vs. 37%, p < 0.001), and more of their infants had at least one infection in the first 6 months (78.3% and 59.6% of infants, respectively, p = 0.022). We next explored the relationship between maternal plasma 25(OH)D concentration and infant infections using Spearman correlations. Maternal 25(OH)D concentration was inversely correlated with the number of all infections (p = 0.033), eye, ear, nose, and throat (EENT) infections (p = 0.043), and skin infection (p = 0.021) in the first 6 months. A model that included maternal education, income, and 25(OH)D identified maternal education as the only significant predictor of infection risk in the first 6 months (p = 0.045); however, maternal education, income, and 25(OH)D were all significantly lower in AA women compared to non-AA women . The high degree of correlation between these variables does not allow determination of which factor is driving the risk of infection; however, the one that is most easily remediated is vitamin D status. It would be of value to learn if vitamin D supplementation in this at-risk group could ameliorate at least part of the increased infection risk.
Keywords: 25-hydroxycholecalciferol; African Americans; infancy; infection; maternal nutrition; pregnancy; vitamin D.