Vitamin D prenatal programming of childhood metabolomics profiles at age 3 y

Abstract

Background: Vitamin D deficiency is implicated in a range of common complex diseases that may be prevented by gestational vitamin D repletion. Understanding the metabolic mechanisms related to in utero vitamin D exposure may therefore shed light on complex disease susceptibility.Objective: The goal was to analyze the programming role of in utero vitamin D exposure on children's metabolomics profiles.Design: First, unsupervised clustering was done with plasma metabolomics profiles from a case-control subset of 245 children aged 3 y with and without asthma from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), in which pregnant women were randomly assigned to vitamin D supplementation or placebo. Thereafter, we analyzed the influence of maternal pre- and postsupplement vitamin D concentrations on cluster membership. Finally, we used the metabolites driving the clustering of children to identify the dominant metabolic pathways that were influential in each cluster.Results: We identified 3 clusters of children characterized by 1) high concentrations of fatty acids and amines and low maternal postsupplement vitamin D (mean ± SD; 27.5 ± 11.0 ng/mL), 2) high concentrations of amines, moderate concentrations of fatty acids, and normal maternal postsupplement vitamin D (34.0 ± 14.1 ng/mL), and 3) low concentrations of fatty acids, amines, and normal maternal postsupplement vitamin D (35.2 ± 15.9 ng/mL). Adjusting for sample storage time, maternal age and education, and both child asthma and vitamin D concentration at age 3 y did not modify the association between maternal postsupplement vitamin D and cluster membership (P = 0.0014). Maternal presupplement vitamin D did not influence cluster membership, whereas the combination of pre- and postsupplement concentrations did (P = 0.03).Conclusions: Young children can be clustered into distinct biologically meaningful groups by their metabolomics profiles. The clusters differed in concentrations of inflammatory mediators, and cluster membership was influenced by in utero vitamin D exposure, suggesting a prenatal programming role of vitamin D on the child's metabolome. This trial was registered at clinicaltrials.gov as NCT00920621.

Keywords: airway inflammation; metabolomics; polyunsaturated fatty acids; prenatal programming; vitamin D.

FIGURE 1

Log_e levels of metabolites across cluster groups highlights the main drivers of group segregation. Only metabolites identified as exhibiting variability across the identified cluster groups by medoid |z| >1 in the 3-cluster solution and that were additionally significant by Kruskal-Wallis P < 0.001 across these groups were chosen. Their natural log metabolite concentrations were plotted to reveal true patterns of similarity and difference across each group. (A) Box plots with pairwise group comparisons for each metabolite (Mann-Whitney U test). (B) Sample and metabolite cluster dendrograms with heat map and box plot of metabolite concentrations. Sample dendrogram and heat map divided by sample-to-cluster assignment. Total sample N = 245: group 1, 46; group 2, 94; group 3, 105. GPC, glycerophosphorylcholine.

FIGURE 2

Pre- and postsupplement maternal vitamin D concentrations significantly associate with cluster group segregation. Postsupplement concentrations were significantly lower when cluster group 1 was compared with groups 2 and 3 separately (Mann-Whitney U test). In addition, through a multinomial logistic regression model with sample-to-cluster assignment as outcome and adjusting for significant confounders, sample storage time, maternal age, and education, and the child’s asthma status and vitamin D level at age 3 y, the postsupplement concentration of vitamin D was a significant predictor of cluster grouping (P = 0.0014; OR: 1.032; 95% CI: 1.0021, 1.065). The presupplementation concentration of vitamin D was not a statistically significant predictor of cluster grouping. Presupplementation concentrations (means ± SDs): group 1, 21.10 ± 8.01 ng/mL; group 2, 23.60 ± 10.30 ng/mL; and group 3, 23.60 ± 11.00 ng/mL. Postsupplementation concentrations (means ± SDs): group 1, 27.5 ± 11.0 ng/mL; group 2, 34.0 ± 14.1 ng/mL; and group 3 (35.2 ± 15.9 ng/mL). Total sample N = 245: group 1, 46; group 2, 94; and group 3, 105.

FIGURE 3

The combination of maternal vitamin D concentrations pre- and postsupplement is a determinant of cluster membership. Maternal pre- and postsupplement vitamin D concentrations were encoded as “low” (<30 ng/mL) or “high” (≥30 ng/mL), forming the basis for a combined variable describing the intrauterine exposure at both times (e.g., low-low means that both pre- and postsupplement concentrations of vitamin D were <30 ng/mL). This combined variable was a strong determinant of the child’s cluster membership (χ² P = 0.03). An overrepresentation of low-low and underrepresentation of high-high is observed in cluster 1, suggesting that the presupplement concentrations combined with postsupplement concentrations play a role for cluster segregation. Total sample N = 245: group 1, 46; group 2, 94; and group 3, 105.