Correlation of Maternal Vitamin D Status in Early Pregnancy and Vitamin D Supplementation during Pregnancy with Atopic Dermatitis in Infants: A Prospective Birth Cohort Study

Abstract

Objective: This study aimed to investigate the association of maternal first-trimester vitamin D levels and vitamin D supplementation during pregnancy with infant atopic dermatitis (AD) and to determine the effect of variables such as mode of conception on the association.

Methods: This study was based on the Shanghai sub-cohort of the International Birth Cohort of China. A total of 4051 woman-infant pairs with singleton pregnancies were recruited. Vitamin D deficiency and insufficiency were defined as serum 25-hydroxyvitamin D concentrations of 25 and 50 nmol/L, respectively. AD in infants was assessed during the first six months using a standardized questionnaire based on the British Working Party criteria. Modified Poisson regression estimated the association between maternal vitamin D status and infant AD.

Results: The risk of AD in infants was higher in women with deficient 25-hydroxyvitamin D levels in the first trimester (RR: 1.77, 95% CI: 1.41-2.23). This increased risk was seen in naturally conceived pregnancies, but not in those conceived using assisted reproductive technology (ART). The incidence of AD decreased in infants of mothers who took multi-vitamin (RR: 0.79, 95% CI: 0.67-1.98) and vitamin D supplements (RR: 0.51, 95% CI: 0.37-0.71) compared to those whose mothers did not take any supplements. Maternal vitamin D deficiency had varying effects on AD risk based on passive smoking exposure and breastfeeding patterns.

Conclusions: Our findings highlight the importance of monitoring and supplementing vitamin D during pregnancy, especially in specific maternal populations, to reduce the risk of AD in offspring.

Keywords: assisted reproductive technology; atopic dermatitis; eczema; exclusive breastfeeding; vitamin D; vitamin D supplementation.

Figure 1

Flowchart of this study.

Figure 2

Distribution of maternal serum 25(OH)D levels between infants with AD and those without (non-AD) in the overall population (A), mothers who conceived through ART (B), and mothers who conceived naturally (C). The association between maternal first-trimester vitamin D levels and the AD in infants. Comparison of maternal serum 25(OH)D concentrations between mothers who conceived naturally and those who conceived through ART (D). The dashed lines indicate the standard deviation (SD) values of each population. The non-linear association between maternal first-trimester vitamin D levels and the risk of AD in infants (E). Plots show the non-linear regression models for maternal first-trimester serum 25(OH)D concentrations and RR of infant AD within 6 months of age (solid line) with 95% CI (dashed line,) assessed using restricted cubic spline (RCS). Knots were set to the 10th, 50th, and 90th percentiles. The analysis was adjusted for all covariates from adjusted Model 1, which included maternal gestational age, pre-pregnancy BMI, mode of conception, maternal ethnicity, gravidity, parity, maternal education level, drinking during pregnancy, smoking during pregnancy, exercise during pregnancy, passive smoking during pregnancy, family income, season of birth of infant, parental allergy history, hypertension during pregnancy, diabetes mellitus during pregnancy, and thyroid disease during pregnancy.

Figure 3

Subgroup analysis of maternal first-trimester vitamin D levels and the risk of AD in infants. The subgroup analyses were conducted according to the variable factors and presented in forest plots, categorized by whether maternal first-trimester serum 25(OH)D was deficient (<25 nmol/L) or not (≥25 nmol/L). The analyses were adjusted for all covariates from the adjusted Model 1, which included maternal gestational age, pre-pregnancy BMI, mode of conception, maternal ethnicity, gravidity, parity, maternal education level, drinking during pregnancy, smoking during pregnancy, exercise during pregnancy, passive smoking during pregnancy, family income, season of birth of infant, parental allergy history, hypertension during pregnancy, diabetes mellitus during pregnancy and thyroid disease during pregnancy. Stratification variables were not included in the adjustment.