Background: Elevated cord blood IgE (cIgE), a predictor of atopic diseases, is influenced by genetic and environmental factors. However, gene-environment interactions on cIgE elevation and their difference by sex remain largely unexplored.
Objective: This study aimed to determine whether there are sex-moderated interactions between genetic variants in the IL4/IL13 pathway and prenatal environments on cIgE elevation.
Methods: Comprehensive information on environmental tobacco smoke (ETS), home dampness (indexed by combining mildewy odour, visible mould and water stamp on the wall) and other household environments was obtained using a structured questionnaire during the third trimester of pregnancy in 1107 full-term newborns. The cord blood was collected for measuring cIgE levels, with elevation defined as ≥0.5 IU/mL, and for genotyping of five single nucleotide polymorphisms of three candidate genes (IL-13 rs1800925, rs20541, rs848, IL-4 rs2243250 and STAT6 rs324011).
Results: Gene-environment interactions on cIgE elevation were observed in male but not female newborns, including those between ETS and IL13 rs20541, between home dampness and STAT6 rs324011, and between composite environmental exposure (combined ETS and the three home dampness indices) and STAT6 rs324011 (P for interaction = 0.03, 0.006, and 0.001, respectively). Male newborns carrying STAT6 rs324011 CT or TT genotype manifested with a significant dose-response association of the composite environmental exposure with cIgE elevation.
Conclusion and clinical relevance: Sex moderates the gene-environment interactions involving IL4/IL13 pathway genes and prenatal household environments on cIgE elevation. The absence of prenatal exposure to ETS and home dampness in male neonates carrying the STAT6 rs324011 CT or TT genotype is least likely associated with cIgE elevation.
Keywords: IgE; cord blood; prenatal environment; sex; single nucleotide polymorphism.
© 2019 John Wiley & Sons Ltd.