Mediation Effects of Placental Inflammatory Transcriptional Biomarkers on the Sex-Dependent Associations between Maternal Phthalate Exposure and Infant Allergic Rhinitis: A Population-Based Cohort Study

Objective Prenatal phthalate exposure has been associated with placental inflammatory factors and infant allergic rhinitis (AR). However, the results are inconclusive. We designed a population-based cohort study to examine the effects of placental inflammatory biomarkers on the sex-dependent associations between maternal phthalate exposure and infant AR.Methods A total of 2,348 pregnant women from Ma'anshan, Anhui Province, China, who were screened before antenatal visits and met the inclusion criteria, were included in the present study. We assessed AR in their offspring aged 36 months with a questionnaire. Quantitative PCR was performed to measure placental inflammatory factor mRNAs. The independent samples t-test and multivariable logistic regression were used to determine the associations between infant AR and maternal phthalates.Results Childhood AR may be related to education and family monthly income (P = 0.01). The phthalate metabolites, mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-hydroxyl) phthalate (MEHHP), in pregnant women were associated with a significantly increased risk for infant AR in males [P < 0.05; odds ratio (OR): 1.285; 95% confidence interval (CI): 1.037-1.591, and OR: 1.232, 95% CI: 1.008-1.507, respectively], but not females. Additionally, irritably-increased expression levels of HO-1 and IL-4 were associated with AR in male infants (OR: 1.175; 95% CI: 1.038-1.329 and OR: 1.181; 95% CI: 1.056-1.322, respectively). The association between maternal urinary MEHHP and placental HO-1 was marginally significant according to mediation analysis.Conclusion The associations of maternal MEHHP and MEOHP levels with fetal AR in males were significant. Placental HO-1 was a fractional mediator in the associations between MEHHP and AR. Thus, the placenta should be further investigated as a potential mediator of maternal exposure-induced disease risk in children.

Automated summary

Maternal exposure to phthalate metabolites is associated with an increased risk of infant allergic rhinitis (AR) in males, with placental inflammatory biomarkers playing a potential mediating role.