Pregnancy exposure to individual phthalate concentrations and their mixtures in relation to pediatric serum antibody response

The objective of this study was to estimate the association between gestational phthalate metabolite concentrations and mixtures and pediatric antibody response at 4-years of age to common childhood vaccines, while also exploring sexually dimorphic effects. This study utilized data from the Programming, Research, Obesity, and Social Stressors (PROGRESS) Study, an ongoing, longitudinal cohort of mother-child pairs residing in Mexico City. Fifteen phthalate metabolites were measured in spot urine samples collected from mothers during their second and third trimesters. Children have been regularly followed, with data collection on lifestyle, clinical, socio-economic, and demographic factors, and archived biologic specimen. IgG-specific antibody serum levels to measles, mumps, rubella, diphtheria, tetanus, and pertussis were quantified from children at the mean 4.7 years of age. Linear regression models, with log2 transformation of both the outcome and exposure variables, estimated the association between individual phthalate metabolites and antibody concentrations. Phthalate mixtures were analyzed using the Quantile G-Computational approach and Bayesian Kernel Machine regression. All analyses were also sex-stratified to investigate sexually dimorphic effects. The present analysis included 362 mother-child pairs. During the second trimester of pregnancy, a doubling increase of mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) concentrations was associated with a 6.98% decrease (95% CI: - 11.68%, - 2.04%) in diphtheria and a 2.57% decrease (95% CI: - 4.74%, - 0.35%) in mumps antibody levels, respectively. No statistically significant sex-differences were observed. Mixtures analyses did not reach statistical significance but observed similar associations with MECPTP. Concentrations of MECPTP, a replacement phthalate, were negatively associated with anti-diphtheria antibody levels in Hispanic children indicating a potential detrimental effect of newer alternative phthalates on pediatric health.