Associations of prenatal exposure to phthalates and their mixture with lung function in Mexican children

Early life phthalates exposure has been associated with adverse respiratory outcomes. However, evidence linking prenatal phthalates exposure and childhood lung function has been inconclusive. Additionally, few studies have examined phthalates exposure as a mixture and explored sexually dimorphic associations. We aimed to investigate sex-specific associations of prenatal phthalates mixtures with childhood lung function using the PROGRESS cohort in Mexico (N = 476). Prenatal phthalate concentrations were measured in maternal urine collected during the 2^nd and 3^rd trimesters. Children's lung function was evaluated at ages 8–13 years. Individual associations were assessed using multivariable linear regression, and mixture associations were modeled using repeated holdout WQS regression and hierarchical BKMR; data was stratified by sex to explore sex-specific associations. We identified significant interactions between 2^nd trimester phthalates mixture and sex on FEV₁ and FVC z-scores. Higher 2^nd trimester phthalate concentrations were associated with higher FEV₁ (β = 0.054, 95 %CI: 0.005, 0.104) and FVC z-scores (β = 0.074, 95 % CI: 0.024, 0.124) in females and with lower measures in males (FEV₁, β = −0.017, 95 %CI: −0.066, 0.026; FVC, β = −0.014, 95 %CI: −0.065, 0.030). This study indicates that prenatal exposure to phthalates is related to childhood lung function in a sex-specific manner.