Joint effects of prenatal exposure to bisphenols and air pollution on intelligence quotient in preschool children: A prospective cohort study in China

Background Intelligence quotient (IQ) plays a significant role in assessing neurodevelopment. However, the effects of prenatal exposure to bisphenols or air pollution on intelligence quotient in preschool children remain unclear. Methods A total of 231 mother–child pairs were from Guangxi Zhuang Birth Cohort. Single- and multiple-pollution methods were performed to examine the effects of prenatal exposure to bisphenols and air pollutants on IQ in preschool children, including generalized linear models, restricted cubic spline (RCS), principal component analysis (PCA), quantile G-computation (Qgcomp), and Bayesian kernel machine regression (BKMR). Results In generalized linear model, prenatal exposure to bisphenol A (BPA) (β=−3.55; 95%CI: −7.04, −0.06) and bisphenol F (BPF) (β=−12.68; 95%CI: −21.31, −4.05) was negatively associated with working memory index (WMI) in preschool children. Similarly, prenatal tetrabromobisphenol A (TBBPA) exposure was associated with lower verbal comprehension index (VCI) (β=−4.23; 95%CI: −7.90, −0.57), FRI (β=−5.59; 95%CI: −9.88, −1.30), WMI (β=−5.40; 95%CI: −9.47, −1.32), processing speed index (PSI) (β=−4.79; 95%CI: −9.25, −0.33), and full-scale IQ (FSIQ) (β=−4.38; 95%CI: −7.92, −0.84). Among air pollution, higher O 3 exposure was correlated with lower VCI (β=−138.44; 95%CI: −198.55, −78.34), visuospatial index (VSI) (β=−64.41; 95%CI: −126.53, −2.29), WMI (β=−93.59; 95%CI: −162.67, −24.50), and FSIQ (β=−114.85; 95%CI: −173.79, −55.92). Furthermore, prenatal exposure to PM 2.5 and PM 10 was correlated with decreased VCI (PM 2.5 : β=−45.64; 95%CI: −82.77, −8.51 and PM 10 : −61.85; 95%CI: −107.36, −16.35) and FSIQ (PM 2.5 : β=−49.76; 95%CI: −85.57,−13.95 and PM 10 : β=−60.23; 95%CI: −104.28, −16.19). After gender stratification, the above effects were more significant in boys. In Bayesian kernel machine regression, prenatal exposure to the mixtures of 10 pollutants (5 bisphenols and 5 air pollutants) or 5 air pollution components was associated with less VCI, VSI, WMI, and FSIQ, and an inverted U-shaped association was found between these mixtures and FRI. Conclusions Prenatal exposure to both single and mixed bisphenols and air pollutants may decrease the IQ of preschool children. These adverse effects appear to be more pronounced in boys and exhibit a nonlinear exposure-response relationship. This work offers epidemiological support for public health interventions that reduce co-exposure to multiple pollutants during pregnancy.