The Association between Prenatal Quaternary Ammonium Compounds (QACs) Exposure and Neonatal Birth Obesity: Insights from Epidemiology and <i>In Vitro</i> Evidence

Quaternary ammonium compounds (QACs) are frequently used chemicals in consumer, medical, and personal care products that could be detected in blood samples from the general population. Cord blood samples are frequently employed in epidemiological studies to evaluate the links between contaminant exposure and birth outcomes. However, a significant knowledge gap persists regarding the presence of QACs in cord blood and their potential associations with birth outcomes. In this study, QACs were analyzed in 235 cord blood samples collected in a hospital in Jinan, Shandong Province, from February 2017 to January 2022. QACs were detected in the investigated cord blood samples, with total concentrations reaching up to 47.3 ng/mL. Benzylalkyldimethyl ammonium compounds (BACs) accounted for the largest proportion, with BAC-C12 and BAC-C14 being the most abundant QACs. The multiple linear regression (MLR) and Bayesian kernel machine regression (BKMR) models were developed to explore the relationships between QACs exposure and newborn birth outcomes. Results showed that BAC-C10, BAC-C16, and octyl decyldimethyl ammonium-8:10 were positively associated with birth weight and ponderal index (p for trend < 0.05), suggesting an obesogenic hypothesis. Furthermore, these three QAC structures can activate peroxisome proliferator-activated receptor γ (PPARγ, the core adipogenesis receptor). The margin of exposure results indicated that the obesogenic risks of QACs were limited under current exposure distributions, but ongoing attention is warranted due to uncertainties and sensitive life stages.