Environmentally relevant antibiotic exposure in school-age children: unraveling socio-dietary drivers in a multi-ethnic region of Northwest China.

While existing biomonitoring studies have extensively characterized the prevalence of antibiotic exposure, the complex sociodemographic and behavioral determinants underlying individual exposure profiles remain insufficiently understood. This study addressed the important research gap by examining antibiotic exposure in a distinctive socio-cultural setting-the Ningxia Hui Autonomous Region of China. We analyzed urinary concentrations of 22 antibiotics from four classes (tetracyclines, sulfonamides, macrolides, and fluoroquinolones) and one additional synthetic antibacterial agent in a cohort of 295 children in 2024. A brief food-frequency survey was concurrently administered to evaluate the nutritional preferences of children. The results revealed extensive exposure to antimicrobial agents, with 55.4% of the participants exhibiting measurable traces of at least one target antimicrobial compound. Detection frequencies for individual compounds ranged from 0.7% to 26.4%. Multivariable logistic regression analyses revealed that specific dietary habits were associated with increased odds of antibiotic detection; notably, after false discovery rate (FDR) adjustment, frequent consumption of white meat and eggs was significantly associated with higher detection odds for tetracyclines (OR = 2.54) and fluoroquinolones (OR = 2.96), respectively. Health risk assessment based on the hazard index (HI) and hazard quotient indicated that 9.15% of the children had HI values exceeding 1. Ciprofloxacin was the primary contributor to HI, with hazard quotient values exceeding 1 detected in 2.71% of children. Overall, this biomonitoring study indicates frequent internal exposure to environmentally relevant antibiotics among school-age children in this region, underscoring the need for further multi-pathway exposure assessments.