Ultraviolet Absorbers Exhibit Dual Modulatory Effects on Oxidative Stress Biomarkers in Exposed Populations

Health risks due to ultraviolet absorbers (UVAs), which are emerging contaminants prevalent in plastics and consumer products, are poorly understood. This study quantified 10 UVA congeners in urinary samples from 254 Beijing residents aged 19-44 years, revealing pervasive exposure to UVAs. The specific gravity-adjusted concentrations of 10 UVAs (∑₁₀UVAs) ranged from 1.90 ng/mL to 2.03 × 10³ ng/mL (geometric mean: 43.7 ng/mL), with UV-P (20.3 ng/mL), UV-360 (11.2 ng/mL), and UV-329 (6.34 ng/mL) as dominant compounds, indicating substantial environmental bioavailability. Women showed 2.7-fold higher ∑₁₀UVAs in the summer (80.0 vs 29.3 ng/mL) and 1.7-fold higher ∑₁₀UVAs in the winter (48.6 vs 28.0 ng/mL) than men, revealing sex-dependent and season-dependent exposure. Congener-specific detection patterns indicated multiple exposure sources and differential bioaccumulation behaviors. Critically, UVA exposure showed congener-specific and nonlinear associations with oxidative stress biomarkers (OSBs). UV-329, in particular, exhibited dual pro-oxidative and antioxidant effects across all four measured urinary OSBs. Bayesian kernel machine regression (BKMR) analyses further revealed significant effect modifications by sex, season, and alcohol consumption, underscoring interactions between chemical coexposure and individual susceptibility. These results illuminate the pathways of UVA exposure, its associated health impacts, and the underlying susceptibilities in reproductive-age populations, thereby providing critical evidence to support enhanced risk management strategies for this vulnerable population.