PM_2.5-Bound Organophosphate Esters and Childhood Sleep Disorders: Evidence from the Pearl River Delta Study

Although particulate matter has been associated with sleep problems, the effects of PM_2.5-bound organophosphate esters (OPEs) on children's sleep remain unclear. OPEs have neurotoxic and endocrine-disrupting effects that may disrupt sleep-wake regulation during neurodevelopment, supporting biological plausibility for sleep impacts. In this study, we quantified the individual and mixture effects of PM_2.5-bound OPEs on the sleep disorder domain. This cross-sectional study included 110,169 children aged 6-18 years from primary and secondary schools in the Pearl River Delta (PRD), China. Sleep disorders were evaluated using the validated Sleep Disturbance Scale for Children (SDSC). Elastic net and mixed effect models identified specific OPE-sleep associations, while weighted quantile sum regression evaluated mixture effects. All odds ratios indicate a change in the likelihood of sleep disorders per interquartile range (IQR) increase in OPE concentrations. The strongest individual associations were observed for TDCIPP with short sleep duration (OR = 1.56-1.61; moderate association), TEHP with short sleep duration (OR = 1.59-1.64; moderate association), and TPHP with overall sleep disorder (OR = 1.32-1.42; modest association). Combined OPE exposure was positively associated with all sleep disorder domains (ORs = 2.02-2.85; moderate-to-large associations). These results indicate that inhaling PM_2.5-bound OPE mixtures could negatively impact children's sleep health. This emphasizes a critical developmental period and highlights the importance of public health concerns related to emerging airborne contaminants.