Association between Ambient Ultrafine Particles and Neurodevelopmental Delay in Preschoolers in Shanghai, China

Previous toxicological research has suggested the potential neurotoxicity of ultrafine particulate matter (UFP, particles <= 0.1 mu m in diameter). However, evidence from human beings, particularly regarding the neurodevelopmental impacts of UFP, is still limited. We enrolled 11,230 children aged 3-5.5 years from Shanghai, China. Residential UFP exposure was assessed by a land use regression model with a spatial resolution of 50 m. The neurodevelopment of preschoolers was assessed using the Ages & Stages Questionnaires, Third Edition. Generalized linear mixed models were used to examine the associations of UFP exposure with risk of suspected neurodevelopmental delay. For our participants, the median of UFP exposure was 24,478 [interquartile range (IQR): 22,773-27,657] number per cubic centimeter. We observed that each IQR increase in UFP was associated with 8% [odds ratio (OR), 1.08; 95% CI, 1.02-1.15] and 12% (OR, 1.12; 95% CI, 1.02-1.22) higher odds of suspected neurodevelopmental delay in gross and fine motor skills, respectively. These associations show a monotonically upward dose-response manner across overall UFP concentrations. Our findings suggest that UFP exposure during early childhood is associated with an increased risk of neurodevelopmental delay among Chinese preschoolers.