| Background. Traffic related air pollution, using measurements of specific pollutants such as PAH or NO2, highly associated with traffic exhaust, have been found to significantly decrease cognitive ability in children. However, freeway proximity models are a better proxy for a global measurement of ambient pollutants associated with freeway traffic.;Objectives. Using distance to nearest freeway as a proxy, determine whether traffic related air pollution is associated with developmental delays, evaluated using cognitive and adaptive assessments. Further analyze the association between freeway air pollution and cognitive and adaptive ability among cases and controls.;Methods. Data from the Childhood Autism Risks from Genetics and the Environment (CHARGE) Study was utilized to obtain freeway distance and information on pertinent covariates. The Mullen Scales of Early Learning (MSEL) and Vineland Adaptive Behavior Scales (VABS) were used to diagnose 132 children with a developmental delay and 259 children as typically developing controls. Birth certificate residence was geocoded using ArcGIS software to obtain distance measures, categorized four different ways according to previous research and distribution. Logistic regression was used to compare cases and controls for each method of categorization as well as continuously. Linear regression was used to analyze assessment scores among controls, and logistic regression was used to analyze assessment scores among cases, for each method of freeway distance categorization.;Results. Close proximity to a freeway around time of birth, characterized as living within 300 m relative to greater than 1400 m, is significantly associated with developmental delays (Adjusted OR = 2.38, 95% Confidence Interval (CI) = (1.12, 5.11), p = 0.024). Even among typically developing controls, freeway air pollution significantly decreases cognitive ability, with no significant effects on adaptive ability.;Conclusions. Results suggest a significant effect of a wide range of air pollutants associated with freeway exhaust on a child's neurodevelopment early in life. |
