Prenatal exposure to outdoor air pollution and child behavioral problems at school age in Japan

Introduction Recent studies suggest positive associations between prenatal exposure to ambient air pollution and neurodevelopment of children, but evidence on the adverse effects of exposure to air pollution on child neurobehavioral development remains limited. We thus examined associations between prenatal exposure to outdoor air pollution and child behavioral problems at school age, using data from a nationwide population-based longitudinal survey in Japan, where participants were recruited in 2001 and are continuously followed. Methods Suspended particulate matter (SPM), nitrogen dioxide, and sulfur dioxide concentrations during the 9 months before birth were obtained at municipality level and assigned to those participants born in the corresponding municipality. We analyzed data from singleton births with linked pollution data available (e.g., n = 33,911 for SPM). We used responses to survey questions about behavioral problems at age 8 years. We conducted multilevel logistic regression analysis, adjusting for individual and municipality-level variables. Results Air pollution exposure during gestation was positively associated with risk for behavioral problems related to attention and delinquent or aggressive behavior. In the fully adjusted models, odds ratios following a one-interquartile-range increase in SPM were 1.06 (95% confidence interval: 1.01, 1.11) for interrupting others, 1.09 (1.03, 1.15) for failure to pay attention when crossing a street, 1.06 (1.01, 1.11) for lying, and 1.07 (1.02, 1.13) for causing public disturbance. Conclusions Prenatal exposure to outdoor air pollution was associated with behavioral problems related to attention and delinquent or aggressive behavior at age 8 years in a nationally representative sample in Japan.