Exposure to fine particle matter, nitrogen dioxide and benzene during pregnancy and cognitive and psychomotor developments in children at 15months of age

BACKGROUND: Prenatal exposure to air pollutants has recently been identified as a potential risk factor for neuropsychological impairment. OBJECTIVES: To assess whether prenatal exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2) and benzene were associated with impaired development in infants during their second year of life. METHODS: Regression analyses, based on 438 mother-child pairs, were performed to estimate the association between mother exposure to air pollutants during pregnancy and neurodevelopment of the child. The average exposure to PM2.5, NO2 and benzene over the whole pregnancy was calculated for each woman. During the second year of life, infant neuropsychological development was assessed using the Bayley Scales of Infant Development. Regression analyses were performed to estimate the association between exposure and outcomes, accounting for potential confounders. RESULTS: We estimated that a 1 μg/m(3) increase during pregnancy in the average levels of PM2.5 was associated with a -1.14 point decrease in motor score (90% CI: -1.75; -0.53) and that a 1 μg/m(3) increase of NO2 exposure was associated with a -0.29 point decrease in mental score (90% CI: -0.47; -0.11). Benzene did not show any significant association with development. Considering women living closer (≤ 100 m) to metal processing activities, we found that motor scores decreased by -3.20 (90% CI: -5.18; -1.21) for PM2.5 and -0.51 (-0.89; -0.13) for NO2, while mental score decreased by -2.71 (90% CI: -4.69; -0.74) for PM2.5, and -0.41 (9% CI: -0.76; -0.06) for NO2. CONCLUSIONS: Our findings suggest that prenatal residential exposure to PM2.5 and NO2 adversely affects infant motor and cognitive developments. This negative effect could be higher in the proximity of metal processing plants.