Exposure to Air Pollution during Pregnancy and Childhood, and White Matter Microstructure in Preadolescents

BACKGROUND: Air pollution has been related to brain structural alterations, but a relationship with white matter microstructure is unclear. OBJECTIVES: We assessed whether pregnancy and childhood exposures to air pollution are related to white matter microstructure in preadolescents. METHODS: We used data of 2,954 children from the Generation R Study. a population-based birth cohort from Rotterdam, Netherlands (2002-2006). Concentrations of 17 air pollutants including nitrogen oxides (NOx), particulate matter (PM), and components of PM were estimated at participants' homes during pregnancy and childhood using land-use regression models. Diffusion tensor images were obtained at child's 9-12 years of age, and fractional anisotropy (FA) and mean diffusivity (MI)) were computed. We performed linear regressions adjusting for socioeconomic and lifestyle characteristics. Single-pollutant analyses were followed by multipollutant analyses using the Deletion/Substitution/Addition (DSA) algorithm. RESULTS: In the single-pollutant analyses, higher concentrations of several air pollutants during pregnancy or childhood were associated with significantly lower FA or higher MD (p < 0.05). In multipollutant models of pregnancy exposures selected by DSA, higher concentration of fine particles was associated with significantly lower FA [-0.71 (95% CI: -1.26, -0.16) per 5 mu g/m(3) fine particles] and higher concentration of elemental silicon with significantly higher MD [0.06 (95% CI: 0.01, 0.11) per 100 ng/m(3) silicon]. Multipollutant models of childhood exposures selected by DSA indicated significant associations of NOx with FA [-0.14 (95% CI: -0.23, -0.04) per 20-mu g/m(3) NOx increase], and of elemental zinc and the oxidative potential of PM with MD [0.03 (95% CI: 0.01, 0.04) per 10-ng/m(3) zinc increase and 0.07 (95% CI: 0.00, 0.44) per 1-nmol DTT/min/m(3) oxidative potential increase]. Mutually adjusted models of significant exposures during pregnancy and childhood indicated significant associations of silicon during pregnancy, and zinc during childhood, with MD. DISCUSSION: Exposure in pregnancy and childhood to air pollutants from tailpipe and non-tailpipe emissions were associated with lower FA and higher MD in white matter of preadolescents.