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Background Little is known about developmental neurotoxicity of particulate matter composition. We aimed to investigate associations between exposure to elemental composition of outdoor PM2.5 at birth and cognitive and psychomotor functions in childhood. Methods We analyzed data from 4 European population-based birth cohorts in the Netherlands, Germany, Italy and Spain, with recruitment in 2000–2006. Elemental composition of PM2.5 measurements were performed in each region in 2008–2011 and land use regression models were used to predict concentrations at participants' residential addresses at birth. We selected 8 elements (copper, iron, potassium, nickel, sulfur, silicon, vanadium and zinc) and used principal component analysis to combine elements from the same sources. Cognitive (general, verbal, and non-verbal) and psychomotor (fine and gross) functions were assessed between 1 and 9 years of age. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. Results 7246 children were included in this analysis. Single element analysis resulted in negative association between estimated airborne iron and fine motor function (− 1.25 points [95% CI − 2.45 to − 0.06] per 100 ng/m3 increase of iron). Association between the motorized traffic component, derived from principal component analysis, and fine motor function was not significant (− 0.29 points [95% CI − 0.64 to 0.06] per unit increase). None of the elements were associated with gross motor function or cognitive function, although the latter estimates were predominantly negative. Conclusion Our results suggest that iron, a highly prevalent element in motorized traffic pollution, may be a neurotoxic compound. This raises concern given the ubiquity of motorized traffic air pollution.


Mary MacKillop Institute for Health Research

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Journal Article

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