Associations between hair manganese levels and cognitive, language, and motor development in preschool children from Montevideo, Uruguay.

Environmental manganese (Mn) exposure in childhood has been associated with developmental deficits. This study investigated associations between low-level Mn exposure and developmental scores in children aged 14-45 months. Children's hair samples (n = 60) were analyzed for Mn and lead (Pb) using inductively coupled plasma mass spectrometry (ICP-MS). Children were assessed with the Bayley Scales of Infant Development III (BSID). Mean hair Mn and Pb concentrations were 0.98 ± 0.74 and 10.1 ± 10.5 μg/g, respectively. Unadjusted inverse associations were seen between Mn and BSID subscales, with girls having lower scores related to Mn than boys. No significant associations remained in covariate-adjusted models, although when stratified by sex boys had a positive association between hair Mn levels and language scores. This study does not show clear evidence of an association between hair Mn concentrations and children's developmental scores in a region of low-level Mn exposure.