Hemoglobin Status Is Positively Associated with Neurodevelopment in Lead-Exposed Preschool Children from Montevideo, Uruguay

Abstract

Micronutrient deficiencies and environmental toxicants have been shown to contribute to children’s neurodevelopmental deficits. Despite intense research on anemia and lead exposure, we know little about how these two factors together affect children’s development. The objective of this study was to test the association of hemoglobin (Hb) and blood lead (BLL) concentrations with measures of development in preschool children (n=69, ages 14.4 – 45.6 mo) from Montevideo, Uruguay. Children were assessed with Bayley Scales of Infant Development III (Bayley); maternal IQ, depressive symptoms and parenting stress were assessed as contextual factors. The mean BLL was 6.0 ± 3.0 μg/dL and 11.5% of children had levels ≥ 10μg/dL. The mean Hb was 12.3 ± 1.7 g/dL and 18.8% of children experienced anemia (Hb <11 g/dL). Mean composite Bayley cognitive, language and motor scores were: 90.3 ± 12.4, 90.1 ± 17.4 and 96.4 ± 14.6 points, respectively. In unadjusted regressions, higher Hb was associated with higher cognitive, language and fine motor scores (point estimates: 0.4 – 0.6, p<0.05). BLL was not associated with scores. Covariate adjustment slightly attenuated estimates for Hb (p<0.1). There was an Hb-BLL interaction on fine motor scores (p<0.15): Hb was positively associated with performance but only for children with BLL <5 μg/dL. We found an association between Hb and Bayley scores, and a suggestion of an interaction between Hb and BLL. But based on the obtained data we were unable to conclude whether children with anemia are more susceptible to the toxic effects of lead. Keywords-Lead; Hemoglobin; Preschool; Cognition; Uruguay