TY - JOUR
T1 - Efficacy of iron and/or zinc supplementation on cognitive performance of lead-exposed Mexican schoolchildren
T2 - A randomized, placebo-controlled trial
AU - Rico, Javier Alatorre
AU - Kordas, Katarzyna
AU - López, Patricia
AU - Rosado, Jorge L.
AU - Vargas, Gonzalo García
AU - Ronquillo, Dolores
AU - Stoltzfus, Rebecca J.
PY - 2006/3
Y1 - 2006/3
N2 - OBJECTIVE. Lead exposure in children has been associated with both global and specific cognitive deficits. Although chelation therapy is advised for children with blood lead concentrations of >44 μg/dL, treatment options for children with lower blood lead values are limited. Because lead absorption is related to children's nutritional status, micronutrient supplements may be 1 strategy for combating low-level, chronic lead exposure. This study was designed to test the efficacy of iron and zinc supplementation for lowering blood lead concentrations and improving cognitive performance in schoolchildren who live in a lead-contaminated city. METHODS. This randomized, double-blind, placebo-controlled field trial was conducted in public elementary schools in Torreón, an industrialized city in northern Mexico. A metal foundry, located close to the city center and within 3.5 km of 9 schools, was the main source of lead exposure. A total of 602 children who were aged 6 to 8 years and regularly attending first grade in the study schools were enrolled. Children were given 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 months. A total of 527 completed the treatment, and 515 were available for long-term follow-up, after another 6 months without supplementation. Eleven cognitive tests of memory, attention, visual-spatial abilities, and learning were administered at baseline and each follow-up. RESULTS. There were no consistent or lasting differences in cognitive performance among treatment groups. CONCLUSIONS. Daily supplementation with iron and/or zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren. However, these treatments may be effective in settings with higher prevalence of nutritional deficiencies or in younger children.
AB - OBJECTIVE. Lead exposure in children has been associated with both global and specific cognitive deficits. Although chelation therapy is advised for children with blood lead concentrations of >44 μg/dL, treatment options for children with lower blood lead values are limited. Because lead absorption is related to children's nutritional status, micronutrient supplements may be 1 strategy for combating low-level, chronic lead exposure. This study was designed to test the efficacy of iron and zinc supplementation for lowering blood lead concentrations and improving cognitive performance in schoolchildren who live in a lead-contaminated city. METHODS. This randomized, double-blind, placebo-controlled field trial was conducted in public elementary schools in Torreón, an industrialized city in northern Mexico. A metal foundry, located close to the city center and within 3.5 km of 9 schools, was the main source of lead exposure. A total of 602 children who were aged 6 to 8 years and regularly attending first grade in the study schools were enrolled. Children were given 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 months. A total of 527 completed the treatment, and 515 were available for long-term follow-up, after another 6 months without supplementation. Eleven cognitive tests of memory, attention, visual-spatial abilities, and learning were administered at baseline and each follow-up. RESULTS. There were no consistent or lasting differences in cognitive performance among treatment groups. CONCLUSIONS. Daily supplementation with iron and/or zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren. However, these treatments may be effective in settings with higher prevalence of nutritional deficiencies or in younger children.
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U2 - 10.1542/peds.2005-1172
DO - 10.1542/peds.2005-1172
M3 - Article
C2 - 16510631
AN - SCOPUS:33645019697
SN - 0031-4005
VL - 117
SP - e518-e527
JO - Pediatrics
JF - Pediatrics
IS - 3
ER -