BackgroundPrevious studies have suggested an effect of high arsenic concentration on cognitive and neurobehavioral function in humans.ObjectiveOur goal was to identify demographic and nutritional factors that are associated with As exposure and the influence of this exposure on cognitive function in school-age children.MethodsWe recruited 602 children 6–8 years of age living within 3.5 km of a metallurgic smelter complex in the city of Torreón, Mexico, to participate in a cross-sectional evaluation. Of these, 591 had complete anthropometry, iron, and zinc status by biochemical measurements in serum, blood lead concentration (PbB), and arsenic in urine (UAs), and 557 completed several cognitive performance tests.ResultsThe mean for UAs was 58.1 ± 33.2 μg/L; 52% of the children had UAs concentrations > 50 μg/L, and 50.7% of children had PbB ≥10 μg/dL. UAs concentration was associated with low socioeconomic status. Nutritional status indicators were not related to UAs concentrations. Linear and logistic regressions adjusted for hemoglobin concentration, PbB, and sociodemographic confounders showed a significant inverse association between UAs and Visual–Spatial Abilities with Figure Design, the Peabody Picture Vocabulary Test, the WISC-RM Digit Span subscale, Visual Search, and Letter Sequencing Tests (p < 0.05). Boys excreted significantly more UAs (p < 0.05) and were affected on different cognitive areas than girls.ConclusionsChildren living in an area contaminated with both As and lead showed that As contamination can affect children’s cognitive development, independent of any effect of lead.
There is increasing interest in the interaction of nutritional deficiencies with toxic metals. Iron deficiency and elevated blood lead concentrations (PbB) reportedly occur together, and zinc also plays an important role in lead metabolism. The objective was to evaluate the effect of zinc and/or iron supplementation on PbB of children attending schools in the neighborhood of a smelter complex for 6 mo. We conducted a double-blind, placebo-controlled field trial in 9 elementary schools located within a 3.5-km radius of a metal foundry in Torreón, Mexico. Of the 602 first-graders enrolled, 517 completed supplementation and had initial and final PbBs. Children were given either 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 mo. Baseline and final measures included nutritional status and PbB. The overall prevalence of iron and zinc deficiencies was 12.1 and 30.3%, respectively, and 10.3% were anemic. The PbB concentration decreased in all experimental groups (P < 0.05). After controlling for initial PbB, groups administered zinc and/or iron did not have lower PbB concentrations than the placebo group (P < 0.05). In conclusion, iron supplementation of lead-exposed children significantly improved iron status but did not reduce PbBs. Zinc supplementation did not reduce PbBs independently of zinc nutritional status. Neither iron nor zinc can be recommended as the sole treatment for lead-exposed school children.
del Soco and Laguna de Oviedo. With the plant samples taken in the above mentioned sites, we created a synthetic table out of 16 phytosociological tables belonging to 6 original associations and 9 associations obtained from the bibliographical study. With the purpose of obtaining a similarity gradient (matching) between the associations under study, we carried out a statistical analysis (clustering, principal component analysis and Jaccard similarity/dissimilarity analysis). Our phytosociological approach relied on criteria such as biogreography and dynamic-catenal contact. Our sampling analysis has led us to propose the following syntaxa: Machaerio lunati-Rhizophoretum manglis; Rhabdadenio biflorae-Laguncularietum racemosae; Sthalio monospermae-Laguncularietum racemosae; Lonchocarpo pycnifolii-Conocarpetum erecatae; Lonchocarpo sericeiLaguncularietum racemosae; Crataevo tapiae-Conocarpetum erectae. We also propose a new alliance and a change of status: Phyllantho elsiae-Laguncurion racemosae; Dalbergio-Rhizophorion manglis (Borhidi 1991) status novo. The mangrove swamps of Central America are arranged in three vegetation bands corresponding to different plant associations. The analysis of the three sampled area not only revealed the degradation of the vegetation but also the causative factors.
Objective: To determine the effectiveness of the nutritional supplement developed for the Oportunidades programme on growth, prevalence of anaemia, morbidity and cognitive function of pre-school children.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.