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Background: Anemia and lead exposure remain significant public health issues in many parts of the world, often occurring together. Animal studies suggest that the dopamine D2 receptor (DRD2) mediates the effects of both lead and iron on cognition and behavior. Objective: We tested the hypothesis that the DRD2 Taq IA polymorphism modifies the effects of lead and hemoglobin on intelligence quotient (IQ) among children. Methods: Blood lead and hemoglobin were assessed in 717 children 3-7 years of age attending 12 schools in Chennai, India. IQ was determined using the Binet-Kamat scales of intelligence. Genotyping for the DRD2 polymorphism was carried out using a MassARRAY iPLEX platform. Stratified analyses and interaction models, using generalized estimating equations (GEEs), were used to explore interactions between lead and hemoglobin, and DRD2 Taq IA categories [homozygous variant (A1) vs. presence of wild-type allele (A2)]. Results: After we controlled for potential confounders, a one-unit increase in log blood lead was associated with a decrease of 9 IQ points [95% confidence interval (CI), -18.08 to -0.16] in the homozygous-variant children (n = 73) compared with a decrease of 4 IQ points (95% CI, -7.21 to -0.69) among those with the wild-type allele (n = 644). Higher hemoglobin levels were associated with higher IQ in the children who carried the wild-type allele DRD2, but in children homozygous for the variant allele, an increase of 1 g/dL hemoglobin was associated with a decrease in 1.82 points of IQ (95% CI, -5.28 to 1.64; interaction term p-value = 0.02). Conclusion: The results of this study suggest that the DRD2 Taq IA polymorphism disrupts the protective effect of hemoglobin on cognition and may increase the susceptibility to the deficits in IQ due to lead exposure. [ABSTRACT FROM AUTHOR]

In vitrobioaccessibility of Pb, As, Cd and Hg in five traditional Indian medicine samples was measured as a determinant of bioavailability. The method is based on simulation of human digestion in the passage of material from the gastric to intestinal portions of the gastrointestinal tract. Total concentration and concentration in extracts from gastric and intestinal phases were analyzed for Pb, As and Cd by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) and for Hg by direct mercury analyzer (DMA). Total lead ranged from 1.9 to 36000 μg g−1. In each of the samples bioaccessibility of lead was significantly higher (range 28–88%) in the gastric phase than in the intestinal phase (range 1.4–75.4%). Only Ekangvir Ras had measurable arsenic (304 μg g−1). Its bioaccessibility in the gastric phase and intestinal phase was 82.6% and 78.1%, respectively. Only Ayu-Nephro-Tone had measurable cadmium (14.4 μg g−1). Its bioaccessibility in the gastric phase and intestinal phase was 80.5% and 2.2%, respectively. Three samples had measurable mercury (range 37 μg g−1–10000 μg g−1). Mercury in these samples was not bioaccessible. For the samples with measurable amount of metal, the estimated daily amount of bioaccessible (EDAB) metal was calculated. When compared with the most liberal published safety guideline, EDAB-Pb in Mahayograj Guggulu and Ekangvir Ras were 37 and 45 fold greater. When compared with the most conservative published safety guideline, all samples had higher EDAB-Pb or EDAB-As than the suggested limits. The EDAB-Cd and EDAB-Hg were acceptably below published safety limits. [ABSTRACT FROM AUTHOR]

Background: Lead exposure has long been associated with deficits in IQ among children. However, few studies have assessed the impact of lead on specific domains of behavior and cognition. Objective: We evaluated the associations between lead and different domains of neurobehavior and their relative sensitivity to lead. Methods: We determined blood lead levels using a LeadCare instrument in 756 children 3-7 years of age attending pre- and elementary schools in Chennai, India. Anxiety, social problems, inattention, hyperactivity, and attention deficit hyperactivity disorder (ADHD), as well as executive function were assessed in children by their schoolteachers using Conners' Teacher Rating Scales-39, Conners' ADHD/Diagnostic and Statistical Manual for Mental Disorders, 4th Edition Scales (CADS), and the Behavior Rating Inventory of Executive Function questionnaires, with higher scores denoting worse behavior. Analyses were carried out using multivariate generalized estimating equations with comparisons of outcome Z-scores to assess the relative strengths of the associations between log-blood lead and the different domains of behavior. Results: Mean blood lead level was 11.4 ± 5.3 μg/dL. Blood lead was associated with higher anxiety (β = 0.27, p = 0.01), social problems (β = 0.20, p = 0.02), and higher scores in the ADHD index (β = 0.17; p = 0.05). The effect estimate was highest for global executive function (β = 0.42; p < 0.001). Conclusions: Higher blood lead levels in this population of young children is associated with increased risk of neurobehavioral deficits and ADHD, with executive unction and attention being particularly vulnerable domains to the effects of lead. [ABSTRACT FROM AUTHOR]

Background: Iron deficiency and lead exposure remain significant public health issues in many parts of the world and are both independently associated with neurocognitive deficits. Polymorphisms in iron transport pathways have been shown to modify the absorption and toxicity of lead., Objective: We hypothesized that the transferrin (TF) C2 polymorphism modifies the effects of lead and hemoglobin on intelligence., Methods: Children aged 3-7 years (N=708) were enrolled from 12 primary schools in Chennai, India. The Binet-Kamath Scale of Intelligence were administered to ascertain intelligence quotient (IQ). Venous blood was analyzed for lead and hemoglobin levels. Genotyping for the TF C2 polymorphism (rs1049296) was carried out using a MassARRAY iPLEXTM platform. Stratified analyses and interaction models, using generalized estimating equations, were examined to explore interactions between lead, hemoglobin, and TF C2 categories., Results: A one-unit increase in log blood lead and 1g/dl higher hemoglobin was associated with -77 (95% CI: -136, -18) and 17 (95% CI 14, 21) IQ points, respectively, among children carrying the C2 variant. In comparison, among children who had the homozygous wildtype allele, the same increment of lead and hemoglobin were associated with -21(95% CI: -65, 24) and 28 (95% CI: 15, 40) IQ points, respectively. There was a significant interaction between lead (p=0.04) and hemoglobin (p=0.07) with the C2 variant., Conclusion: Children who carry the TF C2 variant may be more susceptible to the neurotoxic effects of lead exposure and less protected by higher levels of hemoglobin., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Lead has been phased out of gasoline in India since 2001. However, elevated blood lead levels continue to be reported, and little is known about the predictors of lead exposure. The purpose of this study was to examine the lead burden and identify possible predictors of blood lead among children in Chennai, India after the phase-out of leaded gasoline. Subjects were children from twelve schools in Chennai. Venous blood was collected and analyzed for lead. Demographic, environmental, and nutritional information was collected using questionnaires administered to the primary caregiver. Generalized estimating equations were used to assess predictors of blood lead. We found that lead exposure remains elevated among children four or more years after the phase-out of lead from gasoline. Industrial activity, water storage vessels, and lower socio-economic status are predictors of elevated blood lead in this population, but additional work is required to better define preventable risk factors.