Latent subgroups of cognitive performance in lead- and manganese-exposed Uruguayan children: Examining behavioral signatures.

OBJECTIVES: Lead (Pb) and manganese (Mn) are confirmed neurotoxins but it is unclear to what extent low-level exposure produces a unique behavioral signature. The objective of this study was to investigate latent cognitive profiles among children (6-8 years) from Montevideo, Uruguay co-exposed to these metals. METHOD: Among 345 children, blood Pb and hair Mn were measured using atomic absorption spectroscopy and ICP-MS, respectively. Sixteen measures, reflecting multiple domains of cognitive functioning were gathered: (1) three tests from Cambridge Neuropsychological Test Automated Battery (CANTAB): Intra-Extra Dimensional Shift (IED), Spatial Span (SSP) and Stockings of Cambridge (SOC), (2) ten tasks from Woodcock-Muñoz Achievement Battery, Revised (WM): Visual-Motor Integration, Verbal Comprehension (Vocabulary, Synonyms, Antonyms, Analogies), Visual-Auditory Comprehension, Concept Formation, Visual Spatial Thinking, Number Inversion and Spatial Relations, (3) Bender Gestalt task, and (4) Weschler block design task. Scores were modeled using latent profile analysis (LPA). Association between blood Pb and hair Mn on performance profiles was assessed using ordinal regression, controlling for confounders. An interaction between Pb and Mn was tested. RESULTS: Mean ± SD of blood Pb was 4.1 ± 2.1 µg/dL and 35% of children had blood Pb ≥ 5 µg/dL. Median [5%, 95%] hair Mn level was 0.8 [0.3, 4.1] ppb. Three latent cognitive performance profiles were identified: high (n = 46, 13%), average (n = 209, 61%) and low (n = 90, 26%). Each one-unit increase in blood Pb was associated with a 28% greater likelihood of belonging to a poorer-performing profile. The association was non-linear, with the effect of Pb on profile membership strongest at lower levels of exposure. There was no meaningful interaction between Pb and Mn. CONCLUSIONS: A behavioral signature for low-level Pb & Mn exposure was not identified, but the likelihood of membership in low-performing profile was higher at lowest levels of blood Pb. There was no effect measure modification between Pb and Mn. Future research should address how complex environments created by chemical exposures and the social context relate to cognitive performance in young children.

[Intelligence quotient loss in Mexican pottery artisan's children]. / Pérdida de coeficiente intelectual en hijos de alfareros mexicanos.

BACKGROUND: In Mexico, artisans frequently use lead oxide or greta in order to produce utensils, which are destined to preparation and storage of food and drinks. Additionally, the risk of lead poisoning of artisans and their families is greater than in general population, and within these families, children are the most susceptible to lead poisoning. The aim of this study was to estimate IQ loss in Mexican children from potter families exposed to lead. METHODS: Lead concentrations in soil were determined in 19 potter's homes that functioned as pottery workshops in seven Mexican states between 2009 and 2012. This information was used to estimate blood lead levels through the integrated exposure uptake biokinetic (IEUBK) model. The loss of IQ points was then estimated according to the Lanphear and Schwartz models. RESULTS: The mean lead concentration found in the workshops' soil was 1098.4 ppm. Blood lead levels estimated in children under 8 years old were 26.4 µg/dL and the loss of IQ points comprised from 7.13 to 8.84 points depending on the model. CONCLUSIONS: It is possible that 11 children from families of artisans in Mexico may be losing between 7.13 to 8.84 IQ points, due to lead exposure in their houses-workshops. This loss in IQ points could have important health, economic and social impacts.

Introducción: en México, los alfareros continúan usando frecuentemente el óxido de plomo o greta para producir utensilios, los cuales se destinan a la preparación y almacenamiento de alimentos y bebidas. Adicionalmente, el riesgo de intoxicación por plomo de los alfareros y sus familias es mayor que en la población general, y en tales familias, los niños son los más susceptibles a la intoxicación por plomo. El objetivo del estudio fue estimar la pérdida de puntos de coeficiente intelectual (CI) en hijos de alfareros mexicanos expuestos al plomo. Métodos: durante el periodo de 2009 a 2012 se determinaron las concentraciones de plomo en suelo de 19 casas-talleres de alfareros en siete estados mexicanos. Esta información se utilizó para estimar el nivel de plomo en sangre, por medio del modelo biocinético integrado de absorción por exposición (IEUBK, por sus siglas en inglés). Posteriormente, se calcularon los puntos perdidos de CI según los modelos de Schwartz y Lanphear. Resultados: la concentración promedio de plomo en suelo fue de 1098.4 ppm. Se estimó un nivel de plomo en sangre de 26.4 µg/dL para menores de 8 años. La pérdida de puntos de CI estimada fue 7.13 y 8.84, según el modelo utilizado. Conclusión: es posible que al menos 11 niños de familias alfareras mexicanas estén perdiendo entre 7.13 y 8.84 puntos de CI, debido a la exposición al plomo en sus casas-talleres, lo que supone importantes impactos económicos, sociales y de salud.

Primary prevention of pediatric lead exposure requires new approaches to transfusion screening.

OBJECTIVE: To facilitate further assessment of transfusion-associated lead exposure by designing a procedure to test packed red blood cells (pRBCs) prepared for transfusion. STUDY DESIGN: The relationship between pRBCs and whole blood lead concentration was investigated in 27 samples using a modified clinical assay. Lead concentrations were measured in 100 pRBC units. RESULTS: Our sample preparation method demonstrated a correlation between whole blood lead and pRBC lead concentrations (R(2) = 0.82). In addition, all 100 pRBC units tested had detectable lead levels. The median pRBC lead concentration was 0.8 µg/dL, with an SD of 0.8 µg/dL and a range of 0.2-4.1 µg/dL. In addition, after only a few days of storage, approximately 25% of whole blood lead was found in the supernatant plasma. CONCLUSION: Transfusion of pRBCs is a source of lead exposure. Here we report the quantification of lead concentration in pRBCs. We found a >20-fold range of lead concentrations in the samples tested. Pretransfusion testing of pRBC units according to our proposed approach or donor screening of whole blood lead and selection of below-average units for transfusion to children would diminish an easily overlooked source of pediatric lead exposure.

The conjoint influence of home enriched environment and lead exposure on children's cognition and behaviour in a Mexican lead smelter community.

A range of studies has been conducted on the detrimental effects of lead in mining and smelting communities. The neurocognitive and behavioural health effects of lead on children are well known. This research characterized the conjoint influence of lead exposure and home enriched environment on neurocognitive function and behaviour for first-grade children living in a Mexican lead smelter community. Structural equation models were used for this analysis with latent outcome variables, Cognition and Behaviour, constructed based on a battery of assessments administered to the first-grade children, their parents, and teachers. Structural equation modelling was used to describe complex relationships of exposure and health outcomes in a manner that permitted partition of both direct and indirect effects of the factors being measured. Home Environment (a latent variable constructed from information on mother's education and support of school work and extracurricular activities), and child blood lead concentration each had a main significant effect on cognition and behaviour. However, there were no statistically significant moderation relationships between lead and Home Environment on these latent outcomes. Home Environment had a significant indirect mediation effect between lead and both Cognition and Behaviour (p-value<0.001). The mediation model had a good fit with Root Mean Square Error of Approximation <0.0001 and a Weighted Root Mean Square Residual of 0.895. These results were highly significant and suggest that Home Environment has a moderate mediation effect with respect to lead effects on Behaviour (ß=0.305) and a lower mediation effect on Cognition (ß=0.184). The extent of home enrichment in this study was most highly related to the mother's support of schoolwork and slightly less by the mother's support of extracurricular activities or mother's education. Further research may be able to develop approaches to support families to make changes within their home and child rearing practices, or advocate for different approaches to support their child's behaviour to reduce the impact of lead exposure on children's cognitive and behavioural outcomes.

Neurotoxicity and aggressiveness triggered by low-level lead in children: a review / Neurotoxicidad y agresividad desencadenadas por bajos niveles de plomo en niños: una revisión

Lead-induced neurotoxicity acquired by low-level long-term exposure has special relevance for children. A plethora of recent reports has demonstrated a direct link between low-level lead exposure and deficits in the neurobehavioral-cognitive performance manifested from childhood through adolescence. In many studies, aggressiveness and delinquency have also been suggested as symptoms of lead poisoning. Several environmental, occupational and domestic sources of contaminant lead and consequent health risks are largely identified and understood, but the occurrences of lead poisoning remain numerous. There is an urgent need for public health policies to prevent lead poisoning so as to reduce individual and societal damages and losses. In this paper we describe unsuspected sources of contaminant lead, discuss the economic losses and urban violence possibly associated with lead contamination and review the molecular basis of lead-induced neurotoxicity, emphasizing its effects on the social behavior, delinquency and IQ of children and adolescents.

La neurotoxicidad adquirida inducida por la exposición prolongada a bajos niveles de plomo tiene una importancia especial en los niños. Una plétora de publicaciones recientes ha demostrado el vínculo directo existente entre la exposición a bajos niveles de plomo y el déficit en el desempeño neuroconductual-cognitivo manifestado desde la infancia hasta el final de la adolescencia. En numerosos estudios, la agresividad y la delincuencia juvenil también se han considerado síntomas de la intoxicación por plomo. Se han identificado y explicado ampliamente varias fuentes ambientales, laborales y domésticas de contaminación por plomo y los riesgos resultantes para la salud, pero aún son numerosos los casos de intoxicación por plomo. Se necesitan urgentes políticas de salud pública para prevenir la intoxicación por plomo de manera de reducir los daños y las pérdidas, tanto individuales como para la sociedad. En este artículo se describen algunas fuentes no sospechadas de contaminación por plomo y se discuten las pérdidas económicas y la violencia urbana posiblemente asociada con este tipo de contaminación. Además, se hace una revisión de las bases moleculares de la neurotoxicidad inducida por plomo, con énfasis en sus efectos sobre el comportamiento social, la delincuencia juvenil y el coeficiente intelectual de los niños y los adolescentes.

Higher infant blood lead levels with longer duration of breastfeeding.

OBJECTIVE: To determine whether longer breastfeeding is associated with higher infant lead concentrations. STUDY DESIGN: Data were analyzed from 3 studies of developmental effects of iron deficiency in infancy: Costa Rica (1981-1984), Chile (1991-1996), and Detroit (2002-2003). The relation between duration of breastfeeding and lead levels was assessed with Pearson product-moment or partial correlation coefficients. RESULTS: More than 93% of the Costa Rica and Chile samples was breastfed (179 and 323 breastfed infants, respectively; mean weaning age, 8-10 months), as was 35.6% of the Detroit sample (53 breastfed infants; mean weaning age, 4.5 months). Lead concentrations averaged 10.8 microg/dL (Costa Rica, 12-23 months), 7.8 microg/dL (Chile, 12 months), and 2.5 microg/dL (Detroit, 9-10 months). Duration of breastfeeding as sole milk source and total breastfeeding correlated with lead concentration in all samples (r values = 0.14-0.57; P values = .06-<.0001). CONCLUSIONS: Longer breastfeeding was associated with higher infant lead concentration in 3 countries, in 3 different decades, in settings differing in breastfeeding patterns, environmental lead sources, and infant lead levels. The results suggest that monitoring lead concentrations in breastfed infants be considered.

Neurotoxicity and aggressiveness triggered by low-level lead in children: a review.

Lead-induced neurotoxicity acquired by low-level long-term exposure has special relevance for children. A plethora of recent reports has demonstrated a direct link between low-level lead exposure and deficits in the neurobehavioral-cognitive performance manifested from childhood through adolescence. In many studies, aggressiveness and delinquency have also been suggested as symptoms of lead poisoning. Several environmental, occupational and domestic sources of contaminant lead and consequent health risks are largely identified and understood, but the occurrences of lead poisoning remain numerous. There is an urgent need for public health policies to prevent lead poisoning so as to reduce individual and societal damages and losses. In this paper we describe unsuspected sources of contaminant lead, discuss the economic losses and urban violence possibly associated with lead contamination and review the molecular basis of lead-induced neurotoxicity, emphasizing its effects on the social behavior, delinquency and IQ of children and adolescents.

Pseudotumor cerebral maligno en niños por intoxicación plumbica / Lead poisoning presenting as malignant pseudotumor cerebri in children

Introducción: El pseudotumor cerebral (PTC), o hipertensión endocraneana benigna, se caracteriza por sintomatología compatible con aumento de la presión endocraneana en ausencia de lesión espacio-ocupante o dilatación ventricular por obstrucción en la circulación del LCR. Se presenta con cefalea, náuseas-vómitos, y variadas alteraciones visuales con edema de papila. Las causas subyacentes son múltiples: alteraciones endocrinas y metabólicas, obesidad, medicamentos, trombosis senos venosos, megadosis de vitamina A, sinusopatías, etc. como así también intoxicación plúmbica. Objetivo: Detectar etiología tóxica en pacientes con PTC en los cuales no se evidenció factor causal mediante interrogatorio dirigido a pesquisa de fuentes contaminantes de plomo. Material y Métodos: Análisis prospectivo de pacientes ambulatorios o internados con diagnóstico de PTC. Estudios de Rx de cráneo, oftalmológicos y neuroimágenes. Aplicación de protocolo de investigación de contacto con plomo. Determinaciones en sangre y orina del bioperfil plúmbico: ALA-D, ALA-U, plombemia, PPE, coproporfirinas III. Comparación con grupo control de los niños intoxicados. Aplicación del test de Fisher. Resultados: Fueron evaluados 66 niños entre 4 meses y 13 años, 49 varones. Las manifestaciones clínicas fueron: cefalea (85 por ciento), náuseas-vómitos (94 por ciento), alteraciones visuales: diplopia, disminución agudeza visual, estrabismo (91 por ciento), edema de papila (89 por ciento). Hipertensión radiológica (55 por ciento). Neuroimágenes: negativas para tumor (100 por ciento), compatible con edema cerebral (27 por ciento). Los factores etiológicos fueron identificados en 55 casos (83 por ciento) obesidad, endocrinopatía, corticoterapia, megadosis de vitamina A, sinusopatías, etc. En el 17 por ciento restante (11 casos) se sospechó etiología tóxica, comprobándose intoxicación plúmbica en 8 niños (12 por ciento). Conclusiones: Sugerimos aplicar interrogatorio dirigido hacia pesquisa de fuentes contaminantes de plomo en casos de PTC sin causa establecida, y confirmación con análisis de nivel de plomo en sangre y bioperfil plúmbico. El diagnóstico y tratamiento oportunos evitarán el pronóstico desfavorable de la afección, por eso consideramos como "maligno" a este tipo de pseudotumor. (AU)

Environmental factors associated with blood lead levels in Venezuelan children.

A preliminary study explored the relative contribution of residential sources of lead exposure on mentally challenged children who attend "special education" institutions (GI) compared to a group of age and sex matched school children (G2). We captured descriptive information and analyzed demographic variables, personal and household information, medical effects, environmental exposure factors, and children habits. Home paint, dust, soil, and water sampling was conducted and blood lead (BPb) levels determined. Eighteen G1 and 20 G2 children were studied. The mean G1 BPb was 16.9 +/- 7.9 microg/dl and was significantly higher than that in G2. Fifty percent of G1 children had PbB >20 microg/dl and 72.2% were >10 microg/dl. Low muscular strength, decreased osteotendinose reflexes, fine and gross motricity, deficient equilibrium, and hipotonic muscular tone coincided with >18 microg/dl BPb levels. In 61.1% of G1 homes paint lead levels were higher than permissible levels and 33.3% had dust lead exceeding that level. The high BPb levels in G1 probably resulted from ingestion of household paint, dust, and soil via "hand-to-mouth" activity. Environmental exposure to lead can be an important source of lead intake by infants and children and could affect neurological development. This study provides new insights currently unavailable for these children in Venezuela.