1
|
Bider RC, Sheehan B, Bock N, McNeill FE. The feasibility of K XRF bone lead measurements in mice assessed using 3D-printed phantoms. Biomed Phys Eng Express 2024; 10:035027. [PMID: 38447224 DOI: 10.1088/2057-1976/ad30ca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 03/06/2024] [Indexed: 03/08/2024]
Abstract
This article describes the development of a system forin vivomeasurements of lead body burden in mice using109Cd K x-ray fluorescence (XRF). This K XRF system could facilitate early-stage studies on interventions that ameliorate or reverse organ tissue damage from lead poisoning by reducing animal numbers through a cross-sectional study approach. A novel mouse phantom was developed based on a mouse atlas and 3D-printed using PLA plastic with plaster of Paris 'bone' inserts. PLA plastic was found to be a good surrogate for soft tissue in XRF measurements and the phantoms were found to be good models of mice. As expected, lead detection limits varied with mouse size, mouse orientation, and mouse position with respect to the source and detector. The work suggests that detection limits of 10 to 20μg Pb per g bone mineral may be possible for a 2 to 3 hour XRF measurement in a single animal, an adequate limit for some pre-clinical studies. The109Cd K XRF mouse measurement system was also modeled using the Monte Carlo code MCNP. The combination of experiment and modeling found that contrary to expectation, accurate measurements of lead levels in mice required calibration using mouse-specific calibration standards due to the coherent scatter peak normalization failing when small animals are measured. MCNP modeling determined that this was because the coherent scatter signal from soft tissue, which until now has been assumed negligible, becomes significant when compared to the coherent scatter signal in bone in small animals. This may have implications for some human measurements. This work suggests that109Cd K x-ray fluorescence measurements of lead body burden are precise enough to make the system feasible for small animals if appropriately calibrated. Further work to validate the technology's measurement accuracy and performancein vivowill be required.
Collapse
Affiliation(s)
- R C Bider
- McMaster University - Department of Physics and Astronomy, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - B Sheehan
- McMaster University - Department of Physics and Astronomy, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- McMaster University - Radiation Sciences Graduate Program, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - N Bock
- McMaster University - Department of Psychology, Neuroscience and Behaviour 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - F E McNeill
- McMaster University - Department of Physics and Astronomy, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- McMaster University - Radiation Sciences Graduate Program, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| |
Collapse
|
2
|
Sharma S, Wakode S, Sharma A, Nair N, Dhobi M, Wani MA, Pottoo FH. Effect of environmental toxicants on neuronal functions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:44906-44921. [PMID: 32996088 DOI: 10.1007/s11356-020-10950-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 09/20/2020] [Indexed: 05/22/2023]
Abstract
In the last few years, neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) have attracted attention due to their high prevalence worldwide. Environmental factors may be one of the biggest reasons for these diseases related to neuronal dysfunctions. Most of neuronal disorders are strongly associated with pre- and postnatal exposure to environmental toxins released from industries. Some of the neurotoxic metals such as lead, aluminum, mercury, manganese, cadmium, and arsenic as well as some pesticides and metal-based nanoparticles have been involved in AD and PD due to their ability to produce senile/amyloid plaques and NFTs which are the main feature of these neuronal dysfunctions. Exposure to solvents is also majorly responsible for neurodegenerative disorders. The present review highlights the impact of omnipresent heavy metals with some other neurotoxins on human health and how they give rise to neuronal dysfunctions which in turn causes socio-economic consequences due to increasing pollution worldwide. Graphical abstract.
Collapse
Affiliation(s)
- Supriya Sharma
- Department of Pharmacognosy, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Sharad Wakode
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Anjali Sharma
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Nisha Nair
- Department of Pharmaceutical Chemistry, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Mahaveer Dhobi
- Department of Pharmacognosy, Delhi Pharmaceutical Sciences and Research University, Sector-3, MB road, Pushp Vihar, New Delhi, 110017, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Kolkata, 163, Maniktala Main road, Kolkata, 700054, India
| | - Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O.BOX 1982, Damman, 31441, Saudi Arabia.
| |
Collapse
|
3
|
Lewis BA, Minnes S, Min MO, Short EJ, Wu M, Lang A, Weishampel P, Singer LT. Blood lead levels and longitudinal language outcomes in children from 4 to 12 years. JOURNAL OF COMMUNICATION DISORDERS 2018; 71:85-96. [PMID: 29373108 PMCID: PMC5801000 DOI: 10.1016/j.jcomdis.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 12/27/2017] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
OBJECTIVES In this study, the authors aimed to examine the association of a range of blood lead levels on language skills assessed at 4, 6, 10 and 12 years of age using a prospective longitudinal design controlling for potential confounding variables including maternal vocabulary, caregiver's psychological distress and symptomatology, child's race and prenatal drug exposure. METHODS The participants (N = 278) were a subsample of a large longitudinal study that examined the association of prenatal drug exposure on children who were followed prospectively from birth and assessed for receptive and expressive language skills at 4, 6, 10 and 12 years of age. Blood lead levels were determined at 4-years of age by atomic absorption spectrometry. A mixed model approach with restricted maximum likelihood procedures was used to assess the association of lead on language outcomes. RESULTS Longitudinal mixed model analyses suggested a negative effect of lead exposure on both receptive and expressive language, with the adverse outcomes of lead exposure appearing to become more prominent at 10 and 12 years. Higher caregiver vocabulary was positively associated with child's language scores whereas caregiver psychological distress appeared to negatively affect language scores. Prenatal drug exposure was not related to the effects of lead on language skills. CONCLUSIONS These findings suggest that elevated blood lead levels occurring early in life may be associated with poorer language skills at older ages. A language rich environment may minimize the negative influence of early lead exposure on language skills, with psychological distress seemingly exacerbating the negative outcome.
Collapse
Affiliation(s)
- Barbara A Lewis
- Department of Psychological Sciences, Case Western Reserve University, United States.
| | - Sonia Minnes
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Meeyoung O Min
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Elizabeth J Short
- Department of Psychological Sciences, Case Western Reserve University, United States
| | - Miaoping Wu
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Adelaide Lang
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Paul Weishampel
- Mandel School of Applied Social Sciences, Case Western Reserve University, United States
| | - Lynn T Singer
- Departments of Pediatrics and Environmental Health Sciences, Case Western Reserve University, United States
| |
Collapse
|
4
|
Abstract
Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barré disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration.
Collapse
Affiliation(s)
- Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
| | - Mahfuzur Rahman Miah
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, USA
| |
Collapse
|
5
|
Sindhu KK, Sutherling WW. Role of Lead in the Central Nervous System: Effect on Electroencephlography, Evoked Potentials, Electroretinography, and Nerve Conduction. Neurodiagn J 2015; 55:107-21. [PMID: 26173349 DOI: 10.1080/21646821.2015.1043222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The toxic effects of lead on the brain are well known, but its effects on EEG and evoked potentials (EPs) are not generally known in the neurodiagnostic community. Despite public health efforts, lead is still widely present at low levels in the environment. Even at low concentrations, lead is known to cause biochemical and physiological dysfunction. The present article reviews the effects of lead exposure on the central nervous system, with a special emphasis on the developing brain. Additionally, it describes the effects of lead on EEG, EPs, electroretinography, and nerve conduction studies.
Collapse
|
6
|
Mason LH, Harp JP, Han DY. Pb neurotoxicity: neuropsychological effects of lead toxicity. BIOMED RESEARCH INTERNATIONAL 2014; 2014:840547. [PMID: 24516855 PMCID: PMC3909981 DOI: 10.1155/2014/840547] [Citation(s) in RCA: 306] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 10/09/2013] [Accepted: 10/14/2013] [Indexed: 11/18/2022]
Abstract
Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposure's pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored.
Collapse
Affiliation(s)
- Lisa H. Mason
- Department of Neurology, University of Kentucky College of Medicine, 740 S. Limestone, Lexington, KY 40536, USA
- Department of Psychology, University of Kentucky College of Arts and Sciences, 106b Kastle Hall, Lexington, KY 40506, USA
| | - Jordan P. Harp
- Department of Neurology, University of Kentucky College of Medicine, 740 S. Limestone, Lexington, KY 40536, USA
- Department of Psychology, University of Kentucky College of Arts and Sciences, 106b Kastle Hall, Lexington, KY 40506, USA
| | - Dong Y. Han
- Department of Neurology, University of Kentucky College of Medicine, 740 S. Limestone, Lexington, KY 40536, USA
| |
Collapse
|
7
|
Sanna E, De Micco A, Vallascas E. Evaluation of association between biomarkers of lead exposure in Sardinian children (Italy). Biol Trace Elem Res 2011; 143:1383-92. [PMID: 21318620 DOI: 10.1007/s12011-011-8988-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 01/26/2011] [Indexed: 01/06/2023]
Abstract
The aim of this work is to verify whether there are statistically significant correlations between the concentrations of lead in blood, urine, and hair in children. The sample collected in 2007 consists of 163 children of both sexes from 11-14-year-olds, living in three municipalities of Sardinia (Italy). Inductively coupled plasma atomic mass spectrometry has been used in the determination of lead concentration in biological material. For the overall sample, there is a non-significant partial correlation among the three matrices. However, for subjects with blood lead levels ≥5 μg/dL, there is a significant positive partial correlation between the lead levels in blood and hair, but not between blood and urine or between urine and hair. The results suggest that blood is the preferred biomarker to ascertain lead exposure in human populations, whereas hair can be used as a tool screening when an area is exposed to medium or high lead pollution.
Collapse
Affiliation(s)
- Emanuele Sanna
- Anthropological Science Research Unit, Department of Experimental Biology, University of Cagliari, Cittadella Universitaria, Monserrato, 09042, Sardinia, Italy.
| | | | | |
Collapse
|
8
|
Abstract
Abstract
Speech-language pathologists typically use standardized assessments to diagnose language disorders. Although standardized tests are important in diagnosing school-age language disorders, the use of language sample analysis should not be ignored. This article summarizes the benefits of language sample analysis and introduces considerations for collecting and analyzing language samples.
Collapse
|
9
|
Tracking Childhood Exposure to Lead and Developmental Disabilities. JOURNAL OF PUBLIC HEALTH MANAGEMENT AND PRACTICE 2008; 14:577-80. [DOI: 10.1097/01.phh.0000338370.59080.4b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
10
|
Gahyva DLC, Crenitte PDAP, Caldana MDL, Hage SRDV. [Characterization of language disorders in children with lead poisoning]. PRO-FONO : REVISTA DE ATUALIZACAO CIENTIFICA 2008; 20:55-60. [PMID: 18408865 DOI: 10.1590/s0104-56872008000100010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 01/11/2008] [Indexed: 11/22/2022]
Abstract
BACKGROUND lead poisoning can have a negative impact on the neuropsychological functions, including language, due to the damage it causes to the development of the Central Nervous System. AIM to verify the occurrence of language disorders in children who suffered from led poisoning and to verify the correlation between the lead concentration level in the blood and the language disorders presented by the children. METHOD language evaluation of 20 preschoolers, with lead concentration level in the blood above 10 microg/dl. RESULTS 13 children presented language impairment involving only phonology or more than one language subsystem. The statistical analysis indicated that no correlation exists between the severity of the language impairment and the concentration levels of lead. CONCLUSION the number of children with language impairment indicates lead poisoning as a risk factor for the present alterations, even though other risk factors for language disorders were found and the absence of correlation between the investigated variables.
Collapse
|
11
|
Yuan W, Holland SK, Cecil KM, Dietrich KN, Wessel SD, Altaye M, Hornung RW, Ris MD, Egelhoff JC, Lanphear BP. The impact of early childhood lead exposure on brain organization: a functional magnetic resonance imaging study of language function. Pediatrics 2006; 118:971-7. [PMID: 16950987 DOI: 10.1542/peds.2006-0467] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The purpose of this work was to assess the long-term impact of childhood lead exposure on the neurosubstrate of language function and brain organization. METHODS Young adults from the Cincinnati Lead Study were recruited to undergo functional magnetic resonance image scanning while performing a verb generation task. These subjects have been followed from birth through early childhood with extensive documentation of lead exposure, neuropsychology, and behavior. Forty-two subjects provided useful imaging data. The locale, strength, and the correlation between brain language activation and childhood blood lead concentration were studied. RESULTS After adjusting for potential confounders, the activation in left frontal cortex, adjacent to Broca's area, and left middle temporal gyrus, including Wernicke's area, were found to be significantly associated with diminished activation in subjects with higher mean childhood blood lead levels, whereas the compensatory activation in the right hemisphere homolog of Wernicke's area was enhanced in subjects with higher blood lead levels. CONCLUSION This study indicates that childhood lead exposure has a significant and persistent impact on brain reorganization associated with language function.
Collapse
Affiliation(s)
- Weihong Yuan
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lidsky TI, Schneider JS. Adverse effects of childhood lead poisoning: the clinical neuropsychological perspective. ENVIRONMENTAL RESEARCH 2006; 100:284-93. [PMID: 16442997 DOI: 10.1016/j.envres.2005.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 03/01/2005] [Accepted: 03/08/2005] [Indexed: 05/06/2023]
Abstract
Elevated blood lead levels in children can result in brain injury and, as a consequence, have negative effects on cognitive functioning and behavior. Risk assessment studies have focused on psychological measures, especially IQ, and also school achievement and behavioral adjustment as endpoints. Such studies, like epidemiological work in other areas, by necessity examine effects in large groups rather than in individuals. Since the peer-reviewed literature primarily describes those adverse effects noted in epidemiological studies, little or no attention has been directed to what is observed in the individual. The present review describes the presentation of individual lead-poisoned children from the perspective of the clinical neuropsychologist. The sequelae of lead poisoning typically observed in evaluation of individuals provide information in addition to that gained from risk assessment studies and has implications for the mechanisms and treatment of this disease. In addition, attention to certain aspects of individual case presentation does provide information relevant to issues of public health.
Collapse
Affiliation(s)
- T I Lidsky
- Department of Psychobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA.
| | | |
Collapse
|
13
|
Koger SM, Schettler T, Weiss B. Environmental Toxicants and Developmental Disabilities: A Challenge for Psychologists. AMERICAN PSYCHOLOGIST 2005; 60:243-55. [PMID: 15796678 DOI: 10.1037/0003-066x.60.3.243] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Developmental, learning, and behavioral disabilities are a significant public health problem. Environmental chemicals can interfere with brain development during critical periods, thereby impacting sensory, motor, and cognitive function. Because regulation in the United States is based on limited testing protocols and essentially requires proof of harm rather than proof of lack of harm, some undefined fraction of these disabilities may reflect adverse impacts of this "vast toxicological experiment" (H. L. Needleman, as quoted in B. Weiss & P. J. Landrigan, 2000, p. 373). Yet the hazards of environmental pollutants are inherently preventable. Psychologists can help prevent developmental disabilities by mobilizing and affecting public policy, educating and informing consumers, contributing to interdisciplinary research efforts, and taking action within their own homes and communities to reduce the toxic threat to children.
Collapse
Affiliation(s)
- Susan M Koger
- Department of Psychology, Willamette University, Salem, OR 97301, USA.
| | | | | |
Collapse
|
14
|
Hasan MY, Alshuaib WB, Adem A, Singh S, Fahim MA. alpha-Tocopherol modifies lead induced functional changes at murine neuromuscular junction. Free Radic Res 2005; 38:1321-8. [PMID: 15763956 DOI: 10.1080/10715760400017236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Lead impacts neuromuscular junction and might induce skeletal muscle weakness. Antioxidants may prevent toxic actions of lead on muscle. In this study, resting membrane potentials, endplate potentials, miniature endplate potentials (MEPPs) and isometric twitch tensions were recorded to investigate effects of alpha-tocopherol (Vitamin E) on lead induced changes at murine dorsiflexor muscle. Moreover, levels of endplate nicotinic receptors were measured by receptor autoradiography. Forty rats were divided into four groups (lead alone, alpha-tocopherol, lead plus alpha-tocopherol and saline). Lead (1 mg/kg, i.p.), was administered daily for 2 weeks and alpha-tocopherol (100 mg/kg, i.p.) was given daily for 3 weeks. Lead treatment significantly reduced twitch tension (from 4.4+/-0.4 to 2.2+/-0.3 g) and delayed half time of decay. MEPP frequencies and quantal content were also significantly reduced after lead treatment. Pretreatment with alpha-tocopherol reversed twitch tension reduction (4.1+/-0.3 g) and modified lead induced delay in half time of decay. Similarly, alpha-tocopherol modified the negative actions of lead exposure on MEPP frequencies and quantal content. Receptor autoradiographic studies revealed significant increase of nicotinic receptor levels at the endplate region of flexor muscle in lead treated mice. However, animals treated with lead plus alpha-tocopherol showed significantly decreased levels of nicotinic receptors. alpha-Tocopherol appears to protect against lead induced neuromuscular dysfunction. These effects of alpha-tocopherol are possibly mediated via a free radical mechanism or modification of calcium homeostasis.
Collapse
Affiliation(s)
- M Y Hasan
- Department of Pharmacology, Faculty of Medicine, UAE University, Al-Ain, United Arab Emirates
| | | | | | | | | |
Collapse
|
15
|
Kordas K, Lopez P, Rosado JL, García Vargas G, Alatorre Rico J, Ronquillo D, Cebrián ME, Stoltzfus RJ. Blood lead, anemia, and short stature are independently associated with cognitive performance in Mexican school children. J Nutr 2004; 134:363-71. [PMID: 14747673 DOI: 10.1093/jn/134.2.363] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lead exposure and nutritional factors are both associated with cognitive performance. Lead toxicity and nutritional status are also associated with each other. We examined whether nutritional status variables account for part or all of the association between cognitive performance and lead exposure. First-grade children (n = 724) ages 6-8 y, attending Mexican public schools located in the vicinity of a metal foundry were asked to participate and 602 enrolled in the study. Blood lead, iron status, anemia, anthropometry, and cognitive function were assessed. Results from 7 standardized tests are presented here. The mean blood lead concentration was 11.5 +/- 6.1 micro g/dL (0.56 +/- 0.30 micro mol/L) and 50% of the children had concentrations >10 micro g/dL (0.48 micro mol/L). The prevalence of mild anemia (<124 g/L) was low (10%) and stunting (<2 SD) was nonexistent (2.3%). In bivariate analyses, lead was negatively associated with 4 cognitive tests and was also inversely correlated with iron status, height-for-age Z scores, and head circumference. In multivariate models, the association between lead and cognitive performance was not strongly affected by nutritional variables, suggesting that the relation of lead to cognition is not explained by lead's relation to iron deficiency anemia or growth retardation. In multivariate models, hemoglobin concentration was also positively associated with Peabody Picture Vocabulary Test and Number Sequencing performance, whereas serum ferritin was negatively related to the Coding subscale of the Wechsler Intelligence Scales for Children-Revised Mexican Version (WISC-RM).
Collapse
Affiliation(s)
- Katarzyna Kordas
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
| | | | | | | | | | | | | | | |
Collapse
|