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Singh S, Sharma P, Pal N, Kumawat M, Shubham S, Sarma DK, Tiwari RR, Kumar M, Nagpal R. Impact of Environmental Pollutants on Gut Microbiome and Mental Health via the Gut–Brain Axis. Microorganisms 2022; 10:microorganisms10071457. [PMID: 35889175 PMCID: PMC9317668 DOI: 10.3390/microorganisms10071457] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 02/01/2023] Open
Abstract
Over the last few years, the microbiome has emerged as a high-priority research area to discover missing links between brain health and gut dysbiosis. Emerging evidence suggests that the commensal gut microbiome is an important regulator of the gut–brain axis and plays a critical role in brain physiology. Engaging microbiome-generated metabolites such as short-chain fatty acids, the immune system, the enteric nervous system, the endocrine system (including the HPA axis), tryptophan metabolism or the vagus nerve plays a crucial role in communication between the gut microbes and the brain. Humans are exposed to a wide range of pollutants in everyday life that impact our intestinal microbiota and manipulate the bidirectional communication between the gut and the brain, resulting in predisposition to psychiatric or neurological disorders. However, the interaction between xenobiotics, microbiota and neurotoxicity has yet to be completely investigated. Although research into the precise processes of the microbiota–gut–brain axis is growing rapidly, comprehending the implications of environmental contaminants remains challenging. In these milieus, we herein discuss how various environmental pollutants such as phthalates, heavy metals, Bisphenol A and particulate matter may alter the intricate microbiota–gut–brain axis thereby impacting our neurological and overall mental health.
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Affiliation(s)
- Samradhi Singh
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Poonam Sharma
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Namrata Pal
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Manoj Kumawat
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Swasti Shubham
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Devojit Kumar Sarma
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Rajnarayan R. Tiwari
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
| | - Manoj Kumar
- National Institute for Research in Environmental Health, Bhopal 462030, India; (S.S.); (P.S.); (N.P.); (M.K.); (S.S.); (D.K.S.); (R.R.T.)
- Correspondence: (M.K.); (R.N.)
| | - Ravinder Nagpal
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL 32302, USA
- Correspondence: (M.K.); (R.N.)
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Vlasak T, Jordakieva G, Gnambs T, Augner C, Crevenna R, Winker R, Barth A. Blood lead levels and cognitive functioning: A meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 668:678-684. [PMID: 30856576 DOI: 10.1016/j.scitotenv.2019.03.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 06/09/2023]
Abstract
OBJECTIVE The neurotoxicity of lead is well-known and even low exposure levels potentially impact neurocognitive abilities. This metaanalysis aimed to investigate associations between neurocognitive performance and lead exposure in adults and further assess potential effect thresholds. MATERIAL AND METHODS Articles indexed in Medline published until January 2017 reporting associations between lead exposure, blood lead, cognitive abilities and sensomotoric performance were included. The unbiased, standardized mean differences g between lead exposure and control groups extracted from the primary studies were pooled using a three-level, random-effects meta-analytic model with a restricted maximum likelihood estimator. Moderator analyses were conducted using weighted, mixedeffects regression analyses. RESULTS We identified 22 articles (n=3,849 participants, mean age 39.94±7.87years) published between 1976 and 2014 reporting lead exposure effects on cognitive and sensomotoric parameters (verbal abilities, visuospatial abilities, memory, attention, psychomotor function). On average, blood lead concentrations were 21.09±6.44 μg/dl higher in exposed than in control subjects. After exclusion of outliers, the random-effects three-level meta-analysis identified a significant (p<.001) pooled mean difference between exposure and control groups. Except for a smaller effect in the digit symbol test (p<.05), lead exposure did not result in different outcomes across the examined cognitive measures. Based on a marginally significant (p=.06) effect of difference in exposure levels, a blood lead increase of 10 μg/dl translated into a decline in cognitive abilities of Hedges g=.09. CONCLUSIONS Neurocognitive performance in adults with occupational or environmental lead exposure was significant impaired with regard to the examined parameters. However, further studies are needed for the determination of effect thresholds and reversibility.
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Affiliation(s)
- Thomas Vlasak
- Institute for Psychology, Sigmund Freud University Linz, Linz, Austria
| | - Galateja Jordakieva
- University Department of Physical Medicine, Rehabilitation and Occupational Medicine, Medical University of Vienna, Vienna, Austria
| | - Timo Gnambs
- Leibniz-Institute for Educational Trajectories, Bamberg, Germany; Institute of Education and Psychology, Johannes Keppler University Linz, Linz, Austria
| | - Christoph Augner
- IGGMB-Health Research Institute, University Clinics of the Paracelsus Medical University, Salzburg, Austria
| | - Richard Crevenna
- University Department of Physical Medicine, Rehabilitation and Occupational Medicine, Medical University of Vienna, Vienna, Austria
| | - Robert Winker
- Health and Prevention Center of the Insurance Institution for the Vienna Employee, Vienna, Austria
| | - Alfred Barth
- Institute for Psychology, Sigmund Freud University Linz, Linz, Austria.
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Sachdeva C, Thakur K, Sharma A, Sharma KK. Lead: Tiny but Mighty Poison. Indian J Clin Biochem 2018; 33:132-146. [PMID: 29651203 PMCID: PMC5891462 DOI: 10.1007/s12291-017-0680-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/11/2017] [Indexed: 01/24/2023]
Abstract
The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.
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Affiliation(s)
- Chaffy Sachdeva
- Department of Biochemistry, Dr. Yashwant Singh Parmar Government Medical College, Nahan, Distt. Sirmaur, Himachal Pradesh 173001 India
| | - Kshema Thakur
- Department of Biochemistry, Dr. Yashwant Singh Parmar Government Medical College, Nahan, Distt. Sirmaur, Himachal Pradesh 173001 India
| | - Aditi Sharma
- Department of Microbiology and Community Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, 160012 India
| | - Krishan Kumar Sharma
- Department of Biochemistry, Dr. Yashwant Singh Parmar Government Medical College, Nahan, Distt. Sirmaur, Himachal Pradesh 173001 India
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Farooqui Z, Bakulski KM, Power MC, Weisskopf MG, Sparrow D, Spiro A, Vokonas PS, Nie LH, Hu H, Park SK. Associations of cumulative Pb exposure and longitudinal changes in Mini-Mental Status Exam scores, global cognition and domains of cognition: The VA Normative Aging Study. ENVIRONMENTAL RESEARCH 2017; 152:102-108. [PMID: 27770710 PMCID: PMC5135609 DOI: 10.1016/j.envres.2016.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/23/2016] [Accepted: 10/11/2016] [Indexed: 05/16/2023]
Abstract
BACKGROUND Lead (Pb) exposure has been associated with poorer cognitive function cross-sectionally in aging adults, however the association between cumulative Pb exposure and longitudinal changes in cognition is little characterized. METHODS In a 1993-2007 subcohort of the VA Normative Aging Study (Mini-mental status exam (MMSE) n=741; global cognition summary score n=715), we used linear mixed effects models to test associations between cumulative Pb exposure (patella or tibia bone Pb) and repeated measures of cognition (MMSE, individual cognitive tests, and global cognition summary). Cox proportional hazard modeling assessed the risk of an MMSE score falling below 25. RESULTS Among men 51-98 at baseline, higher patella Pb concentration (IQR: 21μg/g) was associated with -0.13 lower baseline MMSE (95% CI: -0.25, -0.004) and faster longitudinal MMSE decline (-0.016 units/year, 95% CI: -0.032, -0.0004) over 15 years. Each IQR increase in patella Pb was associated with increased risk of a MMSE score below 25 (HR=1.21, 95% CI: 0.99, 1.49; p=0.07). There were no significant associations between Pb and global cognition (both baseline and longitudinal change). Patella Pb was associated with faster longitudinal decline in Word List Total Recall in the language domain (0.014 units/year, 95% CI: -0.026, -0.001) and Word List Delayed Recall in the memory domain (0.014 units/year, 95% CI: -0.027, -0.002). We found weaker associations with tibia Pb. CONCLUSIONS Cumulative Pb exposure is associated with faster declines in MMSE and Word List Total and Delayed Recall tests. These findings support the hypothesis that Pb exposure accelerates cognitive aging.
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Affiliation(s)
- Zishaan Farooqui
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Kelly M Bakulski
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Melinda C Power
- Department of Epidemiology and Biostatistics, George Washington University Milken Institute of Public Health, Washington, DC, USA
| | - Marc G Weisskopf
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - David Sparrow
- VA Normative Aging Study, Veterans Affairs Boston Health Care System, Boston, MA, USA; Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Avron Spiro
- VA Normative Aging Study, Veterans Affairs Boston Health Care System, Boston, MA, USA; Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA; Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Pantel S Vokonas
- VA Normative Aging Study, Veterans Affairs Boston Health Care System, Boston, MA, USA; Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Linda H Nie
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Howard Hu
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Sung Kyun Park
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA; Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
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Bellinger DC, Matthews-Bellinger JA, Kordas K. A developmental perspective on early-life exposure to neurotoxicants. ENVIRONMENT INTERNATIONAL 2016; 94:103-112. [PMID: 27235688 DOI: 10.1016/j.envint.2016.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/14/2016] [Accepted: 05/14/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective. OBJECTIVES The goal of this paper is to describe the key principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures. METHODS Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention. DISCUSSION Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades. CONCLUSION Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02112, USA; Department of Psychiatry, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
| | - Julia A Matthews-Bellinger
- Department of Psychiatry, University of Massachusetts Medical School, Boston Psychoanalytic Society and Institute, 19 Fair Oaks Park, Needham, MA 02492, USA.
| | - Katarzyna Kordas
- Department of Epidemiology and Environmental Health, University at Buffalo, 270 Farber Hall, Buffalo, NY 14214, USA.
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Ravibabu K, Barman T, Rajmohan HR. Serum neuron-specific enolase, biogenic amino-acids and neurobehavioral function in lead-exposed workers from lead-acid battery manufacturing process. THE INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE 2015; 6:50-7. [PMID: 25588226 PMCID: PMC6977058 DOI: 10.15171/ijoem.2015.436] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/23/2014] [Indexed: 11/22/2022]
Abstract
Background: The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). Methods: In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests—simple reaction time (SRT), symbol digit substitution test (SDST), and serial digit learning test (SDLT). Results: There was a significant correlation (r 0.199, p<0.05) between SDST and BLL. SDLT and SRT had also a significant positive correlation (r 0.238, p<0.01). NSE had a negative correlation (r –0.194, p<0.05) with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Conclusion: Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the "attention and perception" (SDST).
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Affiliation(s)
- K Ravibabu
- Regional Occupational Health Centre (Southern), Nirmal Bhavan, ICMR Complex, Kannamangala (Post), Devanahalli, Bangalore-562110, Karnataka, India.
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Abstract
Psychiatric disorders are associated with long-term disability and huge social and economic costs. The possible influence of heavy metals exposure on public health remains a matter of concern. A recurring research question that persisted among researchers in neuropsychiatry has been “are psychiatric patients more likely to have a high body burden of lead or other heavy metals?” This is an update account on the role of lead and cadmium in psychiatry. This review, which has employed search words like “lead and cadmium in psychiatry”, “lead and cadmium in schizophrenia”, “lead and cadmium in psychosis” in citation indices such as PubMed, Google Scholar, Scirus, and Scopus. A total of 415 articles were found; 60 fulfiled the inclusion criteria. Evidence-based information suggests that lead and cadmium may be involved in psychiatry. Should environmental lead and cadmium be implicated in the etiogenesis of psychiatry given the characteristic high environmental pollution in Sub Sahara Africa, it is worthwhile for toxicologists and scientists in Sub-Sahara Africa to investigate if lead and cadmium can become additional biomarkers in the diagnosis of psychiatric disorders.
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Affiliation(s)
- Orish Ebere Orisakwe
- Department of Experimental Pharmacology and Clinical Pharmacy, Toxicology Unit, Clinical Pharmacy, Faculty of Pharmacy, University of Port-Hacourt, Rivers State, Nigeria
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Pfadenhauer LM, Burns J, Rohwer A, Rehfuess EA. A protocol for a systematic review of the effectiveness of interventions to reduce exposure to lead through consumer products and drinking water. Syst Rev 2014; 3:36. [PMID: 24731516 PMCID: PMC4049510 DOI: 10.1186/2046-4053-3-36] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/27/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The toxic heavy metal lead continues to be a leading environmental risk factor, with the number of attributable deaths having doubled between 1990 and 2010. Although major sources of lead exposure, in particular lead in petrol, have been significantly reduced in recent decades, lead is still used in a wide range of processes and objects, with developing countries disproportionally affected. The objective of this systematic review is to assess the effectiveness of regulatory, environmental and educational interventions for reducing blood lead levels and associated health outcomes in children, pregnant women and the general population. METHODS/DESIGN The databases MEDLINE, Embase and the Global Health Library (GHL) will be searched using a sensitive search strategy. Studies in English, German, French, Spanish, Italian or Afrikaans will be screened according to predefined inclusion and exclusion criteria. We will consider randomized and non-randomized studies accepted by the Cochrane Effective Practice and Organization of Care (EPOC) Group, as well as additional non-randomized studies. Screening of titles and abstracts will be performed by one author. Full texts of potentially relevant studies will be independently assessed for eligibility by two authors. A single author will extract data, with a second reviewer checking the extraction form. Risk of bias will be assessed by two researchers using the Graphical Appraisal Tool for Epidemiological studies, as modified by the Centre for Public Health at the UK National Institute for Health and Care Excellence. Any inconsistencies in the assessment of eligibility, data extraction or quality appraisal will be resolved through discussion. Where two or more studies report the primary outcome blood lead levels within the same population group, intervention category and source of lead exposure, data will be pooled using random effects meta-analysis. In parallel, harvest plots as a graphical method of evidence synthesis will be used to present findings for blood lead levels and secondary outcomes. DISCUSSION This systematic review will fill an important evidence gap with respect to the effectiveness of interventions to reduce lead in consumer products and drinking water in the context of new WHO guidelines for the prevention and management of lead poisoning. It will also contribute to setting a future research agenda.
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Affiliation(s)
- Lisa Maria Pfadenhauer
- Institute for Medical Informatics, Biometry and Epidemiology, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany.
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Grashow R, Spiro A, Taylor KM, Newton K, Shrairman R, Landau A, Sparrow D, Hu H, Weisskopf M. Cumulative lead exposure in community-dwelling adults and fine motor function: comparing standard and novel tasks in the VA normative aging study. Neurotoxicology 2013; 35:154-61. [PMID: 23370289 DOI: 10.1016/j.neuro.2013.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIMS Lead exposure in children and occupationally exposed adults has been associated with reduced visuomotor and fine motor function. However, associations in environmentally exposed adults remain relatively unexplored. To address this, we examined the association between cumulative lead exposure-as measured by lead in bone-and performance on the grooved pegboard (GP) manual dexterity task, as well as on handwriting tasks using a novel assessment approach, among men in the VA Normative Aging Study (NAS). METHODS GP testing was done with 362 NAS participants, and handwriting assessment with 328, who also had tibia and patella lead measurements made with K-X-Ray Fluorescence (KXRF). GP scores were time (s) to complete the task with the dominant hand. The handwriting assessment approach assessed the production of signature and cursive lowercase l and m letter samples. Signature and lm task scores reflect consistency in repeated trials. We used linear regression to estimate associations and 95% confidence intervals (CI) with adjustment for age, smoking, education, income and computer experience. A backward elimination algorithm was used in the subset with both GP and handwriting assessment to identify variables predictive of each outcome. RESULTS The mean (SD) participant age was 69.1 (7.2) years; mean patella and tibia concentrations were 25.0 (20.7)μg/g and 19.2 (14.6)μg/g, respectively. In multivariable-adjusted analyses, GP performance was associated with tibia (β per 15μg/g bone=4.66, 95% CI: 1.73, 7.58, p=0.002) and patella (β per 20μg/g=3.93, 95% CI: 1.11, 6.76, p=0.006). In multivariable adjusted models of handwriting production, only the lm-pattern task showed a significant association with tibia (β per 15μg/g bone=1.27, 95% CI: 0.24, 2.29, p=0.015), such that lm pattern production was more stable with increasing lead exposure. GP and handwriting scores were differentially sensitive to education, smoking, computer experience, financial stability, income and alcohol consumption. CONCLUSIONS Long-term cumulative environmental lead exposure was associated with deficits in GP performance, but not handwriting production. Higher lead appeared to be associated with greater consistency on the lm task. Lead sensitivity differences could suggest that lead affects neural processing speed rather than motor function per se, or could result from distinct brain areas involved in the execution of different motor tasks.
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MESH Headings
- Age Factors
- Aged
- Aged, 80 and over
- Aging/psychology
- Algorithms
- Body Burden
- Central Nervous System/drug effects
- Central Nervous System/physiopathology
- Environmental Exposure/adverse effects
- Environmental Pollutants/adverse effects
- Environmental Pollutants/metabolism
- Handwriting
- Humans
- Lead/adverse effects
- Lead/metabolism
- Lead Poisoning, Nervous System, Adult/etiology
- Lead Poisoning, Nervous System, Adult/metabolism
- Lead Poisoning, Nervous System, Adult/physiopathology
- Lead Poisoning, Nervous System, Adult/psychology
- Linear Models
- Male
- Middle Aged
- Motor Activity
- Multivariate Analysis
- Neuropsychological Tests
- Patella/metabolism
- Predictive Value of Tests
- Risk Factors
- Socioeconomic Factors
- Spectrometry, X-Ray Emission
- Tibia/metabolism
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Affiliation(s)
- Rachel Grashow
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
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Kordas K, Ardoino G, Ciccariello D, Mañay N, Ettinger AS, Cook CA, Queirolo EI. Association of maternal and child blood lead and hemoglobin levels with maternal perceptions of parenting their young children. Neurotoxicology 2011; 32:693-701. [PMID: 21925208 DOI: 10.1016/j.neuro.2011.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 06/15/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022]
Abstract
Biological and psychosocial factors affect child development and behavior. Whereas biological underpinnings behind the neurotoxic effects of lead are studied extensively, the effects of psychosocial factors contributing to poor behavioral outcomes in lead-exposed children are not well understood. Parental attributes and practices may moderate or mediate the effects of lead on children's behavioral outcomes. We investigated the hypothesis that maternal and child lead and hemoglobin levels are associated with maternal perceptions of their parenting. Specifically, we hypothesized that children with higher blood lead (BLL) and lower hemoglobin concentrations would be associated with poorer maternal self-assessments of their parenting skills or the mother-child relationship. Children aged 13-55 months and their mothers (n=109) were recruited from among the participants of a previous lead and anemia screening study and from preschools in Montevideo, Uruguay. The mother-child pair attended two study visits: one to collect biological samples and answer demographic and child questionnaires, including statements regarding parenting; and a second to evaluate maternal IQ, depression and stress, and child development. Of the children, 51.6% had blood lead concentrations (BLLs) ≥ 5 μg/dL, 18.0% had anemia, and 8% had both conditions. Among mothers, 48.4% had BLLs ≥ 5 μg/dL, 16.0% had anemia, and 11% had both. BLLs ≥ 5 μg/dL in mother or child were associated with lower maternal perceptions of being skilled at discipline (p<0.05). Maternal anemia was associated with lower likelihood that mothers would let their children explore and play (p<0.05), whereas child anemia was associated with maternal perception of lower emotional support (p<0.01). In addition to shared environmental exposures, parenting and family interactions need to be considered as potentially contributing factors to poorer outcomes in lead-exposed children.
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Affiliation(s)
- Katarzyna Kordas
- Department of Nutritional Sciences, Pennsylvania State University, University Park, PA 16802, USA.
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Corbacio M, Brown S, Dubois S, Goulet D, Prato FS, Thomas AW, Legros A. Human cognitive performance in a 3 mT power-line frequency magnetic field. Bioelectromagnetics 2011; 32:620-33. [DOI: 10.1002/bem.20676] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 04/10/2011] [Indexed: 11/07/2022]
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Golub NI, Winters PC, van Wijngaarden E. A population-based study of blood lead levels in relation to depression in the United States. Int Arch Occup Environ Health 2009; 83:771-7. [PMID: 19967393 DOI: 10.1007/s00420-009-0497-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 11/18/2009] [Indexed: 11/29/2022]
Abstract
PURPOSE Lead is a known neurotoxicant. Several studies have suggested that occupational exposure to lead may lead to depression, anxiety and other psychiatric illness, but few studies have examined environmental lead exposure and depression. We evaluated the relationship between blood lead levels (BLL) and depression in a sample representative of the US population. METHODS We analyzed data from 4,159 adults ages ≥20 who participated in the 2005-2006 cycle of the National Health and Nutrition Examination Survey (NHANES). Depression was assessed by the Patient Health Questionnaire-9 (PHQ-9). Relative risks were calculated using Poisson regression, and odds ratios were calculated with ordinal logistic regression using SUDAAN, controlling for pertinent covariates. RESULTS The risk of depression was only slightly elevated with increasing blood lead levels when lead was modeled as a categorical variable, with adjusted relative risks of 1.16 (95% confidence interval (CI) = 0.99-1.36), 1.20 (CI = 1.07-1.36) and 1.16 (CI = 0.87-1.54) for 0.89-1.40 μg/dL, 1.41-2.17 μg/dL and >2.17 μg/dL, respectively, when compared to 0-0.88 μg/dL using Poisson regression. Similar results were obtained with ordinal logistic regression. Analyses using BLL as a continuous variable did not show a significant relationship with depression. CONCLUSIONS This cross-sectional study did not provide consistent evidence for an association between environmental lead exposure and depression within the investigated blood lead levels.
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Affiliation(s)
- Natalia I Golub
- Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 644, Rochester, NY 14642, USA
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Roy A, Bellinger D, Hu H, Schwartz J, Ettinger AS, Wright RO, Bouchard M, Palaniappan K, Balakrishnan K. Lead exposure and behavior among young children in Chennai, India. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:1607-11. [PMID: 20019913 PMCID: PMC2790517 DOI: 10.1289/ehp.0900625] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 06/26/2009] [Indexed: 05/21/2023]
Abstract
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 microg/dL. Blood lead was associated with higher anxiety (beta = 0.27, p = 0.01), social problems (beta = 0.20, p = 0.02), and higher scores in the ADHD index (beta = 0.17; p = 0.05). The effect estimate was highest for global executive function (beta = 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 function and attention being particularly vulnerable domains to the effects of lead.
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Affiliation(s)
- Ananya Roy
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA.
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Asa-Mäkitaipale S, Jehkonen M, Uitti J, Vilkki J. Memory functions in recreational pistol sport shooters: does lead matter? ENVIRONMENTAL HEALTH INSIGHTS 2009; 3:13-8. [PMID: 20508753 PMCID: PMC2872573 DOI: 10.4137/ehi.s894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE The aim of our study was to examine the memory functions of pistol sport shooters using powder charges when exposure to lead is expected to be considerably lower than in occupational circumstances. METHODS A neuropsychological battery of memory and intelligence tests was administered to 20 sport shooters and 20 controls whose mean ages (SDs) were 55 (9.6) and 54 (9.3) years respectively. Memory functions were evaluated with three subtests of the Wechsler Memory Scale - Revised (WMS-R) and an incidental memory test. Intelligence was assessed with four subtests of the Wechsler Adult Intelligence Scale - Revised (WAIS-R). The level of alcohol consumption and depression were examined in both groups. Blood lead level was determined among the shooters. RESULTS The shooters performed worse than the controls in the tests of incidental and logical memory. The groups did not differ in intelligence, mood or alcohol consumption. The mean (SD) blood lead level of the sport shooters was 0.52 mumol/L (0.40), responding 10.76 mug/dl (8.28). CONCLUSIONS Low lead exposure in recreational shooting conditions may impair verbal memory. Therefore it is important to ensure that lead exposure is prevented among those shooting for sport.
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Affiliation(s)
- Sanna Asa-Mäkitaipale
- South Karelian Central Hospital, Department of Neurology, Lappeenranta, Finland
- University of Helsinki, Department of Psychology, Helsinki, Finland
| | - Mervi Jehkonen
- University of Tampere, Department of Psychology, Tampere, Finland
- Correspondence: Mervi Jehkonen, University of Tampere, Department of Psychology, FIN-33014 University of Tampere, Finland. Fax: +358 3 3551 7345;
| | - Jukka Uitti
- Finnish Institute of Occupational Health, Tampere, Finland
- Clinic of Occupational Medicine, Tampere University Hospital, Tampere, Finland
| | - Juhani Vilkki
- University of Helsinki, Department of Psychology, Helsinki, Finland
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Interaction of the delta-aminolevulinic acid dehydratase polymorphism and lead burden on cognitive function: the VA normative aging study. J Occup Environ Med 2009; 50:1053-61. [PMID: 18784554 DOI: 10.1097/jom.0b013e3181792463] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE We evaluated the modifying influence of a delta-aminolevulinic acid dehydratase (ALAD) polymorphism on the relation between lead burden and cognition among older men. METHODS Information on ALAD genotype, lead measurements, potential confounders, and cognitive testing was collected from 982 participants. For each cognitive test and lead biomarker, we fit separate multiple linear regression models, which included an interaction term for ALAD genotype and the lead biomarker and adjusted for potential confounders. RESULTS With higher levels of tibia lead, ALAD 1-2/2-2 carriers exhibited worse performance on a spatial copying test in comparison with ALAD 1-1 carriers (P interaction = 0.03). However, there was no consistent pattern of an ALAD genotype-lead interaction for the other tests. CONCLUSIONS The results provide some evidence that ALAD genotype may modify the relation between lead and cognition among older men with low lead burden. However, future work in this area is needed to confirm these suggestive findings.
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Schwartz BS, Stewart WF. Lead and cognitive function in adults: a questions and answers approach to a review of the evidence for cause, treatment, and prevention. Int Rev Psychiatry 2007; 19:671-92. [PMID: 18092244 DOI: 10.1080/09540260701797936] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Lead has been extensively used worldwide in gasoline, consumer products, commercial applications, and industrial settings. Its use in gasoline and paint has been particularly hazardous to public health leading to widespread population exposure and substantial lifetime cumulative doses in most Americans over age 40 years. Cumulative lead dose can be estimated by measuring the current concentration of lead in tibia bone by X-ray fluorescence. A growing literature has documented that tibia lead levels are associated with decrements in cognitive function and declines in cognitive function over time. Furthermore, there are several interesting lines of biochemical and epidemiological investigation that have demonstrated potential links of lead to neurodegenerative diseases. These studies support the inference that a proportion of what has been termed 'normal' age-related cognitive decline may, in fact, be due to exposure to neurotoxicants such as lead. Well-designed studies of cumulative lead dose and Alzheimer's disease risk should be conducted to follow-up on these leads. The strong and compelling body of literature on lead and cognitive dysfunction and decline also supports a need for intervention studies to prevent lead-related cognitive decline.
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Affiliation(s)
- Brian S Schwartz
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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Ademuyiwa O, Ugbaja RN, Rotimi SO, Abam E, Okediran BS, Dosumu OA, Onunkwor BO. Erythrocyte acetylcholinesterase activity as a surrogate indicator of lead-induced neurotoxicity in occupational lead exposure in Abeokuta, Nigeria. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2007; 24:183-188. [PMID: 21783808 DOI: 10.1016/j.etap.2007.05.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 04/29/2007] [Accepted: 05/01/2007] [Indexed: 05/31/2023]
Abstract
Dose-effect and dose-response relationships in occupational neurotoxicology are rarely studied by means of biochemical methods. In order to investigate the potential neurotoxic effects of lead during occupational exposure to this metal, the activity of erythrocyte acetylcholinesterase (AcChE), as well as blood pressure and pulse, were determined in various artisans in Abeokuta, Nigeria, who have been shown to be occupationally exposed to lead, and these were related to blood lead levels. AcChE activity in the artisans was inhibited to varying extents. While AcChE activity was inhibited to the tune of 39% in the male petrol station attendants, the inhibition amounted to 32% in female petrol station attendants. In other artisans, AcChE inhibition ranged from 31% in the welders to 38% in painters. The lowest inhibition of 15% was obtained in the panel beaters. Correlations, as calculated by Pearson's method, revealed a significant (p<0.001) inverse linear relationship between AcChE activity and blood lead levels (r=-0.40; y=-120.38x+13935.59; p<0.001). Blood pressure and pulse were not significantly different between control and lead-exposed subjects. Our findings suggest that erythrocyte AcChE activity could be used as a biomarker of lead-induced neurotoxicity in occupationally exposed subjects.
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Affiliation(s)
- O Ademuyiwa
- Department of Biochemistry, University of Agriculture, Abeokuta, Nigeria; Toxicokinetics Section, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow 226001, India
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Kosnett MJ, Wedeen RP, Rothenberg SJ, Hipkins KL, Materna BL, Schwartz BS, Hu H, Woolf A. Recommendations for medical management of adult lead exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:463-71. [PMID: 17431500 PMCID: PMC1849937 DOI: 10.1289/ehp.9784] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 12/21/2006] [Indexed: 05/14/2023]
Abstract
Research conducted in recent years has increased public health concern about the toxicity of lead at low dose and has supported a reappraisal of the levels of lead exposure that may be safely tolerated in the workplace. In this article, which appears as part of a mini-monograph on adult lead exposure, we summarize a body of published literature that establishes the potential for hypertension, effects on renal function, cognitive dysfunction, and adverse female reproductive outcome in adults with whole-blood lead concentrations < 40 microg/dL. Based on this literature, and our collective experience in evaluating lead-exposed adults, we recommend that individuals be removed from occupational lead exposure if a single blood lead concentration exceeds 30 microg/dL or if two successive blood lead concentrations measured over a 4-week interval are > or = 20 microg/dL. Removal of individuals from lead exposure should be considered to avoid long-term risk to health if exposure control measures over an extended period do not decrease blood lead concentrations to < 10 microg/dL or if selected medical conditions exist that would increase the risk of continued exposure. Recommended medical surveillance for all lead-exposed workers should include quarterly blood lead measurements for individuals with blood lead concentrations between 10 and 19 microg/dL, and semiannual blood lead measurements when sustained blood lead concentrations are < 10 microg/dL. It is advisable for pregnant women to avoid occupational or avocational lead exposure that would result in blood lead concentrations > 5 microg/dL. Chelation may have an adjunctive role in the medical management of highly exposed adults with symptomatic lead intoxication but is not recommended for asymptomatic individuals with low blood lead concentrations.
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Affiliation(s)
- Michael J Kosnett
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80202, USA.
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Blond M, Netterstrom B. Neuromotor function in a cohort of Danish steel workers. Neurotoxicology 2007; 28:336-44. [PMID: 17030061 DOI: 10.1016/j.neuro.2006.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 06/09/2006] [Accepted: 07/18/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE With a longitudinal design to evaluate possible neuromotor impairment in a cohort of steel workers exposed to metal dust. MATERIAL Ninety-two employees from a steel works were examined in 1989 and 1995. Sixty were re-examined in 2003. A non-matched control group was examined in 1996 (n=19) and in 2003 (n=14). Median blood manganese in 1989, 1995 and 2003 was 149, 171 and 155 nmol/l. Median blood lead in 1989 and 2003 was 0.76 and 0.22 micromol/l. Median air concentration of manganese at the steel works was estimated to be 0.11 mg/m3 in 1970s and was 0.03 mg/m3 in 1990s. Median air concentration of lead was estimated to be 0.13 mg/m3 in 1970s and was 0.01 mg/m3 in 1990s. METHOD The Catsys 2000 system developed by Danish Product Development is computer-based device for measuring hand tremor, hand coordination and reaction time. RESULTS Over all there were no statistically significant differences in neuromotor function between the participating steel workers, non-participating steel workers and controls in 1995/1996. Only reaction time for the right hand was slower for the participating steel workers. Compared with the control group the steel workers showed a decline in the ability to perform fast precise hand pronation/supination and finger tapping from 1995 to 2005. Correlation analysis showed no associations between test results for fast hand coordination and blood manganese and lead. Only seniority was associated with deterioration of beat regulation of fast pronation/supination of the hands. DISCUSSION On a group basis the changes were subclinical, but they should none the less be taken seriously. CONCLUSION Changes of neuromotor function measured as the ability to perform fast precise pronation/supination of the hands and fast precise finger tapping was shown in this cohort of steel workers. No causal relationships could be shown.
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Shih RA, Hu H, Weisskopf MG, Schwartz BS. Cumulative lead dose and cognitive function in adults: a review of studies that measured both blood lead and bone lead. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:483-92. [PMID: 17431502 PMCID: PMC1849945 DOI: 10.1289/ehp.9786] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 11/15/2006] [Indexed: 05/14/2023]
Abstract
OBJECTIVE We review empirical evidence for the relations of recent and cumulative lead dose with cognitive function in adults. DATA SOURCES A systematic search of electronic databases resulted in 21 environmental and occupational studies from 1996 to 2006 that examined and compared associations of recent (in blood) and cumulative (in bone) lead doses with neurobehavioral outcomes. DATA EXTRACTION Data were abstracted after consideration of exclusion criteria and quality assessment, and then compiled into summary tables. CONCLUSIONS At exposure levels encountered after environmental exposure, associations with bio-markers of cumulative dose (mainly lead in tibia) were stronger and more consistent than associations with blood lead levels. Similarly, in studies of former workers with past occupational lead exposure, associations were also stronger and more consistent with cumulative dose than with recent dose (in blood). In contrast, studies of currently exposed workers generally found associations that were more apparent with blood lead levels; we speculate that the acute effects of high, recent dose may mask the chronic effects of cumulative dose. There is moderate evidence for an association between psychiatric symptoms and lead dose but only at high levels of current occupational lead exposure or with cumulative dose in environmentally exposed adults.
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Affiliation(s)
- Regina A. Shih
- Division of Epidemiology, Statistics, and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland, USA
| | - Howard Hu
- Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
- Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marc G. Weisskopf
- Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
- Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Brian S. Schwartz
- Departments of Environmental Health Sciences and Epidemiology, Johns Hopkins Bloomberg School of Public Health and
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Address correspondence to B.S. Schwartz, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe St., Rm. W7041, Baltimore, Maryland 21205 USA. Telephone: (410) 955-4130. Fax: (410) 955-1811. E-mail:
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Blond M, Netterstrom B, Laursen P. Cognitive function in a cohort of Danish steel workers. Neurotoxicology 2007; 28:328-35. [PMID: 17335905 DOI: 10.1016/j.neuro.2007.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 12/12/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the level of possible cognitive impairment in a cohort of steel workers occupationally exposed to manganese and lead. MATERIAL Ninety-two employees from an electro-steel works were examined in 1989 and 1995. Fifty-three were re-examined in 2003. Median age of the participants was 53 years, median duration of employment was 24 years, median blood manganese in 1989 and 1995 was 148 and 171 nmol/l, respectively, and median blood lead in 1989 was 0.79 micromol/l. Non-participants were comparable with participants, although they had a higher level of blood manganese in 1989 (186 nmol/l) and 1995 (186 nmol/l). Manganese level in the air was estimated below 1.9 mg/m3 in the 1970s. In the 1990s, manganese level in the air was below 0.28 mg/m3 in the majority of measurements. METHOD Cognitive function was examined with the Cognitive Function Scanner, a computer-based neuropsychological test battery. From a published set of norms a subgroup (n=106) matched for gender, age and social status was extracted and used for comparison. RESULTS Learning and memory, visuomotor and visuospatial function, concentration, attention, perception and vigilance were examined. Despite many statistically significant differences between the groups, it was not possible to interpret the results for the steel workers as being better or worse. In a visuomotor subtest, the pen-to-point test, the steel workers were much less accurate than the comparison group. This could be the result of an impaired ability to make fast accurate movements. There were no associations between pen-to-point test results and duration of employment or blood levels of manganese and lead. CONCLUSION Intellectual impairment could not be shown with the Cognitive Function Scanner in this cohort of low to moderate manganese and lead exposed steel workers. A slight subclinical impairment of the visuomotor function was possibly found.
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Affiliation(s)
- Morten Blond
- Clinic of Occupational Medicine, Hilleroed Hospital, Hilleroed, Denmark.
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Weisskopf MG, Proctor SP, Wright RO, Schwartz J, Spiro A, Sparrow D, Nie H, Hu H. Cumulative lead exposure and cognitive performance among elderly men. Epidemiology 2007; 18:59-66. [PMID: 17130688 DOI: 10.1097/01.ede.0000248237.35363.29] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Recent evidence suggests that cumulative lead exposure among adults in nonoccupational settings can adversely affect cognitive function. Which cognitive domains are affected has not been explored in detail. METHODS We used nonlinear spline regressions and linear repeated-measures analysis to assess the association between scores on a battery of cognitive tests over time and both blood and bone lead concentrations in the Normative Aging Study, a cohort of community-dwelling elderly men. Bone lead was measured from 1991 through 1999 with K-shell x-ray fluorescence. A total of 1089 men with a mean (+/-standard deviation) age of 68.7 (+/-7.4) years with blood lead measurements, 761 of whom also had valid bone lead measurements, completed at least one of a battery of cognitive tests. Approximately 3.5 years later, 69% of the men had at least one repeat test. Cognitive testing was performed from 1993 through 2001. RESULTS On a cross-sectional basis, there was little association between blood or bone lead and cognitive test scores. Change in performance over time on virtually all tests worsened as bone lead increased, with the most robust effects on performance and reaction time scores on visuospatial/visuomotor tests. CONCLUSIONS Low-level cumulative exposure to lead in nonoccupational settings may adversely affect cognitive function, particularly in the visuospatial/visuomotor domain.
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Affiliation(s)
- Marc G Weisskopf
- Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA.
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Dorsey CD, Lee BK, Bolla KI, Weaver VM, Lee SS, Lee GS, Todd AC, Shi W, Schwartz BS. Comparison of patella lead with blood lead and tibia lead and their associations with neurobehavioral test scores. J Occup Environ Med 2006; 48:489-96. [PMID: 16688005 DOI: 10.1097/01.jom.0000199678.86629.3b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Lead exposure in adults is associated with worse cognitive function in cross-sectional and longitudinal studies. Previous studies have mainly examined relations with blood lead or cortical bone lead; few have examined trabecular bone lead. METHODS We performed a cross-sectional analysis of the relations of patella lead and other lead biomarkers with measures of neurobehavioral and peripheral nervous system function in 652 lead workers. RESULTS Patella lead was found to be associated with worse performance on seven of 19 tests of manual dexterity, sensory vibration threshold, and depressive symptoms. The associations of patella lead with cognitive function were essentially similar to those with blood lead or tibia lead but of somewhat lower magnitude. CONCLUSIONS In this study, measurement of patella lead did not aid causal inference regarding cognitive effects when compared with blood lead and tibia lead.
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Affiliation(s)
- Carrie D Dorsey
- Division of Occupational and Environmental Health, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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Bleecker ML, Ford DP, Vaughan CG, Lindgren KN, Tiburzi MJ, Walsh KS. Effect of lead exposure and ergonomic stressors on peripheral nerve function. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:1730-4. [PMID: 16330355 PMCID: PMC1314913 DOI: 10.1289/ehp.8106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In this study we investigated the effect of recent and chronic lead exposure, and its interaction with ergonomic stressors, on peripheral nerve function. In a cross-sectional design, we used retrospective exposure data on 74 primary lead smelter workers. We measured blood and bone lead levels and, from historical records, calculated lead dose metrics reflecting cumulative lead exposure: working-lifetime integrated blood lead (IBL) and working-lifetime weighted-average blood lead (TWA). We additionally created five metrics related to IBL that cumulated exposure only above increasing blood lead levels ranging from 20 to 60 microg/dL (IBL20-IBL60). Current perception threshold (CPT) assessed large myelinated (CPT2000), small myelinated (CPT250), and unmyelinated (CPT5) sensory nerve fibers. Using multiple linear regression, we modeled CPT on the different measures of lead dose after adjusting for relevant covariates. CPT had a curvilinear relationship with TWA, with a minimum at a TWA of 28 microg/dL. Both TWA and IBL accounted for a significant percentage of the variance of CPT2000 (DeltaR2 = 8.7% and 3.9%, respectively). As the criterion blood lead level increased from IBL20 through IBL60, so did the percentage of CPT2000 variance explained, with DeltaR2 ranging from 5.8% (p < 0.03) for IBL20 to 23.3% (p < 0.00) for IBL60. IBL60 also significantly contributed to the explanation of variance of CPT250 and significantly interacted with ergonomic stressors. Measures of chronic blood lead exposure are associated with impairment of large and small myelinated sensory nerve fibers. This effect is enhanced at the highest doses by ergonomic stressors.
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Affiliation(s)
- Margit L Bleecker
- Center for Occupational and Environmental Neurology, Baltimore, Maryland 21211, USA.
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Bleecker ML, Ford DP, Lindgren KN, Hoese VM, Walsh KS, Vaughan CG. Differential effects of lead exposure on components of verbal memory. Occup Environ Med 2005; 62:181-7. [PMID: 15723883 PMCID: PMC1740967 DOI: 10.1136/oem.2003.011346] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS To determine if verbal learning and memory requiring acquisition and retention of information is differentially affected by lead exposure. METHODS The Rey Auditory Verbal Learning Test (RAVLT), a test of verbal learning and memory, was administered to 256 English speaking lead smelter workers who had a mean (SD) age of 41 (9.4) years and employment duration of 17 (8.1) years. Lead exposure variables, based on up to 25 years of prior blood lead data, included a mean (SD) current blood lead (PbB) of 28 (8.8) microg/dl, working lifetime time weighted average blood lead (TWA) of 39 (12.3) microg/dl, and working lifetime integrated blood lead index (IBL) of 728 (434.4) microg-y/dl. Associations of these chronic and recent lead exposure variables with measures from the RAVLT were modelled through multiple linear regressions after controlling for age and educational achievement. RESULTS PbB was not associated with any of the RAVLT variables. However, TWA and IBL contributed significantly to the explanation of variance of measures of encoding/storage and retrieval but not to immediate memory span, attention, and learning. Grouping study participants by RAVLT performance according to three recognised clinical memory paradigms showed significantly higher TWA and IBL in the group with "generalised memory impairment" after adjusting for age and educational achievement. We examined recall mechanisms in each group by serial position in the word list and found stronger primacy (recall of words from the beginning of the list) in the "no impairment" and "retrieval difficulties" groups while the "generalised memory impairment" group had better performance on recency (recall of words from the end of the list). CONCLUSIONS Lead exposure over years and not PbB interfered with the organisation and recall of previously learned verbal material. Chronic lead exposure affects encoding/storage and retrieval of verbal information.
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Affiliation(s)
- M L Bleecker
- Center for Occupational and Environmental Neurology, 3901 Greenspring Ave., Suite 101, Baltimore, Maryland 21211, USA.
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Weisskopf MG, Wright RO, Schwartz J, Spiro A, Sparrow D, Aro A, Hu H. Cumulative lead exposure and prospective change in cognition among elderly men: the VA Normative Aging Study. Am J Epidemiol 2004; 160:1184-93. [PMID: 15583371 DOI: 10.1093/aje/kwh333] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Lead exposure has been found to affect cognitive function in several different populations. Whether chronic low-level environmental exposure to lead results in cognitive decline among adults has not been examined. The authors assessed the relation between biomarkers of lead exposure and change in Mini-Mental State Examination (MMSE) scores in the Normative Aging Study, a cohort of elderly US men. Bone lead was measured with K-shell x-ray fluorescence. A total of 466 men aged 67.4 (standard deviation, 6.6) years took the MMSE on two occasions that were an average of 3.5 (standard deviation, 1.1) years apart during the period 1993-2001 and had bone lead concentrations measured during the period 1991-2002. A one-interquartile range (20 microg/g of bone mineral) higher patella bone lead concentration was associated with a change in MMSE score of -0.24 (95% confidence interval: -0.44, -0.05) after adjustment for age, education, smoking, alcohol intake, and time between MMSE tests. This effect is approximately equivalent to that of aging 5 years in relation to the baseline MMSE score in study data. The association with tibia lead was weaker and that with blood lead was absent. The data suggest that higher patella bone lead levels, a marker of mobilizable accumulated lead burden, are associated with a steeper decline over time in performance on the MMSE test among nonoccupationally exposed elderly men.
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Affiliation(s)
- Marc G Weisskopf
- Department of Environmental Health, Occupational Health Program, Harvard School of Public Health, Landmark Center, 401 Park Drive, PO Box 15697, Boston, MA 02215, USA.
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Weisskopf MG, Hu H, Mulkern RV, White R, Aro A, Oliveira S, Wright RO. Cognitive deficits and magnetic resonance spectroscopy in adult monozygotic twins with lead poisoning. ENVIRONMENTAL HEALTH PERSPECTIVES 2004; 112:620-625. [PMID: 15064171 PMCID: PMC1241931 DOI: 10.1289/ehp.6687] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Seventy-one-year-old identical twin brothers with chronic lead poisoning were identified from an occupational medicine clinic roster. Both were retired painters, but one brother (J.G.) primarily removed paint and had a history of higher chronic lead exposure. Patella and tibia bone lead concentrations measured by K-X-ray fluorescence in each brother were 5-10 times those of the general population and about 2.5 times higher in J.G. than in his brother (E.G.). Magnetic resonance spectroscopy (MRS) studies examined N-acetylaspartate:creatine ratios, a marker of neuronal density. Ratios were lower in J.G. than in his brother. Scores on neurocognitive tests that assess working memory/executive function were below expectation in both twins. Short-term memory function was dramatically worse in J.G. than in his brother. These results demonstrate some of the more subtle long-term neurologic effects of chronic lead poisoning in adults. In particular, they suggest the presence of frontal lobe dysfunction in both twins, but more dramatic hippocampal dysfunction in the brother with higher lead exposure. The MRS findings are consistent with the hypothesis that chronic lead exposure caused neuronal loss, which may contribute to the impairment in cognitive function. Although a causal relation cannot be inferred, the brothers were genetically identical, with similar life experiences. Although these results are promising, further study is necessary to determine whether MRS findings correlate both with markers of lead exposure and tests of cognitive function. Nevertheless, the results point to the potential utility of MRS in determining mechanisms of neurotoxicity not only for lead but also for other neurotoxicants as well.
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Affiliation(s)
- Marc G Weisskopf
- Department of Environmental Health, Occupational Health Program, Harvard School of Public Health, Landmark Center, 401 Park Drive, PO Box 15697, Boston, MA 02215, USA.
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Fiedler N, Weisel C, Lynch R, Kelly-McNeil K, Wedeen R, Jones K, Udasin I, Ohman-Strickland P, Gochfeld M. Cognitive effects of chronic exposure to lead and solvents. Am J Ind Med 2003; 44:413-23. [PMID: 14502770 DOI: 10.1002/ajim.10287] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Occupational exposure to lead and solvents has declined steadily over the past 20 years, however, construction workers continue to be exposed to these neurotoxicants. The purpose of this study was to investigate the cognitive effects of chronic occupational exposure to lead and solvents. METHOD Based on K-XRF of tibial bone lead and occupational history of solvent exposure, subjects were classified into four exposure groups: lead (N = 40), solvent (N = 39), lead/solvent (N = 45), and control (N = 33). All subjects completed tests to assess concentration, motor skills, memory, and mood. RESULTS Relative to controls, the lead, solvent, and lead/solvent groups performed significantly more poorly on a test of verbal memory, while the lead and lead/solvent groups were slower than the solvent and control groups on a task of processing speed. Bone lead was a significant predictor of information processing speed and latency of response while solvent exposure was a significant predictor of verbal learning and memory. CONCLUSIONS Bone lead was associated with slower speed of processing while exposure to lead and/or solvents reduced efficiency of verbal learning.
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Affiliation(s)
- Nancy Fiedler
- UMDNJ-RWJ Medical School, Environmental & Occupational Health Sciences Inst., Piscataway, New Jersey 08854, USA.
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Bleecker ML, Lindgren KN, Ford DP, Tiburzi MJ. The interaction of education and cumulative lead exposure on the Mini-Mental State Examination. J Occup Environ Med 2002; 44:574-8. [PMID: 12085485 DOI: 10.1097/00043764-200206000-00021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of lead exposure on neurobehavioral performance is modified by age. Whether educational achievement can serve as an effect modifier on the lead-cognitive performance relationship is examined. The Mini-Mental State Examination (MMSE) and the reading section of the Wide Range Achievement Test-Revised (WRAT-R), a measure of educational achievement, were administered to 256 lead smelter workers. The workers had a mean (standard deviation) age of 41 (7.9) years, education of 10 (2.8) years, employment duration of 17 (8.1) years, current blood lead of 28 (8.8) micrograms/dL, and working lifetime integrated blood lead index (IBL) of 725 (434) micrograms-yr/dL. The median (range) MMSE score was 29 (19 to 30). Multiple linear regression assessed the contribution of age, WRAT-R, education, alcohol intake, cigarette use, IBL, and IBL x WRAT-R on MMSE performance. A significant IBL x WRAT-R interaction examined by stratification found a significant dose-effect relationship between IBL and MMSE, but only in the 78 workers with a WRAT-R reading grade level below 6 years. Workers with higher educational achievement compensated for the effect of lead on cognitive performance.
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Affiliation(s)
- Margit L Bleecker
- Center for Occupational and Environmental Neurology, 3901 Greenspring Avenue, Suite 101, Baltimore, MD 21211, USA.
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Schwartz BS, Lee BK, Lee GS, Stewart WF, Lee SS, Hwang KY, Ahn KD, Kim YB, Bolla KI, Simon D, Parsons PJ, Todd AC. Associations of blood lead, dimercaptosuccinic acid-chelatable lead, and tibia lead with neurobehavioral test scores in South Korean lead workers. Am J Epidemiol 2001; 153:453-64. [PMID: 11226977 DOI: 10.1093/aje/153.5.453] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The authors performed a cross-sectional study to evaluate associations between blood lead, tibia lead, and dimercaptosuccinic acid (DMSA)-chelatable lead and measures of neurobehavioral and peripheral nervous system function among 803 lead-exposed workers and 135 unexposed controls in South Korea. The workers and controls were enrolled in the study between October 1997 and August 1999. Central nervous system function was assessed with a modified version of the World Health Organization Neurobehavioral Core Test Battery. Peripheral nervous system function was assessed by measuring pinch and grip strength and peripheral vibration thresholds. After adjustment for covariates, the signs of the beta coefficients for blood lead were negative for 16 of the 19 tests and blood lead was a significant predictor of worse performance on eight tests. On average, for the eight tests that were significantly associated with blood lead levels, an increase in blood lead of 5 microg/dl was equivalent to an increase of 1.05 years in age. In contrast, after adjustment for covariates, tibia lead level was not associated with neurobehavioral test scores. Associations with DMSA-chelatable lead were similar to those for blood lead. In these currently exposed workers, blood lead was a better predictor of neurobehavioral performance than was tibia or DMSA-chelatable lead, mainly in the domains of executive abilities, manual dexterity, and peripheral motor strength.
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Affiliation(s)
- B S Schwartz
- Division of Occupational and Environmental Health, Johns Hopkins School of Hygiene and Public Health, 615 North Wolfe St., Room 7041, Baltimore, MD 21205, USA.
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Viaene MK, Masschelein R, Leenders J, De Groof M, Swerts LJ, Roels HA. Neurobehavioural effects of occupational exposure to cadmium: a cross sectional epidemiological study. Occup Environ Med 2000; 57:19-27. [PMID: 10711265 PMCID: PMC1739855 DOI: 10.1136/oem.57.1.19] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND A patient with unexplained minor behavioural changes associated with an axonal sensorimotor polyneuropathy had a history of chronic occupational exposure to cadmium (Cd). Although animal studies have shown that Cd is a potent neurotoxicant, little is known about its toxicity for the human central nervous system. The aim of this study was to investigate the toxic potential of chronic occupational exposure to Cd on neurobehavioural functions. METHODS A cross sectional epidemiological study was conducted ina group of Cd workers and an age matched control group. Eighty nine adult men (42 exposed to Cd and 47 control workers) were given a blinded standardised examination that consisted of computer assisted neurobehavioural tests (neurobehavioural examination system), a validated questionnaire to assess neurotoxic complaints (neurotoxicity symptom checklist--60, NSC-60), and a standardised self administered questionnaire to detect complaints consistent with peripheral neuropathy and dysfunction of the autonomic nervous system. Historical and current data on biomonitoring of exposure to Cd, either the highest value of Cd in urine (CdU in microgram Cd/g creatinine) of each Cd worker during work (CdUmax) or the current value (CdUcurrent) of each control, were available as well as data on microproteinuria. RESULTS Cd workers (CdUmax: mean (range), 12.6 (0.4-38.4)) performed worse than the controls (CdUcurrent: mean (range), 0.7 (0.1-2.0)) on visuomotor tasks, symbol digit substitution (p = 0.008), and simple reaction time to direction (p = 0.058) or location (p = 0.042) of a stimulus. In multiple linear regression analysis, symbol digit substitution, simple direction reaction time test, and simple location reaction time test were significantly related to CdUmax, (beta = 0.35 (p < 0.001), beta = 0.25 (p = 0.012), and beta = 0.23 (p = 0.021) respectively). More complaints consistent with peripheral neuropathy (p = 0.004), complaints about equilibrium (p = 0.015), and complaints about concentration ability (p = 0.053) were found in the group exposed to Cd than in the control group, and these variables correlated positively with CdUmax (peripheral neuropathy: beta = 0.38, p < 0.001; equilibrium: beta = 0.22, p = 0.057; concentration ability: beta = 0.27, p = 0.020). CONCLUSION Slowing of visuomotor functioning on neurobehavioural testing and increase in complaints consistent with peripheral neuropathy, complaints about equilibrium, and complaints about concentration ability were dose dependently associated with CdU. Age, exposure to other neurotoxicants, or status of renal function could not explain these findings. The present study also indicates that an excess of complaints may be detected in Cd workers before signs of microproteinuria induced by Cd occur.
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Affiliation(s)
- M K Viaene
- Department of Occupational Medicine, Catholic University of Leuven, Belgium
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Abstract
An estimated one million construction workers are currently occupationally exposed to lead. Until 1993, construction workers were not offered the protections of OSHA's 1978 standard for lead exposure in industrial activities. Preventing exposure to lead in the construction setting presents many challenges, given the rapidly and frequently changing work environment. This article reviews the adverse effects of lead on human health and presents an approach to the diagnosis, management, and prevention of lead-related illness. The medical aspects of the 1993 OSHA standard for lead in construction are described.
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Affiliation(s)
- S M Levin
- Department of Community and Preventive Medicine, Mount Sinai School of Medicine, New York, NY, USA.
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Draper WM, Ashley K, Glowacki CR, Michael PR. Industrial hygiene chemistry: keeping pace with rapid change in the workplace. Anal Chem 1999; 71:33R-60R. [PMID: 10384781 DOI: 10.1021/a19900058] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- W M Draper
- Sanitation and Radiation Laboratory, California Department of Health Services, Berkeley 94704, USA
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