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Chen E, Schreier HMC, Strunk RC, Brauer M. Chronic traffic-related air pollution and stress interact to predict biologic and clinical outcomes in asthma. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:970-5. [PMID: 18629323 PMCID: PMC2453169 DOI: 10.1289/ehp.11076] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 02/26/2008] [Indexed: 05/04/2023]
Abstract
BACKGROUND Previous research has documented effects of both physical and social environmental exposures on childhood asthma. However, few studies have considered how these two environments might interact to affect asthma. OBJECTIVE This study aimed to test interactions between chronic exposure to traffic-related air pollution and chronic family stress in predicting biologic and clinical outcomes in children with asthma. METHOD Children with asthma (n = 73, 9-18 years of age) were interviewed about life stress, and asthma-relevant inflammatory markers [cytokine production, immunoglobulin E (IgE), eosinophil counts] were measured. Parents reported on children's symptoms. Children completed daily diaries of symptoms and peak expiratory flow rate (PEFR) measures at baseline and 6 months later. Exposure to traffic-related air pollution was assessed using a land use regression model for nitrogen dioxide concentrations. RESULTS NO(2) by stress interactions were found for interleukin-5 (beta for interaction term = -0.31, p = 0.02), IgE (interaction beta = -0.29, p = 0.02), and eosinophil counts (interaction beta = -0.24, p = 0.04). These interactions showed that higher chronic stress was associated with heightened inflammatory profiles as pollution levels decreased. Longitudinally, NO(2) by stress interactions emerged for daily diary symptoms (interaction beta = -0.28, p = 0.02), parent-reported symptoms (interaction beta = -0.25, p = 0.07), and PEFR (interaction beta = 0.30, p = 0.03). These interactions indicated that higher chronic stress was associated with increases over time in symptoms and decreases over time in PEFR as pollution levels decreased. CONCLUSIONS The physical and social environments interacted in predicting both biologic and clinical outcomes in children with asthma, suggesting that when pollution exposure is more modest, vulnerability to asthma exacerbations may be heightened in children with higher chronic stress.
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Affiliation(s)
- Edith Chen
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada.
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Theppeang K, Glass TA, Bandeen-Roche K, Todd AC, Rohde CA, Schwartz BS. Gender and race/ethnicity differences in lead dose biomarkers. Am J Public Health 2008; 98:1248-55. [PMID: 18511728 DOI: 10.2105/ajph.2007.118505] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES We sought to identify predictors of lead concentrations in the blood, tibias, and patellae of older adults and to describe differences by gender, race/ethnicity, and other factors that can influence lead toxicokinetics and, thus modify health effects. METHODS Participants aged 50 to 70 years (N=1140) were randomly identified from selected neighborhoods in Baltimore, Maryland. We measured lead concentrations by anodic stripping voltammetry (in blood) and (109)Cd-induced K-shell x-ray fluorescence (in bone). We used multiple linear regression to identify predictors of lead concentrations. RESULTS Mean (SD) lead concentrations in blood, tibias, and patellae were 3.5 (2.4) mug/dL, 18.9 (12.5) mug/g, and 6.8 (18.1) mug/g, respectively. Tibia concentrations were 29% higher in African Americans than in Whites (P < .01). We observed effect modification by race/ethnicity on the association of gender and physical activity to blood lead concentrations and by gender on the association of age to tibia lead concentrations. Patella lead concentrations differed by gender; apolipoprotein E genotype modified this relation. CONCLUSIONS African Americans evidenced a prominent disparity in lifetime lead dose. Women may be at higher risk of release of lead from bone and consequent health effects because of increased bone demineralization with aging.
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Affiliation(s)
- Keson Theppeang
- Department of Environmental Health Sciences, Division of Occupational and Environmental Health, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe St, Room W7041, Baltimore, MD 21205, USA
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Wright JP, Dietrich KN, Ris MD, Hornung RW, Wessel SD, Lanphear BP, Ho M, Rae MN. Association of prenatal and childhood blood lead concentrations with criminal arrests in early adulthood. PLoS Med 2008; 5:e101. [PMID: 18507497 PMCID: PMC2689664 DOI: 10.1371/journal.pmed.0050101] [Citation(s) in RCA: 218] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 03/18/2008] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Childhood lead exposure is a purported risk factor for antisocial behavior, but prior studies either relied on indirect measures of exposure or did not follow participants into adulthood to examine the relationship between lead exposure and criminal activity in young adults. The objective of this study was to determine if prenatal and childhood blood lead concentrations are associated with arrests for criminal offenses. METHODS AND FINDINGS Pregnant women were recruited from four prenatal clinics in Cincinnati, Ohio if they resided in areas of the city with a high concentration of older, lead-contaminated housing. We studied 250 individuals, 19 to 24 y of age, out of 376 children who were recruited at birth between 1979 and 1984. Prenatal maternal blood lead concentrations were measured during the first or early second trimester of pregnancy. Childhood blood lead concentrations were measured on a quarterly and biannual basis through 6.5 y. Study participants were examined at an inner-city pediatric clinic and the Cincinnati Children's Hospital Medical Center in Cincinnati, Ohio. Total arrests and arrests for offenses involving violence were collected from official Hamilton County, Ohio criminal justice records. Main outcomes were the covariate-adjusted rate ratios (RR) for total arrests and arrests for violent crimes associated with each 5 microg/dl (0.24 micromol/l) increase in blood lead concentration. Adjusted total arrest rates were greater for each 5 microg/dl (0.24 micromol/l) increase in blood lead concentration: RR = 1.40 (95% confidence interval [CI] 1.07-1.85) for prenatal blood lead, 1.07 (95% CI 0.88-1.29) for average childhood blood lead, and 1.27 (95% CI 1.03-1.57) for 6-year blood lead. Adjusted arrest rates for violent crimes were also greater for each 5 microg/dl increase in blood lead: RR = 1.34 (95% CI 0.88-2.03) for prenatal blood lead, 1.30 (95% CI 1.03-1.64) for average childhood blood lead, and 1.48 (95% CI 1.15-1.89) for 6-year blood lead. CONCLUSIONS Prenatal and postnatal blood lead concentrations are associated with higher rates of total arrests and/or arrests for offenses involving violence. This is the first prospective study to demonstrate an association between developmental exposure to lead and adult criminal behavior.
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Affiliation(s)
- John Paul Wright
- Cincinnati Children's Environmental Health Center, Division of Criminal Justice, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Kim N Dietrich
- Cincinnati Children's Environmental Health Center, Division of Epidemiology and Biostatistics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * To whom correspondence should be addressed. E-mail:
| | - M. Douglas Ris
- Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Richard W Hornung
- Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Stephanie D Wessel
- Cincinnati Children's Environmental Health Center, Division of Epidemiology and Biostatistics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Bruce P Lanphear
- Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Mona Ho
- Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Mary N Rae
- Cincinnati Children's Environmental Health Center, Division of Epidemiology and Biostatistics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
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Lead neurotoxicity and socioeconomic status: conceptual and analytical issues. Neurotoxicology 2008; 29:828-32. [PMID: 18501967 DOI: 10.1016/j.neuro.2008.04.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2008] [Revised: 04/11/2008] [Accepted: 04/11/2008] [Indexed: 01/14/2023]
Abstract
Socioeconomic status (SES) is usually considered to be a potential confounder of the association between lead exposure and children's neurodevelopment, but experimental and epidemiological data suggest that SES might also modify lead neurotoxicity. The basis of this effect modification is uncertain, but might include differences among SES strata in co-exposures to other neurotoxicants, genetic susceptibilities, environmental enrichment, and stress. The role of SES in the causal nexus is likely to include other dimensions, however. It conveys information about lead exposure opportunities as well as about predictors of child outcome that are correlated with but causally independent of lead. Failure to distinguish these aspects of SES will lead to an underestimate of lead's contribution, and might even result in attributing to SES health effects that should be attributed to lead. Conventional models, which treat SES and SES-related factors solely as potential confounders, do not capture the possibility that a child's early lead exposure alters the behaviors that the child elicits from others. Failure to model lead's contribution to such time-varying covariates will also tend to bias estimates of lead neurotoxicity toward the null. On a trans-generational level, low SES might be a proxy for vulnerability to lead. To estimate the burden of lead-associated neurotoxicity on a population level, we need to apply analytical approaches that model a child's development and its context as a complex system of interdependent relationships that change over time.
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Rohlman DS, Lucchini R, Anger WK, Bellinger DC, van Thriel C. Neurobehavioral testing in human risk assessment. Neurotoxicology 2008; 29:556-67. [PMID: 18539229 DOI: 10.1016/j.neuro.2008.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 04/09/2008] [Accepted: 04/10/2008] [Indexed: 02/06/2023]
Abstract
Neurobehavioral tests are being increasingly used in human risk assessment and there is a strong need for guidance. The field of neurobehavioral toxicology has evolved from research which initially focused on using traditional neuropsychological tests to identify "abnormal cases" to include methods used to detect sub-clinical deficits, to further incorporate the use of neurosensory assessment, and to expand testing from occupational populations to vulnerable populations including older adults and children. Even as exposures in the workplace are reduced, they have been increasing in the environment and research on exposure has now expanded to cross the entire lifetime. These neurobehavioral methods are applied in research and the findings used for regulatory purposes to develop preventative action for exposed populations. This paper reflects a summary of the talks presented at the Neurobehavioral Testing in Human Risk Assessment symposium presented at the 11th meeting of the International Neurotoxicology Association.
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Affiliation(s)
- Diane S Rohlman
- Center for Research on Occupational and Environmental Toxicology, L606, Oregon Health & Science University, Portland, OR 97239, USA.
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Abstract
PURPOSE OF REVIEW We remain far from achieving the goal of eliminating lead-associated neurodevelopmental morbidities in children. New evidence regarding the blood lead levels at which morbidities occur have led to calls for the Centers for Disease Control and Prevention to reduce the current screening guideline of 10 microg/dl. The review evaluates the basis for these calls. RECENT FINDINGS Adverse outcomes, such as reduced intelligence quotient and academic deficits, occur at levels below 10 microg/dl. Some studies suggest that the rate of decline in performance is greater at levels below 10 microg/dl than above 10 microg/dl, although a plausible mechanism has not been identified. Increased exposure is also associated with neuropsychiatric disorders such as attention deficit hyperactivity disorder and antisocial behavior. Functional imaging studies are beginning to provide insight into the neural substrate of lead's neurodevelopmental effects. Current protocols for chelation therapy appear ineffective in preventing such effects, although environmental enrichment might do so. SUMMARY No level of lead exposure appears to be 'safe' and even the current 'low' levels of exposure in children are associated with neurodevelopmental deficits. Primary prevention of exposure provides the best hope of mitigating the impact of this preventable disease.
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Bellinger DC. Late neurodevelopmental effects of early exposures to chemical contaminants: reducing uncertainty in epidemiological studies. Basic Clin Pharmacol Toxicol 2008; 102:237-44. [PMID: 18226079 DOI: 10.1111/j.1742-7843.2007.00164.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Early exposures to environmental chemicals are reliably associated with late neurotoxicities in children. However, substantial scatter of observations exists around the estimated dose-effect relationships. This variability has many potential sources, one of which is interindividual differences in susceptibility. Such differences imply that the long-term impacts of exposure will not the same for all individuals, but will vary depending on a variety of factors that might either aggravate or mitigate contaminant effects. These include co-exposures, genetic polymorphisms and characteristics of the social environment. The context dependence of contaminant effects has implications both for study designs and analytical approaches. In addition, a systems approach to understanding the associations among contaminant exposures, covariates and health outcomes is necessary.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Children's Hospital Boston, Boston, MA 02115, USA.
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Gee D. Establishing evidence for early action: the prevention of reproductive and developmental harm. Basic Clin Pharmacol Toxicol 2008; 102:257-66. [PMID: 18226081 DOI: 10.1111/j.1742-7843.2008.00207.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Developmental and reproductive toxicants that cause serious disease and dysfunction, either lifelong or occurring late in life, can be initiated in the early life stages of human beings and other species. It is often the timing of the dose more than the dose itself that distinguishes harmful from harmless exposures to such toxicants. As much of the harm is irreversible, and sometimes multigenerational, the timing of actions to prevent such harm is also critical. In determining when there is a sufficiency of evidence to justify early prevention of harm, decision-makers need to take account of the implications of multicausality, the methodological biases within environmental sciences, and the need to take precautionary, as well as preventive actions to eliminate or reduce exposures. The widely used Bradford Hill causal 'criteria' are briefly reviewed in light of multicausality. Reaching agreement between stakeholders on a sufficiency of evidence for early action to reduce exposures to toxicants requires the consistent use of transparent definitions of the concepts and terms used to characterize the strength of evidence between causes and effects. Proposals are made to improve those in current use, including a definition of the precautionary principle.
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Affiliation(s)
- David Gee
- Strategic Knowledge and Innovation, European Environment Agency, Copenhagen, Denmark.
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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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Bellinger DC. Lead neurotoxicity in children: decomposing the variability in dose-effect relationships. Am J Ind Med 2007; 50:720-8. [PMID: 17290364 DOI: 10.1002/ajim.20438] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Enormous progress has been made in recent decades in our understanding of lead neurotoxicology in children, but an important obstacle to additional progress is the striking variability that is evident in any plot of a lead biomarker versus a health endpoint. METHODS In this article, three potential sources of variability are identified: (1) errors or imprecision in characterizing dose (and/or outcome); (2) incomplete characterization of endpoint variance attributable to factors other than lead; and (3) inter-individual differences in susceptibility to lead neurotoxicity. RESULTS Strategies are suggested for reducing the variability contributed by these sources, including the development of validated PBPK models and biomarkers of early biological effects; the development of more comprehensive models of outcome variance and, specifically, the application of multi-level models that incorporate supra-individual and supra-family risk factors; and the use of study designs that permit assessments of the effect modifying influence of contextual factors on the form and severity of neurotoxicity. CONCLUSION Decomposing the variability in the distribution of observed scores around the best-fit lines that describe the dose-effect relationships for lead neurotoxicity in children is a major research need.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Children's Hospital Boston and Harvard Medical School, Boston, MA, USA.
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Clougherty JE, Levy JI, Kubzansky LD, Ryan PB, Suglia SF, Canner MJ, Wright RJ. Synergistic effects of traffic-related air pollution and exposure to violence on urban asthma etiology. ENVIRONMENTAL HEALTH PERSPECTIVES 2007; 115:1140-6. [PMID: 17687439 PMCID: PMC1940095 DOI: 10.1289/ehp.9863] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 03/22/2007] [Indexed: 05/16/2023]
Abstract
BACKGROUND Disproportionate life stress and consequent physiologic alteration (i.e., immune dysregulation) has been proposed as a major pathway linking socioeconomic position, environmental exposures, and health disparities. Asthma, for example, disproportionately affects lower-income urban communities, where air pollution and social stressors may be elevated. OBJECTIVES We aimed to examine the role of exposure to violence (ETV), as a chronic stressor, in altering susceptibility to traffic-related air pollution in asthma etiology. METHODS We developed geographic information systems (GIS)-based models to retrospectively estimate residential exposures to traffic-related pollution for 413 children in a community-based pregnancy cohort, recruited in East Boston, Massachusetts, between 1987 and 1993, using monthly nitrogen dioxide measurements for 13 sites over 18 years. We merged pollution estimates with questionnaire data on lifetime ETV and examined the effects of both on childhood asthma etiology. RESULTS Correcting for potential confounders, we found an elevated risk of asthma with a 1-SD (4.3 ppb) increase in NO(2) exposure solely among children with above-median ETV [odds ratio (OR) = 1.63; 95% confidence interval (CI), 1.14-2.33)]. Among children always living in the same community, with lesser exposure measurement error, this association was magnified (OR = 2.40; 95% CI, 1.48-3.88). Of multiple exposure periods, year-of-diagnosis NO(2) was most predictive of asthma outcomes. CONCLUSIONS We found an association between traffic-related air pollution and asthma solely among urban children exposed to violence. Future studies should consider socially patterned susceptibility, common spatial distributions of social and physical environmental factors, and potential synergies among these. Prospective assessment of physical and social exposures may help determine causal pathways and critical exposure periods.
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Affiliation(s)
- Jane E Clougherty
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02215, USA.
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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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Gilbert SG, Weiss B. A rationale for lowering the blood lead action level from 10 to 2 microg/dL. Neurotoxicology 2006; 27:693-701. [PMID: 16889836 PMCID: PMC2212280 DOI: 10.1016/j.neuro.2006.06.008] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 06/28/2006] [Accepted: 06/29/2006] [Indexed: 11/23/2022]
Abstract
Fifteen years ago, in 1991, the U.S. Centers for Disease Control and Prevention (CDC) established 10 microg/dL as the lowest level of concern for children's blood lead levels. This value is extremely important because, historically, policy makers and public health officials generally have acted to remove sources of lead exposure only after the CDC's level of concern had been exceeded. A growing body of evidence, however, reveals that blood lead levels below 10 microg/dL may impair neurobehavioral development. There is now sufficient and compelling scientific evidence for the CDC to lower the blood lead action level in children. This review argues that a level of 2 microg/dL is a useful and feasible replacement. Although it can be argued, in turn, that no threshold for the health effects of lead is demonstrable, analytically a blood level of 2 microg/dL is readily and accurately measured and provides a benchmark for successful prevention. Lowering the level of concern would encourage and accelerate the investments needed to ensure that children are protected from lead exposure in their homes, schools, and play settings. Such a program would also offer economic advantages because of the coupling between lead, educational attainment, earnings and anti-social conduct. By lowering the blood action level, CDC will promote policies and initiatives designed to further reduce children's exposure to this potent developmental neurotoxicant.
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Affiliation(s)
- Steven G Gilbert
- Institute of Neurotoxicology & Neurological Disorders, 8232 14th Avenue NE, Seattle, WA 98115, USA.
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