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Mobilization of lead from bone is known to increase with age. The authors performed the current study to determine whether there was an association between current blood lead and bone lead in workers with no current exposure but with significant past workplace exposure. The authors assessed 58 men, aged 40 to 76 years, who had earlier exposure to lead and determined both current blood lead levels and bone lead levels. At the time of the current assessment, the average blood lead level was 10.9 μg/dL and tibia bone lead concentrations ranged from -12.5 to 223.3. The authors divided workers into 3 groups by age (40-49, 50-59, and 60-76). Correlations between blood lead and bone lead were highest in the 2 oldest age groups (.49 and .75, respectively). Hierarchical regression analysis was significant for an interaction between bone lead and age in predicting blood lead (the combination of age and bone lead significantly predicted an increase in current blood lead levels). The results support the hypothesis that lead stored in bone is a significant source of blood lead later in life. Older workers with past occupational exposure may face a particular risk for recirculation of lead in blood with advancing age. [ABSTRACT FROM AUTHOR]

In the environmental health literature, errors in interpreting studies or data are not infrequent. Many are of the Type II variety. Common solecisms of this type are: treating the criterion of p [ABSTRACT FROM AUTHOR]

In the environmental health literature, errors in interpreting studies or data are not infrequent. Many are of the Type II variety. Common solecisms of this type are: treating the criterion of p < 0.05 as a sacrament; demanding complete confounder control; arguing for the existence of phantom confounders; arguing that the effect size is trivial; building nonveridical models; arguing for no effect from inadequate sample size; demanding causal proof; arguing that causality is reversed; conducting a ballot of published studies. These are examined in this paper. [ABSTRACT FROM AUTHOR]

Background: Lead exposure shares many risk factors with delinquent behavior, and bone lead levels are related to self-reports of delinquent acts. No data exist as to whether lead exposure is higher in arrested delinquents. The goal of this study is to evaluate the association between lead exposure, as reflected in bone lead levels, and adjudicated delinquency. Methods: This is a case-control study of 194 youths aged 12–18, arrested and adjudicated as delinquent by the Juvenile Court of Allegheny County, PA and 146 nondelinquent controls from high schools in the city of Pittsburgh. Bone lead was measured by K-line X-ray fluorescence (XRF) spectroscopy of tibia. Logistic regression was used to model the association between delinquent status and bone lead concentration. Covariates entered into the model were race, parent education and occupation, presence of two parental figures in the home, number of children in the home and neighborhood crime rate. Separate regression analyses were also conducted after stratification on race. Results: Cases had significantly higher mean concentrations of lead in their bones than controls (11.0±32.7 vs. 1.5±32.1 ppm). This was true for both Whites and African Americans. The unadjusted odds ratio for a lead level ≥25 vs. <25 ppm was 1.9 (95% CL: 1.1–3.2). After adjustment for covariates and interactions and removal of noninfluential covariates, adjudicated delinquents were four times more likely to have bone lead concentrations >25 ppm than controls (OR=4.0, 95% CL: 1.4–11.1). Conclusion: Elevated body lead burdens, measured by bone lead concentrations, are associated with elevated risk for adjudicated delinquency. [Copyright &y& Elsevier]

The relation between bone lead absorption and language processing abilities in 156 randomly selected 11- to 14-year-old boys who were asymptomatic for lead toxicity is examined. Tibial lead concentrations were measured by X-ray fluorescence spectroscopy. The language processing outcome variables consisted of the least and most difficult subtests from the Nonword Repetition Task, Competing Language Processing Task, and the Revised Token Test. Participants were classified by quartiles according to bone lead concentrations, and analysis of variance and analysis of covariance measured the impact on language processing scores. Results showed that children in the highest bone lead quartile displayed decreased language processing performance on the most difficult language processing tasks but not on the easier tasks. [ABSTRACT FROM AUTHOR]

In 1991, the Public Health Service published the Strategic Plan for the Elimination of Childhood Lead Poisoning. This document marked a fundamental shift in federal policy from finding and treating lead-poisoned children to authentic primary prevention. It spelled out a 15-year strategy to achieve this goal and provided a cost-benefit analysis showing that the monetized benefits far exceeded the costs of abatement. A strong national effort to eliminate the disease developed. Now, 7 years after publication of the plan, primary prevention of lead exposure has Been abandoned. This article examines the role of some prevailing attitudes and institutions in derailing the effort. Some institutions-the lead industry, real estate interests, and insurance interests-behaved as anticipated. Others, including private pediatricians, the American Academy of Pediatrics, some federal agencies, and a public interest group ostensibly dedicated to eliminating lead poisoning, also played an unexpected part in derailing the plan. [ABSTRACT FROM AUTHOR]

Relates some inadequacies and inequities in the investigation of scientific misconduct in environmental research such as lead toxicity. Information on the lead poisoning outbreak in a tetraethyl lead plant at Deepwater, New Jersey; Use of teeth as a marker of lead exposure; Suggestions on how to avoid charges of scientific misconduct.

Evaluates the association between body lead burden and social adjustment in a population of 850 first-grade boys at public schools. Lead-related association with teachers' aggression, delinquency and externalizing scores; Somatic complaints; Social problems.

Studies the effects of low-level lead exposure on the intelligence of children using a multiple regression analysis. Neurotoxic properties of lead; Methodological difficulties encountered in conducting the lead exposure studies; Type of tissue analyzed for lead exposure; Use of Weschler Intelligence Scale for Children in measuring the intelligence quotient.

Why did the EPA dismiss a highly respected neurotoxicologist as chair of its external review panel on the fire retardant deca? Pioneering lead researcher Herbert Needleman, MD, argues that the answer has little to do with science. [ABSTRACT FROM AUTHOR]

Replies to a critique of a study on lead toxicity. Relation of the critics to the lead industry; Efforts of the lead industry to retard control of lead.

Discusses the challenges facing the prevention of childhood lead poisoning in the United States. Changes in the understanding on the role of lead in human health since 1940s; Analysis of studies on the impact of lead exposure on intelligence; Changes in the definition of lead toxicity set by the Centers for Disease Control; Reasons for the reluctance of clinicians to conduct medical screening on blood lead levels; Variations in the treatment and the criteria for instituting it.

Examines the effect of lead on the intelligence of children. Details of the inferior performance of children with asymptomatic elevations of blood lead level; Physiological implications of lead reflected in cognitive and verbal results; Methodologic issues associated with lead exposure.

The article reflects on the issues regarding childhood lead poisoning. It mentions that the amount of lead in the portion of bread wrappers ranges from zero to 84 milligrams per bag. It believes that a more serious issue about lead poisoning is its insertion to the ecosystem through the use of the said source.

Recent data have demonstrated health effects of lead in children at doses previously believed to be harmless. Data from epidemiological studies in many countries, and from experimental studies of animals given lead, demonstrate psychological impairment at blood lead concentrations of 0.5-0.7 µmol/L. Current estimates are that 17 per cent of American children (3-4 million) exceed the level of 0.7 µmol/L. Lead exposure is not a problem for urban poor children alone, but inner-city minorities have a higher rate of exposure. The overabundance of lead coexists in the same area with two serious shortages: affordable housing and jobs. It is argued that a program to train unemployed inner-city residents in safe de-leading, while expensive, makes hygienic, economic, and common sense. (Am J Public Health 1989; 79:643-645.) [ABSTRACT FROM AUTHOR]

A response by Herbert L. Needleman to letters to the editor about his article "Mercury in dental amalgam--a neurotoxic risk?" in a previous issue is presented.

The article examines whether mercury found in dental amalgams is a neurotoxic risk. Dental amalgams contain 50% mercury by weight and have been used by dentists for 150 years. The article refers to two medical studies published in this issue of the "Journal of the American Medical Association," including the study by David C. Bellinger and colleagues and Timothy A. DeRouen and colleagues. According to the author, more medical studies researching the subtle effects and risks of mercury in dental amalgams are needed.

The article presents a letter to the editor in response to the review of the history of the U.S. Environmental Protection Agency's response to the question of human testing of pesticides by David B. Resnick and Christopher Portier.

Presents a letter to the editor commenting on an article published in the periodical "Environmental Health Perspectives" concerning the issue of human experimentation.

Presents a letter to the editor about the industrial testing of toxic pesticides on human subjects.

Evaluates the neurological and neurobehavioral effects of workplace toxins in workers in the United States. Determination of the dose- response relationships for neuropsychological functional changes in workers; Need of direct monitoring on the levels of exposure; Influence of workplace on the tempo of the aging process and other central nervous system diseases.

The article presents a letter to the editor in response to the article "Should the Centers for Disease Control and Prevention Childhood Lead Poisoning Intervention Level Be Lowered," by S. M. Bernard in a 2003 issue of the "American Journal of Public Health."

A letter to the editor is presented in response to the article "Intellectual impairment in children with blood lead concentrations below 10 mcg per deciliter," by R. L. Canfield, et al in the 2003 issue.

Presents several letters to the editor concerning environmental health. Lead content in the teeth of children; Analysis on the factors affecting the high levels of lead in the teeth; Evaluation on the clinical preceptorship in occupational medicine for medical students.

A letter to the editor is presented in response to an article which reported that asymptomatic children with elevated dentine lead levels had significant cognitive and behavioral deficits after covariate adjustment.

Reports on the correlation between lead ingestion and antisocial behavior among children. Signs and symptoms; Lead measures in children and their implications.

Presents statements on the critique received by the authors regarding their work published in the December 1974 issue of the periodical 'Journal of Learning Disabilities' citing the effect of lead levels on child development. Observation of a minimal effect of lead levels on cognitive development; Inappropriate conclusion on the relationship of lead level and cognitive development.

Abstract. The implications of low-level lead exposure for children's intellectual and academic performance at school age are uncertain. This issue was investigated in a prospective study of middle-class and upper-middle-class children with low lifetime exposures to lead. A battery of neuropsychological tests was administered at age 10 years to 148 children whose lead exposure and cognitive function had been previously assessed at ages 6, 12, 18, 24, and 57 months. Primary endpoints were Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Kaufman Test of Educational Achievement (K-TEA). Higher levels of blood lead at age 24 months, but not at other ages, were significantly associated with lower global scores on both the WISC-R and the K-TEA after adjustment for potential confounders. Over the range of approximately 0 to 25 micro g/dL, a 0.48 micro mol/L (10 micro g/dL) increase in blood lead at 24 months was associated with a 5.8-point decline in WISC-R Full-Scale IQ (95% confidence interval: 1.7 to 9.9, P = .007) and an 8.9-point decline in K-TEA Battery Composite score (95% confidence interval: 4.2 to 13.6, P = .0003). Mean blood lead level at age 24 months was 0.31 micro mol/L (6.5 micro g/dL; SD: 4.9, 90% percentile: 12.5). Slightly elevated blood lead levels around the age of 24 months are associated with intellectual and academic performance deficits at age 10 years. [ABSTRACT FROM AUTHOR]

Background: Animal studies suggest that early-life lead exposure influences gene expression and production of proteins associated with Alzheimerfs disease (AD). Objectives: We attempted to assess the relationship between early-life lead exposure and potential biomarkers for AD among young men and women. We also attempted to assess whether early-life lead exposure was associated with changes in expression of AD-related genes. Methods: We used sandwich enzyme-linked immunosorbent assays (ELISA) to measure plasma concentrations of amyloid β proteins Aβ40 and Aβ42 among 55 adults who had participated as newborns and young children in a prospective cohort study of the effects of lead exposure on development. We used RNA microarray techniques to analyze gene expression. Results: Mean plasma Aβ42 concentrations were lower among 13 participants with high umbilical cord blood lead concentrations (≥ 10 µg/dL) than in 42 participants with lower cord blood lead concentrations (p = 0.08). Among 10 participants with high prenatal lead exposure, we found evidence of an inverse relationship between umbilical cord lead concentration and expression of ADAM metallopeptidase domain 9 (ADAM9), reticulon 4 (RTN4), and low-density lipoprotein receptor-related protein associated protein 1 (LRPAP1) genes, whose products are believed to affect Aβ production and deposition. Gene network analysis suggested enrichment in gene sets involved in nerve growth and general cell development. Conclusions: Data from our exploratory study suggest that prenatal lead exposure may influence Aβ-related biological pathways that have been implicated in AD onset. Gene network analysis identified further candidates to study the mechanisms of developmental lead neurotoxicity. [ABSTRACT FROM AUTHOR]

Background: Early life lead exposure might be a risk factor for neurocognitive impairment in adulthood.Objectives: We sought to assess the relationship between early life environmental lead exposure and intellectual function in adulthood. We also attempted to identify which time period blood-lead concentrations are most predictive of adult outcome.Methods: We recruited adults in the Boston area who had participated as newborns and young children in a prospective cohort study that examined the relationship between lead exposure and childhood intellectual function. IQ was measured using the Wechsler Abbreviated Scale of Intelligence (WASI). The association between lead concentrations and IQ scores was examined using linear regression.Results: Forty-three adults participated in neuropsychological testing. Childhood blood-lead concentration (mean of the blood-lead concentrations at ages 4 and 10 years) had the strongest relationship with Full-Scale IQ (β = -1.89 ± 0.70, p = 0.01). Full-scale IQ was also significantly related to blood-lead concentration at age 6 months (β = -1.66 ± 0.75, p = 0.03), 4 years (β = -0.90 ± 0.41, p = 0.03) and 10 years (β = -1.95 ± 0.80, p = 0.02). Adjusting for maternal IQ altered the significance of the regression coefficient.Conclusions: Our study suggests that lead exposure in childhood predicts intellectual functioning in young adulthood. Our results also suggest that school-age lead exposure may represent a period of increased susceptibility. Given the small sample size, however, the potentially confounding effects of maternal IQ cannot be excluded and should be evaluated in a larger study. [ABSTRACT FROM AUTHOR]

Lead is a confirmed neurotoxin, but questions remain about lead-associated intellectual deficits at blood lead levels < 10 μg/dL and whether lower exposures are, for a given change in exposure, associated with greater deficits. The objective of this study was to examine the association of intelligence test scores and blood lead concentration, especially for children who had maximal measured blood lead levels < 10 μg/dL. We examined data collected from 1,333 children who participated in seven international population-based longitudinal cohort studies, followed from birth or infancy until 5–10 years of age. The full-scale IQ score was the primary outcome measure. The geometric mean blood lead concentration of the children peaked at 17.8 μg/dL and declined to 9.4 μg/dL by 5–7 years of age; 244 (18%) children had a maximal blood lead concentration < 10 μg/dL, and 103 (8%) had a maximal blood lead concentration < 7.5 μg/dL. After adjustment for covariates, we found an inverse relationship between blood lead concentration and IQ score. Using a log-linear model, we found a 6.9 IQ point decrement [95% confidence interval (CI), 4.2–9.4] associated with an increase in concurrent blood lead levels from 2.4 to 30 μg/dL. The estimated IQ point decrements associated with an increase in blood lead from 2.4 to 10 μg/dL, 10 to 20 μg/dL, and 20 to 30 μg/dL were 3.9 (95% CI, 2.4–5.3), 1.9 (95% CI, 1.2–2.6), and 1.1 (95% CI, 0.7–1.5), respectively. For a given increase in blood lead, the lead-associated intellectual decrement for children with a maximal blood lead level < 7.5 μg/dL was significantly greater than that observed for those with a maximal blood lead level ≥ 7.5 μg/dL (p = 0.015). We conclude that environmental lead exposure in children who have maximal blood lead levels < 7.5 μg/dL is associated with intellectual deficits. [ABSTRACT FROM AUTHOR]

Several letters to the editor are presented in response to the article "Childhood Poisoning: The Promise and Abandonment of Primary Prevention," by Herbert Needleman in the 1998 issue.

Presents letters to the editors on occupational health issues. Comments on the update of the Brown and Jones study; Problems in environmental and occupational epidemiology; Criticism on the article 'Mortality experience of employees with occupational exposure to DBCP'; Insufficiency of data supporting the conclusion of Schneiderman.

Discusses the respiratory hazards faced by children due to ambient air pollution. List of the respiratory effects of ozone, an ambient air pollutant; Relationship between outdoor air pollution and adverse respiratory effects in children; Factor that increases children's vulnerability to airborne pollution; Recommendations to pediatricians.

Abstract. In a cohort of 170 middle and upper-middle class children participating in a prospective study of child development and low-level lead exposure, higher blood lead levels at age 24 months were associated with lower scores at age 57 months on the McCarthy Scales of Children's Abilities. The mean blood lead level at age 24 months was 6.8 micro g/dL (SD = 6.3; 75th, 90th, and 99th percentiles: 8.8, 13.7, 23.6, respectively) and for all but 1 child was less than 25 micro g/dL, the current definition of an "elevated" level. After adjustment for confounding, scores on the General Cognitive Index decreased approximately 3 points (SE = 1.4) for each natural log unit increase in 24-month blood lead level. The inverse association between lead level and performance was especially prominent for visual-spatial and visual-motor integration skills. Higher prenatal exposures were not associated with lower scores at 57 months except in the subgroup of children with "high" concurrent blood lead levels (ie, Is greater than or equal to 10 micro g/dL). The concentration of lead in the dentine of shed deciduous teeth was not significantly associated with children's performance after adjustment for confounding. [ABSTRACT FROM AUTHOR]

Discusses the health hazards of children's exposure to radon, a radioactive material, in the United States. Background on the toxicity of radon gas; Nature and sources of radon; Synergistic effect between radon and cigarette smoking in the development of lung cancer.