80 research outputs found
The Case of Deborah Rice: Who Is the Environmental Protection Agency Protecting?
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
Low-level environmental lead exposure in childhood and adult intellectual function: a follow-up study
<p>Abstract</p> <p>Background</p> <p>Early life lead exposure might be a risk factor for neurocognitive impairment in adulthood.</p> <p>Objectives</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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 (Ī² = -1.89 Ā± 0.70, p = 0.01). Full-scale IQ was also significantly related to blood-lead concentration at age 6 months (Ī² = -1.66 Ā± 0.75, p = 0.03), 4 years (Ī² = -0.90 Ā± 0.41, p = 0.03) and 10 years (Ī² = -1.95 Ā± 0.80, p = 0.02). Adjusting for maternal IQ altered the significance of the regression coefficient.</p> <p>Conclusions</p> <p>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.</p
Low-level environmental lead exposure in childhood and adult intellectual function: a follow-up study
<p>Abstract</p> <p>Background</p> <p>Early life lead exposure might be a risk factor for neurocognitive impairment in adulthood.</p> <p>Objectives</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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 (Ī² = -1.89 Ā± 0.70, p = 0.01). Full-scale IQ was also significantly related to blood-lead concentration at age 6 months (Ī² = -1.66 Ā± 0.75, p = 0.03), 4 years (Ī² = -0.90 Ā± 0.41, p = 0.03) and 10 years (Ī² = -1.95 Ā± 0.80, p = 0.02). Adjusting for maternal IQ altered the significance of the regression coefficient.</p> <p>Conclusions</p> <p>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.</p
Prenatal Lead Levels, Plasma Amyloid Ī² Levels, and Gene Expression in Young Adulthood
Background: Animal studies suggest that early-life lead exposure influences gene expression and production of proteins associated with Alzheimerās disease (AD)
Low-Level Environmental Lead Exposure and Childrenās Intellectual Function: An International Pooled Analysis
Lead is a confirmed neurotoxin, but questions remain about lead-associated intellectual deficits at blood lead levels < 10 Ī¼g/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 Ī¼g/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 5ā10 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 Ī¼g/dL and declined to 9.4 Ī¼g/dL by 5ā7 years of age; 244 (18%) children had a maximal blood lead concentration < 10 Ī¼g/dL, and 103 (8%) had a maximal blood lead concentration < 7.5 Ī¼g/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), 4.2ā9.4] associated with an increase in concurrent blood lead levels from 2.4 to 30 Ī¼g/dL. The estimated IQ point decrements associated with an increase in blood lead from 2.4 to 10 Ī¼g/dL, 10 to 20 Ī¼g/dL, and 20 to 30 Ī¼g/dL were 3.9 (95% CI, 2.4ā5.3), 1.9 (95% CI, 1.2ā2.6), and 1.1 (95% CI, 0.7ā1.5), respectively. For a given increase in blood lead, the lead-associated intellectual decrement for children with a maximal blood lead level < 7.5 Ī¼g/dL was significantly greater than that observed for those with a maximal blood lead level ā„7.5 Ī¼g/dL (p = 0.015). We conclude that environmental lead exposure in children who have maximal blood lead levels < 7.5 Ī¼g/dL is associated with intellectual deficits
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