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Yu Chen,
Fen Wu,
Mengling Liu,
Faruque Parvez,
Vesna Slavkovich,
Mahbub Eunus,
Alauddin Ahmed,
Stephanie Segers,
Maria Argos,
Tariqul Islam,
Muhammad Rakibuz-Zaman,
Rabiul Hasan,
Golam Sarwar,
Diane Levy, Joseph Graziano,
Habibul Ahsan
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ABSTRACT: BACKGROUND: Prospective studies that evaluate the influence of arsenic methylation capacity on cardiovascular disease (CVD) risk are lacking. OBJECTIVE: To evaluate the association of arsenic exposure from drinking water and arsenic methylation capacity with CVD risk. METHOD: We conducted a case-cohort study of 369 incident fatal and non-fatal cases of CVD, including 148 stroke cases and 211 cases of heart disease, and a subcohort of 1,109 subjects randomly selected from the 11,224 participants in the Health Effects of Arsenic Longitudinal Study. RESULTS: The adjusted hazard ratio (HR) for all CVD, heart disease, and stroke in association with a standard deviation increase in baseline well arsenic (112 µg/L) was 1.15 (95% CI: 1.01, 1.30), 1.20 (95% CI: 1.04, 1.38), and 1.08 (95% CI: 0.90, 1.30), respectively. Adjusted HRs for the second and third tertiles of urinary monomethylarsonic acid (MMA)% relative to the lowest tertile, respectively, were 1.27 (95% CI: 0.85, 1.90) and 1.55 (95% CI: 1.08, 2.23) for all CVD, and 1.65 (95% CI: 1.05, 2.60) and 1.61 (95% CI: 1.04, 2.49) for heart disease specifically. The highest versus lowest ratio of urinary dimethylarsinic acid (DMA) to MMA was associated with a significantly decreased risk of CVD (HR=0.54; 95% CI: 0.34, 0.85) and heart disease (HR=0.54; 95% CI: 0.33, 0.88). There was no apparent association between arsenic metabolite indices and stroke risk. The joint effects of incomplete arsenic methylation capacity, indicated by higher urinary MMA% or lower urinary DMA%, with higher levels of well arsenic on heart disease risk were additive. There was some evidence of a synergy of incomplete methylation capacity with older age and cigarette smoking. CONCLUSIONS: Arsenic exposure from drinking water and incomplete methylation capacity of arsenic were adversely associated with heart disease risk.
Environmental Health Perspectives 05/2013; · 7.04 Impact Factor
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Christine M George,
Alexander V Geen,
Vesna N Slavkovich,
Ashit Singha,
Diane Levy,
Tariqul Islam,
Kazi Ahmed,
Joyce Moon-Howard,
Alessandro Tarozzi,
Xinhua Liu,
Pam Factor-Litvak, Joseph Graziano
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ABSTRACT: OBJECTIVE: To reduce arsenic (As) exposure, we evaluated the effectiveness of training community members to perform water arsenic (WAs) testing and provide As education compared to sending representatives from outside communities to conduct these tasks. METHODS: We conducted a cluster based randomized controlled trial of 20 villages in Singair, Bangladesh. Fifty eligible respondents were randomly selected in each village. In 10 villages, a community member provided As education and WAs testing. In a second set of 10 villages an outside representative performed these tasks. RESULTS: Overall, 53 % of respondents using As contaminated wells, relative to the Bangladesh As standard of 50 ¿g/L, at baseline switched after receiving the intervention. Further, when there was less than 60 % arsenic contaminated wells in a village, classification used by the Bangladeshi government and UNICEF, 74 % of study households in the community tester villages, and 72 % of households in the outside tester villages reported switching to an As safe drinking water source . Switching was more common in the outside-tester (63 %) versus community-tester villages (44 %). However, after adjusting for the availability of arsenic safe drinking water sources, well switching did not differ significantly by type of As tester (Odds ratio =0.81[95 % confidence interval 0.41-1.58). At follow-up, among those using As contaminated wells who switched to safe wells, average urinary As concentrations significantly decreased. CONCLUSIONS: The overall intervention was effective in reducing As exposure provided there were As-safe drinking water sources available. However, there was not a significant difference observed in the ability of the community and outside testers to encourage study households to use As-safe water sources. The findings of this study suggest that As education and WAs testing programs provided by As testers, irrespective of their residence, could be used as an effective, low cost approach to reduce As exposure in many As-affected areas of Bangladesh.
Environmental Health 06/2012; 11(1):41. · 2.65 Impact Factor
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Stephanie Melkonian,
Maria Argos,
Brandon L Pierce,
Yu Chen,
Tariqul Islam,
Alauddin Ahmed,
Emdadul H Syed,
Faruque Parvez, Joseph Graziano,
Paul J Rathouz,
Habibul Ahsan
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ABSTRACT: Skin lesions are classic clinical signs of toxicity due to long-term exposure to arsenic, and they are considered precursors to arsenic-related skin cancer. The authors prospectively evaluated synergisms between effects of arsenic exposure and those of tobacco use, sun exposure, and pesticide and fertilizer use on incident skin lesions using risk factor data from 5,042 men from the Health Effects of Arsenic Longitudinal Study in Araihazar, Bangladesh, which recruited participants from October 2000 to May 2002. Discrete time hazard models were used to estimate measures of synergistic interactions on the additive scale. The authors observed significant synergistic effects between various measures of arsenic exposure and smoking and fertilizer use. The relative excess risks for the interactions between smoking status and arsenic exposure were 0.12 (95% confidence interval: 0.06, 0.19) for water arsenic and 0.11 (95% confidence interval: 0.05, 0.15) for urinary arsenic measures, respectively. Significant synergistic effects were also observed between fertilizer use and water arsenic (relative excess risk for the interaction = 0.06, 95% confidence interval: 0.01, 0.12). This is the first prospective study based on individual-level data that supports a role for smoking and certain occupational risk factors in modification of the effect of long-term arsenic exposure on skin lesions. Understanding differential arsenic susceptibility allows researchers to develop interventions to prevent the health consequences of this massive problem in the Bangladeshi population and beyond.
American journal of epidemiology 01/2011; 173(2):183-91. · 5.59 Impact Factor
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The Lancet 11/2010; 376(9753):1642. · 38.28 Impact Factor
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Brandon L Pierce,
Tara Kalra,
Maria Argos,
Faruque Parvez,
Yu Chen,
Tariqul Islam,
Alauddin Ahmed,
Rabiul Hasan,
Muhammad Rakibuz-Zaman, Joseph Graziano,
Paul J Rathouz,
Habibul Ahsan
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ABSTRACT: Body mass index (BMI) (kg/m(2)) has a U- or J-shaped relationship with all-cause mortality in Western and East Asian populations. However, this relationship is not well characterized in Bangladesh, where the BMI distribution is shifted towards lower values.
Using data on 11,445 individuals (aged 18-75 years) participating in the Health Effects of Arsenic Longitudinal Study (HEALS) in Araihazar, Bangladesh, we prospectively examined associations of BMI (measured at baseline) with all-cause mortality during approximately 6 years of follow-up. We also examined this relationship within strata of key covariates (sex, age, smoking, education and arsenic exposure). Cox proportional hazards models adjusted for these covariates and BMI-related illnesses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for BMI categories defined by the World Health Organization.
Low BMI was strongly associated with increased mortality in this cohort (P-trend < 0.0001). Severe underweight (BMI < 16 kg/m(2); HR 2.06, CI 1.53-2.77) and moderate underweight (16.0-16.9 kg/m(2); HR 1.39, CI 1.01-2.90) were associated with increased all-cause mortality compared with normal BMI (18.6-22.9 kg/m(2)). The highest BMI category (> or =23.0 kg/m(2)) did not show a clear association with mortality (HR 1.10, CI 0.77-1.53). The BMI-mortality association was stronger among individuals with <5 years of formal education (interaction P = 0.02).
Underweight (presumably due to malnutrition) is a major determinant of mortality in the rural Bangladeshi population.
International Journal of Epidemiology 08/2010; 39(4):1037-45. · 6.41 Impact Factor
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Maria Argos,
Tara Kalra,
Paul J Rathouz,
Yu Chen,
Brandon Pierce,
Faruque Parvez,
Tariqul Islam,
Alauddin Ahmed,
Muhammad Rakibuz-Zaman,
Rabiul Hasan,
Golam Sarwar,
Vesna Slavkovich,
Alexander van Geen, Joseph Graziano,
Habibul Ahsan
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ABSTRACT: Millions of people worldwide are chronically exposed to arsenic through drinking water, including 35-77 million people in Bangladesh. The association between arsenic exposure and mortality rate has not been prospectively investigated by use of individual-level data. We therefore prospectively assessed whether chronic and recent changes in arsenic exposure are associated with all-cause and chronic-disease mortalities in a Bangladeshi population.
In the prospective cohort Health Effects of Arsenic Longitudinal Study (HEALS), trained physicians unaware of arsenic exposure interviewed in person and clinically assessed 11 746 population-based participants (aged 18-75 years) from Araihazar, Bangladesh. Participants were recruited from October, 2000, to May, 2002, and followed-up biennially. Data for mortality rates were available throughout February, 2009. We used Cox proportional hazards model to estimate hazard ratios (HRs) of mortality, with adjustment for potential confounders, at different doses of arsenic exposure.
407 deaths were ascertained between October, 2000, and February, 2009. Multivariate adjusted HRs for all-cause mortality in a comparison of arsenic at concentrations of 10.1-50.0 microg/L, 50.1-150.0 microg/L, and 150.1-864.0 microg/L with at least 10.0 microg/L in well water were 1.34 (95% CI 0.99-1.82), 1.09 (0.81-1.47), and 1.68 (1.26-2.23), respectively. Results were similar with daily arsenic dose and total arsenic concentration in urine. Recent change in exposure, measurement of total arsenic concentrations in urine repeated biennially, did not have much effect on the mortality rate.
Chronic arsenic exposure through drinking water was associated with an increase in the mortality rate. Follow-up data from this cohort will be used to assess the long-term effects of arsenic exposure and how they might be affected by changes in exposure. However, solutions and resources are urgently needed to mitigate the resulting health effects of arsenic exposure.
US National Institutes of Health.
The Lancet 07/2010; 376(9737):252-8. · 38.28 Impact Factor
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David S Grass,
James M Ross,
Farnosh Family,
Jonathan Barbour,
H James Simpson,
Drissa Coulibaly,
Jennifer Hernandez,
Yingdi Chen,
Vesna Slavkovich,
Yongliang Li, Joseph Graziano,
Regina M Santella,
Paul Brandt-Rauf,
Steven N Chillrud
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ABSTRACT: A prior study in New York City observed that airborne concentrations of three metals found in steel - iron, manganese, and chromium - are more than 100 times higher in the subway system than in aboveground air. To investigate the potential for health effects of exposure at these levels, we conducted a pilot study of subway workers comparing personal exposures to steel dust with biomarkers of metal exposure, oxidative stress, and DNA damage in blood and urine samples. Workers wore a personal air sampler operating at 4L/m for one to three work shifts with blood and urine samples collected at the end of the final shift. We found that PM(2.5) exposures varied among subway workers on the basis of job title and job activity. The subway workers' mean time-weighted PM(2.5) exposure was 52 microg/m3, with a median of 27 microg/m3, and a range of 6-469 microg/m3. The observed concentrations of PM(2.5), iron, manganese, and chromium fell well below occupational standards. Biomarker concentrations among the 39 subway workers were compared with a group of 11 bus drivers, and a group of 25 suburban office workers. Concentrations of DNA-protein crosslinks and chromium in plasma were significantly higher in subway workers than in bus drivers, but no significant difference was observed for these biomarkers between subway workers and office workers. Urinary isoprostane concentrations were significantly correlated with the number of years working in the subway system, and were detected at higher, though not significantly higher, concentrations in subway workers than in bus drivers or office workers. At the group level, there was no consistent pattern of biomarker concentrations among subway workers significantly exceeding those of the bus drivers and office workers. At the individual level, steel dust exposure was not correlated with any of the biomarkers measured.
Environmental Research 11/2009; 110(1):1-11. · 3.40 Impact Factor
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ABSTRACT: Mutations in SCO2, a protein required for the proper assembly and functioning of cytochrome c oxidase (COX; complex IV of the mitochondrial respiratory chain), cause a fatal infantile cardioencephalomyopathy with COX deficiency. We have generated mice harboring a Sco2 knock-out (KO) allele and a Sco2 knock-in (KI) allele expressing an E-->K mutation at position 129 (E129K), corresponding to the E140K mutation found in almost all human SCO2-mutated patients. Whereas homozygous KO mice were embryonic lethals, homozygous KI and compound heterozygous KI/KO mice were viable, but had muscle weakness; biochemically, they had respiratory chain deficiencies as well as complex IV assembly defects in multiple tissues. There was a concomitant reduction in mitochondrial copper content, but the total amount of copper in examined tissues was not reduced. These mouse models should be of use in further studies of Sco2 function, as well as in testing therapeutic approaches to treat the human disorder.
Human Molecular Genetics 10/2009; 19(1):170-80. · 7.64 Impact Factor
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Mark G A Opler,
Stephen L Buka,
Justina Groeger,
Ian McKeague,
Catherine Wei,
Pam Factor-Litvak,
Michaeline Bresnahan, Joseph Graziano,
Jill M Goldstein,
Larry J Seidman,
Alan S Brown,
Ezra S Susser
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ABSTRACT: A previously conducted study of prenatal lead exposure and schizophrenia using delta-aminolevulinic acid, a biologic marker of Pb exposure, in archived maternal serum samples collected from subjects enrolled in the Childhood Health and Development Study (1959-1966) based in Oakland, California, suggested a possible association between prenatal Pb exposure and the development of schizophrenia in later life.
In the present study we extend these findings using samples collected from the New England cohort of the National Collaborative Perinatal Project (1959-1966). Using similar methods, in this study we found results that suggest a comparable association in this cohort.
We pooled matched sets of cases and controls from both the California and New England sites using a multilevel random-intercept logistic regression model, accounting for matching and site structure as well as adjusting for maternal age at delivery and maternal education.
The estimated odds ratio for schizophrenia associated with exposure corresponding to 15 microg/dL of blood Pb was 1.92 (95% confidence interval, 1.05-3.87; p = 0.03).
Although several limitations constrain generalizability, these results are consistent with previous findings and provide further evidence for the role of early environmental exposures in the development of adult-onset psychiatric disorders.
Environmental Health Perspectives 12/2008; 116(11):1586-90. · 7.04 Impact Factor
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Journal of Development Economics 02/2008; 85(1-2):349-347. · 2.13 Impact Factor
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Marni Hall,
Mary Gamble,
Vesna Slavkovich,
Xinhua Liu,
Diane Levy,
Zhongqi Cheng,
Alexander van Geen,
Mahammad Yunus,
Mahfuzar Rahman,
J Richard Pilsner, Joseph Graziano
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ABSTRACT: In Bangladesh, tens of millions of people have been consuming waterborne arsenic for decades. The extent to which As is transported to the fetus during pregnancy has not been well characterized.
We therefore conducted a study of 101 pregnant women who gave birth in Matlab, Bangladesh.
Maternal and cord blood pairs were collected and concentrations of total As were analyzed for 101 pairs, and As metabolites for 30 pairs. Maternal urinary As metabolites and plasma folate, cobalamin, and homocysteine levels in maternal cord pairs were also measured. Household tube well-water As concentrations exceeded the World Health Organization guideline of 10 microg/L in 38% of the cases.
We observed strong associations between maternal and cord blood concentrations of total As (r = 0.93, p < 0.0001). Maternal and cord blood arsenic metabolites (n = 30) were also strongly correlated: in dimethylarsinate (DMA) (r = 0.94, p < 0.0001), monomethylarsonate (r = 0.80, p < 0.0001), arsenite (As(+3)) (r = 0.80, p < 0.0001), and arsenate (As(+5)) (r = 0.89, p < 0.0001). Maternal homocysteine was a strong predictor of %DMA in maternal urine, maternal blood, and cord blood (beta = -6.2, p < 0.02; beta = -10.9, p < 0.04; and beta = -13.7, p < 0.04, respectively). Maternal folate was inversely associated with maternal blood As(5+) (beta = 0.56, p < 0.05), and maternal cobalamin was inversely associated with cord blood As(5+) (beta = -1.2, p < 0.01).
We conclude that exposure to all metabolites of inorganic As occurs in the prenatal period.
Environmental Health Perspectives 11/2007; 115(10):1503-9. · 7.04 Impact Factor
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ABSTRACT: This paper provides a survey on studies that analyze the macroeconomic effects of intellectual property rights (IPR). The first part of this paper introduces different patent policy instruments and reviews their effects on R&D and economic growth. This part also discusses the distortionary effects and distributional consequences of IPR protection as well as empirical evidence on the effects of patent rights. Then, the second part considers the international aspects of IPR protection. In summary, this paper draws the following conclusions from the literature. Firstly, different patent policy instruments have different effects on R&D and growth. Secondly, there is empirical evidence supporting a positive relationship between IPR protection and innovation, but the evidence is stronger for developed countries than for developing countries. Thirdly, the optimal level of IPR protection should tradeoff the social benefits of enhanced innovation against the social costs of multiple distortions and income inequality. Finally, in an open economy, achieving the globally optimal level of protection requires an international coordination (rather than the harmonization) of IPR protection.
Journal of Development Economics 01/2007; 84(2):731-754. · 2.13 Impact Factor
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ABSTRACT: Exposure to arsenic (As)-contaminated drinking water affects millions of people worldwide. Arsenic exposure is associated with skin lesions, skin, lung, kidney and liver cancers, neurologic and cardiovascular effects. Past studies involving biomarkers of As exposure have typically examined urinary As (UAs) (adjusted for urinary creatinine), hair or toenail As, but not blood As (BAs) since blood concentrations are exceedingly low and are not detectable by conventional atomic absorption spectrophotometric techniques. In a case-cohort analysis of 303 newly diagnosed cases of skin lesions, and 849 subcohort members randomly selected from 8092 participants in the health effects of as longitudinal study (HEALS) in Araihazar, Bangladesh, we measured blood, urine and water As concentrations, and examined their associations with each other, and with the risk for skin lesions. BAs concentrations were highly correlated with creatinine-adjusted UAs concentrations (r=0.85) and with water As (WAs) (r=0.75). We observed consistent dose-response relationships between the risk of skin lesions and all the measures of As exposure. Rate ratios (RRs) for skin lesions by quintile of As exposure, adjusted for age and gender, revealed that the two highest quintiles were significantly related to an increased risk of skin lesions for each measure of exposure: BAs, UAs, WAs and a time-weighted water As variable. This prospective study confirms the increased risk of skin lesions in relation to As concentrations in blood, urine and water and also establishes that BAs is a useful biomarker of As exposure in this study population.
Toxicology 09/2006; 225(2-3):225-33. · 3.68 Impact Factor
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ABSTRACT: Health Effects of Arsenic Longitudinal Study (HEALS), a multidisciplinary and large prospective cohort study in Araihazar, Bangladesh, was established to evaluate the effects of full-dose range arsenic (As) exposure on various health outcomes, including premalignant and malignant skin tumors, total mortality, pregnancy outcomes, and children's cognitive development. In this paper, we provide descriptions of the study methods including study design, study population, data collection, response rates, and exposure and outcome assessments. We also present characteristics of the study participants including the distribution of exposure and the prevalence of skin lesion at baseline recruitment. A total of 11,746 married men and women between 18 and 75 years of age participated in the study at baseline (a response rate of 98%) and completed a full questionnaire interview that included a food frequency questionnaire, with a response rate of 98%. Among the 98% of the participants who completed the clinical evaluation, over 90% provided blood samples and spot urine samples. Higher educational status, male gender, and presence of premalignant skin lesions were associated with an increased likelihood of providing blood and urine samples. Older participants were less likely to donate a blood sample. About one-third of the participants consumed water from a well with As concentration in each of three groups: >100 microg/l, 25-100 microg/l, and <25 microg/l. Average urinary As concentrations were 140 and 136 microg/l for males and females, respectively. HEALS has several unique features, including a prospective study design, comprehensive assessments of both past and future changes in As exposure at the individual level, a large repository of biological samples, and a full dose range of As exposures in the study population. HEALS is a valuable resource for examining novel research questions on the health effects of As exposure.
Journal of Exposure Science and Environmental Epidemiology 04/2006; 16(2):191-205. · 2.93 Impact Factor
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Bruce P Lanphear,
Richard Hornung,
Jane Khoury,
Kimberly Yolton,
Peter Baghurst,
David C Bellinger,
Richard L Canfield,
Kim N Dietrich,
Robert Bornschein,
Tom Greene,
Stephen J Rothenberg,
Herbert L Needleman,
Lourdes Schnaas,
Gail Wasserman, Joseph Graziano,
Russell Roberts
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ABSTRACT: Lead is a confirmed neurotoxin, but questions remain about lead-associated intellectual deficits at blood lead levels < 10 microg/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 microg/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 microg/dL and declined to 9.4 microg/dL by 5-7 years of age; 244 (18%) children had a maximal blood lead concentration < 10 microg/dL, and 103 (8%) had a maximal blood lead concentration < 7.5 microg/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 microg/dL. The estimated IQ point decrements associated with an increase in blood lead from 2.4 to 10 microg/dL, 10 to 20 microg/dL, and 20 to 30 microg/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 microg/dL was significantly greater than that observed for those with a maximal blood lead level > or = 7.5 microg/dL (p = 0.015). We conclude that environmental lead exposure in children who have maximal blood lead levels < 7.5 microg/dL is associated with intellectual deficits.
Environmental Health Perspectives 07/2005; 113(7):894-9. · 7.04 Impact Factor
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ABSTRACT: We test the hypothesis that chronic lead (Pb) exposure may be associated with an inability to maintain an adequate serum erythropoietin (EPO) concentration. From a longitudinal study of Pb exposure and infant and childhood development, we measured blood Pb (BPb) and serum EPO concentrations serially at ages 4.5, 6.5, 9.5, and 12 and tibia (cortical) Pb concentration at age 12. Pb-exposed children aged 4.5 and 6.5 produced increased concentrations of EPO to maintain normal Hgb concentrations. EPO production declined between ages 4.5 and 6.5. At ages 9.5 and 12, further diminution of the association was found. No association was found between tibia Pb and EPO. The continued decline in the slope of the relationship between EPO and BPb with age, after adjustment for hemoglobin, implies a gradually decreasing capacity to produce EPO.
Journal of Occupational and Environmental Medicine 10/2004; 46(9):924-9. · 2.06 Impact Factor
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ABSTRACT: Schizophrenia is a severe mental disorder of unknown etiology. Recent reports suggest that a number of environmental factors during prenatal development may be associated with schizophrenia. We tested the hypothesis that environmental lead exposure may be associated with schizophrenia using archived serum samples from a cohort of live births enrolled between 1959 and 1966 in Oakland, California. Cases of schizophrenia spectrum disorder were identified and matched to controls. A biologic marker of lead exposure, delta-aminolevulinic acid (delta-ALA), was determined in second-trimester serum samples of 44 cases and 75 controls. delta-ALA was stratified into high and low categories, yielding 66 subjects in the high category, corresponding to a blood lead level (BPb) greater than or equal to 15 micro g/dL, and 53 in the low category, corresponding to BPb less than 15 micro g/dL. Using logistic regression, the odds ratio (OR) for schizophrenia associated with higher delta-ALA was 1.83 [95% confidence interval (CI), 0.87-3.87; p = 0.1]. Adjusting for covariates gave an OR of 2.43 (95% CI, 0.99-5.96; p = 0.051). This finding suggests that the effects of prenatal exposure to lead and/or elevated delta-ALA may extend into later life and must be further investigated as risk factors for adult psychiatric diseases.
Environmental Health Perspectives 05/2004; 112(5):548-52. · 7.04 Impact Factor
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ABSTRACT: There is widespread concern regarding the safety of silver-mercury amalgam dental restorations, yet little evidence to support their harm or safety. We examined whether mercury dental amalgams are adversely associated with cognitive functioning in a cross-sectional sample of healthy working adults. We studied 550 adults, 30-49 years of age, who were not occupationally exposed to mercury. Participants were representative of employees at a major urban medical center. Each participant underwent a neuropsychologic test battery, a structured questionnaire, a modified dental examination, and collection of blood and urine samples. Mercury exposure was assessed using a) urinary mercury concentration (UHg); b) the total number of amalgam surfaces; and c) the number of occlusal amalgam surfaces. Linear regression analysis was used to estimate associations between each marker of mercury exposure and each neuropsychologic test, adjusting for potential confounding variables. Exposure levels were relatively low. The mean UHg was 1.7 micro g/g creatinine (range, 0.09-17.8); the mean total number of amalgam surfaces was 10.6 (range, 0-46) and the mean number of occlusal amalgam surfaces was 6.1 (range, 0-19). No measure of exposure was significantly associated with the scores on any neuropsychologic test in analyses that adjusted for the sampling design and other covariates. In a sample of healthy working adults, mercury exposure derived from dental amalgam restorations was not associated with any detectable deficits in cognitive or fine motor functioning.
Environmental Health Perspectives 06/2003; 111(5):719-23. · 7.04 Impact Factor
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ABSTRACT: We study how effectively information induces Bangladeshi households to avoid a health risk. The response to information is large and rapid; knowing that the household's well water has an unsafe concentration of arsenic raises the probability that the household changes to another well within one year by 0.37. Households who change wells increase the time spent obtaining water fifteen-fold. We identify a causal effect of information, since incidence of arsenic is uncorrelated with household characteristics. Our door-to-door information campaign provides well-specific arsenic levels without which behavior does not change. Media communicate general information about arsenic less expensively and no less effectively.
Journal of Development Economics.
