21 research outputs found

    Ecological study of Autism Spectrum Disorder prevalence and proximity to industrial facilities

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    Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental disorder that becomes apparent in infancy or early childhood. The etiology of this disorder is not well understood, but it has been hypothesized that environmental exposures are an important factor. For this study, we evaluated the association between Census tract-level ASD prevalence and proximity of tract centroids to point source industrial facilities as well as ambient lead, mercury, and arsenic concentrations within each tract. Additionally, we examined the influence of socioeconomic characteristics of tract population and ASD reporting. Using aggregate data for 2,489 tracts from five sites of the Autism and Developmental Disabilities Monitoring Network (ADDM), we estimated ASD prevalence for 2000 to 2008 surveillance years. Information for industrial facilities in existence during birth years of study participants was downloaded from the US Environmental Protection Agency Toxics Release Inventory (USEPA-TRI) and information on ambient metal concentrations were obtained from the EPA National-Scale Air Toxics Assessment (NATA). We used univariable multi-level negative binomial models to test associations between ASD prevalence and incremental and binary proximity of tract centroids to industrial facilities as well as individual metal air concentrations. Additionally, we built multivariable models adjusting for potential confounders, stratified for effect modification, and examined additive and synergistic effects of combined metal concentrations. We also used ordinal hierarchical models to test the influence of demographic and SES characteristics on the proportion of cases ascertained through schools only. After adjustment for percentage of male, White, Hispanic, and college educated residents, urbanicity, and proportion below poverty, tracts within the closest 10th percentile had a significantly higher ASD prevalence compared to those in the furthest 50th percentile (RR=1.27, 95% CI 1.02, 1.57). ASD prevalence was also higher in tracts where lead concentrations were in the 25th-50th percentile and greater than 75th percentile compared to those with concentrations in the lowest 25th percentile. Alone mercury levels did not show positive associations with ASD prevalence; however, when included in an interaction term to assess synergistic association of all three metals combined, mercury appeared to drive the positive associations with ASD prevalence. Demographic and SES characteristics found to be statistically associated with proportion of cases ascertained through schools only included Black race and maternal education for cases and Hispanic ethnicity in the population from which cases were drawn. Our finding suggests that increased ambient metal exposures in children living near industrial facilities may increase risk of ASD. More research should be done to assess the impact of these exposures and of residential distance from point sources

    Study of Occupational Chromium, Iron, and Nickel Exposure and Amyotrophic Lateral Sclerosis in Denmark

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    Studies of occupational metal exposures and amyotrophic lateral sclerosis (ALS) have focused primarily on known neurotoxicants, including lead, mercury, selenium, and cadmium. However, these exposures are often co-occurring with other lesser studied metals. We conducted a population-based case-control study with the aim of assessing associations between occupational chromium, iron, and nickel exposures and risk of ALS. We identified ALS cases in Denmark from 1982 through 2013 from the Danish National Patient Registry and matched them to 100 controls based on birth year and sex. Cumulative metal exposures were estimated using job exposure matrices applied to occupational history from the Danish Pension Fund. Although mutually adjusted odds of ALS were higher in men with chromium exposures in the third quartile (aOR = 1.24; 95% CI 0.91, 1.69) and fourth quartile (aOR = 1.19; 95% CI: 0.80, 1.76) compared to those with no exposure, differences did not reach statistical significance. We also observed higher odds of ALS in women with nickel exposures in the third quartile (aOR = 2.21; 95% CI: 1.14, 4.28), but not for the fourth quartile (aOR = 0.61; 95% CI: 0.23, 1.64). Our findings do not suggest associations between occupational exposures to these metals and ALS. However, unavoidable non-differential misclassification from the use of JEMs may have masked truly increased risk

    Blood Lead Concentrations in Jamaican Children with and without Autism Spectrum Disorder

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    Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. Lead is a toxic metal shown to cause neurodevelopmental disorders in children. Several studies have investigated the possible association between exposure to lead and ASD, but their findings are conflicting. Using data from 100 ASD cases (2–8 years of age) and their age- and sex-matched typically developing controls, we investigated the association between blood lead concentrations (BLC) and ASD in Jamaican children. We administered a questionnaire to assess demographic and socioeconomic information as well as exposure to potential lead sources. We used General Linear Models (GLM) to assess the association of BLC with ASD status as well as with sources of exposure to lead. In univariable GLM, we found a significant difference between geometric mean blood lead concentrations of ASD cases and controls (2.25 μg/dL cases vs. 2.73 μg/dL controls, p < 0.05). However, after controlling for potential confounders, there were no significant differences between adjusted geometric mean blood lead concentrations of ASD cases and controls (2.55 μg/dL vs. 2.72 μg/dL, p = 0.64). Our results do not support an association between BLC and ASD in Jamaican children. We have identified significant confounders when assessing an association between ASD and BLC

    Characteristics of Biostatistics, Epidemiology, and Research Design Programs in Institutions With Clinical and Translational Science Awards.

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    PurposeTo learn the size, composition, and scholarly output of biostatistics, epidemiology, and research design (BERD) units in U.S. academic health centers (AHCs).MethodEach year for four years, the authors surveyed all BERD units in U.S. AHCs that were members of the Clinical and Translational Science Award (CTSA) Consortium. In 2010, 46 BERD units were surveyed; in 2011, 55; in 2012, 60; and in 2013, 61.ResultsResponse rates to the 2010, 2011, 2012, and 2013 surveys were 93.5%, 98.2%, 98.3%, and 86.9%, respectively. Overall, the size of BERD units ranged from 3 to 86 individuals. The median FTE in BERD units remained similar and ranged from 3.0 to 3.5 FTEs over the years. BERD units reported more availability of doctoral-level biostatisticians than doctoral-level epidemiologists. In 2011, 2012, and 2013, more than a third of BERD units provided consulting support on 101 to 200 projects. A majority of BERD units reported that between 25% and 75% (in 2011) and 31% to 70% (in 2012) of their consulting was to junior investigators. More than two-thirds of BERD units reported their contributions to the submission of 20 or more non-BERD grant or contract applications annually. Nearly half of BERD units reported 1 to 10 manuscripts submitted annually with a BERD practitioner as the first or corresponding author.ConclusionsThe findings regarding BERD units provide a benchmark against which to compare BERD resources and may be particularly useful for institutions planning to develop new units to support programs such as the CTSA

    Characteristics of Biostatistics, Epidemiology, and Research Design Programs in Institutions With Clinical and Translational Science Awards

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    PURPOSE: To learn the size, composition, and scholarly output of Biostatistics, Epidemiology, and Research Design (BERD) units in U.S. academic health centers (AHCs). METHOD: Each year for four years, the authors surveyed all BERD units in U.S. AHCs that were members of the Clinical and Translational Science Award (CTSA) Consortium. In 2010, 46 BERD units were surveyed; in 2011, 55; in 2012, 60; and in 2013, 61. RESULTS: Response rates to the 2010, 2011, 2012, and 2013 surveys were 93.5%, 98.2%, 98.3%, and 86.9%, respectively. Overall, the size of BERD units ranged from 3-86 individuals. The median FTE in BERD units remained similar and ranged from 3.0 to 3.5 FTEs over the years. BERD units reported more availability of doctoral-level biostatisticians than doctoral-level epidemiologists. In 2011, 2012, and 2013, more than a third of BERD units provided consulting support on 101 to 200 projects. A majority of BERD units reported that between 25% and 75% (in 2011) and 31%-70% (in 2012) of their consulting was to junior investigators. More than two thirds of BERD units reported their contributions to the submission of 20 or more non-BERD grant or contract applications annually. Nearly half of BERD units reported 1 to 10 manuscripts submitted annually with a BERD practitioner as the first or corresponding author. CONCLUSIONS: The survey findings regarding BERD units provide a benchmark against which to compare BERD resources and may be particularly useful for institutions planning to develop new units to support programs such as the CTSA

    Concentration of Lead, Mercury, Cadmium, Aluminum, Arsenic and Manganese in Umbilical Cord Blood of Jamaican Newborns

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    The objective of this study was to characterize the concentrations of lead, mercury, cadmium, aluminum, and manganese in umbilical cord blood of Jamaican newborns and to explore the possible association between concentrations of these elements and certain birth outcomes. Based on data from 100 pregnant mothers and their 100 newborns who were enrolled from Jamaica in 2011, the arithmetic mean (standard deviation) concentrations of cord blood lead, mercury, aluminum, and manganese were 0.8 (1.3 μg/dL), 4.4 (2.4 μg/L), 10.9 (9.2 μg/L), and 43.7 (17.7 μg/L), respectively. In univariable General Linear Models, the geometric mean cord blood aluminum concentration was higher for children whose mothers had completed their education up to high school compared to those whose mothers had any education beyond high school (12.2 μg/L vs. 6.4 μg/L; p < 0.01). After controlling for maternal education level and socio-economic status (through ownership of a family car), the cord blood lead concentration was significantly associated with head circumference (adjusted p < 0.01). Our results not only provide levels of arsenic and the aforementioned metals in cord blood that could serve as a reference for the Jamaican population, but also replicate previously reported significant associations between cord blood lead concentrations and head circumference at birth in other populations

    Role of Metabolic Genes in Blood Arsenic Concentrations of Jamaican Children with and without Autism Spectrum Disorder

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    Arsenic is a toxic metalloid with known adverse effects on human health. Glutathione-S-transferase (GST) genes, including GSTT1, GSTP1, and GSTM1, play a major role in detoxification and metabolism of xenobiotics. We investigated the association between GST genotypes and whole blood arsenic concentrations (BASC) in Jamaican children with and without autism spectrum disorder (ASD). We used data from 100 ASD cases and their 1:1 age- and sex-matched typically developing (TD) controls (age 2–8 years) from Jamaica. Using log-transformed BASC as the dependent variable in a General Linear Model, we observed a significant interaction between GSTP1 and ASD case status while controlling for several confounding variables. However, for GSTT1 and GSTM1 we did not observe any significant associations with BASC. Our findings indicate that TD children who had the Ile/Ile or Ile/Val genotype for GSTP1 had a significantly higher geometric mean BASC than those with genotype Val/Val (3.67 µg/L vs. 2.69 µg/L, p < 0.01). Although, among the ASD cases, this difference was not statistically significant, the direction of the observed difference was consistent with that of the TD control children. These findings suggest a possible role of GSTP1 in the detoxification of arsenic

    Concentrations of Polychlorinated Biphenyls and Organochlorine Pesticides in Umbilical Cord Blood Serum of Newborns in Kingston, Jamaica

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    To date much of the biomonitoring related to exposure to polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides is from middle to high income countries, including the U.S., Canada and Europe, but such data are lacking for the majority of low to middle income countries. Using data from 64 pregnant mothers who were enrolled in 2011, we aimed to assess the concentrations of the aforementioned toxins in umbilical cord blood serum of 67 Jamaican newborns. For 97 of the 100 PCB congeners and 16 of the 17 OC pesticides, all (100%) concentrations were below their respective limits of detection (LOD). Mean (standard deviation (SD)) lipid-adjusted concentrations in cord blood serum for congeners PCB-153, PCB-180, PCB-206 and total PCB were 14.25 (3.21), 7.16 (1.71), 7.30 (1.74) and 28.15 (6.03) ng/g-lipid, respectively. The means (SD) for the 4,4′-dichlorodiphenyldichloroethylene (DDE)-hexane fraction and total-DDE were 61.61 (70.78) and 61.60 (70.76) ng/g-lipid, respectively. Compared to the U.S. and Canada, the concentrations of these toxins were lower in cord-blood serum of Jamaican newborns. We discuss that these differences could be partly due to differences in dietary patterns in these countries. Despite limitations in our dataset, our results provide information on the investigated toxins in cord blood serum that could serve as a reference for Jamaican newborns
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