Grantee Research Project Results

2012 Progress Report: An Integrated Geospatial and Epidemiological Study of Associations Between Birth Defects and Arsenic Exposure in New England

EPA Grant Number: R834599C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R834599
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Children's Environmental Health and Disease Prevention Center - Dartmouth College
Center Director: Karagas, Margaret Rita
Title: An Integrated Geospatial and Epidemiological Study of Associations Between Birth Defects and Arsenic Exposure in New England
Investigators: Shi, Xun , Purvis, Lisa A. , Moeschler, John B. , Onega, Tracy L. , Gui, Jiang , Rees, Judy
Current Investigators: Shi, Xun , Purvis, Lisa A. , Moeschler, John B. , Onega, Tracy L. , Gui, Jiang , Rees, Judy , Miller, Stephanie
Institution: Dartmouth Medical School , Dartmouth College
Current Institution: Dartmouth College , Dartmouth Medical School
EPA Project Officer: Callan, Richard
Project Period: February 15, 2010 through February 14, 2013 (Extended to February 14, 2014)
Project Period Covered by this Report: February 15, 2012 through February 14,2013
RFA: Children's Environmental Health and Disease Prevention Research Centers: Formative Centers (with NIEHS) (2009) RFA Text | Recipients Lists
Research Category: Children's Health , Human Health

Objective:

In this pilot project, our multidisciplinary team will: 1) establish a methodology integrating geospatial and epidemiological analyses to quantitatively and geographically monitor, characterize, and evaluate the associations between birth defects and arsenic exposure (i.e., inorganic arsenic) in New England; and 2) conduct a feasibility study for testing associations on an individual level. Epidemiologic studies indicate that birth defects relate to various environmental exposures and specifically suggest arsenic as a possible concern. Geospatial analyses in some regions have revealed considerable non-random spatial variation in the occurrence of birth defects, leading to the hypothesis that this may be due to spatial variation of environmental factors. The combination of geospatial and epidemiological analyses has the potential to create an economical, efficient, and effective procedure covering data preparation, spatial variation detection, case- control sampling, disease-environment relationship modeling, and finally risk mapping. In this project we intend to establish such a procedure and apply it to modeling the birth defect-arsenic exposure relationship in New Hampshire through two integrated specific aims:

Aim 1: Establishing and testing a methodology for characterizing the spatial variation in the associations between birth defects and arsenic exposures in NH. Specifically, we will a) characterize the spatial distribution of birth defect occurrence and detect the presence of special patterns, particularly hot spots; and b) based on a), we will evaluate spatial associations between birth defect occurrence and arsenic exposures.

Aim 2: Examine the birth defect-arsenic exposure relationship in NH and ME through a pilot epidemiological study that also will be used to further confirm the spatial characterization of arsenic risk through Aim 1.

Progress Summary:

For Aim 1: We continued acquiring new data and using the compiled GIS databases to perform planned geospatial analyses. Major achievements and undergoing work since last report include:

For the data of arsenic concentration in groundwater, we acquired three most updated (unpublished) new GIS data layers from USGS NH-VT Water Science Center, representing the probabilities of arsenic concentration > 1, 5, and 10 ug/L, respectively, at each location (represented by 30 m pixel) in New Hampshire (NH).
For the public water supply coverage in NH, we acquired public water supply pipeline data from the NH Department of Environmental Service.
We further compiled the birth defect data of NH for geospatial analysis. Besides the filtering processes reported last time (unique infant, plurality, mothers age, etc), we did literature research and had extensive discussions on identifying non-environmental birth defect types. Therefore, we excluded fetal alcohol syndrome and chromosomal defects (i.e., Down syndrome, Trisomy 13, and Trisomy 18, accounting for about 8% of all the records), because these conditions result from known causes.
We have compiled data for studies of low birth weight (LBW), high birth weight (HBW), and small for gestational age (SGA) in NH.
We further developed and improved the sophisticated geocomputational approach to disease mapping and have named it the RCMC-UCMC approach (restricted-and-controlled-Monte-Carlo and unrestricted-and-controlled-Monte-Carlo). We applied it to NH birth defect mapping and created high- resolution risk maps of birth defects in NH, along with quantified evaluation of spatial uncertainty of the results. A paper of this work has been submitted to the American Journal of Epidemiology. We have established collaboration with the National Center for Supercomputing Applications (NCSA), located at the University of Illinois at Urbana-Champaign, to migrate the software we developed for this method to the Centers supercomputing environment, so as to enhance its computational capability and public accessibility.

We conducted a fairly exhaustive exploration for detecting spatial association between groundwater arsenic and birth defects in NH.
On the arsenic side, we tested the well data collected by the Dartmouth researchers (led by Margaret Karagas, the PI of this Center), and 4 different USGS datasets (raster layers of probabilities for different arsenic concentration levels).
For the public water coverage, using the best available public water supply pipeline data from the NH DES, we tested a number of different buffer distances around the pipelines to define the public water supply coverage.
For confounding factors, besides mother's age, we tested land use (different degrees of urbanization), household medium income, and total population.
For the geographic scale, we conducted analyses at both the town level and very detailed pixel level (30 m).

For NH, we are conducting town-level analysis on spatial association between low birth weight (LBW) and groundwater arsenic, and a paper is under preparation.
The analyses for high birth weight (HBW) and small for gestational age (SGA) in NH are ongoing.
We also have acquired data of the state of Maine. The compilation of Maine data is largely done, and the analysis has started.

For Aim 2: We finalized all study recruitment materials for the Prenatal Environmental Exposures and Child Health (PEECH) Study, and began study subject recruitment in New Hampshire and Maine. This study seeks to evaluate the relationship between birth defects and arsenic exposure in groundwater. Our study subjects are based on birth defect cases only and will be analyzed comparing types of birth defects in arsenic exposed households, to those same types of defects in non-exposed households. For this analysis, arsenic exposed is defined as those households with an arsenic level in tap water that is ≥ 3 ppb. Data analysis will be completed following recruitment of the total subjects budgeted in this pilot (N=50). We anticipate this threshold to be reached by March 1, 2013. Exposure classification will consist of subjects self-reporting of prenatal water usage, results of the analysis of fingernail samples, and tap water samples taken at the time of this study.

Future Activities:

For Aim 1, we will include more data in the analysis, including mothers smoking status, percentage of public water use at Census tract level, and other socioeconomic and healthcare data. Some of these data have been acquired, and some are expected to be available in the near future. We will conduct a darting method, which is a version of the RCMC-UCMC method for detecting spatial association, to further investigate local variation, at the pixel level, in the spatial associations between groundwater arsenic and birth defects, LBW, HBW, and SGA in NH. We will continue the collaboration with NCSA to make the software more versatile, capable, and accessible. We will continue the data compilation and analyses with the Maine data.

For Aim 2, we will continue subject recruitment for the epidemiological study in New Hampshire and Maine until we reach our budgeted maximum of N=50 subjects. We plan to search for new funding to support expansion of this project. If additional funds are received we plan to implement the collection of RNA samples in addition to the DNA samples for use in future analyses of specific gene-environment interactions and the expression of certain arsenic-related genetic pathways.

Journal Articles:

No journal articles submitted with this report: View all 9 publications for this subproject

Supplemental Keywords:

arsenic, birth defects, water, drinking water, ground water, exposure, risk, health effects, human health, vulnerability, sensitive populations, population, infants, children, susceptibility, metals, heavy metals, public policy, decision making, community-based, public good, environmental chemistry, biology, geography, epidemiology, immunology, analytical, surveys, measurement methods, Northeast, EPA Region 1, food processing, water safety, RFA, Health, Scientific Discipline, INTERNATIONAL COOPERATION, ENVIRONMENTAL MANAGEMENT, HUMAN HEALTH, Environmental Policy, Biology, Environmental Chemistry, Exposure, Children's Health, Risk Assessment, dietary exposure, biological markers, drinking water, growth & development, prenatal exposure, children's vulnerablity, arsenic exposure, birth defects, developmental disorders

Relevant Websites:

http://www.dartmouth.edu/~childrenshealth/index.html Exit

Progress and Final Reports:

Original Abstract

2010 Progress Report

2011

Final Report

Main Center Abstract and Reports:

R834599 Children's Environmental Health and Disease Prevention Center - Dartmouth College

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834599C001 Arsenic and Maternal and Infant Immune Function
R834599C002 Food Borne Exposure to Arsenic During the First Year of Life
R834599C003 An Integrated Geospatial and Epidemiological Study of Associations Between Birth Defects and Arsenic Exposure in New England
R834599C004 Determining How Arsenic (As) Modulates Sonic Hedgehog (Shh) Signaling During Development

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.