Superfund Research Program
Early Life Exposure to Tetrachloroethylene (PCE)-Contaminated Drinking Water and Social Stressors may Interact to Increase the Risk of Substance Use Later in Life
Dr. Ann Aschengrau's group is conducting a population-based retrospective cohort study to test the hypothesis that tetrachloroethylene (PCE) found in the public drinking water supplies in Cape Cod, Massachusetts, is associated with an increased risk of nervous system abnormalities among men and women exposed during gestation and childhood. The source of the water contamination was a vinyl liner that was applied to hundreds of miles of asbestos cement water distribution pipes in eight towns in the Cape Cod area from the late 1960s through 1980. The study population is composed of individuals who were exposed to PCE contaminated drinking water during 1969-1983 and a comparable group of unexposed subjects. Exposed subjects include individuals with both prenatal and childhood exposure and their older siblings with only childhood exposure. Hypothesized effects include an increased prevalence of indicators and diagnoses related to vision disorders and developmental disabilities of learning and attention; impaired performance on neuropsychological and vision tests; and increased prevalence of cerebral pathology and dysfunction as seen in neuroimaging studies. Nervous system effects are anticipated to be time-dependent with greater effects among individuals who had both prenatal and childhood exposure compared with those with only childhood exposure.
Over the past year, Dr. Aschengrau and her team have made progress in identifying and tracing study subjects; finalizing the self-administered questionnaire and data collection protocols; conducting epidemiological and statistical analyses; preparing abstracts for scientific meetings; and drafting manuscripts for publication.
To date, the researchers have identified 4,823 subjects and have attempted to trace 3,202 (66%). Eighty-four percent of those traced have been successfully located. Of the remainder, 1.4% are deceased, 5.8% are lost to follow up, and 8.9% have a parent who refused to participate in the prior study and so will not be contacted for the current study. The investigators have finalized the self-administered questionnaire to gather information on indicators and diagnoses of learning, attention, and vision disorders; confounding variables such as other sources of solvent exposures; effect modifying variables such as alcohol consumption; and residential histories. They also have developed protocols and purchased supplies for conducting the follow-up neuropsychological and vision testing and neuroimaging studies. These data collection activities will take place over the coming year.
The research team has conducted a validation study to compare the assessments made with EPANET—a software package used to model water flow—with historical records of PCE concentrations in drinking water samples, and a comparative study contrasting the computerized EPANET assessments with the simplified visual exposure assessment methods used in their prior studies. They have also completed epidemiological and statistical analyses and prepared draft manuscripts on the relationship between pre-natal and, if applicable, post-natal PCE exposure and the occurrence of several reproductive and developmental abnormalities. These manuscripts describe the relationship between PCE exposure and low birth weight, prematurity, and intrauterine growth retardation, pregnancy loss, and learning disabilities (abstract presented at ISEE, September, 2006); and the results of the comparative exposure assessment study (abstract presented at ISEE, September 2006).
In additional, the team and their Superfund and other collaborators have used data from their prior SBRP-funded research to investigate breast cancer risk in relation to: (1) community- and individual-level socioeconomic status (Spatial Epidemiology Conference, May 2006, and ISEE, September, 2006), (2) spatio-temporal factors (Spatial Epidemiology Conference, May 2006, and ISEE, September 2006), (3) exposure to drinking water contaminated by wastewater (Environmental Health: A Global Access Science Journal, 2006), and (4) the interaction between cigarette smoke exposure and catechol-O-methyltransferase genotype (Journal of Carcinogenesis, 2006).