No single epidemiologic study is sufficient to determine whether C8 damages health. The Science Panel has designed a series of different kinds of studies which are described briefly below. These studies began in late 2006 and are currently ongoing, with results already coming out of them (follow link at left to C8 study results). Results from these studies take from one year to five years from starting. Some of these studies are based on already collected information, while others require collection of new information, including interviews and blood samples. Any information gathered on individuals will be kept confidential by the Science Panel. In many cases a study requires a team of investigators, but in all studies a member of the Science Panel is overseeing the conduct of each specific study.

Choose from the list below to jump to a specific study:

Cholesterol, diabetes, uric acid, and C8 levels among participants in the C8 Health Project
Cross Sectional Study of C8 and Immune Function, Hematopoietic Function, Liver, Kidney, and Endocrine Disorders and Cancer Prevalence - a Prevalence study among participants in the C8 Health Project.
Community follow-up study
Worker follow-up study
The Study of Birth Outcomes in the Mid-Ohio Valley
The Study of Birth Outcomes among the C8 Health Project Participants
The Geographic Patterns of Cancer Study
Short Term Follow-up Study of C8 and Immune, Liver, Kidney and Endocrine Function
Exposure study
Half-life study
Study of C8 and Neurobehavioral Development among children from the C8 Health Project

1. Cholesterol, diabetes, uric acid, and C8 levels among participants in the C8 Health Project (study completed)

Investigator: Kyle Steenland, Emory University

Outline of study

The C8 Health Project carried out by Brookmar gathered information from August 2005 to July 2006 and analyzed blood for C8 level, cholesterol and uric acid. Information on self-reported diabetes was also recorded. In three different reports we have looked at the data collected from approximately 55,000 participants over age 20 to determine whether cholesterol and uric acid increased with C8 levels in the blood, and whether those with higher C8 levels in the blood had more diabetes. Analyses were adjusted for other variables which could affect the outcomes, such as age, gender, obesity, and smoking. More detailed results of these studies can be found elsewhere on this website (link). Briefly, higher C8 was linked to higher cholesterol. Those in the highest 25% of C8 had a 50% increased risk of having high cholesterol (>240 mg/dl) compared to those in the lowest 25% of C8. Higher C8 was also associated with high uric acid, although less dramatically, with about a 30% increased risk of high uric acid for those in the top 25% of C8 vs. the lowest 25%. Higher levels of C8S (C8 with a sulfur group attached - this chemical was not used by Dupont nor released into the environment) was also associated with higher levels of cholesterol and uric acid. Neither self-reported nor medically validated diabetes (adult onset, Type II diabetes) were associated with higher levels of C8.

Study status (September 2009)

These three reports were completed in early 2009. Results of these studies are available on the C8 Panel website. Briefly, higher C8 was associated with higher cholesterol and higher uric acid, while self-reported diabetes was not linked to C8.

However, these reports do not provide conclusive evidence regarding whether there is a probable link between C8 and disease because 1) one cannot determine whether C8 exposure preceded or followed the outcome of interest, and 2) in many cases the outcome is a biomarker and not a disease itself. Nonetheless they provide useful evidence that adds to the overall picture.

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2. Cross Sectional Study of C8 and Immune Function, Hematopoietic Function, Liver, Kidney, and Endocrine Disorders and Cancer Prevalence - a Prevalence study among participants in the C8 Health Project.

Investigator: Tony Fletcher, LSHTM

Outline of study

This study addresses the cross sectional relationship of C8 and a number of disease and clinical disease markers in a population of 69,030 participants in the C8 Health Project. They resided or worked in the six water districts near the DuPont plant in Parkersburg, WV and participated in the C8 Health Project. The C8 Health Project collected data during August 2005 to August 2006 and participants completed a questionnaire and gave blood.

The blood was analyzed for C8 and a substantial set of clinical parameters. The questionnaire included self-reported medical history and information on education, smoking habits, age, and other characteristics which are taken into account in the analyses. Self-reported medical history included questions about whether the participant has ever been diagnosed with a number of diseases including cancers. Some analyses will focus on the relationships between C8 blood levels and clinical parameters, including the results of blood tests on liver enzymes, hormones, and markers of immune function. Other analyses will investigate the relationship between reported disease (including cancer, diseases indicating disturbance of the immune system, disease related to hormone imbalances, liver and kidney disease) and estimates of C8 exposure leading up to the reported date of diagnosis. These exposure estimates will make use of measured C8 levels in blood and estimates of exposure to C8 in the past. Comparisons are adjusted for other variables of importance such as age, sex, smoking and weight.

The first phase of analyses uses the C8 concentrations measured at the time of the C8 Health Project. The second phase will allow rates of disease to be analyzed in relation to estimated past C8 exposure. This will focus on diseases including kidney, liver, autoimmune and thyroid diseases and will take place in 2010 once we have integrated historic exposure data and date of disease onset.

Study status (September 2009)

Work progressed on a scientific paper based on the status report on immune biomarkers submitted earlier this year and available here. A presentation based on these results was made at the Annual Conference of the International society for Environmental Epidemiology, August 2009.

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3. Community follow-up study

Investigator: Kyle Steenland, Emory University

Outline of study

This study is a 4 year follow-up study exploring disease occurrence among adult participants in the C8 Health Project, a survey of about 70,000 community residents (of which 55,00 were above age 20) residing in six water districts conducted from July 2005 - August 2006. Among these, about 40,000 have agreed to participate in the community follow-up study. We are interviewing these 40,000, asking about disease occurrence over time. There are two interviews - one in 2009 and another in 2010.

Diseases of interest include cancer, heart disease, and any other important disease such as diabetes and neurologic disease. Interviews can be completed on the phone or on the Web. Forty dollars per person is paid for answering the questionnaire, which takes less than 30 minutes.

For those who answer positively to the occurrence of certain diseases we will ask permission to view medical records to confirm the new disease occurrence. We will also trace any deaths which occur during the 4 year follow-up and determine the cause of death. Finally, we will cross-link study participants with Ohio and WV cancer registries for another source of information on cancer occurrence.

Once all this information has been collected, we will compare the rate of disease occurrence in this population of adults to that expected based on comparable Americans who had minimal or no exposure to C8. If C8 is related to any health damage, then disease rates among the 40,000 living near the Washington Works plant will be higher than those in comparable Americans without exposure. Otherwise, they will not.

We will also make some comparisons of disease rates within the 40,000 adults with past exposure. Here we will draw on the C8 blood level measured during the C8 Health Project. We will compare the rate of new disease occurrence among those with higher levels in 2005-2006 to the rate among those with low levels in 2005-2006.

We will also estimate past levels of C8 exposure over time for all people in the study, based on their residential history and an estimate of C8 levels in the water over time (see Exposure Study). We can then analyze disease occurrence by total C8 in the body. If C8 is related to any health effects, long term exposure could be more important than recent exposure as measured in the blood in 2005-2006 in the C8 Health Project.

Timeline: data collection now to 2010, results in 2011.

Study status (September 2009)

As of Sept 2009, approximately 80% of study subjects had completed initial interviews, and the response rate for those contacted was above 90%.

Subjects report a higher-than-anticipated proportion of medical conditions which require medical verification, which may result in a need for supplemental funds for this study. We are evaluating to what extent we can use the previously collected medical validation data collected by Brookmar in the C8 Health Project. Initial data suggest that for approximately a quarter of the currently reported medical conditions, a prior verification exists from Brookmar. We are now seeking medical records from the first several thousand people who have completed interviews.

Preparation is under way for the next round of interviews: an interview has been drafted.

This study is anticipated to provide important evidence regarding whether there is a probable link between C8 and disease because, as a follow-up study it is clear that C8 exposure preceded disease. Taken together with all the other evidence, it will provide the basis for a judgment about a probable link for chronic diseases such as cancer, heart disease, diabetes.

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4. Worker follow-up study

Investigator: Kyle Steenland, Emory University

Outline of study

C8 has been used in the manufacturing of Teflon and other products by DuPont in its West Virginia Washington Works plant. Many workers in the plant have been exposed to C8 over time, at levels higher than the surrounding community. We will conduct a study of disease occurrence among workers at the plant.

DuPont has already assembled a group of approximately 6,000 workers who worked at the Washington Works plant at any time between 1 Jan 1952 and 31 Dec 2001. DuPont has studied the mortality of these workers to determine whether they died of certain diseases at a higher rate than expected. However, studies of death patterns may be less revealing than studies of disease occurrence (fatal and non-fatal disease). We are following these same workers to determine what diseases they have had, including non-fatal as well as fatal disease. We are interested in major diseases such as cancer, heart disease, diabetes.

Workers are currently being interviewed in 2009, and will be interviewed once more with a shorter second interview in 2010. All workers will be free to participate or not. This study will be conducted independently of DuPont, and all information will be kept confidential. No information collected on any individual worker will be given to DuPont or anyone else. We estimate that about 2/3 of the 6,000 workers are no longer working.

DuPont has developed a way to estimate C8 exposure depending on where a worker has worked, based on C8 blood measurements for approximately 1,000 workers in 2004. DuPont has classified plant jobs into three groups of low, medium, and high exposure to C8. We plan to develop this work further, in order to take into account changes in exposure level over time. We may also create additional exposure categories beyond the low, medium, and high categories.

Interviews are done either via a telephone interview or website interview, and take approximately 30 minutes in length. Interviews cover medical history and other descriptive information such as years of schooling, marital status, smoking history, alcohol history, height, and weight, and medications. Subjects are paid for their time as in the commuhity study.

As part of our study we will determine whether workers have died and if so, cause of death.. In addition, we will check the records of the West Virginia and Ohio cancer registries to see who has developed cancer. For those workers who report having had a disease, we will ask permission to review their medical records to confirm this information. For workers who have died we will interview their relatives to find out what diseases they had.

Once all this information has been collected in 2009-2010, we will then compare the rate of new disease occurrence among the workers to that expected based on comparable Americans who had minimal or no exposure to C8. If C8 is related to any health damage, then disease rates among the workers will be higher than those in comparable Americans without exposure. Otherwise they will not.

We will also make some comparisons within the workers based on their level of exposure to C8. We will compare rate of new disease occurrence among those with higher levels of C8 over time to rate among workers with low levels of exposure.

Timeline: data collection now to 2010, results in 2011

Study Status (September 2009)

As of Sept 2009 approximately 60% of workers had completed initial interviews, and the response rate for those contacted was above 90%. More contact information is being sought from Dupont to help us make contact with past workers for whom the contact information was insufficient.

Preparation is under way for the next round of interviews; an interview has been drafted.

This study is anticipated to provide important evidence regarding whether there is a probable link between C8 and disease because they are follow up studies in which it is clear that C8 exposure preceded disease. Taken together with all the other evidence, it will provide the basis for a judgment about a probable link for chronic diseases such as cancer, heart disease, diabetes.

5. The Study of Birth Outcomes in the Mid-Ohio Valley

Investigator: David Savitz, MSSM

Outline of study

This study will evaluate whether C8 exposure is related to birth outcomes, including stillbirth, preterm birth (early delivery), and birth weight.

Birth outcome information will be collected from state birth records for selected counties in Ohio and West Virginia. We are including areas that had C8 in the drinking water and areas that did not have C8 in the drinking water, all within the same general region. The State Health Departments' Vital Records offices maintain birth records and can provide a complete list of all births in the region. C8 exposure for the mother and child will be based on the estimated amount of C8 in the drinking water where the mother was living at the time the baby was born. We will get this estimate from another Science Panel study (see the Exposure Study).

The Exposure Study is working to estimate exposure for different places at different times based on distance from the Washington Works plant and the amount of C8 released from the plant. The Study of Birth Outcomes in the Mid-Ohio Valley will help to determine whether mothers with higher estimated C8 exposure had a higher risk of having poor birth outcomes. If exposure to C8 increases the risk of a poor birth outcome, we expect to see worse birth outcomes in women with more C8 exposure. We will make adjustments for other influences on pregnancy health, including mother's age, race, education, marital status, number of previous births, and smoking habits. These characteristics about the mother are listed on the birth certificate. We will also take into account information from the U.S. Census about community characteristics, such as average income, proportion below the poverty level, and average housing value.

Study Status (September 2009)

We have received birth records for selected areas of Ohio and West Virginia from the State Health Departments. For Ohio, we have live birth records for the period from 1989 - 2004. For West Virginia, we have live birth and stillbirth records for the period 1980 - 2004. The mother's residence at the time of birth has been assigned to a location using either address or Zip Code. We are tabulating the U.S. Census data about the community characteristics. Once the data from the Exposure Study are available, we will continue with the analyses. This project has begun and is expected to be completed in 2010 once the estimates of C8 exposure are available from the Exposure Study.

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6. The Study of Birth Outcomes among the C8 Health Project Participants

Investigator: David Savitz, MSSM

Study Overview

This study will evaluate whether C8 exposure is related to birth outcomes, including miscarriage (pregnancy loss before 20 weeks), preterm birth (early delivery), low birth-weight, average birth-weight, preeclampsia (pregnancy complication with high blood pressure), and birth defects.

The primary data source for this study is the C8 Health Project questionnaire. Women who enrolled in the C8 Health Project in 2005 - 2006 were asked questions about any pregnancies they had. Because women may not remember exactly how long the pregnancy lasted before the baby was born (important to define preterm birth) or exactly how much a baby weighed at birth (important to define low birth-weight births), we will also use data from birth records kept by the Ohio and West Virginia Health Departments. The birth records are helpful because they have an exact measurement of gestational age and birth-weight. However, we will only be able to use the extra information from the birth certificates for the 70% of women who consented to participate in Science Panel research linking data sources. For all women in the C8 Health Project reporting one or more pregnancies, we will estimate their blood levels at the time of their pregnancies based on where she lived, her water consumption patterns, and her C8 blood level measured at the time of her enrollment. We will get this estimate from another Science Panel study (see the Exposure Study).

The Study of Birth Outcomes among the C8 Health Project Participants will help to determine whether mothers with higher estimated C8 exposure had a higher risk of having poor birth outcomes. If exposure to C8 increases the risk of a poor birth outcome, we expect to see worse birth outcomes in women with more C8 exposure. We will make adjustments for other influences on the health of pregnancy, such as mother's age, race, education, marital status, number of previous births, and smoking habits.

Study Status (September 2009)

An initial analysis of C8 Health Project births was completed and submitted to the court in March 2009. For this initial analysis, we restricted analyses to births in the 5 years before the Health Project and used the C8 blood measurement as the measure of exposure. This analysis used only data from the C8 Health Project questionnaire. For the 70% of the women who provided consent, we are linking the women's pregnancies to the Ohio and West Virginia State Health Department birth records for births from 1980-2004. Once the exposure data are available from the Exposure study we will conduct additional analyses that include more births to more women over longer periods of time.

This project has begun and is expected to be completed in 2010 once the estimates of C8 exposure are available from the Exposure Study.

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7. The Geographic Patterns of Cancer Study

Investigators: Tony Fletcher, LSHTM and Veronica Vieira, Boston University

Outline of study

This study addresses the relationship between past cancer incidence from 1993 to 2005 in regions of West Virginia and Ohio including the six contaminated water districts along with surrounding counties.

The goal is to determine if cancer rates by geographical area vary in relation to the C8 levels in those areas. The study is being carried out in collaboration with researchers at Boston University and Battelle and the state cancer registries in WV and OH. The population of approximately 500,000 people will be grouped by residence into census blocks and tracts according to similar average C8 exposure. The same exposure category will be assigned to all individuals in a geographic area (rather than to each individual as in the community cohort study). Information on cancer cases in the relevant counties is available from the West Virginia Cancer Registry and Ohio Cancer Surveillance Systems.

Estimated exposure to C8 in the water for these same geographical areas over time will be provided by the parallel exposure modeling project. Cancer cases will be assigned to these exposure groups by residence at time of diagnosis. Cancer incidence rates will then be computed to determine whether rates of cancer incidence differ in relation to levels of average exposure to C8. Results from this study will complement the community cohort study results. However, no Probable Link determination concerning cancer and C8 will be made until both studies are completed. Study to be completed in 2010.

Study status (September 2009)

The study is currently on target to be completed in 2010, assuming cancer data are supplied by both State cancer registries. The historical distribution of water systems has been matched to census boundaries and ZIP code areas. We are refining our mapping methods to include as much cancer data as possible in our analysis. Ohio Cancer data have been linked to US Census Bureau data based on address. Provision of detailed cancer data from West Virginia has been somewhat delayed by temporary freeze on recruiting staff in the state. Detailed Exposure data are anticipated by February 2010 to allow completion of the analyses.

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8. Short Term Follow-up Study of C8 and Immune, Liver, Kidney and Endocrine Function

Investigator: Tony Fletcher, LSHTM

Outline of study

This study will primarily assess changes of some clinical markers in relation to changes in C8, and detailed indicators of immune status, in a population of 800 of the C8 Health Project participants who agreed to participate in Science Panel studies. We will also assess the risk of common infectious disease and urinary markers indicative of kidney disease.

These participants will be recalled and invited to participate in a second interview and provide a second blood sample, and a urine sample. Statistical analyses will focus on the relationship between trends in C8 serum levels and trends in various clinical markers: of immune, cancer, thyroid, endocrine, kidney and liver function; both C8 and the biomarkers will then have been measured on two occasions. An extended panel of tests for assessing immune function will be given and the association with C8 investigated. In a subset of 400 of these participants, the extent to which C8 modifies the protection afforded by influenza vaccination will be assessed. The incidence of infectious disease in relation to C8 will be assessed by both questionnaire data on self reported disease, including infectious diseases and serological tests of recent latent viral infections, specifically herpes simplex virus (HSV) infection.

The study will provide important new information because of its longitudinal nature; it will consider change in biomarkers over time in relation to changes in C8 levels in the blood. Particular attention will be given to markers of liver, kidney, endocrine and immune function. Additional, more specific immune screening tests will allow the assessment of the response of the immune system to C8 exposure, and infectious disease risk in relation to C8 will also be assessed. Results are expected in 2011. Results on biomarkers in this study are expected to provide important evidence for the assessment of the relation between C8 and conditions including liver disease, kidney disease, thyroid disease, and auto-immune disease.

Study Status (September 2009)

Work during the last quarter has focused on finalizing detailed arrangements with the various laboratories, for collecting and carrying out laboratory analyses for clinical and chemical serum markers; arranging for hiring of key staff and preparing Institutional Review Board submissions. The first round of collection of blood samples which will enable us in particular to investigate the correlation of changes in C8 with changes in clinical markers, is scheduled to start in January. First results will be available at the end of 2010.

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9. Exposure study

Investigators: Kyle Steenland and Barry Ryan, Emory University

This project will estimate past exposure levels to C8 in the water for community residents living near DuPont's Washington Works plant.

C8 from the plant was released in the air and also released into the Ohio River from the 1950s until recently, resulting in community exposure, largely via drinking water consumption. It is believed that most C8 in the body comes from the water supply rather than breathing air with C8 in it or eating food with C8 in it. C8 reached water supplies by entering the groundwater, which is the source of wells for both public and private drinking water. C8 entered the groundwater both by trickling down through the soil and via the Ohio River, which has some exchange with the groundwater. The peak of C8 use and of emissions occurred in the late 1990s. C8 emissions in the air have been largely eliminated in the last few years, as have any significant releases into the Ohio River. Historical exposure to C8 will be important for the other epidemiologic studies conducted by the Science Panel.

The proposed work will estimate exposure for all times back to the beginning of release of C8 from Washington Works. We will use information on how much C8 was released from the plant each year into air and water, known wind patterns, and whatever actual measurements exist of C8 in the water. This will let us estimate how much C8 was in the drinking water over time at different locations around the plant.

Taken together with residential histories available from the C8 Health Project, we will be able to estimate how much C8 participants in the C8 Health Project have taken into their bodies from drinking water over time. We will also consider what happens to C8 in the body in order to estimate what C8 levels have been in the blood over time for participants in the C8 Health Project.

Timeline: data collection and analysis 2007-8, results 2009

Study Status (September 2009)

Significant progress has been made during the summer months. Estimates of groundwater concentrations in the water districts nearest the Washington Works plant are now available and can lead to estimates of intake and exposure to those individuals on municipal water supplies. These complement the previously available air concentrations and allow for a two-media exposure estimate in these areas. Groundwater estimates for regions further removed from the Washington Works plant are being developed and are expected to be low relative to those nearby. Work continues on developing data on various physical properties of PFOA in the environment. Simplified exposure-to-serum modeling has begun using a simple ratio, with more sophisticated physiologically based pharmacokinetic modeling planned for the next few months.

This study is to be completed in early 2010.

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10. Half-life study

Investigators: Kyle Steenland and Barry Ryan, Scott Bartell, Emory University

Outline of study

This project will examine the blood C8 levels of about 70,000 people who live near the Washington Works plant in West Virginia and had their blood levels of C8 measured in the C8 Health Project. Although many of these people had been exposed to C8 for decades, their blood C8 levels were never measured before 2005. In order to better understand the relationship between past C8 exposures and current blood C8 levels, and to improve the quality of exposure estimates in ongoing health studies, we have invited 200 adults from the C8 Health Project to participate in a longer study designed to determine the rate of removal of C8 from the body. The rate of removal is often called the "half-life", the period of time necessary for the body to clear out half of its C8. Before this study there was an estimate, that the average half-life of C8 for humans was 3-4 years, but this is based on only a few measurements among workers at 3M, another company which has used C8.

During 2007-8 carbon filters were installed to remove C8 from several contaminated water systems near the West Virginia chemical plant. People served by these water systems are expected to have lower exposures to C8 once filtration begins, which should cause a decline in blood C8 levels over time. This presents an opportunity to estimate the rate of decline through a half-life study based on repeated measurement of blood C8 levels before and after the carbon filters are installed.

Each participant in this half-life study has been asked to donate up to eight blood samples during a four year period. Levels of C8 will be measured in each blood sample. Participants will also be asked to complete a short questionnaire each time a blood sample is taken, and receive financial compensation amount? for each blood sample. The results will help us estimate past C8 exposures for participants in the C8 Health Project, which will in turn help determine whether C8 has any health effects in the other studies being done by the Science Panel. As in all Science Panel studies, all individual data will be kept confidential.

Timeline: data collection 2007-2010, analysis and results ongoing, beginning 2009 and completion in 2011

Study Status (September 2009)

Results from the first year of the study, previously submitted to the court and described previously, have been submitted for publication and are now undergoing anonymous peer review. Most of the participants remain enrolled in the study; 191 participants donated blood samples in Summer 2009, completing the second year of follow-up. The final round of blood samples is scheduled for Summer 2011.

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11. Study of C8 and Neurobehavioral Development among children from the C8 Health Project

Investigator: David Savitz, MSSM

Outline of study

This study will evaluate whether neurobehavioral development is related to C8 exposure among children who participated in the C8 Health Project.

Neurobehavioral development refers to how children learn and behave compared to other children the same age. Some of the children who participated in the C8 Health Project and who will be 6-11 years old during the data collection period will be invited to participate in the Neurobehavioral Development Study. We will use data from the C8 Health Project to identify eligible children, and expect to enroll approximately 550 of them. Only one child per family will be allowed to participate. We will enroll only children who were born and lived their entire lives in one of the affected water districts, and provided consent to participate in Science Panel research. By restricting the study to children who spent their entire lives in only one water district we will have a better idea of how much C8 a child was exposed to over his/her lifetime.

A mobile study van will visit eligible families at their home. Children will be weighed and measured, asked questions, and play reading, word, and number games with a specially trained research assistant to assess their skills. At the same time, the child's mother will be interviewed. The mother will be asked questions about the child's health, behavior, and home environment. Additionally, the mother will take a short standardized test on vocabulary, similarities and block design. With the mother's permission, we will contact the child's teacher for an evaluation of the child's performance at school relative to his/her classmates. At the end of the interview we will cut a small piece of hair from the child's head for measuring environmental exposures.

The information we collect from the mother and child, together with the measure of C8 exposure we have from the C8 Health Project, will be used to help us understand whether there is a relation between C8 exposure and the way children learn and behave.

Study Status (September 2009)

We began contacting families that are potentially eligible to enroll in the Study of C8 and Neurobehavioral Development by sending informational letters and following up with telephone calls. Study recruitment began in August 2009. We will continue contacting families and enrolling children and their mothers in this study through late 2010. We expect to have final study results in 2011.

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