VIENNA - The C8 Science Panel released seven new probable link reports, announcing a link between C8 exposure and thyroid disease and ulcerative colitis at a press conference Monday.
No link was found between C8 exposure and chronic obstructive pulmonary disease, asthma, childhood and adult infections such as influenza, neurodevelopmental disorders in children, stroke, and auto-immune diseases of lupus, rheumatoid arthritis, type I juvenile diabetes, Crohn's disease and multiple sclerosis.
C8, also known as perfluorooctanoic acid or PFOA is a manmade chemical used in manufacturing products including nonstick cookware, protective finishes on carpets and water-resistant clothing.
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Dr. David Savitz, one of the epidemiologists on the C8 Science Panel, outlined the panel’s finding that there is no probable link between C8 exposure and neurodevelopmental disorders in children.
A 2004 class action lawsuit regarding the DuPont Washington Works' discharge of C8 into local drinking water ended in a 2005 settlement, which included appointment of a mutually agreed upon, independent three-member science panel tasked with determining if there is a probable link between C8 exposure and disease. Nearly 70,000 people in the six affected water districts who were part of the lawsuit were tested and had medical histories taken in addition to several other studies including DuPont employees.
According to the science panel, evidence on thyroid disease was "mixed," but the panel concluded overall it was "more probable than not that C8 was linked to thyroid disease."
"The settlement agreement requires if it is more probable than not, we have to make a judgment, and overall we had to decide. We go back to the data and review, there is a consensus, it's a deliberation process," said Dr. David Savitz, one of the panel epidemiologists.
Panelists said ulcerative colitis is a relatively rare disease characterized by chronic inflammation of the lining of the digestive tract. It causes chronic pain and discomfort, and generally cannot be cured. Ulcerative colitis is similar to but not the same as Crohn's disease, another disease of the digestive tract. There were about 160 validated cases of ulcerative colitis considered by the science panel as part of their studies.
The panel also found a probable link between C8 and thyroid disease, which is a common condition related to an imbalance in thyroid hormones. It can usually be well-controlled by treatment with thyroid hormones, Savitz said. There were more than 2,000 validated cases of thyroid disease in the second panel study of mid-Ohio valley residents.
"While the evidence on thyroid disease was mixed, the panel concluded, overall, it was more probable than not that C8 was linked to thyroid disease."
DuPont officials issued a written statement following Monday's press conference.
"A probable link report does not mean that the science panel has concluded that PFOA (C8) exposure has caused or will cause any human disease among the class members as a whole, including the Washington Works employees or any individual," said Janet E. Smith with DuPont.
Smith noted a status report filed by the science panel with interim findings addressing kidney function.
"The panel concluded although we observed an association between measured levels of PFOA in serum and reduced kidney function in children and adolescents, our findings highlight the possibility that this association and resulting increased concentrations of PFOA may be a consequence of, rather than a cause of, decreased kidney function," Smith said.
"Consistent with our core values of health, safety and environmental stewardship and before any reports from the science panel, DuPont took actions to minimize PFOA exposure. For decades, DuPont has had industrial hygiene measures in place to minimize worker exposures to PFOA. Data shows that these measures are effective. DuPont has reduced total PFOA emissions by more than 98 percent in our global manufacturing operations since 2000. We also have developed and commercialized new technologies to make fluoropolymers without using PFOA, and to make surface protection products that cannot break down to PFOA in the environment. Regulatory authorities around the world have affirmed that these products are safe for their intended uses. DuPont will continue to meet its obligation under the West Virginia litigation. DuPont will evaluate additional information from the science panel as part of our long-standing commitment to the safety of our employees and customers and to responsible environmental and product," Smith said.
Rob Bilott, one of the plaintiffs' attorneys, commended the science panel for its work.
"We are confident that the panel is working diligently to alert the community by the end of October regarding any additional serious health risks that they may face because of their exposure to C8-contaminated drinking water," Bilott said.
Savitz said the panel looked at looked at a number of neurodevelopmental disorders including development problems like Attention Deficit Hyperactivity Disorder. "We did not find an association," Savitz said.
Panelist Tony Fletcher said studies included mothers exposed to C8 during pregnancy, and no association with any of the common place childhood diseases was found relating to C8 exposure.
Savitz said there were indications of some association of a "small" increase in I.Q. levels among study subject children who had higher C8 levels.
How their findings relate to the general population, panelists were unable to say.
"Everyone has some C8 in their blood at very low levels, among the study participants the levels were lowest in residents of Pomeroy and Mason County. But we don't know how the levels here relate to the general population," panelist Dr. Kyle Steenland said.
The remaining probable link reports are to be filed before the end of October. These will include liver disease; kidney disease; Osteoarthritis; Parkinson's disease; heart disease; hypercholesterolemia, and hypertension.
Probable link judgments for five reproductive outcomes were filed in December 2011, and for diabetes and 21 different cancers in April 2012. Of these, three diseases were deemed to have a probable link with C8 in the Mid-Ohio Valley population: testicular cancer, kidney cancer and pregnancy-induced hypertension.
