By Steven Reinberg
WEDNESDAY, April 8 (HealthDay News) -- Typical exposures to chemicals that are found in a wide range of products, and have been linked to cancer in animals, may not boost risks for a range of malignancies in humans, a new report finds.
The two chemicals, perfluorooctanoate and perfluorooctanesulfonate (PFOA, PFOS) have for decades been ubiquitous in food packaging, pesticides, clothing, upholstery, carpets and personal care products. Earlier studies have found these chemicals in the blood of both people exposed to the chemicals at work and in the general public. High concentrations of the chemicals are associated with cancer in animals, but whether they are linked to cancer in humans is unclear.
One recent study, published in January in Human Reproduction, suggested that PFOA/PFOS might also impair women's ability to become pregnant.
However, the new study, published in the April 7 issue of the Journal of the National Cancer Institute, finds that the chemicals may not be associated with an increased risk for prostate, bladder, pancreatic, or liver cancer.
"This is the first study of PFOA/PFOS and cancer risk in a general population, and the results should, therefore, be treated with caution," said lead researcher Ole Raaschou-Nielsen, a senior researcher at the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen. "This is the beginning of the story rather than the end, since several more studies should be conducted before we can make final conclusions," he said.
"We would not recommend any action or changes in behavior based on the results of this single study," he added. "Future studies should confirm or reject the results of our study before practical implications should be considered."
For the study, the researchers collected data on a large group of Danes who were cancer-free when they were enrolled in the study between 1993 and 1997. The researchers identified 713 people who were later diagnosed with prostate cancer, 332 with bladder cancer, 128 with pancreatic cancer, and 67 with liver cancer. They compared these people with 772 people without cancer.
They also divided the participants into four groups based on their blood levels of PFOA and PFOS.
"We find no association between plasma concentrations of PFOA and PFOS and risk for prostate, bladder, pancreatic, or liver cancer in the general Danish population," Raaschou-Nielsen said.
This study did not investigate a possible cancer risk with higher blood levels of PFOA/PFOS, which can occur among people who work with these chemicals or people living in the vicinity of a chemical plant that pollutes the environment with PFOA/PFOS, Raaschou-Nielsen said.
Any danger with these chemicals may soon become moot, since, in 2006, the U.S. Environmental Protection Agency (EPA) had commitments from eight manufacturers of PFOA to voluntarily reduce emissions and product content of PFOA and related chemicals in the United States and overseas by 95 percent by 2010, and to work toward eliminating emissions and product content of these chemicals by 2015. This action was brought on because the chemical was associated with what the EPA called "systemic and developmental toxicity."
In addition, 3M, the only manufacturer of PFOS in the United States, had agreed to phase out its production and use of the chemical nine years ago, according to the EPA's Web site.
Dr. Michael J. Thun, vice president emeritus for Epidemiology and Surveillance Research at the American Cancer Society, believes the findings are interesting but not conclusive.
"The optimal solution is not to be absorbing these chemicals," Thun said. "The process of proving that they are safe is an impossible task. There are so many different conditions. and it's impossible to look at every single condition that they might affect," he said.
"The bottom line for the public is, 'Great, these chemicals don't cause these cancers -- but I'd rather not have it in my body at all,' " Thun said.
For more about environmental cancer risks, visit the U.S. National Cancer Institute.
SOURCES: Ole Raaschou-Nielsen, Ph.D., senior researcher, Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark; Michael J. Thun, M.D., vice president emeritus, Epidemiology and Surveillance Research, American Cancer Society; April 7, 2009, Journal of the National Cancer Institute
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