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Nov 032009
 

By Melissa Segrest
Green Right Now

Man-made chemicals that have long made life easier for everyone from cooks to clothiers are getting another round of scientific scrutiny. They may be related to unhealthy levels of cholesterol, a study released Monday suggests.

Jessica Nelson BU School of Public Health

Jessica Nelson, one of the authors of a new study of chemicals' impact on cholesterol

The chemicals are PFCs, and they’ve already been proven problematic. The Environmental Protection Agency and the top producers of one PFC (perfluoroalkys) have agreed to eliminate its use and emissions worldwide by 2015.

Even if they were eradicated tomorrow, the researchers at Boston University School of Public Health point out that some PFCs linger in the body a long time – one has a half-life of up to 8½ years.

There are hundreds of PFCs, and science is just scratching the surface of their potential impact on people. The chemicals are used to create non-stick or repellent materials on a laundry list of products. Your cooking pan, that waterproof jacket, your carpet and the packaging your frozen dinner came in all contain PFCs. The chemicals are used in almost every industry, from automobiles to electronics, textiles to cleaning products.

“PFCs have been used for over 50 years,” said Jessica W. Nelson, one of the authors of the study. “It is a large family of chemicals. There has been a fair amount of study in animals, but studies with people have been fewer.”

In studies of animals, there were direct correlations between high PFC levels and a host of illnesses, including cancer and developmental problems, according to the Environmental Protection Agency.

“So far, these have mostly consisted of studies in people who work with PFCs and have higher exposures. Studies of people exposed to background levels are just starting to come out,” Nelson said.

The study’s researchers limited their examination to four PFCs – the most common that appear in humans. Of those, two have not been studied much, the report said. The other two, PFOS (perfluorooctyl sulfonates) and PFOA (perfluorooctanic acid) are well-known and the most commonly used types of PFCs.
Many large companies such as 3M and Dupont have stopped using or are phasing out PFOS and PFOA.
PFCs water repellent fabric

Many water-repellent fabrics and surfaces contain PFCs.

“We really don’t know specifically how people are being exposed to PFCs. . . . They’re used widely in industry as surfactants and coatings. They make products resistant to stains, oil and water,” Nelson said Monday. “They’re used in products like pizza boxes, microwave popcorn bags, take-out food wrappers, textile coatings, carpet treatments . . . “

Researchers believe PFCs may enter the body through food and drinking water, ingesting and inhaling air and dust, or directly from products.

“Other PFCs are still being used that may break down into PFOS and PFOA in the environment or the body,” the researcher said.

So what is the correlation between the PFCs and cholesterol?

The scientists were able to gather blood serum from 2,094 people, making use of a large, varied group of Americans who have been part of an ongoing survey by the U.S. Centers for Disease Control and Prevention.

“Our study found an association between blood levels of several PFCs and higher levels of bad (LDL) cholesterol,” Nelson said. Of the study participants, the 25 percent carrying the highest levels of PFOS, PFOA and PFNA (perfluorononanoic acid) in their bodies had higher levels of “bad” serum cholesterol.

The study participants with the least amount of those three PFCs had less “bad” cholesterol in their bodies. There was not a clear link between PFCs and body size/weight and insulin resistance, which the researchers also analyzed.

PFCs non stick cookware

Non-stick cookware has long been made with PFC coatings.

One interesting finding in the study suggests that even typical adults with relatively low levels of the three PFCs in their bodies had higher LDL cholesterol than the general population. This was especially pronounced in people with PFNA in their systems.

The fourth chemical, PFHxS (perfluorohexane sulfonic acid), which has not been studied extensively, did not appear to have a strong link with cholesterol levels.

Researcher Nelson emphasized that their findings are “exploratory, and need to be followed up.

“Our results do not say that PFCs cause higher cholesterol. However, the association that we found – together with what other studies have found – is cause for concern and more research.”

The most prevalent chemical, PFOS, was more common in non-Hispanic white males, and age didn’t appear to be a factor.

The ranks of people with high levels of “bad” cholesterol has been growing, and that is linked to coronary heart disease, among other health problems.

“Despite its limitations, this study contributes to the literature suggesting that PFC exposure may disrupt cholesterol metabolism or homeostasis in humans,” the report said.

The study appeared in the Environmental Health Perspectives journal and is available online. The journal is part of the National Institute of Environmental Health Sciences.

The EPA has answers to frequent questions about PFCs, and more information is available from the nation’s Agency for Toxic Substances and Disease Registry.

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