The study, by scientists at the Centers for Disease Control and Prevention (CDC) in Atlanta, is the first to detect racial or ethnic differences in levels of PFCs among humans.

PFCs are widely found at low levels in people and at higher levels are suspected of promoting cancer and other health problems in laboratory animals, according to the CDC researchers.

The CDC research team, led by Antonia Calafat, Ph.D., looked for selected PFCs in 54 aggregated blood samples that were collected in 2001 and 2002 as part of the National Health and Nutrition Examination Survey (NHANES). Each aggregated sample contained serum from 34 people, grouped by race, gender and age. Men in all three racial groups had slightly higher blood levels of PFCs than women. Non-Hispanic white males had the highest blood serum levels of most PFCs. However, the CDC team found age had no influence on blood concentrations of these compounds.

Although the researchers can't yet explain why whites had higher blood levels of PFCs, they note that "these differences may be a reflection of greater exposure to PFCs among non-Hispanic whites than among other racial/ethnic groups examined." In addition to environmental exposure, diet, lifestyle and genetic factors could account for elevated PFC blood levels in certain populations, Calafat says. To get a clearer picture of what may be happening, the researchers plan to analyze individual blood samples from NHANES, particularly those taken prior to 2000, the year when leading manufacturer 3M announced a voluntary phase-out of some PFCs.

Introduced in the 1950s, PFCs have long been used in the manufacture of insecticides, non-stick coatings and stain-resistant fabric and carpet. These ubiquitous compounds accumulate in the environment and have been detected far from civilization in Arctic fish and wildlife. The human health effects of PFCs are not yet known. But in laboratory studies, some PFCs have been tied to adverse effects in animals, including cancer and developmental problems, Calafat said. The industry is working on alternatives to PFCs and is attempting to eliminate them or their precursors from products.

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