Widespread Chemicals May Affect Cholesterol Levels

Newswise — A study published November 2, 2009 ahead of print in the peer-reviewed journal Environmental Health Perspectives (EHP) suggests that polyfluoroalkyl chemicals (PFCs) may affect serum cholesterol levels in people. The authors, all from the Boston University School of Public Health, used data from the National Health and Nutrition Examination Survey (NHANES), an ongoing survey of a representative sample of the civilian U.S. population that gathers data on dietary and health factors. NHANES is conducted by the Centers for Disease Control and Prevention (CDC).

PFCs are highly stable compounds used in commercial and industrial applications such as surfactants, paper and textile coatings and food packaging. These compounds have been found to be highly persistent in human tissues, with serum elimination half-lives of more than eight years for some types of PFCs. Past analyses of NHANES data showed that PFCs were present in the bodies of nearly all participants.

The authors analyzed the relationship between serum concentrations of four PFCs—perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS)—and measures of cholesterol, body size and insulin resistance reported in the 2003-2004 NHANES. Participants with PFOS, PFOA and PFNA levels in the top 25% of the study population had higher total and non-HDL cholesterol (which is primarily LDL, or “bad” cholesterol) than participants whose PFOS, PFOA, PFNA concentrations were in the lowest 25%.

Most previous studies of people with high PFC exposures have also reported positive associations, but the current study suggests that much lower PFC exposures experienced by typical U.S. adults may also affect cholesterol levels. The association was most striking for PFNA, with a 13.9 mg/dL difference in estimated serum cholesterol levels between people with the highest and lowest serum PFNA concentrations. In contrast, people with the highest levels of PFHxS, a PFC that has not been extensively studied, had lower total and non-HDL cholesterol than those with lower PFHxS concentrations. There was little evidence of an association between PFCs and body size or insulin resistance.

“Though these results are based on cross-sectional data and are exploratory, they are consistent with much of the human epidemiologic literature and indicate that PFCs may be exerting an effect on cholesterol at environmentally relevant exposures,” wrote first author Jessica Nelson and colleagues. “Our study affirms the importance of investigating PFCs other than PFOS and PFOA, particularly as industrial uses of PFOS and PFOA decline and other PFCs are substituted.”

Other authors include Elizabeth Hatch and Thomas Webster. This study was partially supported by a grant from the National Institute of Environmental Health Sciences (NIEHS).

Upon publication, the article will be available free of charge at http://www.ehponline.org/docs/2009/0901165/abstract.html.

EHP is published by the National Institute of Environmental Health Sciences (NIEHS), part of the U.S. Department of Health and Human Services. EHP is an Open Access journal. More information is available online at http://www.ehponline.org/. Brogan & Partners Convergence Marketing handles marketing and public relations for the publication and is responsible for creation and distribution of this press release.