In that polyfluoroalkyl chemicals (PFCs) are used commonly in commercial applications including food packaging, paper, and textiles, Jessica W. Nelson, from Boston University School of Public Health (Massachusetts, USA), and colleagues studied the association between serum cholesterol levels and four PFCs: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS).  The team found that people with levels of PFOS, PFOA and PFNA in the top 25% had higher total and non-HDL cholesterol, as compared to those with levels in the lowest 25%.  The association was most noticeable for PFNA, with a 13.9 milligram per deciliter difference in estimated cholesterol levels between people with the highest and lowest levels.  Writing that:  "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 metabolism at environmentally-relevant exposures.   While this study does not demonstrate a causal association between PFC exposure and serum cholesterol levels, it provides clues about where to focus future epidemiologic and toxicology research.”