title: Reductions in serum lipids with a 4-year decline in serum perfluorooctanoic acid and perfluorooctanesulfonic acid.
abstract: BACKGROUND
  Several epidemiological cross-sectional studies have found positive associations between serum concentrations of lipids and perfluorooctanoic acid (PFOA, or C8). A longitudinal study should be less susceptible to biases from uncontrolled confounding or reverse causality.
  
  
  METHODS
  We investigated the association between within-individual changes in serum PFOA and perfluorooctanesulfonic acid (PFOS) and changes in serum lipid levels (low-density lipoprotein [LDL] cholesterol, high-density lipoprotein cholesterol, total cholesterol, and triglycerides) over a 4.4-year period. The study population consisted of 560 adults living in parts of Ohio and West Virginia where public drinking water had been contaminated with PFOA. They had participated in a cross-sectional study in 2005-2006, and were followed up in 2010, by which time exposure to PFOA had been substantially reduced.
  
  
  RESULTS
  Overall serum concentrations of PFOA and PFOS fell by half from initial geometric means of 74.8 and 18.5 ng/mL, respectively, with little corresponding change in LDL cholesterol (mean increase 1.8%, standard deviation 26.6%). However, there was a tendency for people with greater declines in serum PFOA or PFOS to have greater LDL decrease. For a person whose serum PFOA fell by half, the predicted fall in LDL cholesterol was 3.6% (95% confidence interval = 1.5-5.7%). The association with a decline in PFOS was even stronger, with a 5% decrease in LDL (2.5-7.4%).
  
  
  CONCLUSIONS
  Our findings from this longitudinal study support previous evidence from cross-sectional studies of positive associations between PFOA and PFOS in serum and LDL cholesterol.
authors.affiliation: Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, United Kingdom. n.fitz-simon@imperial.ac.uk
authors.forename: Nicola
authors.initials: N
authors.lastname: Fitz-Simon
authors.forename: Tony
authors.initials: T
authors.lastname: Fletcher
authors.forename: Michael I
authors.initials: MI
authors.lastname: Luster
authors.forename: Kyle
authors.initials: K
authors.lastname: Steenland
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kato
authors.forename: Ben
authors.initials: B
authors.lastname: Armstrong
mesh_terms: D000328:Adult; D017738:Alkanesulfonic Acids / Q000097:blood*; D002210:Caprylates / Q000097:blood*; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D008055:Lipids / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D055815:Young Adult
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D005466:Fluorocarbons; D008055:Lipids; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid