title: Examining confounding by diet in the association between perfluoroalkyl acids and serum cholesterol in pregnancy.
abstract: BACKGROUND
  Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have consistently been associated with higher cholesterol levels in cross sectional studies. Concerns have, however, been raised about potential confounding by diet and clinical relevance.
  
  
  OBJECTIVE
  To examine the association between concentrations of PFOS and PFOA and total cholesterol in serum during pregnancy taking into considerations confounding by diet.
  
  
  METHODS
  854 Danish women who gave birth in 1988-89 and provided a blood sample and reported their diet in week 30 of gestation.
  
  
  RESULTS
  Mean serum PFOS, PFOA and total cholesterol concentrations were 22.3 ng/mL, 4.1 ng/mL and 7.3 mmol/L, respectively. Maternal diet was a significant predictor of serum PFOS and PFOA concentrations. In particular intake of meat and meat products was positively associated while intake of vegetables was inversely associated (P for trend <0.01) with relative difference between the highest and lowest quartile in PFOS and PFOA concentrations ranging between 6% and 25% of mean values. After adjustment for dietary factors both PFOA and PFOS were positively and similarly associated with serum cholesterol (P for trend ≤0.01). For example, the mean increase in serum cholesterol was 0.39 mmol/L (95%CI: 0.09, 0.68) when comparing women in the highest to lowest quintile of PFOA concentrations. In comparison the mean increase in serum cholesterol was 0.61 mmol/L (95%CI: 0.17, 1.05) when comparing women in the highest to lowest quintile of saturated fat intake.
  
  
  CONCLUSIONS
  In this study associations between PFOS and PFOA with serum cholesterol appeared unrelated to dietary intake and were similar in magnitude as the associations between saturated fat intake and serum cholesterol.
authors.affiliation: Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland; Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik, Iceland.
authors.forename: Margret
authors.initials: M
authors.lastname: Skuladottir
authors.affiliation: Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland; Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik, Iceland.
authors.forename: Alfons
authors.initials: A
authors.lastname: Ramel
authors.affiliation: Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark.
authors.forename: Dorte
authors.initials: D
authors.lastname: Rytter
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Line Småstuen
authors.initials: LS
authors.lastname: Haug
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Azemira
authors.initials: A
authors.lastname: Sabaredzovic
authors.affiliation: Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark.
authors.forename: Bodil Hammer
authors.initials: BH
authors.lastname: Bech
authors.affiliation: Pediatric Department, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Tine Brink
authors.initials: TB
authors.lastname: Henriksen
authors.affiliation: Center for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark; Department of Nutrition, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Sjurdur F
authors.initials: SF
authors.lastname: Olsen
authors.affiliation: Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland; Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik, Iceland; Center for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. Electronic address: tih@hi.is.
authors.forename: Thorhallur I
authors.initials: TI
authors.lastname: Halldorsson
mesh_terms: D000328:Adult; D017738:Alkanesulfonic Acids / Q000097:blood*; D002210:Caprylates / Q000097:blood*; D002784:Cholesterol / Q000097:blood*; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D003718:Denmark; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D018811:Maternal Exposure / Q000706:statistics & numerical data; D011247:Pregnancy; D012307:Risk Factors; D055815:Young Adult
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D004041:Dietary Fats; D005466:Fluorocarbons; C023036:perfluorooctanoic acid; D002784:Cholesterol; C076994:perfluorooctane sulfonic acid
keywords: Cholesterol; Diet; PFOA; PFOS; Pregnancy; Saturated fat