title: Breast cancer risk after exposure to perfluorinated compounds in Danish women: a case-control study nested in the Danish National Birth Cohort.
abstract: OBJECTIVE
  Animal studies have indicated that perfluoroalkylated substances (PFAS) increase mammary fibroadenomas. A recent case-control study in Greenlandic Inuit women showed an association between the PFAS serum levels and breast cancer (BC) risk. The present study evaluates the association between serum levels of PFAS in pregnant Danish women and the risk of premenopausal BC during a follow-up period of 10-15 years using prospectively collected exposure data during the pregnancy.
  
  
  METHODS
  Questionnaire and blood samples were taken during 1996-2002 and at the end of follow-up, all 250 BC cases and 233 frequency-matched controls were chosen for further analyses. Serum levels of ten perfluorocarboxylated acids, five perfluorosulfonated acids, and one sulfonamide (perflurooctane-sulfonamide, PFOSA) were determined by liquid chromatography-tandem mass spectrometry with electrospray ionization in negative mode. Computer-assisted telephone interviews taken during pregnancy provided data on potential confounders.
  
  
  RESULTS
  Weak positive and negative insignificant associations were found between BC risk and levels of perfluorooctane sulfonamide (PFOSA) and perfluorohexanesulfonate (PFHxS), respectively. Grouped into quintile, the BC cases had a significant positive association with PFOSA at the highest quintiles and a negatively association for PFHxS. Sensitivity analyses excluding uncertain cases caused stronger data for PFOSA and weaker for PFHxS. No further significant associations were observed.
  
  
  CONCLUSIONS
  This study does not provide convincing evidence for a causal link between PFAS exposures and premenopausal BC risks 10-15 years later.
authors.affiliation: Department of Public Health, Centre for Arctic Health & Cellular and Molecular Toxicology, Aarhus University, Aarhus, Denmark, ebj@ph.au.dk.
authors.forename: Eva C
authors.initials: EC
authors.lastname: Bonefeld-Jørgensen
authors.forename: Manhai
authors.initials: M
authors.lastname: Long
authors.forename: Stine Overvad
authors.initials: SO
authors.lastname: Fredslund
authors.forename: Rossana
authors.initials: R
authors.lastname: Bossi
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
mesh_terms: D000328:Adult; D017738:Alkanesulfonic Acids; D001943:Breast Neoplasms / Q000097:blood / Q000139:chemically induced / Q000453:epidemiology*; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000097:blood; D005260:Female; D005466:Fluorocarbons; D006801:Humans; D007407:Interviews as Topic; D008875:Middle Aged; D011247:Pregnancy; D012307:Risk Factors; D013451:Sulfonic Acids / Q000009:adverse effects* / Q000097:blood; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D017738:Alkanesulfonic Acids; D004785:Environmental Pollutants; D005466:Fluorocarbons; D013451:Sulfonic Acids; C471071:perfluorohexanesulfonic acid