title: Maternal serum concentrations of perfluoroalkyl acids in five international birth cohorts.
abstract: Perfluoroalkyl acids (PFAAs) are persistent and bioaccumulating compounds, which are spread all over the globe. We aimed to compare the PFAA concentrations in serum from pregnant women in five birth cohorts from four countries (Denmark, China, Norway, and Greenland).
  
  
  
  Serum samples were obtained from the following five birth cohorts including a total of 4718 pregnant women: the Danish National Birth Cohort (DNBC, years 1996-2002, Denmark), the Aarhus Birth Cohort (ABC, years 2008-2013, Denmark), the Shanghai Birth Cohort (SBC, years 2013-2015, China), the Northern Norway Mother-Child Contaminant Cohort (MISA, years 2007-2009, Norway), and the Greenlandic Birth Cohort (ACCEPT, years 2010-2013, Greenland). The samples were analyzed using liquid chromatography triple-quadrupole mass spectrometry. To ensure comparability, all samples except for the MISA samples were measured in the same laboratory. We adjusted the log-transformed PFAA concentrations for age and parity using analysis of covariance.
  
  
  
  The geometric mean (GM) of the summed concentrations of the seven most abundant PFAAs (∑PFAA) was 35ng/mL in the DNBC, 25 ng/mL in the SBC, 18ng/mL in the ACCEPT, 12ng/mL in the MISA cohort, and 12ng/mL in the ABC. The DNBC concentration was highest presumably because these samples were taken in earlier years (i.e. 1996-2002) than the samples from the other cohorts (i.e. 2007-2015), and at a time when the production of PFAAs were at the highest. When excluding the DNBC samples, we found that the concentrations of all the perfluorinated sulfonic acids (PFSAs) and one of the four perfluorinated carboxylic acids (PFCAs) were highest in the Greenlandic women, whereas the other three PFCAs were highest in the Chinese women.
  
  
  
  The concentration and composition of serum PFAAs were similar for the Danish ABC women and the Norwegian MISA women but were otherwise different across the cohorts. The different exposure profiles might partly be related to differences in lifestyle and diet. As the concentrations and compositional patterns vary between the countries, we suggest that the health implications associated with high PFAA exposure might also differ between the countries.
authors.affiliation: Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Bjerregaard-Olesen
authors.affiliation: Department of Environmental Science, Aarhus University, Roskilde, Denmark.
authors.forename: Rossana
authors.initials: R
authors.lastname: Bossi
authors.affiliation: Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA.
authors.forename: Zeyan
authors.initials: Z
authors.lastname: Liew
authors.affiliation: Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Manhai
authors.initials: M
authors.lastname: Long
authors.affiliation: Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Bodil H
authors.initials: BH
authors.lastname: Bech
authors.affiliation: Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark; Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
authors.affiliation: Perinatal Epidemiology Research Unit, Aarhus University Hospital, Skejby, Denmark; Department of Pediatrics, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Tine B
authors.initials: TB
authors.lastname: Henriksen
authors.affiliation: Department of Laboratory Medicine, Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Vivian
authors.initials: V
authors.lastname: Berg
authors.affiliation: Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Fram Centre, Tromsø, Norway, Norway; Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Therese H
authors.initials: TH
authors.lastname: Nøst
authors.affiliation: Shanghai Key Laboratory of Children's Environmental Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Jun J
authors.initials: JJ
authors.lastname: Zhang
authors.affiliation: Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Jon Ø
authors.initials: JØ
authors.lastname: Odland
authors.affiliation: Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark. Electronic address: ebj@ph.au.dk.
authors.forename: Eva C
authors.initials: EC
authors.lastname: Bonefeld-Jørgensen
mesh_terms: D000293:Adolescent; D000328:Adult; D017738:Alkanesulfonic Acids / Q000097:blood*; D002264:Carboxylic Acids / Q000097:blood*; D002681:China; D003718:Denmark; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006116:Greenland; D006801:Humans; D008875:Middle Aged; D009664:Norway; D011247:Pregnancy / Q000097:blood; D055815:Young Adult
chemical_list: D017738:Alkanesulfonic Acids; D002264:Carboxylic Acids; D004785:Environmental Pollutants; D005466:Fluorocarbons
keywords: China; Denmark; Exposure profiles; Greenland; Norway; Perfluorinated compounds