title: Persistent organic pollutants in early pregnancy and risk of gestational diabetes mellitus.
abstract: Persistent organic pollutants (POPs) are a group of diverse substances, including polychlorinated biphenyls (PCBs) and organochlorine pesticides that are resistant to biodegradation and ubiquitously present in our environment. Exposure to endocrine disrupting chemicals such as POPs has been linked to type 2 diabetes and metabolic disturbances in epidemiological and animal studies, but little is known about POPs exposure during pregnancy and the development of gestational diabetes mellitus (GDM). The purpose of this study was to determine the extent to which exposure to current low levels of different POPs in the first trimester of pregnancy is associated with GDM risk in 939 women from the "Rhea" pregnancy cohort in Crete, Greece.
  
  
  
  Concentrations of several PCBs, dichlorodiphenyldichloroethene (DDE), and hexachlorobenzene (HCB) were determined in first trimester maternal serum by triple quadrupole mass spectrometry. We defined total PCBs as the sum of all congeners, nondioxin-like PCBs as the sum of PCB 153, 138, 170 and 180, and dioxin-like PCBs as the sum of PCB 118 and 156. Pregnant women were screened for gestational diabetes mellitus (GDM) between 24 and 28weeks of gestation, and GDM was defined by the criteria proposed by Carpenter and Coustan. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression models.
  
  
  
  Of the 939 women, 68 (7%) developed GDM. Serum concentrations of POPs were higher in women with GDM. Women in the medium and high tertiles of PCBs had 3.90 (95% CI: 1.37, 11.06) and 3.60 (95% CI: 1.14, 11.39) fold respectively higher odds of developing GDM compared to women in the lowest tertile of PCB exposure after adjusting for pre-pregnancy BMI and several other confounders. Odds of GDM for women in the medium and high tertiles of dioxin-like PCBs was 5.63 (95% CI: 1.81, 17.51) and 4.71 (95% CI: 1.38, 16.01) and for nondioxin-like PCBs 2.36 (95% CI: 0.89, 6.23) and 2.26 (95% CI: 0.77, 6.68) respectively. Prenatal DDE and HCB exposure were not significantly associated GDM risk.
  
  
  
  These findings suggest that women with high PCBs levels in early pregnancy had higher risk for GDM. Further studies are needed to replicate these results and to evaluate potential biological mechanisms underlying the observed associations.
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Greece. Electronic address: bafom@uoc.gr.
authors.forename: Marina
authors.initials: M
authors.lastname: Vafeiadi
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Theano
authors.initials: T
authors.lastname: Roumeliotaki
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Chalkiadaki
authors.affiliation: Department of Environmental Health, National Institute for Health and Welfare, Chemicals and Health Unit, Kuopio, Finland.
authors.forename: Panu
authors.initials: P
authors.lastname: Rantakokko
authors.affiliation: Department of Environmental Health, National Institute for Health and Welfare, Chemicals and Health Unit, Kuopio, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Kiviranta
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Fthenou
authors.affiliation: National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, Athens, Greece.
authors.forename: Soterios A
authors.initials: SA
authors.lastname: Kyrtopoulos
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Hospital del Mar Research Institute (IMIM), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.
authors.forename: Manolis
authors.initials: M
authors.lastname: Kogevinas
authors.affiliation: Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Leda
authors.initials: L
authors.lastname: Chatzi
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology*; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D016015:Logistic Models; D016017:Odds Ratio; D011247:Pregnancy / Q000097:blood*; D012306:Risk; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated
keywords: Gestational diabetes mellitus; Organochlorine pesticides; Persistent organic pollutants; Polychlorinated biphenyls (PCBs); Pregnancy