title: Urinary F2-isoprostanes are not associated with increased risk of type 2 diabetes.
abstract: OBJECTIVE
  Free radicals have been implicated in the etiology of type 2 diabetes. Cross-sectional studies have demonstrated associations between oxidative damage and type 2 diabetes. However, no prospective data on this association are available.
  
  
  METHODS
  A case control study was conducted within the prospective cohort of the Insulin Resistance Atherosclerosis Study: 26 cases who developed type 2 diabetes in the follow-up period and 26 controls who remained free of type 2 diabetes were randomly selected. Oxidative status was assessed by measuring 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-IsoPM) in baseline urine samples using gas chromatography/mass spectroscopy. Type 2 diabetes was defined by serial oral glucose tolerance tests and World Health Organization criteria.
  
  
  RESULTS
  Urinary F2-IsoPM varied between 0.18 and 2.60 ng/mg creatinine; 25th/50th/75th percentiles were 0.42, 0.60, and 0.89, respectively. A trend toward higher levels were observed in women and in persons with impaired glucose tolerance at baseline (p = 0.1). F2-IsoPM increased with BMI (r = 0.36, p = 0.01). After adjustment for age, gender, baseline impaired glucose tolerance status, and BMI, F2-IsoPM levels were inversely associated with development of type 2 diabetes: odds ratio = 0.32 (95% confidence interval, 0.12 to 0.81) for the difference between the 75th and 25th percentiles.
  
  
  CONCLUSIONS
  These results suggest that oxidative damage is not a cause of type 2 diabetes. Positive cross-sectional associations of F2-IsoPM with the risk factors for diabetes, BMI, and impaired glucose tolerance and inverse associations with development of type 2 diabetes indicate that F2-IsoPM might reflect a compensatory mechanism.
authors.affiliation: Department of Community and Family Medicine/Cancer Control and Prevention, Duke University Medical Center, Durham, NC 27710, USA. dora.ilyasova@duke.edu
authors.forename: Dora
authors.initials: D
authors.lastname: Il'yasova
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagenknecht
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology*; D028441:F2-Isoprostanes / Q000652:urine*; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D010865:Pilot Projects; D012044:Regression Analysis; D012307:Risk Factors; D018709:Statistics, Nonparametric
chemical_list: D028441:F2-Isoprostanes