title: Undiagnosed diabetes and impaired fasting glucose inHFEC282Y homozygotes andHFEwild-type controls in the HEIRS Study.
abstract: OBJECTIVE
  To determine prevalences and predictors of undiagnosed diabetes mellitus (UDM) and impaired fasting glucose (IFG) in non-Hispanic whites withHFEp.C282Y homozygosity and controls without commonHFEmutations identified in population screening.
  
  
  METHODS
  We analyzed these observations in a postscreening examination: age; sex; body mass index; systolic/diastolic blood pressure; metacarpophalangeal joint hypertrophy; hepatomegaly; blood neutrophils; alanine and aspartate aminotransferase; elevated C reactive protein; transferrin saturation; serum ferritin; and Field Center.
  
  
  RESULTS
  There were 223 p.C282Y homozygotes and 449 controls without diagnosed diabetes (43.9% men). Mean age of p.C282Y homozygotes was 52±13 years (controls 57±14 years; p<0.0001). Mean transferrin saturation in p.C282Y homozygotes was 67±26% (controls 34±14%; p<0.0001). Mean serum ferritin in p.C282Y homozygotes was 607 pmol/L (95% CI 497 to 517; controls 274 pmol/L (247 to 301); p<0.0001). Overall prevalences of UDM (4.0% vs 4.2%) and IFG (23.8% vs 25.6%) did not differ significantly between p.C282Y homozygotes and wt/wt controls, respectively. In logistic regressions, male sex, body mass index, and alanine aminotransferase were significantly associated with UDM. ORs were 2.7 (1.2 to 2.8); 1.0 (1.0 to 1.1); and 1.0 (1.0 to 1.0), respectively. Age, male sex, and body mass index were significantly associated with IFG. ORs were 1.0 (1.0 to 1.1); 2.8 (1.9 to 4.2); and 1.0 (1.0 to 1.1), respectively.
  
  
  CONCLUSIONS
  Prevalences of UDM and IFG were similar in p.C282Y homozygotes and controls in a postpopulation screening examination. Male sex was the strongest predictor of UDM and IFG.
authors.affiliation: Southern Iron Disorders Center, Birmingham, Alabama, USA; Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Barton
authors.affiliation: Southern Iron Disorders Center , Birmingham, Alabama , USA.
authors.forename: J Clayborn
authors.initials: JC
authors.lastname: Barton
authors.affiliation: Department of Medicine , University of Western Ontario , London, Ontario , Canada.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Adams
authors.affiliation: Southern Iron Disorders Center, Birmingham, Alabama, USA; Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Acton
keywords: Epidemiology; Genetic Risk Factors; Hemochromatosis