title: Prediabetes, elevated iron and all-cause mortality: a cohort study.
abstract: OBJECTIVE
  Data have indicated low to non-existent increased mortality risk for individuals with prediabetes, but it is unclear if the risk is increased when the patient has elevated iron markers. Our purpose was to examine the mortality risk among adults with prediabetes in the context of coexisting elevated transferrin saturation (TS) or serum ferritin.
  
  
  METHODS
  Data collected by the third National Health and Nutrition Examination Survey 1988-1994 (NHANES III) in the USA and by the National Center for Health Statistics for the National Death Index from 1988 to 2006.
  
  
  METHODS
  Individuals age 40 and older who participated in the NHANES and provided a blood sample.
  
  
  METHODS
  Mortality was measured as all-cause mortality.
  
  
  RESULTS
  Adjusted analyses show that prediabetes has a small increased mortality risk (HR=1.04; 95% CI 1.00 to 1.08). Persons who had prediabetes and elevated serum ferritin had an increased HR for death (HR=1.14; 95% CI 1.04 to 1.24) compared with those who had normal ferritin and normal glucose. Among persons with prediabetes who had elevated TS, they had an increased mortality risk (HR=1.88; 95% CI 1.06 to 3.30) compared with those with normal TS levels and normal glucose.
  
  
  CONCLUSIONS
  The mortality risk of prediabetes is low. However, among individuals who have coexisting elevated iron markers, particularly TS, the risk rises substantially.
authors.affiliation: Department of Health Services Research, Management and Policy, University of Florida, Gainesville, Florida, USA Department of Community Health and Family Medicine, University of Florida, Gainesville, Florida, USA.
authors.forename: Arch G
authors.initials: AG
authors.lastname: Mainous
authors.affiliation: Department of Health Services Research, Management and Policy, University of Florida, Gainesville, Florida, USA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Tanner
authors.affiliation: Department of Pediatrics and Pathology, University of Southern California, Keck School of Medicine, Los Angeles, California, USA.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Coates
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Baker
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005293:Ferritins / Q000097:blood*; D006801:Humans; D007501:Iron / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D011236:Prediabetic State / Q000097:blood / Q000401:mortality*; D012306:Risk; D014168:Transferrin / Q000378:metabolism*; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D014168:Transferrin; D005293:Ferritins; D007501:Iron
keywords: DIABETES & ENDOCRINOLOGY; HAEMATOLOGY