title: Higher ferritin levels, but not serum iron or transferrin saturation, are associated with Type 2 diabetes mellitus in adult men and women free of genetic haemochromatosis.
abstract: BACKGROUND
  Iron overload predisposes to diabetes and higher ferritin levels have been associated with diabetes. However, it is unclear whether ferritin reflects differences in iron-related parameters between diabetic and nondiabetic persons. We examined associations of serum ferritin, iron and transferrin saturation with Type 2 diabetes in adults without genetic predisposition to iron overload.
  
  
  METHODS
  Cross-sectional analysis of community-dwelling men and women aged 17-97 years from the Busselton Health Survey, Western Australia. Men and women carrying genotypes associated with haemochromatosis (C282Y/C282Y or C282Y/H63D) were excluded. Serum ferritin, iron and transferrin saturation were assayed.
  
  
  RESULTS
  There were 1834 men (122 with diabetes, 6·6%) and 2351 women (141 with diabetes, 6%). In men, higher serum ferritin was associated with diabetes after adjusting for age, smoking, alcohol, cardiovascular history, body mass index (BMI), waist, blood pressure, lipids, C-reactive protein (CRP), adiponectin, alanine transaminase (ALT) and gamma-glutamyl transpeptidase (GGT) [odds ratio (OR): 1·29 per 1 unit increase log ferritin, 95% confidence interval (CI) = 1·01-1·65, P = 0·043]. In women, higher serum ferritin was associated with diabetes [fully adjusted OR: 1·31 per 1 unit increase log ferritin, 95% CI = 1·04-1·63, P = 0·020; 1·84 for tertile (T) 3 vs T1, 95% CI = 1·09-3·11]. Neither iron levels nor transferrin saturation were associated with diabetes risk in men or women. Higher ferritin was not associated with insulin resistance in nondiabetic adults.
  
  
  CONCLUSIONS
  In adults, higher ferritin levels are independently associated with prevalent diabetes while iron and transferrin saturation are not. Ferritin is a robust biomarker for diabetes risk, but further investigation is needed to clarify whether this relationship is mediated via iron metabolism.
authors: School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia; Department of Endocrinology and Diabetes, Fremantle Hospital, Fremantle, WA, Australia.
authors: Bu B
authors: BB
authors: Yeap
authors: Mark L
authors: ML
authors: Divitini
authors: Jenny E
authors: JE
authors: Gunton
authors: John K
authors: JK
authors: Olynyk
authors: John P
authors: JP
authors: Beilby
authors: Brendan
authors: B
authors: McQuillan
authors: Joseph
authors: J
authors: Hung
authors: Matthew W
authors: MW
authors: Knuiman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D005293:Ferritins / Q000097:blood*; D005838:Genotype; D006432:Hemochromatosis / Q000235:genetics; D006801:Humans; D007333:Insulin Resistance; D007501:Iron / Q000097:blood*; D019190:Iron Overload / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012044:Regression Analysis; D014168:Transferrin / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014168:Transferrin; D005293:Ferritins; D007501:Iron