title: Insulin sensitivity and insulin secretion determined by homeostasis model assessment and risk of diabetes in a multiethnic cohort of women: the Women's Health Initiative Observational Study.
abstract: OBJECTIVE
  The homeostasis model assessment (HOMA), based on plasma levels of fasting glucose and insulin, has been widely validated and applied for quantifying insulin resistance and beta-cell function. However, prospective data regarding its relation to diabetes risk in ethnically diverse populations are limited.
  
  
  METHODS
  Among 82,069 women who were aged 50-79 years, free of cardiovascular disease or diabetes, and participating in the Women's Health Initiative Observational Study, we conducted a nested case-control study to prospectively examine the relations of HOMA of insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) with diabetes risk. During a median follow-up period of 5.9 years, 1,584 diabetic patients were matched with 2,198 control subjects by age, ethnicity, clinical center, time of blood draw, and follow-up time.
  
  
  RESULTS
  Baseline levels of fasting glucose, insulin, and HOMA-IR were each significantly higher among case compared with control subjects, while HOMA-B was lower (all P values <0.0001). After adjustment for matching factors and diabetes risk factors, all four markers were significantly associated with diabetes risk; the estimated relative risks per SD increment were 3.54 (95% CI 3.02-4.13) for fasting glucose, 2.25 (1.99-2.54) for fasting insulin, 3.40 (2.95-3.92) for HOMA-IR, and 0.57 (0.51-0.63) for HOMA-B. While no statistically significant multiplicative interactions were observed between these markers and ethnicity, the associations of both HOMA-IR and HOMA-B with diabetes risk remained significant and robust in each ethnic group, including whites, blacks, Hispanics, and Asians/Pacific Islanders. When evaluated jointly, the relations of HOMA-IR and HOMA-B with diabetes risk appeared to be independent and additive. HOMA-IR was more strongly associated with an increased risk than were other markers after we excluded those with fasting glucose > or = 126 mg/dl at baseline.
  
  
  CONCLUSIONS
  High HOMA-IR and low HOMA-B were independently and consistently associated with an increased diabetes risk in a multiethnic cohort of U.S. postmenopausal women. These data suggest the value of HOMA indexes for diabetes risk in epidemiologic studies.
authors.affiliation: Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Yiqing
authors.initials: Y
authors.lastname: Song
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.forename: Lesley
authors.initials: L
authors.lastname: Tinker
authors.forename: Barbara V
authors.initials: BV
authors.lastname: Howard
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
authors.forename: Lauren
authors.initials: L
authors.lastname: Nathan
authors.forename: Nader
authors.initials: N
authors.lastname: Rifai
authors.forename: Simin
authors.initials: S
authors.lastname: Liu
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005006:Ethnicity; D005260:Female; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008875:Middle Aged; D008954:Models, Biological; D017698:Postmenopause; D011446:Prospective Studies; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology
chemical_list: D001786:Blood Glucose; D007328:Insulin