title: Insulin clearance and the incidence of type 2 diabetes in Hispanics and African Americans: the IRAS Family Study.
abstract: OBJECTIVE
  We aimed to identify factors that are independently associated with the metabolic clearance rate of insulin (MCRI) and to examine the association of MCRI with incident type 2 diabetes in nondiabetic Hispanics and African Americans.
  
  
  METHODS
  We investigated 1,116 participants in the Insulin Resistance Atherosclerosis Study (IRAS) Family Study with baseline examinations from 2000 to 2002 and follow-up examinations from 2005 to 2006. Insulin sensitivity (S(I)), acute insulin response (AIR), and MCRI were determined at baseline from frequently sampled intravenous glucose tolerance tests. MCRI was calculated as the ratio of the insulin dose over the incremental area under the curve of insulin. Incident diabetes was defined as fasting glucose ≥126 mg/dL or antidiabetic medication use by self-report.
  
  
  RESULTS
  We observed that S(I) and HDL cholesterol were independent positive correlates of MCRI, whereas fasting insulin, fasting glucose, subcutaneous adipose tissue, visceral adipose tissue, and AIR were independent negative correlates (all P < 0.05) at baseline. After 5 years of follow-up, 71 (6.4%) participants developed type 2 diabetes. Lower MCRI was associated with a higher risk of incident diabetes after adjusting for demographics, lifestyle factors, HDL cholesterol, indexes of obesity and adiposity, and insulin secretion (odds ratio 2.01 [95% CI 1.30-3.10], P = 0.0064, per one-SD decrease in loge-transformed MCRI).
  
  
  CONCLUSIONS
  Our data showed that lower MCRI predicts the incidence of type 2 diabetes.
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
authors.forename: C Christine
authors.initials: CC
authors.lastname: Lee
authors.forename: Steven M
authors.initials: SM
authors.lastname: Haffner
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagenknecht
authors.forename: Carlos
authors.initials: C
authors.lastname: Lorenzo
authors.forename: Jill M
authors.initials: JM
authors.lastname: Norris
authors.forename: Richard N
authors.initials: RN
authors.lastname: Bergman
authors.forename: Darko
authors.initials: D
authors.lastname: Stefanovski
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Anderson
authors.forename: Jerome I
authors.initials: JI
authors.lastname: Rotter
authors.forename: Mark O
authors.initials: MO
authors.lastname: Goodarzi
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hanley
mesh_terms: D000328:Adult; D001741:Black or African American; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged
chemical_list: D007328:Insulin