title: Comparison of HOMA-IR, HOMA-β% and disposition index between US white men and Japanese men in Japan: the ERA JUMP study.
abstract: OBJECTIVE
  At the same level of BMI, white people have less visceral adipose tissue (VAT) and are less susceptible to developing type 2 diabetes than Japanese people. No previous population-based studies have compared insulin resistance and insulin secretion between these two races in a standardised manner that accounts for VAT. We compared HOMA-IR, HOMA of beta cell function (HOMA-β%) and disposition index (DI) in US white men and Japanese men in Japan.
  
  
  METHODS
  We conducted a population-based, cross-sectional study, comprising 298 white men and 294 Japanese men aged 40-49 years without diabetes. Insulin, glucose, VAT and other measurements were performed at the University of Pittsburgh. We used ANCOVA to compare geometric means of HOMA-IR, HOMA-β% and DI, adjusting for VAT and other covariates.
  
  
  RESULTS
  White men had higher HOMA-IR, HOMA-β% and DI than Japanese men, and the difference remained significant (p < 0.01) after adjusting for VAT (geometric mean [95% CI]): 3.1 (2.9, 3.2) vs 2.5 (2.4, 2.6), 130.8 (124.6, 137.3) vs 86.7 (82.5, 91.0), and 42.4 (41.0, 44.0) vs 34.8 (33.6, 36.0), respectively. Moreover, HOMA-IR, HOMA-β% and DI were significantly higher in white men even after further adjustment for BMI, impaired fasting glucose and other risk factors.
  
  
  CONCLUSIONS
  The higher VAT-adjusted DI in white men than Japanese men may partly explain lower susceptibility of white people than Japanese people to developing type 2 diabetes. The results, however, should be interpreted with caution because the assessment of insulin indices was made using fasting samples and adjustment was not made for baseline glucose tolerance. Further studies using formal methods to evaluate insulin indices are warranted.
authors.affiliation: Department of Epidemiology, University of Pittsburgh, 130 N. Bellefield Avenue, Suite 546, Pittsburgh, PA, 15213, USA.
authors.forename: Vasudha
authors.initials: V
authors.lastname: Ahuja
authors.forename: Takashi
authors.initials: T
authors.lastname: Kadowaki
authors.forename: Rhobert W
authors.initials: RW
authors.lastname: Evans
authors.forename: Aya
authors.initials: A
authors.lastname: Kadota
authors.forename: Tomonori
authors.initials: T
authors.lastname: Okamura
authors.forename: Samar R
authors.initials: SR
authors.lastname: El Khoudary
authors.forename: Akira
authors.initials: A
authors.lastname: Fujiyoshi
authors.forename: Emma J M
authors.initials: EJ
authors.lastname: Barinas-Mitchell
authors.forename: Takashi
authors.initials: T
authors.lastname: Hisamatsu
authors.forename: Abhishek
authors.initials: A
authors.lastname: Vishnu
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Miura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maegawa
authors.forename: Aiman
authors.initials: A
authors.lastname: El-Saed
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
authors.forename: Akira
authors.initials: A
authors.lastname: Sekikawa
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D020022:Genetic Predisposition to Disease; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance / Q000208:ethnology*; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D007564:Japan; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires; D014481:United States; D044465:White People
chemical_list: D001786:Blood Glucose