title: Impact of impaired insulin secretion and insulin resistance on the incidence of type 2 diabetes mellitus in a Japanese population: the Saku study.
abstract: OBJECTIVE
  To assess the impact of impaired insulin secretion (IIS) and insulin resistance (IR) on type 2 diabetes incidence in a Japanese population.
  
  
  METHODS
  This 4 year cohort study included 3,059 participants aged 30-69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Based on their insulinogenic index and HOMA-IR values, participants were classified by the criteria of the Japan Diabetes Society into four categories: normal; isolated IIS (i-IIS); isolated IR (i-IR); and IIS plus IR. They were followed up until March 2011. The incidence of type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations and from receiving medical treatment for diabetes.
  
  
  RESULTS
  At baseline, 1,550 individuals (50.7%) were classified as normal, 900 (29.4%) i-IIS, 505 (16.5%) i-IR, and 104 (3.4%) IIS plus IR. During 10,553 person-years of follow-up, 219 individuals developed type 2 diabetes, with 126 (57.5%) having i-IIS at baseline. Relative to the normal group, the multivariable-adjusted HRs for type 2 diabetes in the i-IIS, i-IR and IIS plus IR groups were 8.27 (95% CI 5.33, 12.83), 4.90 (95% CI 2.94, 8.17) and 16.93 (95% CI 9.80, 29.25), respectively. The population-attributable fractions of type 2 diabetes onset due to i-IIS, i-IR, and IIS plus IR were 50.6% (95% CI 46.7%, 53.0%), 14.2% (95% CI 11.8%, 15.6%) and 12.9% (95% CI 12.3%, 13.2%), respectively.
  
  
  CONCLUSIONS
  Compared with IR, IIS had a greater impact on the incidence of type 2 diabetes in a Japanese population.
authors.affiliation: Department of Clinical Nursing, Shiga University of Medical Science, Shiga, Japan. aki62@belle.shiga-med.ac.jp
authors.forename: Akiko
authors.initials: A
authors.lastname: Morimoto
authors.forename: Yukako
authors.initials: Y
authors.lastname: Tatsumi
authors.forename: Kijyo
authors.initials: K
authors.lastname: Deura
authors.forename: Shoichi
authors.initials: S
authors.lastname: Mizuno
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ohno
authors.forename: Naomi
authors.initials: N
authors.lastname: Miyamatsu
authors.forename: Shaw
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D015994:Incidence; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007328:Insulin