title: Effect of body mass index on insulin secretion or sensitivity and diabetes.
abstract: BACKGROUND
  Although the association between obesity and diabetes is well known, the factors predisposing to diabetes in non-obese Asians are less clearly characterized.
  
  
  OBJECTIVE
  To investigate the effects of impaired insulin secretion (IIS) and insulin resistance (IR) according to BMI on the incidence of diabetes in the Saku Study.
  
  
  METHODS
  This 4-year cohort study involved 3,083 participants aged 30-69 years without diabetes at baseline (2006-2007). Participants were stratified by BMI (<23.0, 23.0-24.9, and ≥25). Based on insulinogenic index and homeostasis model of IR values, participants were classified into four categories: normal; isolated IIS (i-IIS); isolated IR (i-IR); and IIS plus IR. All data were collected in 2006-2011 and analyzed in 2013-2014.
  
  
  RESULTS
  For participants with BMI <23.0, the risk of developing diabetes was higher in the i-IIS (adjusted hazard ratio=6.6; 95% CI=3.7, 11.6) and IIS plus IR groups (9.4; 3.1, 28.4) than in the normal group. For participants with BMI 23.0-24.9, risk was higher in the i-IIS (9.9; 4.4, 22.1); i-IR (3.4; 1.2, 9.5); and IIS plus IR (23.4; 9.3, 58.9) groups. Among participants with BMI ≥25, risk was higher in the i-IIS (16.9; 6.0, 47.7); i-IR (7.9; 2.8, 22.6); and IIS plus IR (26.9; 9.0, 80.8) groups. BMI was negatively associated with incidence of IIS but positively associated with IR incidence.
  
  
  CONCLUSIONS
  Individuals with normal BMI may develop diabetes mainly through IIS, whereas individuals with high BMI may develop diabetes primarily through IR.
authors.affiliation: Department of Mathematical Health Science, Graduate School of Medicine, Osaka University, Osaka. Electronic address: y-tatumi@sahs.med.osaka-u.ac.jp.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Tatsumi
authors.affiliation: Department of Clinical Nursing, Shiga University of Medical Science, Shiga.
authors.forename: Akiko
authors.initials: A
authors.lastname: Morimoto
authors.affiliation: Department of Clinical Nursing, Shiga University of Medical Science, Shiga.
authors.forename: Naomi
authors.initials: N
authors.lastname: Miyamatsu
authors.affiliation: Department of Diabetes Research, National Center for Global Health and Medicine, Tokyo.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Noda
authors.affiliation: Department of Mathematical Health Science, Graduate School of Medicine, Osaka University, Osaka.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Complete Health Check Center, Saku Central Hospital, Nagano, Japan.
authors.forename: Kijyo
authors.initials: K
authors.lastname: Deura
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D007328:Insulin