title: The relative associations of β-cell function and insulin sensitivity with glycemic status and incident glycemic progression in migrant Asian Indians in the United States: the MASALA study.
abstract: OBJECTIVE
  We assessed the relative associations of β-cell dysfunction and insulin sensitivity with baseline glycemic status and incident glycemic progression among Asian Indians in the United States.
  
  
  METHODS
  A 5-sample oral glucose tolerance test was obtained at baseline. Normoglycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and type 2 diabetes (T2DM) were defined by ADA criteria. The Matsuda Index (ISIM) estimated insulin sensitivity, and the Disposition Index (DIo) estimated β-cell function. Visceral fat was measured by abdominal CT. After 2.5years, participants underwent a 2-sample oral glucose tolerance test. Standardized polytomous logistic regression was used to examine associations with prevalent and incident glycemia.
  
  
  RESULTS
  Mean age was 57±8years and BMI 26.1±4.6kg/m(2). Log ISIM and log DIo were associated with prediabetes and T2DM after adjusting for age, sex, BMI, family history of diabetes, hypertension, and smoking. After adjusting for visceral fat, only DIo remained associated with prediabetes (OR per SD 0.17, 95% CI: 0.70, 0.41) and T2DM (OR 0.003, 95% CI: 0.0001, 0.03). Incidence rates (per 1,000 person-years) were: normoglycemia to IGT: 82.0, 95% CI (40, 150); to IFG: 8.4, 95% CI (0, 41); to T2DM: 8.6, 95% CI (0, 42); IGT to T2DM: 55.0, 95% CI (17, 132); IFG to T2DM: 64.0, 95% CI (3, 316). The interaction between sex and the change in waist circumference (OR 1.8, per SD 95% CI: 1.22, 2.70) and the change in log HOMA-β (OR 0.37, per SD 95% CI: 0.17, 0.81) were associated with glycemic progression.
  
  
  CONCLUSIONS
  The association of DIo with baseline glycemia after accounting for visceral fat as well as the association of the change in log HOMA-β with incident glycemic progression implies innate β-cell susceptibility in Asian Indians for glucose intolerance or dysglycemia.
authors.affiliation: Nutrition and Health Sciences Program, Graduate Division of Biomedical and Biological Sciences, Laney Graduate School, Emory University, 1518 Clifton Road NE, Atlanta, GA 30329, USA.
authors.forename: Unjali P
authors.initials: UP
authors.lastname: Gujral
authors.affiliation: Nutrition and Health Sciences Program, Graduate Division of Biomedical and Biological Sciences, Laney Graduate School, Emory University, 1518 Clifton Road NE, Atlanta, GA 30329, USA; Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA; Department of Medicine, School of Medicine, Emory University, Atlanta, GA, USA.
authors.forename: K M Venkat
authors.initials: KM
authors.lastname: Narayan
authors.affiliation: Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA, USA.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Kahn
authors.affiliation: Division of General Internal Medicine, University of California, San Francisco, San Francisco, CA, USA. Electronic address: alka.kanaya@ucsf.edu.
authors.forename: Alka M
authors.initials: AM
authors.lastname: Kanaya
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data; D001786:Blood Glucose / Q000378:metabolism*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000208:ethnology*; D018450:Disease Progression; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D015994:Incidence; D007194:India / Q000208:ethnology; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000208:ethnology*; D014171:Transients and Migrants / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Asian Indians; Ethnicity; Impaired fasting glucose; Impaired glucose tolerance; Incidence; Insulin sensitivity; Type 2 diabetes mellitus; β-cell dysfunction