title: Ethnic differences in cross-sectional associations between impaired glucose regulation, identified by oral glucose tolerance test or HbA1c values, and cardiovascular disease in a cohort of European and South Asian origin.
abstract: OBJECTIVE
  We contrasted impaired glucose regulation (prediabetes) prevalence, defined according to oral glucose tolerance test or HbA1c values, and studied cross-sectional associations between prediabetes and subclinical/clinical cardiovascular disease (CVD) in a cohort of European and South Asian origin.
  
  
  METHODS
  For 682 European and 520 South Asian men and women, aged 58-85 years, glycaemic status was determined by oral glucose tolerance test or HbA1c thresholds. Questionnaires, record review, coronary artery calcification scores and cerebral magnetic resonance imaging established clinical plus subclinical coronary heart and cerebrovascular disease.
  
  
  RESULTS
  Prediabetes was more prevalent in South Asian participants when defined by HbA1c rather than by oral glucose tolerance test criteria. Accounting for age, sex, smoking, systolic blood pressure, triglycerides and waist-hip ratio, prediabetes was associated with coronary heart disease and cerebrovascular disease in European participants, most obviously when defined by HbA1c rather than by oral glucose tolerance test [odds ratios for HbA1c -defined prediabetes 1.60 (95% CI 1.07, 2.39) for coronary heart disease and 1.57 (95% CI 1.00, 2.51) for cerebrovascular disease]. By contrast, non-significant associations were present between oral glucose tolerance test-defined prediabetes only and coronary heart disease [odds ratio 1.41 (95% CI 0.84, 2.36)] and HbA1c -defined prediabetes only and cerebrovascular disease [odds ratio 1.39 (95% CI 0.69, 2.78)] in South Asian participants. Prediabetes defined by HbA1c or oral glucose tolerance test criteria was associated with cardiovascular disease (defined as coronary heart and/or cerebrovascular disease) in Europeans [odds ratio 1.95 (95% CI 1.31, 2.91) for HbA1c prediabetes criteria] but not in South Asian participants [odds ratio 1.00 (95% CI 0.62, 2.66); ethnicity interaction P = 0.04].
  
  
  CONCLUSIONS
  Prediabetes appeared to be less associated with cardiovascular disease in the South Asian than in the European group. These findings have implications for screening, and early cardiovascular prevention strategies in South Asian populations.
authors: UCL Institute of Cardiovascular Science, University College London, London.
authors: S V
authors: SV
authors: Eastwood
authors: UCL Institute of Cardiovascular Science, University College London, London.
authors: T
authors: T
authors: Tillin
authors: National Heart and Lung Institute, Imperial College London, London.
authors: J
authors: J
authors: Mayet
authors: Department of Radiology, University of Washington Medical Centre, Seattle, WA, USA.
authors: D K
authors: DK
authors: Shibata
authors: Department of Radiology, Imperial College NHS Healthcare Trust, London, UK.
authors: A
authors: A
authors: Wright
authors: Department of Radiology, Imperial College NHS Healthcare Trust, London, UK.
authors: J
authors: J
authors: Heasman
authors: Department of Radiology, University of Washington Medical Centre, Seattle, WA, USA.
authors: N
authors: N
authors: Beauchamp
authors: MRC Epidemiology Unit, University of Cambridge, Cambridge, UK.
authors: N G
authors: NG
authors: Forouhi
authors: UCL Institute of Cardiovascular Science, University College London, London.
authors: A D
authors: AD
authors: Hughes
authors: UCL Institute of Cardiovascular Science, University College London, London.
authors: N
authors: N
authors: Chaturvedi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data; D001786:Blood Glucose / Q000032:analysis; D002318:Cardiovascular Diseases / Q000097:blood / Q000208:ethnology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000208:ethnology*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000208:ethnology; D044465:White People / Q000706:statistics & numerical data
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin