Associations Between Prediabetes, by Three Different Diagnostic Criteria, and Incident CVD Differ in South Asians and Europeans.
OBJECTIVE
We examined longitudinal associations between prediabetes and cardiovascular disease (CVD) (coronary heart disease [CHD] and stroke) in Europeans and South Asians.


METHODS
This was a U.K. cohort study of 1,336 Europeans and 1,139 South Asians, aged 40-69 years at baseline (1988-1991). Assessment included blood pressure, blood tests, anthropometry, and questionnaires. Prediabetes was determined by OGTT or HbA1c, using either International Expert Committee (IEC) (HbA1c 6.0-6.5% [42-48 mmol/mol]) or American Diabetes Association (ADA) (HbA1c 5.7-6.5% [39-48 mmol/mol]) cut points. Incident CHD and stroke were established at 20 years from death certification, hospital admission, primary care record review, and participant report.


RESULTS
Compared with normoglycemic individuals, IEC-defined prediabetes was related to both CHD and CVD risk in Europeans but not South Asians (subhazard ratio for CHD 1.68 [95% CI 1.19, 2.38] vs. 1.00 [0.75, 1.33], ethnicity interaction P = 0.008, and for CVD 1.49 [1.08, 2.07] vs. 1.03 [0.78, 1.36], ethnicity interaction P = 0.04). Conversely, IEC-defined prediabetes was associated with stroke risk in South Asians but not Europeans (1.73 [1.03, 2.90] vs. 0.85 [0.44, 1.64], ethnicity interaction P = 0.11). Risks were adjusted for age, sex, smoking, total-to-HDL cholesterol ratio, waist-to-hip ratio, systolic blood pressure, and antihypertensive use. Associations were weaker for OGTT or ADA-defined prediabetes. Conversion from prediabetes to diabetes was greater in South Asians, but accounting for time to conversion did not account for these ethnic differences.


CONCLUSIONS
Associations between prediabetes and CVD differed by prediabetes diagnostic criterion, type of CVD, and ethnicity, with associations being present for overall CVD in Europeans but not South Asians. Substantiation of these findings and investigation of potential explanations are required.
Institute of Cardiovascular Science, University College London, London, U.K. sophie.eastwood@ucl.ac.uk.
Sophie V
SV
Eastwood
Institute of Cardiovascular Science, University College London, London, U.K.
Therese
T
Tillin
Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, U.K.
Naveed
N
Sattar
Medical Research Council Epidemiology Unit, University of Cambridge, Cambridge, U.K.
Nita G
NG
Forouhi
Institute of Cardiovascular Science, University College London, London, U.K.
Alun D
AD
Hughes
Institute of Cardiovascular Science, University College London, London, U.K.
Nish
N
Chaturvedi
D044466:Asian People / Q000706:statistics & numerical data; D015331:Cohort Studies; D003327:Coronary Disease / Q000453:epidemiology*; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D044465:White People / Q000706:statistics & numerical data