Cardiovascular risk profile in individuals with borderline glycemia - The effect of the 1997 American Diabetes Association diagnostic criteria and the 1998 World Health Organization Provisional Report

OBJECTIVE - In 1997, the American Diabetes Association (ADA) recommended a new diagnostic category, impaired fasting glucose (IFG), to describe indivi duals with borderline glucose tolerance. On the other hand, the World Healt h Organization (WHO) suggested retaining the category of impaired glucose t olerance (IGT). We studied the prevalence of IFG and IGT in a multiethnic s ociety and compared the cardiovascular risk profiles of subjects with IFG, IGT, or both IFG and IGT. RESEARCH DESIGN AND METHODS - A total of 3,568 subjects were examined from the 1992 National Health Surrey of Singapore, which involved a combination of disproportionately stratified sampling and systematic sampling. Anthropo metric, blood pressure, insulin, lipid profile, and uric acid measurements were taken, and a standard 75-g oral glucose tolerance test was performed a fter a 10-h overnight fast. RESULTS - The prevalence rates of IFG only IGT only and both IFT and IGT we re 3.45, 10.2, and 3.4%. respectively The degree of agreement (kappa) betwe en the two diagnostic criteria (the ADA IFG and the WHO IGT) was only 0.25. A fasting glucose level of 5.5 mmol/l was the optimal cutoff for predictin g a 2-h postload glucose level of greater than or equal to 7.8 mmol/l. The following cardiovascular risk factors were higher in subjects with both IFG and IGT compared with those with either IFG or IGT alone: systolic blood p ressure (131 +/- 20 vs. 125 +/- 21 and 125 +/- 19 mmHg, respectively: P < 0 .05 and P < 0.001, respectively): diastolic blood pressure (77 +/- 12 vs. 7 3 +/- 12 and 74 +/- 12 mmHg, respectively; P < 0.05); BMI (26.2 +/- 4.2 vs. 24.4 +/- 4.0 and 24.6 +/- 4.4 kg/m(2), respectively; P < 0.01 and P < 0.00 1, respectively); waist circumference (84.1 +/- 10.3 vs. 79.3 +/- 10.7 and 79.3 +/- 10.6 cm, respectively: P < 0.001); waist-to-hip ratio (0.84 +/- 0. 08 vs. 0.82 +/- 0.09 and 0.81 +/- 0.08, respectively; P < 0.05 and P < 0.00 1, respectively); fasting insulin (12.1 +/- 9.7 vs. 9.2 +/- 5.3 and 9.9 +/- 7.7 mU/l: P < 0.01); insulin resistance (by homeostasis model assessment [ HOMA]) (3.41 +/- 2.77 vs. 2.58 +/- 1.50 and 2.43 +/- 1.83, respectively; P < 0.01 and P < 0.001, respectively): total cholesterol (5.81 +/- 1.1 vs. 5. 51 +/- 1.1 and 5.53 +/- 1.1 mmol/l, respectively; P < 0.05) and apolipoprot ein(B) [apo(B)] (1.5 +/- 0.38 vs. 1.40 +/- 0.34 and 1.39 +/- 0.35 mmol/l, r espectively : P < 0.01). The pattern of difference remained significant onl y for fasting insulin, insulin resistance (HOMA), and apo(R) (borderline) a fter adjustment for age, sex, and ethnic differences. CONCLUSIONS - Obvious discordance was evident in the classification of glyc emic status when applying the criteria proposed bg the ADA (IFG) or WHO (IG T) in a multiethnic society like Singapore. However, subjects with either I FG or IGT had similar cardiovascular risk profiles. Therefore, both criteri a identified individuals at high risk for cardiovascular disease. Individua ls with both. IFG and IGT. had a greater incidence of the cardiovascular: d ysmetabolic syndrome.