Postchallenge plasma glucose and glycemic spikes are more strongly associated with atherosclerosis than fasting glucose or HbA1c level

OBJECTIVE - To observe the relationship of fasting plasma glucose (FPG), postchallenge plasma glucose CPG) (30, 60, 90, and 120 min during an oral glucose tolerance test [OGTT], as well as maximal PG during an OGTT, postchallenge glucose spikes [PGS], and glucose under the OGTT curve), and HbA(1c) to intima-media thickness (IMT) as a marker of atherosclerosis. RESEARCH DESIGN AND METHODS - OGTT, ultrasound measurement of carotid IMT, and various atherosclerosis risk factors, such as family history of diabetes, obesity, and/or hyperlipoproteinemia. but without known diabetes, were analyzed in 582 individuals aged 40-70 years and at risk for type 2 diabetes. RESULTS - In univariate analysis, all examined glycemic parameters were significantly correlated to IMT The 2-h postchallenge plasma glucose showed the strongest odds ratio (OR) of 1.88 (1.34-2.63) in relation to abnormal IMT. AII PG variables, except for 30-min glucose in OGTT, showed a significant OR, whereas the OR for HbA(1c) and FPG was not significant. In logistic regression analysis, 2-h PG was identified as the strongest determinant of IMT from all glycemic parameters. The 2-h PG and PGS, but not FPG, were associated with a significant rise of IMT in tertiles of HbA(1c). Glycemic parameters were strongly related to each other and to many atherosclerosis risk factors. In multivariate analysis including a variety of atherosclerosis risk factors, 2-h PG was a significant independent determinant of IMT. CONCLUSIONS - PG and PGS are more strongly associated with carotid IMT than FPG and HbA(1c) level and modify substantially the risk for atherosclerosis, estimated by HbA(1c) alone, in a cohort at risk for diabetes and in the early diabetes stage.