Association between glycosylated hemoglobin, left ventricular mass and aortic function in nondiabetic individuals with insulin resistance

Objective: An association between glycosylated hemoglobin (GHb) and cardiovascular mortality in nondiabetic individuals has recently been reported. Prompt detection of nondiabetic individuals with high-normal GHb and early cardiovascular involvement may be of value for preventive strategies. In this investigation, a possible relationship between GHb, aortic function and left ventricular (LV) mass in nondiabetic individuals has been studied. Methods: A total of 263 nondiabetic African-Americans, aged 22-63 (mean 42 ±8) years were studied. All individuals were first degree relatives of diabetic patients, had normal oral glucose tolerance test (2-h OGTT) and decreased peripheral action of insulin. LV diameters and mass (echocardiography): ascending and abdominal aortic distensibility (echocardiography, arterial pressure); pulse wave velocity (PWV; electrocardiography, Doppler); fasting glucose; GHb; insulin sensitivity index (Si) and 2-h OGTT were measured. Multiple linear and logistic regression analyses were used to identify significant independent associations of fasting glucose; GHb; Si and 2-h OGTT with aortic function and LV mass. Results: In fully adjusted multivariate logistic regression analysis, GHb predicted lower values of aortic distensibility (odds ratio (OR) 1.67 95% CI (1.04-2.75), P=0.04); higher PWV (OR 1.79 95% CI (1.09-2.93), P=0.022); and higher values of LV mass (OR 1.56 95% CI (1.08-2.88), P=0.029). Fasting glucose, Si, and 2 h OGTT were not associated with aortic function and LV mass. Conclusion: Higher GHb concentrations, even within 'normal' range, are independently associated with stiffer aorta and increased LV mass and thus may detect nondiabetic individuals at increased cardiovascular risk.