Asymptomatic hyperglycemia is associated with lipid and lipoprotein changes favoring atherosclerosis

We studied lipid and lipoprotein concentrations and their relationships to insulin level in 994 men and 1246 women ages 50 to 91 years in the upper middle-class community of Rancho Bernardo in southern California. Altogether, 593 men and 741 women had normal glucose tolerance, 240 men and 348 women, impaired glucose tolerance (IGT), 104 men and 117 women, newly diagnosed noninsulin-dependent diabetes (NIDDM), and 57 men and 40 women, previously diagnosed NIDDM. In women but not men, total cholesterol and low density lipoprotein were significantly higher in those with newly diagnosed NIDDM, compared to subjects with normal glucose tolerance. In both men and women, high density lipoprotein (HDL) cholesterol was significantly lower, and total triglyceride significantly higher, in subjects with IGT and NIDDM compared to those with normal glucose tolerance; these differences persisted after adjusting for age, body mass index, smoking, alcohol intake, and exercise level. Multiple linear-regression analyses showed that fasting insulin (but not 2-hour insulin) was significantly associated with low HDL cholesterol and high total triglycerides independently from other variables (age, body mass index, waist/hip ratio, alcohol intake, smoking, exercise, and 2-hour glucose). Overall, these results show that asymptomatic hyperglycemia (IGT, newly diagnosed NIDDM) is associated with lipid and lipoprotein changes favoring atherosclerosis and that fasting hyperinsulinemia (insulin resistance) is the most important factor associated with these lipid and lipoprotein abnormalities