Early abnormalities in coronary heart disease risk factors in relatives of subjects with non-insulin-dependent diabetes.

Coronary heart disease risk factor levels were studied in 184 first-degree relatives (sisters and brothers) of non-insulin-dependent diabetic subjects (124 relatives with normoglycemia, 34 relatives with impaired glucose tolerance [IGT], and 26 relatives with non-insulin-dependent diabetes mellitus [NIDDM]) and in 215 relatives of nondiabetic subjects (194 relatives with normoglycemia and 21 relatives with IGT). Subjects with IGT exhibited the highest insulin responses to an oral glucose load. Systolic blood pressure was significantly higher; serum high density lipoprotein cholesterol level was significantly lower; and total, low density lipoprotein, and very low density lipoprotein triglyceride levels were higher in the relatives with a family history of diabetes who had IGT or NIDDM than in the normoglycemic relatives without a family history of diabetes. These abnormal changes were not seen in normoglycemic relatives or relatives with IGT who had no family history of NIDDM. Thus, in relatives of diabetics, abnormal glucose tolerance seems to induce changes in cardiovascular heart disease risk factor levels that are similar to those observed in NIDDM. Therefore, a family history of diabetes adds substantially to the risk for atherosclerosis, particularly in subjects with IGT.