Population-based study of glycosylated hemoglobin, lipids, and lipoproteins in nondiabetic adults.

Glycosylated hemoglobin levels reflect glucose homeostasis over the preceding months. Many investigators have reported levels of glycosylated hemoglobin in diabetics and have noted a strong correlation of these levels with lipids and lipoproteins, but not with HDL cholesterol. We report here the first population-based study of the predominant fraction of glycosylated hemoglobin, HbA1, and its correlates in nondiabetics. In 558 euglycemic adults (fasting plasma glucose less than 140 mg/dl) aged 40 to 79 years who had no history of diabetes, HbA1 was normally distributed, was unrelated to age, and was correlated with fasting plasma glucose in men and women and with obesity in women. After adjusting for age and obesity, HbA1 was significantly correlated with total plasma cholesterol and LDL cholesterol in both sexes and with total plasma triglyceride and VLDL cholesterol in men. HDL cholesterol was not significantly associated with HbA1 in men or women. These associations are similar, although weaker, than those reported in most studies of diabetics. The finding that the association of glycosylated hemoglobin with lipids and lipoproteins extends throughout the normal range of blood sugar suggests that this association may be relevant to both the excess risk of ischemic heart disease in diabetics and in nondiabetics with higher levels of fasting plasma glucose.