Possible risk factors of carotid artery atherosclerosis in the Japanese population: a primary prevention study in non-diabetic subjects.

OBJECTIVE

Hyperinsulinemia has been associated with the risk of coronary heart disease, stroke, and renal disease in nondiabetic subjects. However, direct evidence that hyperinsulinemia per se is directly associated with atherosclerosis has been conflicting. The present study was designed to investigate the cross-sectional association of carotid artery atherosclerosis with insulin, independent of well-known cardiovascular risk factors, in nondiabetic subjects.

METHODS AND SUBJECTS

Between 1996 and 1997, 1,335 subjects (620 men and 715 women) were recruited from one Japanese community, interviewed, and examined. Clinical measurements in the study included intimal-medial thickness (IMT) of the carotid artery, fasting plasma insulin, serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), hemoglobin type HbA1c, systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index (BMI). We divided the subjects of both genders into three subgroups according to age (40-49 years of age; 50-59; and 60-69).

RESULTS

Using simple regression analysis, we found that IMT was significantly correlated with at least one of TC, LDL-C, HbA1c, SBP, DBP, and BMI in each subgroup. The results of multivariate analysis showed that IMT was independently correlated with TC, HDL-C, LDL-C, SBP and BMI in males and with TC, TG, HDL-C, LDL-C, HbA1c, SBP, DBP, and BMI in females. Insulin levels showed no correlation with IMT in either males or females.

CONCLUSION

Fasting hyperinsulinemia does not appear to be correlated with carotid artery atherosclerosis based on the present cross-sectional results.