Insulin resistance has been identified as one of the risk factor of atherosclerosis. Hypertension, obesity, glucose intolerance and dyslipidemia could induce atherosclerosis through mechanism of insulin resistance. And there are some reports that hyperinsulinemia itself could induce coronary artery disease(CAD). Then we planed to investigate relationship between CAD and insulin resistance. And smoking is also known as one major risk factor of CAD. So we also investigated the relationship between smoking and insulin resistance in the CAD patients.

Among 36 subjects in whom coronary angiography was done, we grouped 25 subjects who had stenotic coronary artery as a CAD group and 11 subjects without stenosis as control group. We compared insulin and glucose response to oral glucose load(75g), serum lipid concentrations, blood pressure, and degree of obesity between two groups. We also divided CAD group into smoking and nonsmoking subgroups, compared the above parameters.

1) There were no significant difference in body mass index, blood pressure, creatinine, cholesterol, HDL-cholesterol, between the CAD group and the control group. There were significantly higher incidence of smokers in CAD group. 2) Insulin concentration at 120 minutes after glucose load were significantly higher in the CAD group than the control group. 3) In the CAD group, fasting plasma insulin concentration insulin area, peak plasma insulin concentration and insulin concentration at 60,90,120 minutes after glucose load were significantly higher in non-smoking group.

Enhanced insulin reponse such as higher insulin concentration 60 minutes after glucose load in the CAD group suggests that insulin resistance is a risk factor of CAD. And insulin response was more pronounced in the non-smoker subgroup than smoker subgroup in the CAD patients. Thus role of insulin resistance in provoking coronary artery disease is more important in the non-smoker.