한국 중년 인에서 관상동맥경화증의 위험요인들과 혈청 인슐린 농도와의 관계

Abstract

Objectives: Hyperinsulinemia has been reported as a risk factor for coronary artery disease in western society. However, Koreans have shown about half of western people in fasting insulin and insulin secretion levels during oral glucose tolerance test (OGTT). The purpose of this study was to determine the relationship of serum insulin levels to various cardiovascular risk factors in healthy middleaged Koreans. Methods: We studied 143 subjects including 97 women and 46 men. Subjects had not received any medication for diabetes, hypertension or hyperlipidemia and had normal liver and kidney function. Anthropometric parameters and abdominal fat areas by computed tomography at the umbilical level were measured. Blood pressure, nutrient intake, total energy expenditure, serum levels of lipids and the levels of glucose, C-peptide, insulin and free fatty acid during OGTT were determined. Hyperinsulinemia was defined as both fasting and 2-hour serum insulin levels above the 80th percentile of respective serum insulin distributon in study subjects after an oral glucose load. Characteristics of hyperinsulinemic subjects were compared to normoinsulinemic subjects matehed for age, sex, and body mass index. Results: In subjects with normal glucose tolerance, hypertriglyceridemic subjects showed significantly higher serum insulin levels at 30, 60, 120 minutes during OGTT than normotriglyceridemic subjects. Similar results were observed in hypertension and low HDL cholesterolemia. A less significant difference was shown in the insulin pattern during OGTT between subjects with high LDL cholesterol and subjects with normal LDL cholesterol. Hyperinsulinemic subjects had significantly higher levels of systolic blood pressure, serum triglycerides, total cholesterol and glucose than normoinsulinernic subject. HDL cholesterol level was significantly lower in hyperinsulinemic subjects than in normoinsulinrnic subjects. No significant difference in the serum LDL cholesterol was found between two groups. Hyperinsulinernic subjects showed an increase in visceral fat area and percent calorie intake per total energy expenditure, compared with normoinsulinemic subjects. Conclusion: Our results showed that insulin levels in middle-aged Koreans are closely related to serum triglycerides and HDL cholesterol levels. In addition, healthy Koreans with normal glucose tolerance and hyperinsulinemia have an increase in risk factors for coronary artery disease such as hypertension, hypertriglyceridemia and low HDL cholesterol levels as compared with healthy subjects with normal insulin level. Therefore, it is recommended that insulin resistance subjects increase insulin sensitivity and decrease serum insulin level through lifestyle modification to prevent coronary artery disease.