以因素分析探討凝血因子、血清生化值、血壓、血脂前蛋白及肥胖指標因素與心肌缺氧指標（心電圖ST段改變）年齡趨勢之關係

Problems exist in simultaneously relating physiological variables such as obesity indices, blood pressure and biochemistry indices to disease. Correlation of these variables is very strong. Collinearity is difficult to handle. Physiological meanings of these variables largely overlap. We discuss these difficulties in this paper. The purpose of this study is to describe the age trend of ST segment depression and to examine whether such trends differ in subjects with variables cardiovasculav disease (CVD) risk profiles. Using data from CVD facts, we used factor analysis to organize the correlated CVD risk factors. There were 22 CVD risk factors selected for this study including body mass index (BMI), skinfold measure, diastolic and systolic blood pressure, seven hemostatic parameters, and apolipoproteins A-I and B-100. Eight factors were studied in men. These were obesity factor, coagulation factor, cholesterol factor, blood pressure factor, coagulation time factor, apolipoprotein-A1 factor, central-obesity factor, and insulin-related factor. In females seven factors were studied including the obesity factor, coagulation factor, cholesterol factor, blood pressure factor, coagulation time factor, apolipoprotein-A1 factor, and central- obesity-and-insulin-related factor. The correlation coefficients among these factors were lower than those among original CVD risk variables. Regression analysis revealed that age, sex, obesity, blood pressure, and apolipoprotein-A1 were predictors of ST segment change. The magnitude of ST segment depression decreased with age. These decreasing trends showed the same shape between the obese group and the lean group. But there was not no difference beteen the group with high levels of apo-A and the group with low levels. These results indicate that the aging effect can not be completely explained by CVD risk factor studies.