Insulin Resistance Syndrome Predicts the Risk of Coronary Heart Disease and Stroke in Healthy Middle-Aged Men

TLDR

Conventional analyses of insulin’s link to atherosclerotic disease are confounded by its correlations with other risk factors. The study applied factor analysis to baseline data of 970 healthy men to examine whether risk factor clusters predict coronary heart disease and stroke. Factor analysis was performed on 10 baseline risk variables, including AUC glucose and AUC insulin from oral glucose tolerance tests, to identify underlying risk factor clusters. During 22 years, an insulin‑resistance factor independently predicted CHD (HR 1.28) and stroke (HR 1.64), a lipid factor predicted CHD but not stroke, and a lifestyle factor reduced CHD risk.

Abstract

Abstract —The interpretation of conventional multivariate analyses concerning the relation of insulin to the risk of atherosclerotic disease is complex because of correlations of insulin with other risk factors. Therefore, we applied factor analysis to study the clustering of risk factors in the baseline data of the Helsinki Policemen Study (970 healthy men aged 34 to 64 years) and investigated whether these clusterings predict coronary heart disease (CHD) and stroke risk. Areas under the glucose and insulin response curves (AUC glucose and AUC insulin) were used to reflect glucose and insulin levels during oral glucose tolerance tests. During the 22-year follow-up, 164 men had a CHD event, and 70 men had a stroke. Factor analysis of 10 risk factor variables produced 3 underlying factors: insulin resistance factor (comprising body mass index, subscapular skinfold, AUC insulin, AUC glucose, maximal O 2 uptake, mean blood pressure, and triglycerides), lipid factor (cholesterol and triglycerides), and lifestyle factor (physical activity and smoking). In multivariate Cox models, the age-adjusted hazard ratio for insulin resistance factor during the 22-year follow-up was 1.28 (95% CI 1.10 to 1.50) with regard to CHD risk and 1.64 (95% CI 1.29 to 2.08) with regard to stroke risk. Lipid factor predicted the risk of CHD but not that of stroke, and lifestyle factor predicted a reduced CHD risk. Factor analysis including only 6 risk factor variables proposed to be central components of insulin resistance syndrome (body mass index, subscapular skinfold, AUC insulin, AUC glucose, mean blood pressure, and triglycerides) produced only a single insulin resistance factor that predicted the risk of CHD and stroke independently of other risk factors.