IS THERE A SEX DIFFERENCE IN THE ASSOCIATION OF PLASMA-INSULIN LEVEL AND INSULIN SENSITIVITY WITH SERUM-LIPIDS AND LIPOPROTEINS

Previous studies on the relationship between the plasma insulin level, insulin sensitivity (Sl), serum lipids, and lipoproteins have been performed predominantly in men. Therefore, we investigated whether there is a sex difference in the association of insulin level during an oral glucose tolerance test and Sl with lipids and lipoproteins among normoglycemic men and women aged 53 to 61 years. Sl was determined by the minimal model from the frequently sampled intravenous glucose tolerance test (IVGTT). There were no correlations between total cholesterol or low-density lipoprotein (LDL) cholesterol and insulin level or Sl. High-density lipoprotein (HDL) cholesterol correlated inversely with fasting insulin (r = -.26, P < .05 in men; r = -.29, P < .01 in women) and 2-hour insulin (r = -.31, P < .01 in men; r = -.39, P < .001 in women) and positively with SI (r = .28, P = .05 in men; r = .43, P < .001 in women). Total and very-low-density lipoprotein (VLDL) triglycerides correlated positively with fasting insulin (r = .43, P < .001 in men; r = .42, P < .001 in women) and 2-hour insulin (r = .50, P < .001 in men; r = .31, P < .01 in women) and inversely with (r = -.49, P < .001 in men; r = -.40, P < .001 in women). In multiple regression analyses including age, body mass index (BMI), waist to hip ratio, 2-hour glucose, fasting or 2-hour insulin, and SI, only BMI was associated with HDL cholesterol level in men. In women, SI was positively associated with HDL cholesterol level independently of obesity and insulin level. Both in men and in women, SI was inversely associated with total and VLDL triglyceride levels independently of obesity and fasting insulin level. In conclusion, a high insulin level and insulin resistance were associated with low HDL cholesterol and high total triglyceride and VLDL triglyceride levels in both men and women. Therefore, it is probable that insulin resistance is related to an excess risk of atherosclerosis also in postmenopausal women, as previously shown in men. © 1994.