ELEVATED CHOLESTERYL ESTER TRANSFER PROTEIN-ACTIVITY IN IDDM MEN WHO SMOKE - POSSIBLE FACTOR FOR UNFAVORABLE LIPOPROTEIN PROFILE

Objectives: To determine the effect of cigarette smoking on the activity of cholesteryl ester transfer protein (CETP) and high-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins in insulin-dependent diabetic (IDDM) men with microvascular complications. Research Design and Methods: We performed a case-control study in a referral-based diabetes clinic on a sequential sample of 9 cigarette-smoking and 12 nonsmoking IDDM men with microvascular complications and 12 nonsmoking control men. CETP activity was determined in each serum with an isotope assay with exogenous cholesteryl ester-labeled LDL and HDL. The method is independent of the endogenous lipoprotein present in serum. Results: The HDL-cholesterol (VLDL and LDL) ratio was lower in the smoking diabetic men than in the other groups (P < 0.05 vs. the nonsmoking diabetic men and P < 0.01 vs. the control subjects). CETP activity was 70% higher in the smoking diabetic men than in the control subjects (P < 0.01) and 30% higher than in the nonsmoking diabetic men (P < 0.05). The HDL-cholesterol (VLDL and LDL) ratio and the apolipoprotein A-I-B ratio were inversely correlated to CETP activity in the diabetic patients (r = -0.52, P < 0.02 and r = -0.45, P < 0.05, respectively). Conclusions: CETP activity is increased in cigarette-smoking IDDM men with microvascular complications. High CETP activity may contribute to the unfavorable lipoprotein profile in these patients.