Elevated Cholesteryl Ester Transfer Protein Activity in IDDM Men Who Smoke: Possible Factor for Unfavorable Lipoprotein Profile

Abstract

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 insulindependent diabetic (IDDM) men with microvascular complications. Research Design and Methods We perfomed a case-control study in a referral-based diabetes clinic on a sequential sample of 9 cigarettesmoking 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 esterlabeled 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-l-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.