An interaction between the TaqIB polymorphism of cholesterol ester transfer protein and smoking is associated with changes in plasma high‐density lipoprotein cholesterol levels in Turks

Low levels of high‐density lipoprotein cholesterol (HDL‐C) are an independent risk factor for atherosclerosis. We investigated the effects of the TaqIB polymorphism of cholesterol ester transfer protein (CETP) on CETP activity and plasma HDL‐C levels in random nondiabetic and self‐reported diabetic subjects in a population with very low HDL‐C levels. The rare B2B2 genotype was associated with significantly higher HDL‐C levels and lower CETP activity in random subjects and with higher HDL‐C in diabetic subjects. After stratification of random subjects by smoking status, the common B1B1 genotype was associated with lower HDL‐C levels than the B2B2 genotype. Although smoking was associated with lower HDL‐C, especially in men, HDL‐C levels between smokers and nonsmokers were not different in subjects with the B1B2 or B2B2 genotypes. However, smoking (20+ cigarettes/day) was associated with a marked reduction in HDL‐C in the B1B1 subjects. The B1B1/smoking interaction was not reflected in a difference in CETP activity. High triglycerides and elevated body mass index (BMI) lower HDL‐C. The B2B2 genotype was associated with the highest HDL‐C levels, and these levels were significantly lower in the hypertriglyceridemic subjects (≥ 50th percentile). The lowest HDL‐C levels were seen in hypertriglyceridemic subjects with the B1B1 genotype. Although BMI (≥ 50th vs < 50th percentile) did not affect HDL‐C in B2B2 subjects, a high BMI was associated with markedly lower HDL‐C in B1B1 subjects. Thus, HDL‐C levels in Turks may be modulated by an interaction between the CETP TaqIB polymorphism and smoking, as well as an interaction with hypertriglyceridemia and BMI.