Objective:
Cigarette smoking is positively correlated with the morbidity of cardiovascular diseases (CVD). It was reported that reduced high density lipoprotein (HDL) functionality is one of the causes of CVD. In this study, we hypothesized that smoking cessation could lead to improved HDL functions, and evaluated the cholesterol efflux capacity, antioxidative capacity of HDL in participants before and after smoking cessation.

Methods:
Thirty-two Japanese adult smokers aged were enrolled for treatment at the Smoking Cessation Clinic of Fukuoka University Hospital. Participants either received varenicline for 12 weeks or wore a transdermal nicotine patch on their chest for 8 weeks. Successful smoking cessation was identified by both a self-assessment report and the end-expiratory carbon monoxide (CO) concentration (under 8ppm). Plasma lipid profiles, plasma and HDL malondialdehyde (MDA) levels, HDL subfractions as analyzed by capillary isotachophoresis, cholesterol efflux capacity and antioxidative capacity of HDL were measured before and after this intervention.

Results:
After smoking cessation, HDL-C, apoA-I levels and HDL subfractions did not significantly change. Nevertheless, cholesterol efflux capacity and the antioxidative capacity of HDL were significantly improved in the successful smoking cessation group. The extent of the changes in cholesterol efflux capacity and antioxidative capacity of HDL correlated with those in the end-expiratory CO concentration and MDA in HDL, respectively.

Conclusions:
Our findings indicate that cigarette smoking impairs HDL function and smoking cessation restores it. This may be one of the mechanisms by which smoking cessation has beneficial effects against CVD.