Objective:
Smoking is the world’s leading preventable cause of death. Smoking causes a number of atherosclerosis vascular diseases and contributes to the progression of chronic kidney disease. Serum cystatin C has a low molecular weight of 13 kDa and is produced constantly and is not affected by a decrease in muscle mass. Serum cystatin C is useful in evaluation of early renal dysfunction and serves as a cardiovascular prognostic marker. This study aimed to determine changes in serum cystatin C level after smoking cessation.

Methods and Results:
In this study, patients who visited the smoking cessation clinic for the first time and succeeded in smoking cessation for 1 year were enrolled. Among the entire cohort of 86 patients, body mass index (BMI, P < 0.001) and waist circumference (WC, P < 0.001) increased significantly at 3 months after smoking cessation in comparison to the baseline values. These values were further increased significantly (BMI, P < 0.001; WC, P < 0.001) from 3 months to 1 year after smoking cessation. The serum cystatin C level decreased significantly at 3 months (P = 0.045) after smoking cessation, and remained unchanged (P = 0.482) from 3 months to 1 year after smoking cessation. The percent change from the baseline to 3 months after smoking cessation in serum cystatin C was correlated with the percent change in serum MCP-1 (P = 0.047).

Conclusions:
The present study demonstrates that serum levels of cystatin C, a sensitive marker of atherosclerotic vascular, significantly reduced at 3 months after SC. AT-LDL may lead to the marker of future cardiovascular events in smoker.