Smoking, smoking cessation and inflammatory markers in older Chinese men: The Guangzhou Biobank Cohort Study

Aims: Smoking increases the risk of cardiovascular disease and inflammation plays a key role in the process of atherosclerosis. We therefore study the role of smoking and smoking cessation on the levels of inflammatory markers, C-reactive protein (CRP) and white blood cell (WBC) count, in older Chinese men. Methods: This cross-sectional analysis included 2999 men aged 50-85 years who received a medical check-up including measurement of fasting plasma vascular risk factors. Information on smoking status, socioeconomic and lifestyle factors was collected by standardized interview. Results: After adjustment for potential confounders, both CRP and WBC increased linearly across never, former and current smokers (both p < 0.01). The odds ratios of elevated CRP and WBC (upper tertiles) were also increased across never, former and current smokers (both p < 0.01). Dose-response relationships were observed among current smokers. Compared to current smokers, the odds ratios of elevated CRP and WBC and means of CRP and WBC declined with longer duration of smoking cessation (all p < 0.01). Conclusions: Smoking is associated with increased CRP and WBC levels, and smoking cessation is associated with the reduction of the increase, confirming the benefits of quitting. Inflammation may be a potential mechanism by which smoking promotes atherosclerotic disease.