Influence of smoking and smoking cessation on biomarkers of endothelial function and their association with mortality

Background and aims: Endothelial dysfunction precedes atherosclerosis and smoking is a well-known risk factor for the development of endothelial dysfunction. The aim of our study was to analyse the effect of smoking on circulating markers of endothelial function and to investigate whether such effects have an influence on the potential use of these markers to estimate cardiovascular risk. Methods: Stratified for smoking, levels of sE-/sP-/sL-selectin, von Willebrand (vWF), sICAM-1 and sVCAM-1, their association with mortality using Cox regression, and their accuracy of risk prediction using area-under-the-ROC-curve and net-reclassification-index were analysed in 1926 participants from the Ludwigshafen Risk and Cardiovascular Health (LURIC) - a prospective case-control study in patients who underwent coronary angiography with a median mortality follow-up of 10.6 years. Results: In smokers, higher concentrations of sICAM-1, sE-selectin sP-selectin, but lower concentrations of sLselectin and sVCAM-1, were detected compared to never-smokers. A direct association with mortality was found for levels of sICAM-1, sVCAM-1 and vWF regardless of smoking. Low sL-selectin levels were inversely associated with mortality in heavy and light smokers, with hazard ratios of 0.72 and 0.67 per 1-SD increase, adjusted for cardiovascular risk factors. Adding sL-selectin to a model based on traditional risk factors significantly improved AUC from 0.725 to 0.752 (p = 0.034) with an NRI of 43% (16.9%-62.3%). Conclusions: Smoking alters the concentration of circulating markers of endothelial function. sL-selectin is decreased in smokers, inversely associated with risk, and could be a useful marker to improve risk prediction.