Effect of smoking on concentrations of receptor activator of nuclear factor κ B ligand and osteoprotegerin in human gingival crevicular fluid

Abstract

To compare the levels of the soluble receptor activator of nuclear factor kappa B ligand (sRANKL), osteoprotegerin (OPG) and their relative ratio in gingival crevicular fluid (GCF) among periodontitis patients with varying smoking histories. GCF samples were collected from 149 periodontitis patients who were never smokers (n=58), former smokers (n=39) and current smokers (n=52). sRANKL and OPG concentrations in GCF were measured by enzyme-linked immunosorbent assays. sRANKL, OPG and their relative ratio were not statistically significant among the never smokers, former smokers and current smokers. However, OPG was significantly reduced and subsequently the sRANKL:OPG ratio was significantly increased in the high pack-years group as compared with never smokers. The positive correlation between pack-years and the sRANKL:OPG ratio remained statistically significant after adjusting for age and current smoking status. Increased lifetime exposure to cigarette smoking above a minimum threshold suppresses OPG production and leads to increased sRANKL:OPG. This may partially explain increased bone loss in smoking-related periodontitis.