Effect of smoking on serum RANKL and OPG in sex, age and clinically matched supportive-therapy periodontitis patients

Methods: The serum concentrations of receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in age- and sex-matched groups of smokers and non-smokers with almost identical levels of periodontal disease were determined by an enzyme-linked immunosorbent assay (ELISA). We ensured that the 35 smokers were gender, age and clinically matched with a group of 35 non-smokers (confirmed by cotinine immunoassay) from the same population of maintained patients with susceptibility to periodontitis. Results: Cigarette smoker patients tended to have lower serum concentrations of RANKL and OPG than non-smoker patients. While no statistically significant difference was observed for RANKL, there were significant differences in the median serum concentration of OPG (smokers 23.76 pM, non-smokers 59.28 pM) and the ratio of serum concentrations of RANKL and OPG. Concentrations of OPG in the smoker patients also had a statistically significant negative correlation with tobacco consumption. Conclusion: Bone loss in smoker-related periodontitis patients may be partially explained by suppression of OPG production.