Fagerstrom test for nicotine dependence as an indicator in tobacco-related studies in periodontology

Background Smoking is considered a risk factor for periodontitis genesis and progression. Numerous clinical studies have demonstrated the negative effect of smoking, in particular the number of cigarettes consumed (NCC), on periodontal clinical parameters. However, smoking addiction assessed by the Fagerstrom test for nicotine dependence (FTND) has received little attention in periodontal research. Methods In smoking patients presenting with periodontitis, the periodontal clinical features were measured and correlated with smoking status. The ability of FTND and NCC to predict periodontitis severity was assessed and compared. Results Thirty-four smoking patients aged 46.5 +/- 11.5 years were included. The means of NCC and FTND were 16.6 +/- 5.5 and 5.2 +/- 1.8, respectively. NCC and FTND were correlated with each other (r = 0.57,P < 0.001). Patients had stage III (44.1%) or stage IV (55.9%) periodontitis and 73.5% presented a generalized extension of periodontitis. The combination of FTND and NCC in discerning disease severity (ROC curve analysis: AUC = 0.746,P = 0.027) was superior to each indicator separately. A discriminant score based on both indicators (D = -0.42 - 0.15 x NCC + 0.63 x FTND) derived by logistic regression showed the opposite role of the indicators and the greater relevance of FTND (P = 0.031) compared to NCC (P = 0.084) in the relationship. Conclusion This study shows that FTND could substantially complement NCC as an indicator of smoking status in periodontal research.