Background: Previous studies have shown that smoking is a risk factor for periodontitis and that it has a suppressive effect on gingival bleeding. This study examined the relationship between smoking, including past smoking, and periodontal conditions, mainly gingival bleeding, in a community-based health investigation.

Methods: Smoking status was examined in 958 subjects, along with the quantity of tobacco currently or previously smoked (never, former light, former heavy, current light, and current heavy). We analyzed the influence of smoking on probing depth (PD), clinical attachment loss (CAL), and gingival bleeding on probing (BOP).

Results: In multivariate logistic regression analyses, current heavy smokers were at a significantly greater risk for having a higher proportion of teeth with PD ≥4 mm and a higher proportion of teeth with CAL ≥5 mm; however, they had a lower risk for having a high BOP than did those who had never smoked. Moreover, both former light and former heavy smokers had significantly lower risks for high BOP. When the analysis was limited to subjects with PD ≥4 mm, former heavy and current heavy smokers showed a significant suppression of high BOP compared to never smokers.

Conclusion: This study suggests that smoking is significantly associated with PD and CAL and that current and past smoking has a suppressive effect on BOP.