title: The impact of smoking on marginal bone loss in a 10-year prospective longitudinal study.
abstract: OBJECTIVE
  The aim of this epidemiologic study was to determine the impact of smoking on marginal bone loss in a subsample derived from an original randomly selected adult sample, after adjusting for oral and general factors.
  
  
  METHODS
  The number of participants at baseline in this 10-year longitudinal study was 616 (mean age: 42 years, range 21-63 years). The participants underwent a full-mouth radiographic survey. After recall in 2003, 473 (77%) of the participants accepted and completed an identical survey. In 2008, the survey was repeated, and 301 (48.9%) individuals were included in this study. The marginal bone level of each tooth was measured in mm. Age, gender, smoking habits, number of teeth, apical periodontitis, crowns and initial marginal bone level were also recorded for each individual. Only individuals who did not report a change in smoking habits during the 10-year period were included in the study. Multiple regression analyses were used to evaluate crude and adjusted associations between smoking and marginal bone loss.
  
  
  RESULTS
  At the first, radiographic survey smokers had a statistically significantly more reduced marginal bone level (in average 0.9 mm) than nonsmokers. After 10 years, a progression of a mean marginal bone loss of > 2 mm was statistically significantly more common in smokers than in nonsmokers (7.1% and 0%, respectively). Furthermore, a marginal bone loss of 1-2 mm was observed in 29% of the smokers and 19% of the nonsmokers, and ≤ 1 mm marginal bone loss was found in 69% of smokers and 81% of nonsmokers. Even after adjusting for initial marginal bone level, gender, age, and also presence of apical periodontitis and crowns, the difference in progression of marginal bone loss was still statistically higher in smokers (on average 0.36 mm).
  
  
  CONCLUSIONS
  The smokers started out with a more reduced marginal bone level than nonsmokers. However, even after adjusting for the initial marginal bone level, the progression of marginal bone loss in smokers was more pronounced than in nonsmokers. This shows that smoking is a factor with significant impact on the marginal bone level and can be assumed to be a true risk factor for marginal bone loss.
authors.affiliation: Section of Prosthetic Dentistry, Department of Dentistry, Aarhus University, Aarhus, Denmark.
authors.forename: Golnosh
authors.initials: G
authors.lastname: Bahrami
authors.affiliation: Section of Biostatistics, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Vaeth
authors.affiliation: Section of Oral Radiology, Department of Dentistry, Aarhus University, Aarhus, Denmark.|Department of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, Oslo, Norway.
authors.forename: Lise-Lotte
authors.initials: LL
authors.lastname: Kirkevang
authors.affiliation: Section of Oral Radiology, Department of Dentistry, Aarhus University, Aarhus, Denmark.
authors.forename: Ann
authors.initials: A
authors.lastname: Wenzel
authors.affiliation: Section of Prosthetic Dentistry, Department of Dentistry, Aarhus University, Aarhus, Denmark.
authors.forename: Flemming
authors.initials: F
authors.lastname: Isidor
keywords: alveolar bone loss; epidemiologic study; longitudinal study; marginal bone loss; smoking