title: Association between smoking, betel chewing and gingival bleeding in rural Sri Lanka.
abstract: OBJECTIVE
  To ascertain the association between tobacco use and gingival bleeding in a rural community in Sri Lanka.
  
  
  METHODS
  A cross-sectional field-based study was carried out in 2178 rural males aged 20-60 years, employing a multistage cluster sampling technique. The levels of plaque and gingivitis were recorded on four sites of all teeth present excluding third molars, using the plaque index (PLI) and gingival index (GI). Information pertaining to sociodemographic variables, oral hygiene practices and tobacco consumption habits was obtained from all subjects.
  
  
  RESULTS
  One-way anova combined with the Bonferroni test disclosed that betel chewers had a significantly higher mean number of sites with gingival bleeding (22.6+/-21.8) than smokers (10.8+/-11.2) and nontobacco users (8.7+/-6.8) (p<0.0001). A higher proportion of betel chewers (55.1%) showed > or =12 bleeding sites compared to smokers (27.6%). Logistic regression analysis revealed that the association between betel chewing and gingival bleeding was positive (OR=2.41; p<0.0001) whereas that of smoking and gingival bleeding was negative (OR=0.75; p<0.05). Oral hygiene had the strongest relationship with gingival bleeding (OR=18.11).
  
  
  CONCLUSIONS
  While confirming the masking effect of smoking on gingival bleeding, these findings indicate that betel chewing might significantly enhance gingival bleeding in the population studied.
authors.affiliation: Division of Preventive Dentistry, Department of Oral Health Science, Graduate School of Medical and Dental Sciences, Niigata University, Japan. najith@dent.niigata-u.ac.jp
authors.forename: Najith
authors.initials: N
authors.lastname: Amarasena
authors.forename: Asoka N I
authors.initials: AN
authors.lastname: Ekanayaka
authors.forename: Lilani
authors.initials: L
authors.lastname: Herath
authors.forename: Hideo
authors.initials: H
authors.lastname: Miyazaki
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001114:Areca / Q000009:adverse effects*; D016009:Chi-Square Distribution; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D003773:Dental Plaque / Q000453:epidemiology; D003774:Dental Plaque Index; D005884:Gingival Hemorrhage / Q000453:epidemiology*; D005891:Gingivitis / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009910:Oral Hygiene / Q000706:statistics & numerical data; D010512:Periodontal Index; D012423:Rural Health / Q000706:statistics & numerical data*; D012907:Smoking / Q000453:epidemiology*; D013188:Sri Lanka / Q000453:epidemiology; D018709:Statistics, Nonparametric