title: Influence of cigarette filters on the risk of developing oral leukoplakia in a Kenyan population.
abstract: OBJECTIVE
  To determine the influence of cigarette filters and the effect of smoking Kiraiku (home processed, hand rolled tobacco) on the risk of developing oral leukoplakia among cigarette smokers.
  
  
  METHODS
  Case control using population-based study groups in a Kenyan rural community.
  
  
  METHODS
  85 cases and 141 controls identified in a cross-section house-to-house screening of subjects aged 15 years and over and matched for sex, age (+/- 3 years) and cluster origin were compared for their use of filter and non-filter cigarettes as well as their history of smoking Kiraiku.
  
  
  RESULTS
  The relative risk (RR) of oral leukoplakia was 9.1 (95% confidence intervals (CI) = 4.1-20.2) in smokers of filter cigarettes and 9.8 (95% CI = 2.3-47.0) in smokers of non-filter cigarettes. The RR in the latter compared to the former was 1.1 and was not statistically significant. Regarding the influence of smoking Kiraiku, the RR of this lesion was 29.3 in smokers of both Kiraiku and filter cigarettes and 17.3 in smokers of both Kiraiku and non-filter cigarettes.
  
  
  CONCLUSIONS
  There was no statistically significant difference between the influence of filter and non-filter cigarettes on the risk of developing oral leukoplakia. The effect of Kiraiku on the risk of this lesion was stronger in filter than in non-filter cigarettes. However, the confounding effect of tobacco dose response parameters could not be ruled out.
authors.affiliation: Faculty of Dental Sciences, College of Health Sciences, University of Nairobi, P.O. Box 19676, Nairobi, Kenya.
authors.forename: F G
authors.initials: FG
authors.lastname: Macigo
authors.forename: D L
authors.initials: DL
authors.lastname: Mwaniki
authors.forename: S W
authors.initials: SW
authors.lastname: Guthua
authors.forename: E K
authors.initials: EK
authors.lastname: Njeru
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D007630:Kenya; D007972:Leukoplakia, Oral / Q000209:etiology*; D008297:Male; D016017:Odds Ratio; D011159:Population Surveillance; D012307:Risk Factors; D012423:Rural Health; D012907:Smoking / Q000009:adverse effects