title: Calculation of population attributable risk for bidi smoking and oral cancer in south Asia.
abstract: BACKGROUND
  Bidi smoking, which is widely prevalent in India and in other south Asian countries, increases the risk of oral cancer as observed in case-control studies and metaanalysis. However, population attributable risk percent (PAR%) has not been determined yet.
  
  
  METHODS
  Twelve case-control studies conducted in India, Pakistan, and Sri Lanka, which included information on bidi smoking and oral cancer, were analyzed countrywise to estimate PAR%.
  
  
  RESULTS
  The cumulative cases and controls were 4778 and 6271, respectively, based on 10 case-control studies conducted in India. Among the cases, 49.1% were bidi smokers and 7.7% cigarette smokers, while they were 19.9% and 10.3%, respectively, among controls. Pooled odds ratio (OR) of bidi smoking for oral cancer was 3.3 [95% confidence interval (CI), 3.0-3.6] and 2.6 (95% CI 1.8-3.8), respectively, based on fixed- and random-effects model. Cigarette smoking, on the other hand, did not show any significant association. PAR% of bidi smoking for oral cancer ranged from 4.7% to 51.6% on individual study basis, while they were 31.4% and 24.1%, respectively, based on OR derived from fixed- and random-effects models. PAR% was 5.8% and 8.7% based on single study estimate from Pakistan and Sri Lanka, respectively.
  
  
  CONCLUSIONS
  Bidi smoking is considered to account for a sizeable number of oral cancers in south Asian countries, which implies that cessation programs should be formulated and implemented vigorously.
authors.affiliation: Clinical Practice Evaluation and Research Center, St. Luke's International Hospital & St. Luke's Life Science Institute, Akashi-cho 9-1, Chuo-ku, Tokyo 104-8560, Japan. marahman@luke.or.jp
authors.forename: Mahbubur
authors.initials: M
authors.lastname: Rahman
authors.forename: Junichi
authors.initials: J
authors.lastname: Sakamoto
authors.forename: Tsuguya
authors.initials: T
authors.lastname: Fukui
mesh_terms: D000465:Algorithms; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D009062:Mouth Neoplasms / Q000453:epidemiology*; D016017:Odds Ratio; D010154:Pakistan / Q000453:epidemiology; D010947:Plants, Toxic; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D013188:Sri Lanka / Q000453:epidemiology