title: Cigarette smoking and pulmonary tuberculosis in northern California.
abstract: BACKGROUND
  A positive association between smoking and increased risk of tuberculosis disease is well documented for populations outside the USA. However, it is unclear whether smoking increases risk of tuberculosis in the USA, where both smoking prevalence and disease rates are much lower than in the countries where previous studies have been conducted.
  
  
  METHODS
  To explore the tuberculosis-smoking association in a more generalisable US population-based sample, we conducted a nested case-control study among members of Kaiser Permanente Northern California (KPNC). We identified all newly diagnosed cases of active pulmonary tuberculosis (PTB) disease between 1996 and 2010. Each of the 2380 cases were individually matched to two controls by age, gender and race/ethnicity. ORs and 95% CIs for the association between smoking status and PTB were calculated using conditional logistic regression adjusted for all matching factors.
  
  
  RESULTS
  Increased PTB risk was observed among ever-smokers (OR=1.35; 95% CI 1.19 to 1.53), as well as current (OR=1.26; 95% CI 1.08 to 1.48) and past (OR=1.43; 95% CI 1.23 to 1.67) smokers, compared with never-smokers. Increased intensity and duration of smoking were also positively associated with PTB risk.
  
  
  CONCLUSIONS
  Our findings among a more generalisable US population support the hypothesis that smoking increases risk of PTB, underscoring the importance of tobacco cessation and prevention programmes in eliminating tuberculosis.
authors.affiliation: Departments of Epidemiology, Chapel Hill, North Carolina.
authors.forename: Geneé S
authors.initials: GS
authors.lastname: Smith
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Van Den Eeden
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Roger
authors.initials: R
authors.lastname: Baxter
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Jun
authors.initials: J
authors.lastname: Shan
authors.affiliation: Departments of Epidemiology, Chapel Hill, North Carolina.
authors.forename: Annelies
authors.initials: A
authors.lastname: Van Rie
authors.affiliation: Departments of Biostatistics, Chapel Hill, North Carolina Departments of Carolina Population Center, Chapel Hill, North Carolina.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Herring
authors.affiliation: Departments of Epidemiology, Chapel Hill, North Carolina.
authors.forename: David B
authors.initials: DB
authors.lastname: Richardson
authors.affiliation: Departments of Epidemiology, Chapel Hill, North Carolina Departments of Carolina Population Center, Chapel Hill, North Carolina Departments of Geography, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Michael
authors.initials: M
authors.lastname: Emch
authors.affiliation: Departments of Epidemiology, Chapel Hill, North Carolina.
authors.forename: Marilie D
authors.initials: MD
authors.lastname: Gammon
mesh_terms: D000328:Adult; D000368:Aged; D002140:California; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology*; D055815:Young Adult
keywords: PUBLIC HEALTH; SMOKING; TUBERCULOSIS