title: Association between smoking and latent tuberculosis in the U.S. population: an analysis of the National Health and Nutrition Examination Survey.
abstract: BACKGROUND
  Evidence of an association between cigarette smoking and latent tuberculosis infection (LTBI) is based on studies in special populations and/or from high prevalence settings. We sought to evaluate the association between LTBI and smoking in a low prevalence TB setting using population-based data from the National Health and Nutrition Examination Survey (NHANES).
  
  
  METHODS
  In 1999-2000, NHANES assessed LTBI (defined as a tuberculin skin test measurement ≥10 mm) in participants, and those ≥20 years of age were queried regarding their tobacco use and serum cotinine was measured. We evaluated the association of LTBI with self-reported smoking history and smoking intensity in multivariable logistic regression models that adjusted for known confounders (gender, age, birthplace, race/ethnicity, poverty, education, history of BCG vaccination, and history of household exposure to tuberculosis disease).
  
  
  RESULTS
  Estimated LTBI prevalence was 5.3% among those ≥20 years of age. The LTBI prevalence among never smokers, current smokers, and former smokers was 4.1%, 6.6%, and 6.2%, respectively. In a multivariable model, current smoking was associated with LTBI (OR 1.8; 95% CI, 1.1-2.9). The association between smoking and LTBI was strongest for Mexican-American and black individuals. In multivariate analysis stratified by race/ethnicity, cigarette packs per day among Mexican-American smokers and cotinine levels among black smokers, were significantly associated with LTBI.
  
  
  CONCLUSIONS
  In the large, representative, population-based NHANES sample, smoking was independently associated with significantly increased risks of LTBI. In certain populations, a greater risk of LTBI corresponded with increased smoking exposure.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Seattle, WA, USA. dhorne@uw.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Horne
authors.forename: Monica
authors.initials: M
authors.lastname: Campo
authors.forename: Justin R
authors.initials: JR
authors.lastname: Ortiz
authors.forename: Eyal
authors.initials: E
authors.lastname: Oren
authors.forename: Matthew
authors.initials: M
authors.lastname: Arentz
authors.forename: Kristina
authors.initials: K
authors.lastname: Crothers
authors.forename: Masahiro
authors.initials: M
authors.lastname: Narita
mesh_terms: D000328:Adult; D001741:Black or African American; D005260:Female; D006306:Health Surveys; D006801:Humans; D055985:Latent Tuberculosis / Q000453:epidemiology* / Q000208:ethnology; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged; D015999:Multivariate Analysis; D009749:Nutrition Surveys / Q000379:methods; D015995:Prevalence; D057566:Self Report; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology* / Q000208:ethnology; D014481:United States / Q000453:epidemiology; D055815:Young Adult