title: Pneumothorax risk factors in smokers with and without chronic obstructive pulmonary disease.
abstract: BACKGROUND
  The demographic, physiological, and computed tomography (CT) features associated with pneumothorax in smokers with and without chronic obstructive pulmonary disease (COPD) are not clearly defined.
  
  
  OBJECTIVE
  We evaluated the hypothesis that pneumothorax in smokers is associated with male sex, tall and thin stature, airflow obstruction, and increased total and subpleural emphysema.
  
  
  METHODS
  The study included smokers with and without COPD from the COPDGene Study, with quantitative chest CT analysis. Pleural-based emphysema was assessed on the basis of local histogram measures of emphysema. Pneumothorax history was defined by subject self-report.
  
  
  RESULTS
  Pneumothorax was reported in 286 (3.2%) of 9,062 participants. In all participants, risk of prior pneumothorax was significantly higher in men (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.08-2.22) and non-Hispanic white subjects (OR, 1.90; 95% CI, 1.34-2.69). Risk of prior pneumothorax was associated with increased percent CT emphysema in all participants and participants with COPD (OR, 1.04 for each 1% increase in emphysema; 95% CI, 1.03-1.06). Increased pleural-based emphysema was independently associated with risk of past pneumothorax in all participants (OR, 1.05 for each 1% increase; 95% CI, 1.01-1.10). In smokers with normal spirometry, risk of past pneumothorax was associated with non-Hispanic white race and lifetime smoking intensity (OR, 1.20 for every 10 pack-years; 95% CI, 1.09-1.33).
  
  
  CONCLUSIONS
  Among smokers, pneumothorax is associated with male sex, non-Hispanic white race, and increased percentage of total and subpleural CT emphysema. Pneumothorax was not independently associated with height or lung function, even in participants with COPD. Clinical trial registered with www.clinicaltrials.gov (NCT00608764).
authors.affiliation: 1 Channing Division of Network Medicine and.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Hobbs
authors.forename: Marilyn G
authors.initials: MG
authors.lastname: Foreman
authors.forename: Russell
authors.initials: R
authors.lastname: Bowler
authors.forename: Francine
authors.initials: F
authors.lastname: Jacobson
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Make
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Castaldi
authors.forename: Raúl
authors.initials: R
authors.lastname: San José Estépar
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Silverman
authors.forename: Craig P
authors.initials: CP
authors.lastname: Hersh
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000000981:diagnostic imaging / Q000453:epidemiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data
keywords: chronic obstructive pulmonary disease; emphysema; pneumothorax