title: Family history is a risk factor for COPD.
abstract: BACKGROUND
  Studies have shown that family history is a risk factor for COPD, but have not accounted for family history of smoking. Therefore, we sought to identify the effects of family history of smoking and family history of COPD on COPD susceptibility.
  
  
  METHODS
  We compared 821 patients with COPD to 776 control smokers from the Genetic Epidemiology of COPD (COPDGene) Study. Questionnaires captured parental histories of smoking and COPD, as well as childhood environmental tobacco smoke (ETS) exposure. Socioeconomic status was defined by educational achievement.
  
  
  RESULTS
  Parental history of smoking (85.5% case patients, 82.9% control subjects) was more common than parental history of COPD (43.0% case patients, 30.8% control subjects). In a logistic regression model, parental history of COPD (OR, 1.73; P < .0001) and educational level (OR, 0.48 for some college vs no college; P < .0001) were significant predictors of COPD, but parental history of smoking and childhood ETS exposure were not significant. The population-attributable risk from COPD family history was 18.6%. Patients with COPD with a parental history had more severe disease, with lower lung function, worse quality of life, and more frequent exacerbations. There were nonsignificant trends for more severe emphysema and airway disease on quantitative chest CT scans.
  
  
  CONCLUSIONS
  Family history of COPD is a strong risk factor for COPD, independent of family history of smoking, personal lifetime smoking, or childhood ETS exposure. Although further studies are required to identify genetic variants that influence COPD susceptibility, clinicians should question all smokers, especially those with known or suspected COPD, regarding COPD family history.
authors.affiliation: Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA. Electronic address: craig.hersh@channing.harvard.edu.
authors.forename: Craig P
authors.initials: CP
authors.lastname: Hersh
authors.affiliation: Colorado School of Public Health, University of Colorado, Aurora.
authors.forename: John E
authors.initials: JE
authors.lastname: Hokanson
authors.affiliation: Department of Radiology, National Jewish Health, Denver, CO.
authors.forename: David A
authors.initials: DA
authors.lastname: Lynch
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors.forename: George R
authors.initials: GR
authors.lastname: Washko
authors.affiliation: Division of Pulmonary and Critical Care Medicine, National Jewish Health, Denver, CO.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Make
authors.affiliation: Division of Pulmonary and Critical Care Medicine, National Jewish Health, Denver, CO.
authors.forename: James D
authors.initials: JD
authors.lastname: Crapo
authors.affiliation: Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Silverman
mesh_terms: D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000209:etiology / Q000235:genetics* / Q000503:physiopathology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D014028:Tobacco Smoke Pollution
chemical_list: D014028:Tobacco Smoke Pollution