Characteristics of COPD in never-smokers and ever-smokers in the general population: Results from the CanCOLD study

W. C. Tan, D. D. Sin, Jean Bourbeau, P. Hernandez, K. R. Chapman, R. Cowie, J. M. FitzGerald, D. D. Marciniuk, F. Maltais, A. S. Buist, Jeremy Road, J. C. Hogg, Miranda Kirby, Harvey Coxson, Cameron Hague, Jonathon Leipsic, D. E. O'Donnell, S. D. Aaron, Jonathon Samet, Milo PuhanQutayba Hamid, Carole Baglole, Carole Jabet, Sheena Tam, Joe Comeau, Adrian Png, Mohsen Sadatsafavi, Teresa To, Andrea Gershon, Pei Zhi Li, Jean Francois Duquette, Yvan Fortier, Andrea Benedetti, Denis Jensen, Christine Lo, Sarah Cheng, Cindy Fung, Nancy Ferguson, Nancy Haynes, Junior Chuang, Licong Li, Selva Bayat, Amanda Wong, Zoe Alavi, Catherine Peng, Bin Zhao, Nathalie Scott-Hsiung, Tasha Nadirshaw, Palmina Mancino, David Latreille, Jacinthe Baril, Laura Labonte, Patricia McClean, Nadeen Audisho, Ann Cowie, Curtis Dumonceaux, Lisette Machado, Kathy Vandemheen, Gay Pratt, Amanda Bergeron, Cynthia Brouillard, Ron Clemens, Janet Baran

Research output: Contribution to journalArticlepeer-review

140 Scopus citations


Background There is limited data on the risk factors and phenotypical characteristics associated with spirometrically confirmed COPD in never-smokers in the general population. Aims To compare the characteristics associated with COPD by gender and by severity of airway obstruction in never-smokers and in ever-smokers. Method We analysed the data from 5176 adults aged 40 years and older who participated in the initial crosssectional phase of the population-based, prospective, multisite Canadian Cohort of Obstructive Lung Disease study. Never-smokers were defined as those with a lifetime exposure of <1/20 pack year. Logistic regressions were constructed to evaluate associations for 'mild' and 'moderate-severe' COPD defined by FEV1/FVC <5th centile (lower limits of normal). Analyses were performed using SAS V.9.1 (SAS Institute, Cary, North Carolina, USA). Results The prevalence of COPD (FEV1/FVC<lower limits of normal) in never-smokers was 6.4%, constituting 27% of all COPD subjects. The common independent predictors of COPD in never-smokers and ever-smokers were older age, self reported asthma and lower education. In never-smokers a history of hospitalisation in childhood for respiratory illness was discriminative, while exposure to passive smoke and biomass fuel for heating were discriminative for women. COPD in never-smokers and ever-smokers was characterised by increased respiratory symptoms, 'respiratory exacerbation' events and increased residual volume/total lung capacity, but only smokers had reduced DLCO/Va and emphysema on chest CT scans. Conclusions The study confirmed the substantial burden of COPD among never-smokers, defined the common and gender-specific risk factors for COPD in never-smokers and provided early insight into potential phenotypical differences in COPD between lifelong never-smokers and ever-smokers. Trial registration number NCT00920348 (; study ID number: IRO-93326.

Original languageEnglish (US)
Pages (from-to)822-829
Number of pages8
Issue number9
StatePublished - Sep 1 2015

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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