PT  - JOURNAL ARTICLE
AU  - Tan, W C
AU  - Sin, D D
AU  - Bourbeau, J
AU  - Hernandez, P
AU  - Chapman, K R
AU  - Cowie, R
AU  - FitzGerald, J M
AU  - Marciniuk, D D
AU  - Maltais, F
AU  - Buist, A S
AU  - Road, J
AU  - Hogg, J C
AU  - Kirby, M
AU  - Coxson, H
AU  - Hague, C
AU  - Leipsic, J
AU  - O'Donnell, D E
AU  - Aaron, S D
AU  - ,
TI  - Characteristics of COPD in never-smokers and ever-smokers in the general population: results from the CanCOLD study
AID  - 10.1136/thoraxjnl-2015-206938
DP  - 2015 Sep 01
TA  - Thorax
PG  - 822--829
VI  - 70
IP  - 9
4099  - http://thorax.bmj.com/content/70/9/822.short
4100  - http://thorax.bmj.com/content/70/9/822.full
SO  - Thorax2015 Sep 01; 70
AB  - 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 cross-sectional 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 (ClinicalTrials.gov); study ID number: IRO-93326.