Abstract
We hypothesised that biomass smoke exposure is associated with an airway-predominant chronic obstructive pulmonary disease (COPD) phenotype, while tobacco-related COPD is associated with an emphysema-predominant phenotype.
In this cross-sectional study, female never-smokers with COPD and biomass exposure (n=21) and female ex-cigarette smokers with COPD without biomass exposure (n=22) completed computed tomography (CT) at inspiration and expiration, pulmonary function, blood gas, exercise tolerance, and quality of life measures. Two radiologists scored the extent of emphysema and air trapping on CT. Quantitative emphysema severity and distribution and airway wall thickness were calculated using specialised software.
Women in the tobacco group had significantly more emphysema than the biomass group (radiologist score 2.3 versus 0.7, p=0.001; emphysema on CT 27% versus 19%, p=0.046; and a larger size of emphysematous spaces, p=0.006). Women in the biomass group had significantly more air trapping than the tobacco group (radiologist score 2.6 and 1.5, respectively; p=0.02) and also scored lower on the symptom, activities and confidence domains of the quality of life assessment and had lower oxygen saturation at rest and during exercise (p<0.05).
Biomass smoke exposure is associated with less emphysema but more air trapping than tobacco smoke exposure, suggesting an airway-predominant phenotype.
Abstract
Biomass smoke causes less emphysema but more air trapping than tobacco smoke: airway-predominant COPD phenotype? http://ow.ly/rHdju
Footnotes
For editorial comments see page 659.
Support statement: This study was funded by a non-restricted research grant from GlaxoSmithKline Canada, a Canadian Institutes of Health Research Interdisciplinary Capacity Enhancement: Bridging Excellence in Respiratory Disease and Gender Studies (ICEBERGS) team grant, and internal research funds held at the Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas (Mexico). At the time of this study, P.G. Camp was funded by a Canadian Institutes of Health Research Fellowship, a Canadian Respiratory Health Professional Fellowship, and a trainee award from ICEBERGS. She is currently a Michael Smith Foundation for Health Research Clinical Scholar. H.O. Coxson was a CIHR/British Columbia Lung Association New Investigator and is currently funded in part by Pittsburgh Chronic Obstructive Pulmonary Disease (COPD) Specialized Centers of Clinically Oriented Research (SCCOR) NIH 1P50 HL084948 and R01 HL085096 from the National Heart, Lung, and Blood Institute at the National Institutes of Health to the University of Pittsburgh and the British Columbia Lung Association Robert R. Miller Fellowship in Thoracic Imaging. D.D. Sin holds the Canada Research Chair in COPD. P.D. Paré is a Michael Smith Foundation for Health Research Distinguished Scholar and the Jacob Churg Distinguished Researcher.
Conflict of interest: Disclosures can be found alongside the online version of this article at www.erj.ersjournals.com
- Received December 21, 2012.
- Accepted May 15, 2013.
- ©ERS 2014