COPD in Never-Smokers: BOLD Australia Study

Abstract

Purpose

Tobacco smoking is the major risk factor for COPD, and it is common for other risk factors in never-smokers to be overlooked. We examined the prevalence of COPD among never-smokers in Australia and identified associated risk factors.

Methods

We used data from the Australia Burden of Obstructive Lung Disease (BOLD) study, a cross-section of people aged ≥40 years from six sites. Participants completed interviews and post-bronchodilator spirometry. COPD was primarily defined as an FEV₁/FVC ratio <0.70 and secondarily as the ratio less than the lower limit of normal (LLN).

Results

The prevalence of COPD in the 1656 never-smokers who completed the study was 10.5% (95% CI: 9.1–12.1%) [ratio<LLN 4.6%]. The likelihood of having COPD increased with advancing age [odds ratio (OR) 4.11 in those 60–69 years and OR 8.73 in those 70 years and older], having attained up to 12 years of education (OR 1.75) compared to those with more than 12 years, having a history of asthma (OR 2.30), childhood hospitalization due to breathing problems before age 10 years (OR 2.50), or having a family history of respiratory diseases (OR 2.70). Being overweight or obese was associated with reduced prevalence of COPD compared with being normal weight. In males and females, advanced age, a history of asthma, and childhood breathing problems before age 10 were factors that elevated the likelihood of COPD. However, in males, additional factors such as a higher body mass index and a family history of respiratory diseases also contributed to increased odds of COPD.

Conclusion

COPD was prevalent in this population of never-smokers aged 40 years and over. This finding highlights the significance of risk factors other than smoking in the development of COPD.

Keywords:

• non-smokers
• prevalence
• spirometry
• lower limit of normal
• LLN
• burden of obstructive lung disease
• BOLD

Acknowledgments

The authors acknowledge investigators from our BOLD-Australia study-sites who are not co-authors on this paper: Christine Jenkins, David Atkinson, Haydn Walters, Deborah Burton. We thank the research staff and participants at each study site for their important contribution. In particular, the following site members, Busselton: Bill Musk (deceased), Elspeth Inglis and Peta Grayson; Broome/Kimberly: David Reeve, Matthew Yap, Mary Lane, Nathania Cooksley, Sally Young and Wendy Cavilla; Melbourne: Angela Lewis, Joan Raven and Joan Green; Rural New South Wales: Phillipa Southwell, Melanie Heine, Cassanne Eccleston, Julie Cooke, Bruce Graham, Brian Spurrell and Robyn Paton; Sydney: Tessa Bird, Wei Xuan, Kate Hardaker and Paola Espinel; Tasmania: Carol Phillips and Loren Taylor. We also acknowledge the support provided to Graeme Maguire and Guy Marks by NHMRC Practitioner Fellowships and to Graeme Maguire by the Margaret Ross Chair in Indigenous Health.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Guy B Marks has provided independent medical service on an advisory board for Astra Zeneca. Michael J Abramson holds investigator-initiated grants for unrelated research from Pfizer, GSK, Boehringer-Ingelheim and Sanofi and he has also conducted an unrelated consultancy for Sanofi. He has also received a speaker’s fee from GSK. The other authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript or in the decision to publish the results.

The other authors declare no conflicts of interest.

Additional information

Funding

This research was funded by the National Health and Medical Research Council (NHMRC) of Australia, grant number 457385 and supported by the Thoracic Society of Australia and New Zealand, The Robert Pierce Grant-in-Aid for Indigenous Lung Health (2010); Air Liquide, AstraZeneca; GlaxoSmithKline; and Boehringer Ingelheim (2005).