Attention drawn to COPD in never smokers

Sep 16 2013

Research from Denmark shows that, while never smokers with chronic obstructive pulmonary disease (COPD) typically experience milder disease than their smoking counterparts, they still have substantial morbidity due to COPD- and pneumonia-related hospital admissions.

The study authors, led by Børge Nordestgaard (Copenhagen University Hospital), analyzed data from the Copenhagen General Population Study on 6623 patients with COPD, of whom 1476 (22%) were never smokers, 2696 (41%) were former smokers, and 2451 (37%) were current smokers.

They found that almost all never smokers with COPD had mild disease (forced expiratory volume in 1 second [FEV1] >80% predicted), with only 3.5% having an FEV1 under 50% of that predicted compared with 10% and 11% of former and current smokers, respectively. Never smokers also experienced fewer hospital admissions than did smokers during a mean follow-up of 4 years, and were no more likely to die than never smokers without COPD.

Reporting in the Lancet Respiratory Medicine, the team notes several distinct characteristics of patients with COPD who had never smoked.

Unlike former and current smokers, never smokers with COPD did not have elevated levels of inflammatory biomarkers, a finding which the authors say could explain why they did not experience increased cardiovascular and extrapulmonary comorbidities compared with never smokers without COPD. Instead, the disease appeared to be confined to the lungs in never smokers, the team notes.

And the results highlight that, in comparison with the general population, these patients have a significantly elevated risk for COPD- and pneumonia-related hospital admissions, increased by a factor of 8.6 and 1.9, respectively.

Writing in an accompanying editorial, Janice Leung and Don Sin from the University of British Columbia in Vancouver, Canada, say that the study could have major implications for clinical research. Despite there being an estimated 120 million never smokers with COPD worldwide, these patients have been systematically excluded from drug trials, leading to a complete lack of knowledge about how they should be treated, they explain.

“Our attention, long focused on the perils of tobacco, should now in addition turn to the spectre of disease outside cigarettes, and most importantly, we must stop perpetuating the myth that COPD is only for smokers,” they conclude.

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