Chronic obstructive pulmonary disease (COPD) is rarely considered in people who have never smoked. This paper reviews the results of a large US survey which involved a detailed questionnaire, physical examination, and spirometric testing. It looks particularly at airways obstruction in lifelong non-smokers.

A total of 10 276 people aged 30–80 years had spirometric evidence of airway obstruction in this cohort. The overall prevalence of obstructive airways disease was 165 per 1000. Never smokers made up 42% of the sampled group. The prevalence of airway obstruction in this group was 91 per 1000, 68.5% of whom reported no history of either asthma or COPD. The impact of other known risk factors for COPD such as occupational dust exposure, air pollution, and environmental tobacco smoke were assessed by multivariate analysis. None of these was associated with a significantly increased risk. A significantly increased risk was noted with increasing age, male sex, low body mass index, and a history of allergy.

These data can be extrapolated to suggest that there are 4.6 million lifelong non-smokers in the US with obstructive airways disease. Airways reversibility was not assessed, so an unquantified proportion of these patients could have asthma. Other known risk factors for COPD were not found to contribute in this study, although self-reporting of exposure may be inaccurate.

Further research into COPD in never smokers is warranted to clarify the aetiology, prognosis, and clinical significance of this poorly understood group of patients.