Abstract
Background: Current understanding of chronic obstructive pulmonary disease (COPD) is that it results from an interaction of genetic and environmental factors. This study aimed to investigate the strength of association of various known risk factors for COPD.
Methods: Detailed written questionnaires, full pulmonary function tests and atopy testing were completed in 749 people, aged 25-75 years, recruited from a random population sample. COPD was defined, using Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, as a post-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio <0.7.
Results: The prevalence of COPD was higher in men (OR 1.7 (95% CI 1.1-2.7)) and increased with increasing age (OR per decade older 2.1 (95% CI 1.7-2.7)). COPD was more frequent in current and ex-smokers and increased with increasing pack years (OR per 10 pack years 1.3 (95% CI 1.1-1.5)). On a logit scale, a diagnosis of asthma as a child conferred a similar risk as an increase in age of 22 years or 62 pack years of cigarette smoking.
Conclusion: Childhood asthma emerged with the strongest association for GOLD-defined COPD. Possible explanations for this are suggested, including limitations of the current GOLD spirometric definition of COPD, a chance observation because of the high prevalence of both disorders in this population, or alternatively childhood asthma is a risk factor for COPD.