title: COPD prevalence is increased in lung cancer, independent of age, sex and smoking history.
abstract: Chronic obstructive pulmonary disease (COPD) is a common comorbid disease in lung cancer, estimated to affect 40-70% of lung cancer patients, depending on diagnostic criteria. As smoking exposure is found in 85-90% of those diagnosed with either COPD or lung cancer, coexisting disease could merely reflect a shared smoking exposure. Potential confounding by age, sex and pack-yr smoking history, and/or by the possible effects of lung cancer on spirometry, may result in over-diagnosis of COPD prevalence. In the present study, the prevalence of COPD (pre-bronchodilator Global Initiative for Chronic Obstructive Lung Disease 2+ criteria) in patients diagnosed with lung cancer was 50% compared with 8% in a randomly recruited community control group, matched for age, sex and pack-yr smoking exposure (n = 602, odds ratio 11.6; p<0.0001). In a subgroup analysis of those with lung cancer and lung function measured prior to the diagnosis of lung cancer (n = 127), we found a nonsignificant increase in COPD prevalence following diagnosis (56-61%; p = 0.45). After controlling for important variables, the prevalence of COPD in newly diagnosed lung cancer cases was six-fold greater than in matched smokers; this is much greater than previously reported. We conclude that COPD is both a common and important independent risk factor for lung cancer.
authors.affiliation: Department of Medicine, University of Auckland, Auckland, New Zealand. roberty@adhb.govt.nz
authors.forename: R P
authors.initials: RP
authors.lastname: Young
authors.forename: R J
authors.initials: RJ
authors.lastname: Hopkins
authors.forename: T
authors.initials: T
authors.lastname: Christmas
authors.forename: P N
authors.initials: PN
authors.lastname: Black
authors.forename: P
authors.initials: P
authors.lastname: Metcalf
authors.forename: G D
authors.initials: GD
authors.lastname: Gamble
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000453:epidemiology*; D012129:Respiratory Function Tests; D012307:Risk Factors; D012907:Smoking; D013147:Spirometry; D013997:Time Factors