Obstructive lung disease does not increase lung cancer mortality among female never-smokers in Hong Kong

Abstract

Obstructive lung disease exerted differential effects on lung cancer mortality across different sex and smoking subgroups in this Asian population, with a conspicuous absence of effect among female never-smokers.

Chronic obstructive pulmonary disease and risk of lung cancer: a meta-analysis of prospective cohort studies

“…The continents or countries in which the studies were conducted were as follows: China (n=3), the United States (n=9), and Europe (n=6). For the diagnosis of COPD, seven studies [ 12 – 14 , 16 , 18 , 24 , 45 ] used forced expiratory volume (FEV) or radiographic evidence of emphysema, eight studies [ 9 , 11 , 19 , 20 , 22 , 23 , 46 , 47 ] based on self-reported condition from questionnaire, and three studies [ 15 , 17 , 21 ] used physician report, medical report or disease registry.…”

“…Most of the studies reported risk estimations for men and women combined, and three studies [ 20 – 22 ] reported specifically for men and women. Another three studies [ 13 , 15 , 18 ] consisted entirely or almost entirely of men (>90%).…”

“…Three studies [ 11 , 13 , 20 ] reported risk estimations specifically for smoking status (never, ever, former and current smokers), and one study [ 47 ] involved only never smokers. The SRRs were 2.32 (95% CIs: 1.42–3.77) for never smokers, 1.60 (95% CIs: 1.28-2.01) for ever smokers, 1.63(95% CIs: 1.11-2.39) for current smokers and 1.32 (95% CIs: 0.65-2.68) for former smokers, respectively.…”

Chronic Obstructive Pulmonary Disease and Risk of Lung Cancer: The Importance of Smoking and Timing of Diagnosis

“…A more recent study did not detect an association between obstructive lung disease and mortality caused by lung cancer in female never smokers (HR: 0.97, p = 0.909) although the number of exposed cases in this subgroup was also small. 16 Many previous studies of COPD and lung cancer do not assess the effect of timing of diagnoses and those that do have small numbers. 5,11 The authors of a Chinese study, for example, reported ORs for lung cancer of 2.9 (95% CI: 2.0-4.1) and 1.9 (1.2-3.1) in people diagnosed with COPD 1 to 5 and 6 to 10 years before lung cancer diagnoses (compared with those who did not have a diagnosis of COPD at 1 year before lung cancer diagnosis), but there were only 74 and 32 cases in each of these groups.…”

Is Previous Respiratory Disease a Risk Factor for Lung Cancer?

“…Other studies have observed similar results. A Hong Kong longitudinal study that grouped COPD and asthma observed no association with lung cancer mortality in female never-smokers (35). A Chinese occupational cohort study examining chronic bronchitis, asthma, and tuberculosis found that only prior chronic bronchitis was associated with an increased lung cancer risk, with an adjusted HR of 1.50 (95% CI, 1.24-1.81), after including all respiratory diseases in the same model (34).…”