Association between chronic obstructive pulmonary disease and lung cancer: a case-control study in Southern Chinese and a meta-analysis

PLoS One. 2012;7(9):e46144. doi: 10.1371/journal.pone.0046144. Epub 2012 Sep 28.

Abstract

Background: Lung cancer and chronic obstructive pulmonary disease (COPD) share a common risk factor in cigarette smoking and a large portion of patients with lung cancer suffer from COPD synchronously. We therefore hypothesized that COPD is an independent risk factor for lung cancer. Our aim was to investigate the intrinsic linkage of COPD (or emphysema, chronic bronchitis and asthma) and lung cancer.

Methods: The present hospital-based case-control study included 1,069 patients with newly diagnosed lung cancer and 1,132 age frequency matched cancer-free controls. The odds ratios (ORs) for the associations between each previous pulmonary disease and lung cancer were estimated with logistic regression models, adjusting for age, sex, family history of cancer, BMI and pack year smoking. In meta-analysis, the pooled effects of previous pulmonary diseases were analyzed with random effects models; and stratification analyses were conducted on smoking status and ethnicity.

Results: In the case-control study, previous COPD was associated with the odds for increased risk of lung cancer (OR = 1.29, 95% confidence interval [CI] = 1.00∼1.68); so were emphysema (OR = 1.55, 95%CI = 1.03∼2.32) and chronic bronchitis (OR = 1.22, 95%CI = 0.99∼1.67); while asthma was associated with odds for decreased risk of lung cancer (OR = 0.29, 95%CI = 0.16∼0.53). These associations were more pronounced in smokers (P<.05 for all strata), but not in non-smokers. In meta-analysis, 35 studies (22,010 cases and 44,438 controls) were identified. COPD was significantly associated with the odds for increased risk of lung cancer (pooled OR = 2.76; 95% CI = 1.85-4.11), so were emphysema (OR = 3.02; 95% CI = 2.41-3.79) and chronic bronchitis (OR = 1.88; 95% CI = 1.49-2.36); and these associations were more pronounced in smokers than in non-smokers (P<.001 respectively). No significant association was observed for asthma.

Conclusion: Previous COPD could increase the risk of lung cancer, especially in smokers.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Case-Control Studies
  • China / epidemiology
  • Female
  • Humans
  • Lung / pathology*
  • Lung Neoplasms / complications*
  • Lung Neoplasms / diagnosis
  • Lung Neoplasms / epidemiology*
  • Male
  • Middle Aged
  • Odds Ratio
  • Pulmonary Disease, Chronic Obstructive / complications*
  • Pulmonary Disease, Chronic Obstructive / diagnosis
  • Pulmonary Disease, Chronic Obstructive / epidemiology*
  • Risk Factors
  • Smoking / adverse effects

Grant support

This study was supported by the National Natural Scientific Foundation of China Grants 30671813, 30872178, 81072366, 81273149 (Dr. J. Lu), and partly by 81170043 (Dr. P. Ran), 30872142 (Dr. W. Ji); Guangdong Provincial High Level Experts Grants 2010-79 (Dr. J. Lu); Changjiang Scholars and Innovative Research Team in University Grant IRT0961 and Guangdong Natural Science Foundation Team Grant 10351012003000000 (Prof. N. Zhong). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.