A meta-analysis of asthma and risk of lung cancer (United States)

Cancer Causes Control. 2003 May;14(4):327-34. doi: 10.1023/a:1023982402137.


Objective: To review epidemiologic evidence that asthma is a risk factor for lung cancer, with particular attention to the role of smoking on this association.

Methods: Through MEDLINE computer searches (January 1966 to April 2002) and a review of references, we identified studies with quantitative data on the relation of asthma to lung cancer. Summary estimates of relative risks (RR) were calculated using the fixed-effects model or the random-effects model as appropriate.

Results: The combined results from five case-control studies--that presented data limited to individuals who had never smoked--showed a 1.8-fold increase in lung cancer risk among asthmatics (95% confidence interval (CI) = 1.3-2.3). The results from six case-control and four cohort studies, which controlled for smoking history also were significant (RR = 1.7; 95% CI = 1.3-2.2). Finally, to illustrate the potential confounding by tobacco, we combined data from seven cohort studies that did not control for smoking history and found an overall RR of 1.4 (95% CI = 1.2-1.6).

Conclusions: The increased risk of lung cancer among never smoking individuals with asthma supports a direct relation between asthma and lung cancer. There is biological evidence to support this association.

Publication types

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

MeSH terms

  • Asthma / complications*
  • Asthma / epidemiology
  • Case-Control Studies
  • Humans
  • Lung Neoplasms / epidemiology
  • Lung Neoplasms / etiology*
  • Lung Neoplasms / pathology
  • Risk Assessment
  • Smoking / adverse effects
  • United States / epidemiology