Physical activity and lung cancer: A case-control study in Brazil

Background: The aim of this study was to investigate the association between lifetime physical activity and risk of lung cancer. Methods: A case-control study was conducted in southern Brazil. Case subjects were recruited from oncology services of 4 hospitals. Control subjects were selected from the same hospitals, but from different services (traumatology and emergency). Both case subjects (n = 81) and control subjects (n = 168) were interviewed using a questionnaire about sociodemographic characteristics, anthropometric information and family history of cancer. Control subjects were matched to case subjects according to sex and age (± 5 years). Detailed information on smoking was collected. Physical activity was measured using the Lifetime Physical Activity Questionnaire. Results: Of the case subjects, 89% were either current or former smokers; among control subjects, this value was 57%. Participants in the second, third, and fourth quartiles of all-domains physical activity had odds ratios of 0.54 (95% CI, 0.21-1.40), 0.25 (95% CI, 0.08-0.72), and 0.24 (95% CI, 0.07-0.83) for lung cancer, compared with the lowest quartile, after adjusting for confounding. In the fully adjusted models, leisure-time physical activity was not associated with lung cancer risk. Conclusion: Lifetime all-domains physical activity may reduce the risk of lung cancer.