Cardiorespiratory fitness and cancer incidence in men

Purpose: The preventive role of cardiorespiratory fitness (CRF) in cancer is not well established. The present study sought to evaluate the association between CRF and cancer incidence in men. Methods: Maximal exercise testing was performed in 4920 men (59.2 +/- 11.4 years) free from malignancy at baseline who were followed for 12.7 +/- 7.5 years. Relative risks and population attributable risks were determined. Results: During the follow-up, 25.8% were diagnosed with any type of cancer. CRF was inversely associated with total cancer incidence; for each one metabolic equivalent increase in CRF, there was a 4% reduction in cancer incidence (P < .001). Compared with low CRF, moderate and high CRF levels were associated with 14% (95% CI [0.74-0.991) and 26% (95% CI [0.62-0.89]) reduced risks for all cancers, respectively (P for trend = .004). Low CRF had a population attributable risk of 3.0% for cancer incidence. The associations between CRF, prostate, skin and colorectal cancers were not significant. Conclusions: Higher CRF is associated with lower total cancer incidence in men. A novel finding suggests that eliminating low CRF as a risk factor would potentially prevent considerable cancer morbidity and reduce the societal and economic burden associated with cancer. These findings underscore the importance of CRF for primary cancer prevention. (C) 2017 Elsevier Inc. All rights reserved.