In a large cohort of men in Sweden, cardiorespiratory fitness (CRF) levels were associated with risk of death due to colon, prostate, and lung cancers, according to a study published in JAMA Network Open.
In an increasing number of cancer types, physical activity has been recognized as a known modifiable risk factor, the study authors noted, and the current study aimed to assess whether CRF was associated with prostate, colon, and lung cancer incidence and mortality among men in Sweden. Whether age impacted the relationship between CRF and cancer incidence and mortality was also explored.
Data from a total of 177,709 men were included in the analysis. The mean follow-up time was 9.6 years, and there were 499 incident cases of colon cancer, 283 cases of lung cancer, and 1918 cases of prostate cancer during the study period. Colon cancer, lung cancer, and prostate cancer were attributed to 152 deaths, 207 deaths, and 141 deaths, respectively.
In the study population, higher CRF—defined by estimated maximal oxygen consumption (V̇o2max) as determined by standardized submaximal Åstrand cycle ergometer test—was associated with significantly lower incidence of colon and lung cancers ([HR, 0.98; 95% CI, 0.96-0.98] and [HR, 0.98; 95% CI, 0.96-0.99], respectively), but a higher rate of prostate cancer incidence (HR, 1.01; 95% CI, 1.00-1.01).
In terms of mortality risk, higher levels of CRF were associated with a lower risk of cancer-specific death from colon, lung, and prostate cancer ([HR, 0.98; 95% CI, 0.96-1.00], [HR, 0.97; 95% CI, 0.95-0.99], and [HR, 0.95; 95% CI, 0.93-0.97], respectively).
“After further adjusting for length of education, diet habits, comorbidity, and smoking for colon and prostate cancer, only colon cancer incidence and prostate cancer mortality remained significant for the moderate and high groups compared with those with very low CRF,” the authors wrote.
Factoring in age impacted the associations between CRF and lung cancer incidence and mortality, with participants 60 years or older being the only group to show lower risks of incidence and death with higher CRF.
“The novelty of this study is in the analyses of the association between CRF and both incidence and mortality in the 3 most common cancers in men separately in a large sample of differing ages,” the authors wrote. “In line with physical activity and prostate cancer studies, there is considerable inconsistency in findings on the association between CRF and the incidence of prostate cancer. While the results of the present study reflect the positive associations previously reported, others found a protective effect of CRF, albeit limited to participants younger than 60 years.”
While the study was the largest to the authors’ knowledge to examine the relationship between CRF and cancer incidence and cancer-specific mortality in specific cancer types in men, it was limited by voluntary participation and the inclusion of employed individuals only. Genetics surrounding cancer and CRF must also be considered in interpreting the findings, the authors noted.
“If these findings can be supported with randomized clinical trials, CRF appears to have a potentially important role in reducing the risk of developing and dying from certain common cancers in men,” they concluded. “Future research should consider examining exposures at different times in the life course and the associations between CRF and cancer incidence and mortality.”
Reference
Ekblom-Bak E, Bojsen-Møller E, Wallin P, et al. Association between cardiorespiratory fitness and cancer incidence and cancer-specific mortality of colon, lung, and prostate cancer among Swedish men. JAMA Netw Open. 2023;6(6):e2321102. doi:10.1001/jamanetworkopen.2023.21102
