Middle-aged men who are fit are at lower risk for lung and colorectal cancers compared to their unfit peers, suggests a recent study. And those fitter men who are diagnosed with cancer when older may also be at lower risk for earlier death.
The study was published in JAMA Oncology.
For the study, researchers used data from a treadmill test to categorize almost 14,000 men in three fitness levels. At the time of the test, the men were on average in their mid-40s. The men were categorized into a fitness level between 1971 and 2009. Then the researchers used Medicare data from 1999 to 2009 to identify those men who were diagnosed with lung, prostate and colorectal cancers.
During an average 6.5 years, 1,310 of them were diagnosed with prostate cancer, 200 with lung cancer and 181 men with colorectal cancer.
Those men categorized in the highest fitness level had a 55 percent lower risk of lung cancer and a 44 percent lower risk of colorectal cancer compared to those men at the lowest fitness level. The more fit the men; the lower their risk. The link was seen after adjusting for key risk factors, including body mass index, smoking, blood pressure and diabetes. The association was not seen with prostate cancer.
Among the men who did develop lung, colorectal or prostate cancer at age 65 or older, high fitness level in midlife linked to a 32 percent lower risk for cancer death and 68 percent reduced risk of cardiovascular death compared with men at low fitness levels. Among men not diagnosed with cancer, higher fitness levels also linked to lower risk of cardiovascular mortality.
It is unknown why the link with prostate cancer was not seen, write the authors. They theorize that men who exercise regularly and are fit may also be more likely to undergo preventive screenings and therefore have a greater opportunity to be diagnosed with prostate cancer.
The study author was supported by the NIGMS/NIH and NCI. One author (Dr. Jones) is a cofounder of a company, Exercise by Science Inc.
Source: Lee W. Jones, PhD et al. Midlife Cardiorespiratory Fitness, Incident Cancer, and Survival After Cancer in Men: The Cooper Center Longitudinal Study. JAMA Oncology, March 2015.