According to a large Swedish study, men with cardiorespiratory fitness (CRF) who experienced an increase of more than 3% in their CRF had a significantly lower risk of developing prostate cancer.
The prospective analysis, published in the British Journal of Sports Medicine, was conducted in a cohort of nearly 58,000 individuals by Kate A. Bolam, PhD, a clinical exercise physiologist at the Swedish School of Sport and Health Sciences in Stockholm.
„The results suggest that doctors could work to help patients understand which types of activities could improve their fitness and how they could integrate these activities into their lives in a pleasurable way, or at least refer patients to a sports specialist,“ said Dr. Bolam in an interview.
Grouped by initial CRF values, the association between the change in absolute CRF value and prostate cancer incidence was only significant for participants with a moderate initial CRF value. Furthermore, changes in both absolute and relative CRF were not associated with prostate cancer mortality.
The lack of mortality significance could be attributed to the relatively low number of deaths from prostate cancer in the cohort, explained Dr. Bolam. „Perhaps we weren’t able to detect anything with such low numbers. And it’s unlikely that men will die from prostate cancer, but rather from more common chronic diseases, such as heart disease.“ The authors noted that, unlike other common cancers, there are relatively few avoidable risk factors with strong evidence for reducing overall prostate cancer risk. „Aside from developmental factors, being diagnosed with overweight or obesity are the main risk factors for developing advanced prostate cancer, but there isn’t enough evidence to extend this conclusion to non-advanced prostate cancer,“ they wrote.
However, there is evidence that exercise reduces overall mortality risk in many types of cancer, including prostate cancer.
The cohort was assembled from data in the Swedish National Health Profile Database from 1982 to 2019. Participants underwent a health profile assessment at their workplace, including at least two valid CRF tests on a cycle ergometer. During an average follow-up time of 6.7 years, 592 (1%) out of 57,652 men (average age 41.3 years; standard deviation 10.55) were diagnosed with prostate cancer, and 46 (0.08%) had prostate cancer as the primary cause of death.
An increase in absolute CRF (as a percentage of liters per minute of cardiac output) was associated with reduced incidence risk, with a hazard ratio of 0.98 (95% CI: 0.96–0.99). The researchers grouped participants into categories of increased (+3%), stable (±3%), or decreased (–3%) CRF and found that increased fitness was associated with a HR for prostate cancer incidence of 0.65 (95% CI: 0.49–0.86) versus decreased fitness.
According to the authors, these and similar studies of the mechanisms underlying the benefits of physical activity will lead to more targeted prevention recommendations. The results underscore the importance of encouraging the general public to increase their CRF or achieve a moderate level of fitness, wrote Dr. Bolam’s group. The group is planning a similar study on breast cancer.
This study was funded by the Swedish Cancer Society. The authors reported no competing interests.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.