Men who improve their cardiopulmonary fitness over time are less likely to develop prostate cancer, according to a study published in the American Journal of Clinical Chemistry. British Journal of Sports Medicine.
A growing body of research shows that physical cardiovascular and respiratory fitness are associated with reduced cancer risk and improved outcomes, but previous studies in prostate cancer have been limited to specific time points and have produced mixed results.
Dr Kate Bolam from the Swedish Institute of Sport and Health Sciences (GIH) in Stockholm and colleagues investigated the relationship between changes in cardiorespiratory fitness (CRF) and the incidence of prostate cancer and associated mortality.
“In this study of employed Swedish men, changes in cardiorespiratory fitness were inversely associated with the risk of developing prostate cancer, but not with mortality,” the researchers concluded. “Improvements in CRF in adult men should be encouraged and may reduce the risk of prostate cancer.”
For this prospective study, the researchers used data from the Swedish Institute for Health Profiles. The analysis included information on more than 180,000 men who completed an Occupational Health Profile assessment between 1982 and 2019. Prostate cancer incidence and mortality data were obtained from national registries.
The analysis included men who underwent at least two cardiopulmonary tests, spaced at least 11 months apart. The tests measure how efficiently the heart and lungs deliver oxygen to muscles during exercise. Participants rode a stationary bike and their heart rates estimated the amount of oxygen consumed during exercise.
Men whose CRF increased or decreased by 20% over the course of one year were excluded, leaving a study population of 57,652. At the start of the study, the average age was 41 years and the average BMI was 26 (in the overweight range).
During a mean follow-up period of 6.7 years, 592 men (1%) were diagnosed with prostate cancer after their last fitness test and 46 men (0.08%) died from prostate cancer as the primary cause of death.
The study authors found a significant positive correlation between improved cardiorespiratory fitness and a reduced risk of developing prostate cancer, but not with a reduced risk of death. Overall, improved physical fitness was associated with a 2% reduced risk of developing prostate cancer. Men whose physical fitness levels improved by 3% or more per year were 35% less likely to develop prostate cancer than men whose physical fitness decreased by 3%. The authors suggested that the number of deaths from prostate cancer may have been too small to detect an association with physical fitness.
When the researchers divided the participants into groups according to their initial fitness level, they found that men who were moderately fit at baseline saw a more dramatic improvement in prostate cancer risk: They experienced a 15% reduction in prostate cancer risk. However, those at both ends of the fitness spectrum saw more limited improvements in risk.
According to the researchers, men who are already physically fit may not be able to improve their fitness to a level that could further reduce their risk, while those with lower levels of physical fitness may be in poorer health and have other conditions, such as obesity, that affect their prostate cancer risk.
For more news about prostate cancer click here.