Regular Physical Activity Reduces Breast Cancer Risk Irrespective of Age or Weight
Participating in athletic activities for more than an hour a day reduces the risk of breast cancer, and this applies to women of any age and any weight, regardless of geographic location, according to research presented at the 9th European Breast Cancer Conference in Glasgow. Compared with the least active women, those with the highest level of physical activity reduced their risk of breast cancer by 12%, researchers said.
Mathieu Boniol, PhD, Research Director at the International Prevention Research Institute, Lyon, France, reported to a press conference the results of a meta-analysis of 37 studies published between 1987 and 2013, representing over 4 million women. “These are all the studies looking at the relationship between physical exercise and breast cancer risk that have been published to date, so we are confident that the results of our analysis are robust,” he said.
Protective Role of Exercise
Although the results varied according to tumor type, the overall message was encouraging, the researchers said. In women taking hormone replacement therapy, the protective effect of exercise seemed to be cancelled out. However, increased awareness of the side effects of hormone replacement therapy has resulted in a decrease in its use in a number of countries, which means that the beneficial effects of physical activity will potentially grow in years to come. “Whether or not this will be the case is an interesting question and deserves to be followed up at a later date,” Dr. Boniol said.
Physical activity is known to have a protective role in other cancers, as well as in disorders such as cardiovascular disease. Although the mechanisms for its effect are unclear, the results are largely independent of body mass index, so the effect must be due to more than weight control. The age at which physical activity starts also appears to be immaterial; the researchers found no indication that breast cancer risk would decrease only when physical activity started at a young age.
“Adding breast cancer, including its aggressive types, to the list of diseases that can be prevented by physical activity should encourage the development of cities that foster sport by becoming bike- and walk-friendly, the creation of new sports facilities, and the promotion of exercise through education campaigns,” said Dr. Boniol. “This is a low-cost, simple strategy to reduce the risk of a disease that currently has a very high cost, both to health-care systems and to patients and their families. It is good news both for individuals and for policymakers.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
