Physical activity may reduce risk of breast cancer before menopause
Physical activity can reduce a woman’s risk of developing breast cancer before menopause by as much as 10%, the largest study of its kind has suggested.
Regular physical activity during leisure time may reduce the risk of breast cancer for women prior to the menopause, according to new UK research funded by Breast Cancer Now.
“We urgently need to find new ways to prevent people from developing the disease”
Simon Vincent
The charity highlighted that, while breast cancer was more common in older women, 5,000 women aged 45 or younger were diagnosed with breast cancer each year in the UK.
The authors of the new study said there was strong evidence that leisure-time physical activity was protective against postmenopausal breast cancer risk but was less clear for premenopausal risk.
As a result, the team from the Institute of Cancer Research in London set out to examine the association of physical activity with the risk of developing premenopausal breast cancer.
Their research, published in the Journal of Clinical Oncology, analysed data from 19 studies from around the world, including the Breast Cancer Now Generations Study.
In total, it looked at levels of physical activity and cancer diagnoses among 547,000 women who had not gone through menopause.
The women were followed up for an average of 11.5 years, during which time 10,231 were diagnosed with breast cancer before menopause.
The researchers ranked the data by the amount of physical activity women reported they did during their leisure time, such as sports, cycling and recreational walking.
They found women in the top 10% of physical activity levels were 10% less likely to develop breast cancer before menopause, compared to those in the bottom 10% of physical activity levels.
Their analysis took into account other breast cancer risk factors and lifestyle behaviours, such as body mass index, family history of breast cancer, smoking and alcohol consumption.
The researchers found that there was no specific amount of physical activity that women needed to complete to see benefits.
However, the more time they spent doing moderate and vigorous movement outside of work-related physical activity, the lower their risk of breast cancer.
The study authors said: “This large, pooled analysis of cohort studies adds to evidence that engagement in higher levels of leisure-time physical activity may lead to reduced premenopausal breast cancer risk.”
But they noted that how physical activity lowered breast cancer risk was not fully understood. Other studies have suggested it can lower levels of hormones like oestrogen and testosterone, which have been linked to increased breast cancer risk.
One of the authors, senior staff scientist Dr Michael Jones, said: “This new research provides us with solid evidence that greater leisure time physical activity is associated with lower risk of breast cancer in younger women.
“It’s important to remember that breast cancer risk is influenced by several factors – including genetics, lifestyle and environment, and many of these are out of our control,” he said.
“Our research adds to the evidence that engagement in higher levels of leisure-time physical activity may lead to reduced premenopausal breast cancer risk.”
He added: “We still need to better understand the biology behind the link between physical activity and reduced breast cancer risk, but these findings add to the strong body of evidence showing that being physically active is good for our health.”
Dr Simon Vincent, director of research, support and influencing at Breast Cancer Now, said: “Breast cancers in younger women tend to be more aggressive and diagnosed at a later stage, so we urgently need to find new ways to prevent people from developing the disease.”
He said: “This research highlights how vital it is that we support women to start making small, healthy lifestyle changes that can positively impact their health and help lower their risk of breast cancer.”
