Dec 13, 2023Study suggests physical activity reduces risk of breast cancer
Regular leisure time physical activity may reduce the risk of breast cancer for women before menopause, according to new researchers from The Institute of Cancer Research, London.
The article, published Monday 11 December in the Journal of Clinical Oncology, analyzed data from 19 studies from around the world, including the Breast Cancer Now Generations Study. The researchers looked at levels of physical activity and cancer diagnoses among 547,000 women who had not gone through menopause.
The women were followed for an average of 11.5 years, during which time 10,231 were diagnosed with breast cancer before menopause.
Researchers at The Institute of Cancer Research, London, ranked the data by the amount of physical activity women reported they did during their leisure time, such as sports, cycling and recreational walking.
The results showed that the most physically active women, those in the top 10% of physical activity levels, were 10% less likely to develop breast cancer before menopause, compared to the least physically active women, defined as those in the bottom 10% of physical activity levels.
Their analysis took into account other breast cancer risk factors and lifestyle behaviors, such as BMI, 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, but that the more time they spent doing moderate and vigorous movement outside of work-related physical activity, the lower their risk of breast cancer.
How physical activity lowers breast cancer risk is not fully understood. Previous research suggests that physical activity can lower sex hormones like estrogen and testosterone, which have previously been linked to increased breast cancer risk.
Physical activity lowers insulin levels and levels of growth hormones that might encourage breast cancer to grow. It also decreases general inflammation which has been associated with cancer development and progression.