The World Cancer Research Fund and American Institute for Cancer Research established the continuous update programme to monitor all relevant studies and trials looking at the links between cancer risk and lifestyle factors. At the 2017 San Antonio Breast Cancer Symposium they presented the updated findings for breast cancer.
For pre-menopausal women, it is estimated that vigorous exercise will reduce the future risk of breast cancer by 17%. Post-menopausal women will have a 10% breast cancer risk reduction from 30 minutes of moderate exercise e.g. energetic walking or 15 minutes of vigorous exercise every day. Weight gain and increasing body fatness after the menopause increases the risk of breast cancer but greater body fatness as a young woman may reduce overall breast cancer risk.
There is strong evidence that daily drinking of even a minor amount of alcohol (equivalent to a small glass of wine) could increase the risk of pre-menopausal breast cancer by 5% and post-menopausal breast cancer by 9%.