Some factors can help to reduce the risk of breast cancer.
Being physically active
Physical activity can help to prevent breast cancer. Studies have found a protective effect of about 15 to 20% in women who take half an hour of exercise 5 times a week.
So being active might lower your risk of breast cancer by about a fifth.
The reduced risk might be because physical activity lowers oestrogen and testosterone levels.
If you breastfeed you are less at risk of developing breast cancer, particularly if you have your children when you are younger. We don't know exactly why this is.
The reduced risk might be because your ovaries don't produce eggs so often when you are breastfeeding. Or it may be because breastfeeding changes the cells in the breast. So the cells might be more resistant to the changes that lead to cancer.
A healthy diet can help to prevent breast cancer.
Aspirin and anti inflammatory drugs
Research has shown that women who regularly take aspirin or other non steroidal anti inflammatory medicines have a slightly lower risk of developing breast cancer.
Remember though that aspirin can irritate the lining of your stomach and cause bleeding. So you should talk to your own GP before starting to take it regularly.
You shouldn't take these medicines if you have any history of stomach ulcers.
Medicines for women at higher risk
Some medicines can help to prevent breast cancer. Women who have a family history of breast cancer are at a higher risk of developing it than other women in the population. Taking a drug called anastrozole for 5 years can reduce the risk of breast cancer in these women.
Recent research showed that if 1,000 women at high risk of breast cancer took anastrozole for 5 years, it prevented 35 cases of breast cancer. In women taking a similar drug called tamoxifen 21 breast cancers would be prevented.
Speak to your doctor if you have family members with breast cancer and you think you might be at risk of developing it.