Knowing the risk factors that contribute to breast cancer can help you evaluate the likelihood of getting the disease. In some cases, it's possible to make changes now that will improve your chances of avoiding it. Here's what researchers know about breast cancer risks:

1. Menstruating longer, having children late
2. Close relatives with breast cancer and genetic predisposition
3. Use of hormone-replacement therapy
4. Being overweight
5. Lifestyle risks: Being sedentary, exposure to secondhand smoke, and drinking alcohol
6. "Benign" breast conditions
7. Low sun exposure and lack of vitamin D
8. Low melatonin and shift work
9. A diet high in fat (especially for breast cancer survivors)

http://www.caring.com/articles/breast-cancer-risks

Hope it is informative.

As is rightly said, Healthy Diet, Exercise Keeps Mind Sharp As You Age.