Being a woman is the main risk factor for breast cancer. Women are 100 times more likely to develop breast cancer than men.
The rest of this summary relates to breast cancer risk for women. More information about breast cancer in men is available here.
Increasing age is one of the strongest risk factors for developing breast cancer.
Breast cancer can occur in younger women, but about three out of four breast cancer cases occur in women aged 50 years and older.
About one in 250 women in their 30s will develop breast cancer in the next ten years. This compares to about one in 30 for women in their 70s.
Being 175cm or taller is associated with a slightly increased risk for breast cancer.
Women who put on weight after menopause are at greater risk of developing breast cancer, and this risk increases with increasing body weight.
This is thought to be because fat tissue increases levels of the hormone oestrogen in the body – a known risk factor for breast cancer. Studies have shown that post-menopausal women who are overweight (with a BMI greater than 25) are at 21 to 43 per cent increased risk of breast cancer compared to leaner women (with a BMI less than 21).
Your BMI is calculated using your weight and height measurements. It can be used to determine if you are at a healthy weight, overweight, or obese. A BMI from 18.5 to 24.9 is considered a healthy weight range. A BMI between 25 and 29.9 is considered overweight, and a BMI of 30 or more is considered obese.*