Factors that you can control
- Pregnancy: Having no children, or having a first pregnancy after age 30 increases your risk. If a woman has had one or more pregnancies, and if the first child was conceived before age 30, the risk of breast cancer is lower. Additionally, if it is possible to breastfeed your children, you lower your risk even more.
- Breastfeeding: If you have given birth, but not breastfed, your risk is increased. In some studies, the combination of pregnancy and breastfeeding has resulted in a decreased number of menstrual periods, which helps to lower the risk of breast cancer slightly. In one study, it was found that having multiple births and breastfeeding for 1.5 to 2 years may cut your risk of breast cancer in half.
- Birth control pills: It is not yet clear what the role of birth control pills might be in breast cancer risk. Some studies have shown that women who are now using birth control pills have a slightly increased risk of breast cancer. If you have quit taking the pill more than 10 or more years ago, you may not have an increased risk. If you are considering using the pill, discuss the risks and benefits with your doctor.
- Alcohol Use: If you have 1 drink a day, you have a very small increased risk of breast cancer. If you have 2 to 5 drinks daily, you have a much greater risk than that of women who drink no alcohol. Drinking alcohol is linked to a slightly increased risk of getting breast cancer.
- Hormone replacement therapy (HRT): If you have had long-term use (several years or longer) of combined HRT (estrogens combined with progesterone) after menopause, you have an increased risk of breast cancer as well as heart disease, blood clots, and strokes. The breast cancers found in long-term HRT users are also detected at a more advanced stage, perhaps because HRT seems to reduce the effectiveness of mammograms. If you can stop using HRT, after five years, your breast cancer risk appears to drop back to normal. Estrogen, when used alone (ERT) does not seem to increase the risk of breast cancer as much, unless you have had a previous diagnosis of estrogen-receptor positive breast cancer. If you are considering using HRT, you should talk with your doctor about the pros and cons of using it.
- Your Weight and Diet: If you are overweight, you have a higher risk of breast cancer, especially if you are past the change of life (menopause) and if your weight gain took place during adulthood. Also, if the extra fat is in the waist area the risk seems to be higher. Please remember that the link between excess weight and breast cancer risk is complicated, and that studies of the relationship between fat in your diet and your risk of breast cancer have often given conflicting results.
- Your Exercise Routine: If you are not doing regular exercise, you are at greater risk for breast cancer. The only question is how much exercise will reduce your risk. One study found that as little as 1 hour and 15 minutes to 2 and a half hours per week of brisk walking reduced the risk by 18%. If you take 10 hours a week of brisk walking, you can reduce your risk a little more.