Studies have shown that lifestyle factors play an important role in the development of Breast Cancer. Lifestyle risk factors are important to consider when developing a strategy for Breast Cancer prevention.
The most significant modifiable risk factors for breast cancer are
Evidence linking dietary behavior independently to Breast cancer risk is limited. A Mediterranean diet has been associated with a decreased risk of breast cancer. Also, there is some evidence that a diet rich in fruits and vegetables and high in dietary fiber may have a weak effect on Breast cancer risk reduction. World Cancer Research Foundation recommends eating 400-600 g of vegetables and fruits per day to help prevent Breast cancer. The WCRF also recommends limiting consumption of red and processed meats due to a possible association with increased risk of breast cancer.
The association between an increased risk of developing postmenopausal breast cancer and body weight is well documented. When compared with normal weight women (BMI of 18.5-25) the relative risk for postmenopausal Breast cancer is around 1.5 times for overweight women (BMI>25) and two times for obese women( BMI> 30).
Physical inactivity is a stand-alone risk factor for several types of cancer. There is convincing evidence that physical activity is protective against postmenopausal Breast cancer. There is a 25-30% risk reduction due to physical activity. Most studies suggest that 30-60 minutes of moderate to vigorous physical activity per day is associated with a reduction in Breast cancer risk.
Smoking tobacco is well known to be carcinogenic, not only for Breast Cancer but for most types of cancer. In 2012, The International Agency for Research on Cancer confirmed a positive association between tobacco smoking and BC. The 2014 US report estimated 10% increased BC risk for women with a history of smoking.
Although ethanol is not carcinogenic, it’s metabolized compounds have carcinogenic potential. It also potentiates the carcinogenic effect of tobacco metabolites and suppresses their clearance by the liver. To reduce Breast Cancer risk, The World Cancer Research Fund recommends a maximum alcohol consumption equivalent of 10 gm of ethanol per day( 100 ml of wine)
Patients suffering from type II DM are characterized by an insulin resistance combined with hyperinsulinemia. Hyperinsulinemia is associated with carcinogenesis as it is thought to directly stimulate the proliferative pathway after binding to the insulin receptor. Epidemiological evidence exists linking DM to an increased risk of cancer, including Breast cancer. Women with DM have a 20% increased risk for Breast cancer.
Postmenopausal Hormonal Therapy
Although HRT protects against coronary heart disease, osteoporosis, and possibly cognitive decline or dementia, it is associated with an increased risk for developing Breast cancer. There was a significantly increased risk of Breast cancer among women using combined continuous HRT whereas estrogen-only pills have not been associated with this increased risk of Breast cancer.
Silicone breast implants used for breast augmentation have not been found to have any correlation with Breast Cancer in major studies.
Deodorants contain chemicals which have estrogenic properties. But no convincing evidence exists to highlight it’s an association with an increased BC risk.
Job stress is not related to any increase in Breast cancer risk.
Other lifestyle factors
Many other factors like bras, pesticides, cosmic radiation, electromagnetic pollution, use of cellphones, have been studied but no conclusive evidence has been found.