The breasts are hormonally-regulated organs that develop before birth, during puberty, and during lactation and pregnancy. Breast cancer can develop from the milk-producing lobules, the ducts which connect the lobules to the nipple, or within the nipple itself. There are a range of causes of breast cancer, including intrinsic factors such as genetics and a family history of the disease, as well as extrinsic environmental factors.
Exposure to Chemicals
A number of chemicals used in the home, garden and workplace have been identified as possible carcinogens which can contribute to the development of cancers, including breast cancer. Some household chemicals have the ability to mimic female hormones, such as estrogen and progesterone, once they have entered the body. Perceived disruption of female hormone balances by the body have the potential to contribute to breast cancer development.
Cornell University identifies pesticides, cleaning products, paints and automotive chemicals as potentially harmful. Limiting use of potentially harmful chemicals, handling and storing these chemicals safely, and following proper disposal procedures helps lower exposure to carcinogenic chemicals, and may help reduce the risk of developing breast cancer.
Obesity
Obesity, carrying an abnormally high proportion of body fat, is thought to increase a person's risk of developing breast cancer. Obesity is defined by the National Cancer Institute as having a body mass index, or BMI, greater than 30.
According to the National Cancer Institute, obese post-menopausal women have a significantly increased risk of developing breast cancer---around 1.5 times more than that of women with a healthy weight. This may be because fat cells secrete estrogen, a female hormone that promotes breast growth development. Additionally, breast cancer may be less obvious in obese women, since the ducts and lobules are surrounded by more fatty tissue, making it harder to feel lumps caused by tumors.
Alcohol
Alcohol has also been linked to an increased risk of developing breast cancer. According to Cornell University, women who drink alcohol had a slightly higher risk of developing breast cancer than those that do not drink, with the rate of breast cancer increasing in women who drank more alcohol. Alcohol metabolism within the body leads to an increase in circulating estrogen, so a lifestyle of excessive alcohol use could lead to sustained high estrogen levels within the body. This may in turn promote breast cancer development over time.
The direct causes of alcohol on the risk of breast cancer are not yet known, and further research is required to better understand how alcohol contributes to the development of breast cancer. Cornell University advises women with a family history of breast cancer to consider abstaining from alcohol use.
