Breast cancer happens when the cells in the breast multiply and grow more rapidly than they should. The cancer cells can spread to other areas of the body through the lymph vessels and bloodstream.
As with most diseases, there are risk factors associated with breast cancer. There are steps you can take to control some risk factors, but others can’t be changed.
This article will take a closer look at some known risk factors for breast cancer. It will also explain what you can do to help lower your risk with regard to the factors you have control over.
About risk factors
Risk factors are things that can increase the likelihood of developing a disease or condition.
But having one or more risk factors doesn’t mean you’ll develop the disease or condition. It just means that it may increase your chances of getting it.
Many people have one or more risk factors for cancer but will never get it. For instance, most women have some risk factors for breast cancer, but only a small percentage will develop the disease.
While you can’t control or reduce some risk factors — like your age or genetics — there are other risk factors you can influence and change.
Although not every risk factor for breast cancer is covered below, these are the risk factors that are most common and best understood.
Genetic risk factors and personal history
When it comes to your genetics and personal history, there isn’t much you can do to change these factors. But knowing about them can help you stay vigilant when it comes to your health.
Talk with a healthcare professional about these risk factors and what you can do to help minimize them, where possible.
Sex and age
Sex and age are two of the biggest risk factors for breast cancer that can’t be changed.
Women are more likely to develop breast cancer than men. According to the American Cancer Society:
White women are about 100 times more likely to develop breast cancer compared with white men.
Black women are about 70 times more likely to develop breast cancer compared with Black men.
The risk of breast cancer increases with age.
For example, at the age of 40, the risk of developing invasive breast cancer within the next 10 years is 1 in 69 for women. The risk increases as you get older.
According to Breastcancer.org:
At age 50 the risk is 1 in 43.
At age 60 the risk is 1 in 29.
At age 70 the risk is 1 in 26.
Family and personal history and genetics
Having a close family member who has received a breast cancer or ovarian cancer diagnosis raises your risk of breast cancer.
According to data analysisTrusted Source of more than 113,000 women, the risk of breast cancer is more than doubled if you have a first-degree relative who has had breast cancer. A first-degree relative includes your:
parent
sibling
child
If you’ve personally received a breast cancer diagnosis, you also have a higher risk of developing a new cancer in the other breast, or in a different area of the same breast.
This isn’t the same as the risk of recurrence. That means that breast cancer that was diagnosed earlier has come back.
Approximately 5 to 10 percent of breast cancers are hereditary. Most inherited forms of breast cancer are caused by mutations in two genes: BRCA1 and BRCA2.
This doesn’t automatically mean you’ll develop breast cancer if you have either of the mutations, but the risk is increased.
Reproductive factors and menstrual history
According to a 2017 research reviewTrusted Source, getting your first period before the age of 12 or going through menopause after the age of 55 may increase your risk of breast cancer. This has to do with your exposure to the hormone estrogen.
Additionally, not having children, or having your first child after the age of 30Trusted Source, may also increase your risk.
Dense breasts
Having dense breasts can make it harder to detect lumps or abnormalities in a mammogram.
About 30 to 40 percentTrusted Source of women in the United States have dense breasts.
Additionally, research suggests that women with dense breasts may be four to six timesTrusted Source more likely to develop breast cancer compared with women with more fatty breasts.
Talk with your doctor about whether digital or 3-D mammograms may be a better option for you if you have dense breasts.
Previous radiation to the chest
Having had radiation to your chest area for a different kind of cancer in the past increases your risk of developing breast cancer.
The practice of using radiation to treat acne on the face (which is no longer done) also increases the risk of breast cancer, especially if the radiation was done during adolescence, when the breasts were developing.
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Lifestyle risk factors for breast cancer
Unlike the risk factors outline above, lifestyle risk factors are ones that you have control over and can change.
If you want to make changes to your lifestyle behaviors or habits but don’t know where to start, talk with a healthcare professional. They’ll be able to connect you with the resources and support you need.
Diet and exercise
According to a 2014 review of researchTrusted Source, a diet that’s high in saturated fat may increase the risk of breast cancer. Common sources of saturated fats include:
fatty meats
full fat dairy products
palm oils
A sedentary lifestyle may also increase the risk. According to an older review of studiesTrusted Source, regular physical activity that’s done at a moderate to vigorous pace may reduce the risk of breast cancer by as much as 25 percent.
The risk reduction seems to be particularly strong for people who:
are postmenopausal
have a moderate weight
have no family history of breast cancer
have had one or more children
Weight
Having overweight or obesity is an established risk factorTrusted Source for breast cancer, especially in postmenopausal women.
The increased risk is due to the fact that fat cells make estrogen, which increases the amount of estrogen in your body. Having higher levels of estrogen can increase the risk of developing hormone receptor-positive breast cancers.
According to a large 2019 studyTrusted Source, women who lost weight after the age of 50 and kept the weight off had a lower risk of developing breast cancer than women who stayed at the same weight.
According to a large review of researchTrusted Source, the risk of breast cancer is 32 percent higher for women who consume at least three alcoholic drinks per day. The risk increases by more than 7 percent for each additional drink per day.
Hormone therapy
A number of studiesTrusted Source have shown that the use of hormone replacement therapy (HRT) may increase breast cancer risk quite substantially, especially for HRT that includes both progesterone and estrogen.
Use of HRT may also increase the risk of recurrence in breast cancer survivors.
That being said, research seems to indicate that the risk goes back down within 2 years of stopping HRT.
