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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.

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.

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.
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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.
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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 analysis 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 review, 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 30, 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 percent of women in the United States have dense breasts.

Additionally, research suggests that women with dense breasts may be four to six times 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.

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 research, 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 studies, 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


Having overweight or obesity is an established risk factor 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 study, 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.

Alcohol consumption

Drinking alcohol increases the risk of developing hormone receptor-positive breast cancer. This is because alcohol can increase estrogen levels and other hormones associated with breast cancer.

Alcohol can also damage cell DNA which, in turn, can raise the risk of cancer.

According to a large review of research, 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 studies 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.

Breast cancer screening is an important tool in helping to detect cancer at its earliest stage. When breast cancer is diagnosed early, it greatly improves the ability to successfully treat the cancer.

If you have a family history of breast cancer or other risk factors, ask your doctor about personalized screening guidelines and when to start screening.

The American Cancer Society recommends the following breast cancer screening guidelines:

Breast cancer screening guidelines

  • Women ages 40 to 44 have the option to start annual breast cancer screening with mammograms. Breast ultrasound can be added for those with dense breast tissue.
  • Women ages 45 to 54 should get mammograms every year.
  • Women 55 and older can get mammograms every 2 years but can continue yearly if they choose.
  • Screening should continue as long as a person is in good health and expected to live 10 years or more.
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Some women may need breast MRIs with their mammograms due to family or personal history and risk factors. Ask your doctor whether this is right for you.

In addition to your annual breast cancer screening, it’s also important to pay attention to your breasts.

Know how your breasts normally look and feel, and do breast self-exams on a regular basis. Call your doctor if you feel a lump or notice any other changes.

Most people, especially women, have one or more risk factors for breast cancer. Your risk isn’t due to just one factor. Instead, it’s due to a combination of different factors.

You can change some risk factors, like your diet or exercise levels. You don’t have control over other risk factors, though, like your age or genetics. But even so, knowing about your risk factors can help you stay vigilant when it comes to your health and the choices you make.

Talk with your doctor about the risk factors that you might have and how to best address them.