You've heard the statistics—that one in eight women will be diagnosed with breast cancer in her lifetime. But what that stat doesn't tell you is that your risk of breast cancer is probably different from your best friend's, your coworker's, and even maybe your sister's. So do you know your risk? Here are nine factors to keep in mind when assessing your own likelihood of developing the disease. 

Your weight

Being overweight or obese can increase your risk of breast cancer by 30 to 60 percent. Why? Estrogen is produced in fat cells; the more fat cells you have, the more estrogen your body pumps out—and extra estrogen can lead to tumor growth.

Your waist size

It's not simply the number on the scale that matters; where you carry the extra pounds makes a difference too. A recent study from the British Medical Journal determined that the most important factor boosting a woman's postmenopausal breast cancer odds is if and how much her skirt size has gone up since her twenties. Why skirt size? Research suggests that weight specifically carried around the middle is the cause of the increased risk.

Your workout

Staying active can lower your risk in a number of ways. First, it acts as a natural anti-inflammatory and immune system booster. Plus, it can lower the amount of glucose and insulin levels in your bloodstream, and it can help the body break down estrogen in a cancer-preventing way. Research also found that even high-risk women who carry the BRCA mutations can benefit from boosting their exercise. Experts suggest aiming for an hour a day at least four or five times per week.

Your drinking habits

Several studies have linked increased alcohol consumption with a higher risk of breast cancer. Research out last year found that drinking in the years between your first period and first pregnancy especially can increase your risk of the disease. Unfortunately, experts believe that the more you knock back, the higher your risk.

Your diet

A growing body of research suggests that cutting red meat and consuming more plant-based foods can put the brakes on cancer cell growth. The power of plants comes down to this: Cruciferous veggies (think cold weather favorites like Brussels sprouts and cauliflower) lower inflammation and may help balance estrogen. And colorful red-orange produce, like carrots and tomatoes, are loaded with carotenoids, an antioxidant that’s been linked to a lower risk of breast cancer. Limiting your intake of sugar and high-fat dairy may also help you stay protected. 

Your genes

Women who carry mutations on the BRCA1 or BRCA2 genes have a significantly elevated lifetime risk of developing breast cancer over women who didn’t inherit these defective genes. But there’s another recently identified gene to worry about, particularly for younger women. Researchers found that in women under 40, mutations in the PALB2 gene can result in an eight- to nine-times higher risk of breast cancer, compared to women in the same age group without the mutation. If breast cancer runs in your family, talk to your doctor about undergoing testing. Learn more about breast cancer and your genetics.

Your family history

Even if you don’t carry a breast cancer gene mutation and no one else in your family does either, simply having a first-degree relative (i.e., your mom, sister, or daughter) with breast cancer approximately doubles your likelihood of being diagnosed one day too, according to the American Cancer Society. And having two first-degree relatives with the disease triples your risk. If either describes your family, check in with your doctor and ask her if you’re a candidate for earlier and/or more rigorous screening methods.

Your race or ethnicity

While breast cancer strikes women of all ethnic backgrounds and racial groups, black women are 40 percent more likely to die from the disease than their white counterparts, according to a recent study. Experts aren’t sure why, but there are a few theories. Some studies show that black women are more likely to get more aggressive forms of breast cancer, while other researchers suspect the disparity may exist because of limited access to top-notch screening tools and medical advances. Whatever your ethnic background, do regular self checks, get a yearly mammogram, and insist on the best treatment.

Toxins in your environment

Evidence continues to pile up showing that exposure to certain toxins, called endocrine disruptors, can raise your risk of breast cancer. These synthetic chemicals accumulate in fat cells, where they mimic your own natural estrogen, potentially leading to tumor growth. Common endocrine disruptors include bisphenol A (BPA), a type of plastic used in containers and cans, and preservatives found in cosmetics called phthalates.

Signs to look out for...