Breast Cancer Risk and Lifestyle Choices


Healthy lifestyle choices may help lower your risk of breast cancer as well as your risk of heart disease, diabetes, colon cancer and osteoporosis. Adapted from the American Cancer Society’s Nutrition and Physical Activity Guidelines, Washington University School of Medicine’s Siteman Cancer Center’s Your Disease Risk and Institute of Medicine’s Dietary Reference Intakes for Calcium and Vitamin D .

Women who make healthy lifestyle choices lower their risk of developing invasive breast cancer, regardless of whether they have a family history of the disease, according to a new study.

“We have more awareness of our familial risks, and we may be led to believe there’s nothing we can do — that it’s fate,” said study researcher Dr. Robert Gramling, a professor at the University of Rochester in New York. But his study showed “whether or not you have a family history of the disease, engaging in healthy behaviors is beneficial.”

Women with a family history of breast cancer had a higher risk than those without, he said, but both groups lowered their risk by a similar proportion by maintaining a healthy lifestyle.

Specifically, the researchers found women who had a family history of breast cancer lowered their risk by about one-fourth by getting regular exercise, limiting their alcohol intake and maintaining a healthy body weight.

breast cancer

Similarly, women without a family history of the disease who followed a healthy lifestyle lowered their risk by about the same amount, Gramling said.

The researchers based their analysis on data from 85,644 postmenopausal women who participated in the Women’s Health Initiative, a long-term study launched in 1991 and conducted by the National Institutes of Health. They considered a woman to have a family history of breast cancer if her mother or sister developed the disease after age 45.

The German study published today in the journal Cancer Epidemiology compared 6,386 healthy women with 3,074 breast cancer patients who had been diagnosed after the onset of menopause. The researchers then calculated the percentage of cancer cases attributed to a particular risk factor or a particular combination of risk factors.

The researchers determined that about 37 percent of all postmenopausal breast cancers are caused by factors women can’t change, such as their family history, their age, or the age of their first and last menstrual period. But they also determined that nearly 30 percent of breast cancers could be prevented by modifying certain lifestyle habits. (The other 33 percent of breast cancers have undetermined causes.)

Lifestyle changes have been shown in studies to decrease breast cancer risk even in high-risk women. The following are steps you can take to lower your risk:

  • Limit alcohol. The more alcohol you drink, the greater your risk of developing breast cancer. If you choose to drink alcohol — including beer, wine or liquor — limit yourself to no more than one drink a day.
  • Don’t smoke. Accumulating evidence suggests a link between smoking and breast cancer risk, particularly in premenopausal women. In addition, not smoking is one of the best things you can do for your overall health.
  • Control your weight. Being overweight or obese increases the risk of breast cancer. This is especially true if obesity occurs later in life, particularly after menopause.
  • Be physically active. Physical activity can help you maintain a healthy weight, which, in turn, helps prevent breast cancer. For most healthy adults, the Department of Health and Human Services recommends at least 150 minutes a week of moderate aerobic activity or 75 minutes of vigorous aerobic activity weekly, plus strength training at least twice a week.
  • Breast-feed. Breast-feeding may play a role in breast cancer prevention. The longer you breast-feed, the greater the protective effect.
  • Limit dose and duration of hormone therapy. Combination hormone therapy for more than three to five years increases the risk of breast cancer. If you’re taking hormone therapy for menopausal symptoms, ask your doctor about other options. You may be able to manage your symptoms with nonhormonal therapies, such as physical activity. If you decide that the benefits of short-term hormone therapy outweigh the risks, use the lowest dose that works for you.
  • Avoid exposure to radiation and environmental pollution. Medical-imaging methods, such as computerized tomography, use high doses of radiation, which have been linked with breast cancer risk. Reduce your exposure by having such tests only when absolutely necessary. While more studies are needed, some research suggests a link between breast cancer and exposure to the chemicals found in some workplaces, gasoline fumes and vehicle exhaust.


Uncertain or unproven risk factors

Diet and vitamin intake: Many studies have looked for a link between certain diets and breast cancer risk, but so far there are no clear answers. Some studies have seemed to show that diet may play a role, while others found no evidence that diet has an effect on breast cancer risk. Studies have looked at the amount of fat in the diet, intake of fruits and vegetables, and intake of meat. No clear link to breast cancer risk was found. Studies have also looked at vitamin levels, but the results are not clear. So far, no study has shown that taking vitamins lowers breast cancer risk. This is not to say that there is no point in eating a healthy diet. A diet low in fat, low in red meat and processed meat, and high in fruits and vegetables may have other health benefits.

Most studies found that breast cancer is less common in countries where the typical diet is low in fat. On the other hand, many studies of women in the United States have not found breast cancer risk to be linked to how much fat they ate. Researchers are still not sure how to explain this difference. More research is needed to better understand the effect of the types of fat eaten and body weight on breast cancer risk.

The American Cancer Society recommends eating a healthy diet that includes 5 or more servings of vegetables and fruits each day, choosing whole grains over processed (refined) grains, and limiting the amount of processed and red meats.

Antiperspirants and bras: Internet e-mail rumors have suggested that underarm antiperspirants can cause breast cancer. There is very little evidence to support this idea. A large study of breast cancer causes found no increase in breast cancer in women who used antiperspirants. Also, there is no evidence to support the idea that bras cause breast cancer.

Abortions: Several studies show that induced abortions do not increase the risk of breast cancer. Also, there is no evidence to show a direct link between miscarriages and breast cancer.

Breast implants: Silicone breast implants can cause scar tissue to form in the breast. But studies have found that this does not increase breast cancer risk. If you have breast implants, you might need special x-ray pictures during mammograms.

Pollution: A lot of research is being done to learn how the environment might affect breast cancer risk. This issue understandably invokes a great deal of public concern, but at this time research does not show a clear link between breast cancer risk and exposure to substances like plastics, certain cosmetics and personal care products, and pesticides (such as DDE). More research is needed to better define the possible health effects of these and similar substances.

Tobacco smoke: Most studies have found no link between active cigarette smoking and breast cancer. An issue that continues to be a focus of research is whether secondhand smoke (smoke from another person’s cigarette) may increase the risk of breast cancer. But the evidence about secondhand smoke and breast cancer risk in human studies is not clear. In any case, a possible link to breast cancer is yet another reason to avoid being around secondhand smoke.

Night work: A few studies have suggested that women who work at night (nurses on the night shift, for instance) have a higher risk of breast cancer. This is a fairly recent finding, and more studies are being done to look at this.