Check your expertise during Breast Cancer Awareness Month in October.

1. A lot of people talk about preventing breast cancer, but the correct term is risk reduction.

“We don’t really know how to prevent breast cancer. We know how to reduce people’s risks,” said Judith Swasey, a nurse practitioner at the University of North Carolina- Chapel Hill’s cancer hospital. The basics: Don’t smoke, exercise a lot, watch your diet, annual screenings.

2. There has been lots of controversy in recent years over the usefulness of annual mammograms for some women. Some researchers suggest they aren’t needed until women reach 50 and that it’s OK for women not at high risk to have scans every other year.

But the American Cancer Society and many breast cancer centers continue to recommend annual mammograms starting at 40. The cancer society also recommends clinical breast exams by physicians annually, beginning at the same age as mammograms.

For those at high risk for breast cancer because of family history, annual screening should begin before age 40. For example, if you have a sister who developed breast cancer at 45, the recommendation is to start mammograms at 35.

Monthly self-exams have also been the subject of debate, but the cancer society recommends them for women starting in their 20s.

Mammograms are controversial partly because they produce both benefit and harm. Awareness and screening have led to more early detection. But critics say that some patients have been harmed by unneeded surgery, radiation and chemotherapy for small cancers that wouldn’t have been found without mammography and wouldn’t have caused problems.

3. Post-menopause weight gain is particularly dangerous when it comes to breast cancer risk. With extra body fat comes more estrogen, which can stimulate breast cancer growth. A normal body mass index is less than 30.

To calculate BMI, multiply your height in inches by that same number; divide that total into your weight in pounds; then multiply the total by 703. A person who is 5-feet-5 (65 inches) and weighs 150 pounds has a body mass index of 25. (Or Google “BMI calculator” for an online tool.)

4. Many studies have looked for a link between diet and breast cancer risk, but results are conflicting.

Experts say it’s good advice to eat a diet high in fruits, vegetables and whole grains, and low in fat and red meat. “That’s what I tell my patients,” Swasey said. “Whatever diet is heart-healthy is probably the best one to follow.”

5. Evidence is growing that regular exercise lowers the risk of breast cancer. “It doesn’t have to be high-intensity exercise,” said Rachel Burns, dietitian with Levine Cancer Institute at Carolinas Medical Center. “It can be as easy as just walking, being physically active 30 minutes a day.”

6. Avoid soy supplements, Burns said. Soy contains isoflavones, which can act like estrogen and stimulate the growth of certain types of breast cancer. Supplements usually contain more concentrated doses of isoflavones than whole forms of soy, such as soy milk, tofu or edamame, Burns said. “Three servings a day of those (whole) forms are OK.”

7. Smoking hasn’t been linked specifically to breast cancer risk, but a recent study of women at high risk for breast cancer found that, for those who smoked, the more they smoked and the longer they smoked, the more their risk increased, Swasey said.

8. MRI scans are not recommended as regular screening tools for the general population. But they are used, in addition to mammography, for screening high-risk patients and for diagnosis after mammograms that detect suspicious masses.

9. Women with dense breasts are at higher risk for breast cancer, and mammograms aren’t as effective in detecting cancer in very dense breasts. Ask your doctor whether you have dense breasts and, if so, you might benefit from regular MRI scans or ultrasounds along with mammography.

10. Breast cancer risk goes up with age. The often-repeated statistic that “1 in 8” women will get breast cancer is calculated over a lifetime to age 95. The National Cancer Institute has created a Breast Cancer Risk Assessment Tool. Take the test at www.cancer.gov/bcrisktool.