Breast Health
Higher Insulin Levels May Raise Breast Cancer RiskA new study published in the International Journal of Cancer suggests that postmenopausal women with higher insulin levels may be at greater risk for developing breast cancer.
Insulin is a hormone that regulates blood sugar. Too much insulin in the blood is common in people who are obese and can be a sign of type 2 diabetes. It is also common among women with hormonal problems such as polycystic ovary syndrome. Too little insulin may indicate type 1 or type 2 diabetes. Normal values of insulin range from 5 micro units to 20 micro units per milliliter (mcU/mL).
As Insulin Levels Increase, So Does Breast Cancer RiskResearchers measured insulin levels in blood samples provided by 5,450 postmenopausal women who took part in a study called the Women's Health Initiative. The initiative was originally set up to determine the effect of hormone therapy, diet changes and calcium plus vitamin D supplementation on postmenopausal women. More than 100,000 research volunteers ages 50 to 79 from across the U.S. took part. The study began in the mid 1990s. For the analysis described in this new study, women were grouped by their insulin levels at the start of the study and based on the average of their insulin levels from blood drawn at years one, three and six of the study. Over eight years, 190 women developed breast cancer. Women with insulin levels in the highest third (13 mcU/mL or higher) were twice as likely to develop breast cancer as women in the bottom third (less than 8 mcU/mL). This difference occurred when researchers looked at insulin levels at the start of the study and when averaged throughout the study. Results from prior studies that looked at insulin level and breast cancer have conflicted. But none of them examined insulin levels over time, as this study did. Nonetheless, the researchers note that their findings require confirmation in larger studies. Risk May Be Independent of ObesityAlthough obese women tend to have higher insulin levels, the link between higher insulin levels and breast cancer was stronger for thin women than for obese women. This is important because it suggests insulin may contribute to a woman's postmenopausal breast cancer risk regardless of whether she is obese. Christiana Brenin, MD, a breast oncologist at the University of Virginia Health System, notes that insulin receptors are present in most cells in the body, including cancer cells. "So it is no surprise that insulin levels may preferentially affect the growth of certain cancers," she says. "Screening non-diabetic, postmenopausal women for high insulin levels could prove useful in identifying individuals at high risk for breast cancer." Reduce Your Risk for Breast CancerKeeping insulin levels in check may help lower your risk for breast cancer. Here are some tips for reducing your risk:
UVA's Brenin says limiting saturated fats (found in meat and high-fat dairy products) and eating more fiber and complex carbohydrates has been shown to help regularize insulin levels. Eating more whole grains, vegetables, fruits and beans while limiting your consumption of refined carbohydrates (such as sweets, sugary drinks and refined grains like white bread) may also help control your insulin levels, she says. To read a patient story, get additional information on breast cancer treatment or learn about UVA's Breast Care Program, visit www.uvahealth.com. UVA also offers a free, confidential risk assessment through the region's only High Risk Care program to determine if you have a higher-than-normal personal risk of developing breast or ovarian cancer. This free service is particularly encouraged for women with a strong family history of breast or ovarian cancer. To arrange the free screening, call 434-924-1555. Women can learn more about their unique risks for heart disease - and how to better manage those risks - through Club Red, a UVA heart-health initiative. You'll learn how heart attack symptoms can be different for women than for men, and you can take an online risk assessment to learn your personal heart disease risk factors. There, you can sign up for Club Red, our free heart-health club for women. Benefits include tips from UVA healthcare providers and a gift package to help you live red in style. Always consult your physician for more information. Online Resources(Our organization is not responsible for the content of Internet sites.) National Breast Cancer Coalition |
October 2009Higher Insulin Levels May Raise Breast Cancer Risk As Insulin Levels Increase, So Does Breast Cancer Risk Risk May Be Independent of Obesity Reduce Your Risk for Breast Cancer Exercise: A Good Defense Against Breast Cancer Exercise: A Good Defense Against Breast CancerPhysical activity looks like a potent weapon in the fight against breast cancer. Studies show exercise may be able to cut the chance of developing this disease by as much as 40 percent. Scientists are still debating exactly how much and what type of exercise is best, but what's clear is that getting up and moving is important for women's breast health. Most studies suggest that 30 minutes to 60 minutes a day of moderate-to-high-intensity exercise can help lower breast cancer risk. Research suggests the more frequently and the harder you exercise, the lower your risk. One analysis reported a 6 percent decrease in risk for every hour of physical activity per week. Vigorous exercise such as jogging or swimming laps may be better at warding off breast cancer than activities such as walking or playing golf. But moderate exercise can help, too. One study showed that brisk walking just 1 1/4 to 2 1/2 hours a week cut risk by 18 percent. Researchers don't yet understand exactly how physical activity helps protect women against breast cancer. Exercise may act in several different ways, including:
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