High Insulin Levels Raise Risk of Breast Cancer in Postmenopausal Women
Posted Jan 11 2009 2:53pm
Higher-than-normal levels of insulin place postmenopausal women at increased risk of breast cancer, researchers at Albert Einstein College of Medicine of Yeshiva University report. Their findings, published in the January 7 issue of the Journal of the National Cancer Institute, suggest that interventions that target insulin and its signaling pathways may decrease breast cancer risk in these women.
Howard Strickler, MD, MPH Marc Gunter, PhDBreast cancer is the most common cancer among women in the United States. Last year, approximately 182,000 women were diagnosed with breast cancer and more than 40,000 died from the disease. The majority of breast cancers arise in women past the age of menopause.
Obesity is a well-established risk factor for postmenopausal breast cancer, but just how obesity and breast cancer are connected is unclear. Many researchers have assumed that the link is estrogen — a hormone that is known to increase breast-cancer risk and is found at higher-than-average levels in obese women. But obese women also have other hormonal imbalances that may play a role in triggering breast cancer. One such imbalance is elevated levels of insulin, which stimulates the growth of breast cells in tissue culture. The Einstein study is the first to prospectively identify insulin’s role in breast cancer while controlling for estrogen levels.