Elevated insulin link to increased breast cancer risk
Posted Jul 15 2009 5:49pm
Posted by Neill Abayon
Findings on older women based on women's health initiative study
July 9, 2009 - (BRONX, NY) - Elevated insulin levels in the blood appear to raise the risk of breast cancer in postmenopausal women, according to researchers at Albert Einstein College of Medicine of Yeshiva University. Their findings are published in the online version of the International Journal of Cancer.
Increased breast cancer risk for postmenopausal women has previously been linked to obesity and diabetes. Both conditions involve insulin resistance, which causes increases in circulating levels of insulin. Since insulin is known to promote cell division and enhance breast tumor growth in animal models, the Einstein scientists reasoned that relatively high insulin levels may contribute to breast cancer risk in women.
"Up to now, only a few studies have directly investigated whether insulin levels are associated with breast cancer risk, and those studies have yielded conflicting results," says Geoffrey Kabat, Ph.D., senior epidemiologist in the department of epidemiology and population health at Einstein and the lead author of the paper. "Those other studies were based on just a single baseline measurement of insulin, while our study involved analyzing repeated measurements of insulin taken over several years — which provides a more accurate picture of the possible association between insulin levels and breast cancer risk."
An earlier study linking insulin levels with breast cancer risk was carried out by Einstein researchers and was published in the January 7, 2009 issue of the Journal of the National Cancer Institute.