Women with high levels of fasting insulin have a significantly increases risk of death from breast cancer, according to researchers at Mount Sinai Hospital in Toronto, Canada.

Insulin, a member of a family of growth factors, has an effect on normal and malignant breast cell division.

In their study of 512 women without known diabetes and all having early-stage breast cancer, researchers gathered information on predictive factors, body size and fasting blood values.

Women with the highest insulin levels had a two-fold increased risk of developing metastatic cancer and a three-fold increased risk of death compared to women with the lowest insulin levels, according to the study published in the Journal of Clinical Oncology.

Fasting insulin level is associated with outcome in women with early breast cancer, concluded the investigators. "High levels of fasting insulin identify women with poor outcomes in whom more effective treatment strategies should be explored," wrote the researchers.

Other Sources: Journal of Clinical Oncology