Washington (SmartAboutHealth) - Researchers have found that a family history of breast cancer can greatly increase the risk of women developing the disease.

The new study was led by Dr. Steven Narod of the University of Toronto,, and focused on 1,492 Canadian women with an average age of 48.

They found that women had a 40% increased risk of breast cancer if they had a family history of the disease.

This was despite the fact that they tested negative for two genetic mutations linked to breast cancer.

The mutations were with the genes BRCA1 and BRCA2.

The women were far more likely to develop teh disease if they had a family history of breast cancer.

A family history was defined as two or more cases of breast cancer from close relatives under the age of 50.

The study was presented at a meeting of the American Association for Cancer Research.