Women who breastfed their infants for two years or longer reduced their risk of breast cancer by 50 per cent. This confirms other studies from China and the US that prolonged breastfeeding reduces breast cancer risk.

Researcher, Tongzhang Zhen, associated professor of epidemiology and public health at Yale School of Medicine, noted that women have no control over many of the risk factors associated with breast cancer, such as family history and environmental factors, "it is one factor that many people are able to change."

This study, which looked at the medical histories of 808 Chinese women from 1997 to 1999, half had a history of breast cancer and the other half were controls, found a significant inverse relationship between duration of lactation and breast cancer risk.

The authors also found a significantly reduced risk of breast cancer when the lifetime duration of breastfeeding totaled 73 to 108 months.

INFACT Canada recommends exclusive breastfeeding for the first 6 months of life and continued breastfeeding for at least two years with nutritious complementary foods commenced at about 6 months.