Women who experience increased levels of stress are less likely to develop breast cancer, according to a study by Danish scientists (Nielsen, N. R. et al., Br. Med. J. 9 September 2005 (10.1136/bmj.38547.638183.06)).

Stress can reduce oestrogen production and oestrogen is a known risk factor in breast cancer. Therefore, the authors followed the incidence of breast cancer in the 6,689 women of the Copenhagen City Heart Study who had assessed their own stress levels between 1981 and 1983. They found that 251 women developed breast cancer, and that those who had put themselves in the higher stress category were 40% less at risk.

However, caution has been advised from all quarters. “Even though we find a lower risk of breast cancer among stressed women, let me just emphasize that stress cannot be considered a healthy response”, said lead researcher Naja Rod Nielsen of the National Institute of Public Health in Copenhagen (http://www.forbes.com, 9 September 2005).

Previously, stress had been thought to increase the risk of breast cancer. Emma Pennery from Breast Cancer Care, UK, said “We know from talking to women with breast cancer that some of them believe stress to be a contributory factor. This new study is therefore very interesting” (http://news.bbc.co.uk, 9 September 2005).

Summing up, Sarah Rawlings, of Breakthrough Breast Cancer, UK, reminded people that “...maintaining a healthy, balanced lifestyle is important — we know that high stress levels can lead to unhealthy behaviour, which may alter your risk of breast cancer and other diseases” (http://www.guardian.co.uk, 9 September 2005).