Researchers from Harvard Medical School and the Brigham and Women’s Hospital in Boston, in the United States studied the health of almost 800 women diagnosed with breast cancer between 1989 and 2002 and found that older women who have high levels of particular sex hormones are up to twice as likely to develop the disease as those with low levels.
Women most at risk were those with high levels of oestradiol, which is the main form of oestrogen, testosterone, and a hormone produced by the adrenal gland called DHEAS.
A blood test could measure these and be used alongside other factors including family history to identify those at high risk, the researchers suggested.
The researchers also looked at hormone levels in almost 1,600 women from the same group of nurses, who did not develop breast cancer.
They discovered that women in the top 25 per cent of levels for the three hormones were between 50 and 107 per cent more likely to have developed breast cancer than those who were in the bottom 25 per cent.
The team also discovered that having higher levels of the three hormones was linked to having more aggressive breast cancer, which either recurred or caused death.
In addition, they found that particular individual hormones were closely linked to particular types of breast cancer.
Women with higher levels of oestradiol were prone to hormone-receptor positive breast cancer, as were those with high testosterone levels.
Henry Scowcroft, science information manager at Cancer Research UK, said: This intriguing conference report suggests that a simple one-off blood test could spot women