Most women are over-optimistic about the benefits of screening in protecting them against dying from breast cancer, says a survey.

Although breast screening can detect small tumours early, when they are easier to treat, it only reduces the death rate by about 25 per cent.

But a survey of almost 900 women found half of them thought breast screening could cut their risk of dying by 50-75 per cent. Only one in five correctly said it could reduce their risk by a quarter, while the remainder said they did not know.

The women, who were aged from 40 to 80, were asked to estimate the effectiveness of regular screening in reducing death from breast cancer in women over 50.

The authors of the Geneva-based survey said unrealistic expectations or poor information meant women were unable to give properly informed consent for screening. This created a dilemma for public health specialists, as giving women the facts might deter them from being screened. Writing in the Journal of Epidemiology and Public Health, the authors said: "There could be a conflict between achieving high participation rates in screening and giving women accurate information without putting them off screening."

* Heart disease in middle- aged men has not fallen in the past 20 years, despite sharp reductions in heart attacks and deaths. The fall in heart attacks is due to better drugs and treatments, but the continued high levels of heart disease, indicated by thickened artery walls, reflects the persistence of unhealthy lifestyles.

Researchers from the Royal Free and University College medical schools in London say in the journal Heart that "meeting the need for anti-cholesterol and blood-thinning drugs will require intensified and sustained efforts".