Between 5% and 10% of men aged 65 to 79 have abdominal aortic aneurysms, but don't know it. If their weakened arteries burst they stand a very high risk of dying. Ultrasound screening of men in this age group can significantly reduce the numbers of men who die from this condition. The overall benefits of screening are complex, however, because a number of men may be subjected to unnecessary anxiety and/or to the complications of surgery.An aneurysm is a localised widening of an artery. It occurs because the artery wall is weakened and without therapy it could easily burst. If the aneurysm is in the aorta, the main artery that carries blood through the abdomen, the result often can be fatal. Doctors think that any abdominal aortic aneurysm that is greater than 5cm is at a high risk of bursting.To see whether a program of ultrasound screening could detect these aneurysms before they burst, and save lives as a result, Cochrane Scientists performed a systematic review of screening trials. They identified four controlled trials that were conducted in the UK, Denmark and Australia, and involved a total of 127,891 men and 9,342 women.The results showed that men aged 65-79 could benefit from screening, but there were insufficient data on women (whose risk of death from ruptured aortic aneurysm is much lower than the risk in men) to ascertain effectiveness in women....