Changes in diameter of the abdominal aorta with age: an epidemiological study.

Rupture of abdominal aortic aneurysms is a major cause of death for men who are over 60 years old. This study invited 13,000 men aged 60 to 75 years, within the Birmingham conurbation, to have an ultrasound scan of the abdominal aorta. The scan was performed at the patients' own General Practitioner's surgery; 10,061 men were scanned. Only 3% of this population were found to have large aneurysms. An analysis of the distribution of aortic diameters in this population shows that for diameters less than 40 mm, changes in the diameter with age (previously attributed to the growth of small aneurysms) occurs for up to 25% of the population although the median diameter for each year group, 21 mm, does not increase with age. This analysis suggests that the threshold diameter at which the aorta is categorized as abnormal should be related to age, especially by those undertaking mass screening.