Why Is AAA Screening Offered at 65?
If you are a man in the UK, you will normally be invited for abdominal aortic aneurysm (AAA) screening at around age 65.
If you have received an invitation, you might reasonably be wondering:
Why am I being offered this scan — and why now?
There are really two questions:
Is there evidence that AAA screening is beneficial?
And:
Is there evidence that 65 is the right age to have it?
So let’s address those questions.
Why is AAA screening offered?
The main evidence comes from large randomised trials conducted many years ago.
The largest UK trial, the Multicentre Aneurysm Screening Study (MASS), recruited 67,770 men aged 65–74 between 1997 and 1999. Half were invited for screening and half were not.
Over long-term follow-up, fewer men in the group invited for screening died from AAA. Across the screening trials as a whole, however, a reduction in deaths from all causes has not been demonstrated.
That is an important finding. But there are two things to bear in mind when applying it today.
First, AAA was much more common in the men studied then than it is in men being screened now.
Around 50 in every 1,000 men screened in MASS were found to have an AAA. MASS included men aged 65–74, whereas today’s NHS programme routinely screens men at around 65, so the figures are not directly comparable.
In England in 2025–26, AAA was found in about 6 in every 1,000 men screened.
The large decline in AAA prevalence is believed to be mainly related to the substantial fall in smoking. Smoking is the major modifiable risk factor for AAA, and the risk is much lower in men who have never smoked.
Second, screening can have downsides as well as benefits. Finding an aneurysm can lead to years of surveillance and, for some men, planned surgery. Screening therefore potentially prevents some AAA deaths, but it can also lead to investigations and treatment that would not otherwise have happened.
So the original trials tell us something important about the benefits and harms of screening in the populations that were studied. How large the benefit is for men being invited today is a separate question.
Why age 65?
AAA becomes more common as men get older.
That helps explain why screening is aimed at older men rather than, say, men of 55.
But it does not establish 65 as the best age.
MASS studied men aged 65–74. Its purpose was to compare inviting those men for screening with not inviting them.
It did not compare screening at 65 with screening at 70 or 75.
After extensive searching, we have not found a randomised trial showing that having the first scan at 65 produces a better balance of benefits and harms than having it later. Nor have we found the NHS citing such a trial to explain why screening is offered specifically at 65.
Age 65 is therefore a UK screening policy. It is not an age that the randomised trials established as the optimum age to screen.
What do other countries do?
It is useful to put the UK policy in context.
We examined 30 countries: all 27 members of the European Union, plus the UK, United States and Canada.
Two have established nationwide AAA screening programmes routinely centred on men at 65: the UK and Sweden.
Germany provides men with a one-off screening entitlement from age 65, while Malta also operates a national AAA screening programme.
Some of the other countries recommend screening for particular groups, while several are testing screening through pilot programmes.
But most of the 30 countries do not operate a nationwide population AAA screening programme.
All these countries have access to essentially the same major trial evidence, but they have not all turned that evidence into the same screening policy.