In all the talk about annuities and the poor value they currently offer, nearly all of it has been based on standard annuity rates, ie where there is nothing sufficiently medically wrong with you to affect your life expectancy. However this is almost certainly not the rate you should be looking at.

Go to any of the annuity provider or broker websites, sometimes buried away a little, and you will find a link explaining what they can offer in the way of “enhanced” or “impaired lives” annuities. Legal & General’s web page on this looks like the kind of warning notice you find on the wall of your doctor’s surgery waiting room, with headings like Smoking, Type 2 Diabetes and High Blood Pressure. But in the upside-down world of buying annuities these become good things to do or have.

Just Retirement give some handy illustrations of what various conditions could mean for your income: up 20% for minor conditions like obesity and hypertension, up 30% for “moderate” ones like being a heart attack survivor with a bypass and 40% for serious medical conditions like stage 2 bowel cancer one year in. However, you don’t need to get anywhere near the frankly frightening conditions in the moderate and serious boxes to make a big difference to the income you can receive. annuitydiscount.co.uk provide a very long list of medications (covering every letter in the alphabet except J and Y) which could lead to an impaired life annuity if disclosed to the annuity provider.

As the BBC article from 2012 posted by the Better Retirement Group on enhanced annuities says: “At its simplest an annuity is a bet with the insurance company about how long you will live.”

So on that basis, it makes sense to stack the odds in your favour as much as you can. Which makes the 2007 article in the New England Journal of Medicine entitled, rather dully, Incidental Findings on Brain MRI in the General Population, such an interesting read.

They studied 2,000 people (mean age 63.3 years, range 45.7 to 96.7) from the population-based Rotterdam Study in whom high-resolution, structural brain MRI scans had been carried out. Asymptomatic brain infarcts (more commonly known as strokes) were present in 145 people (7.2%). Among other findings, aneurysms (1.8%) were the most frequent. Benign brain tumors also turned up reasonably often (1.6%). The most extreme case was someone with a large, chronic subdural haematoma, who was subsequently found to have had a minor head trauma 4 weeks before the MRI scan. Some of the scans are shown below.

But the really amazing thing is this: only 2 of the 2,000 people scanned (the subdural haemotoma mentioned above and another who had a 12 mm aneurysm of the medial cerebral artery) had any idea that there was anything wrong with them!

Another huge area of undiagnosed disease (and on the annuity.co.uk list for enhanced annuities) is prostate cancer. According to a systematic review of prostate cancer biopsy schemes by the University of York in 2005, where they quoted from the NHS Centre for Reviews and Dissemination publication on screening for prostate cancer, Effectiveness Matters:

Post mortem studies show that 30% of men over 50, who had no symptoms of prostate cancer whilst alive, had histological evidence of prostate cancer at the time of death. This percentage rises to 60-70% in men over 80 years of age. In other words, most men with prostate cancer die with, rather than from, the disease.

The main reason these studies have been carried out is to determine whether screening for prostate cancer, which kills 3.8% of men with the disease, has saved many lives. The Prostate Specific Antigen (PSA) test that is commonly used to detect prostate cancer in the absence of symptoms is not only prone to false positives and negatives (ie telling you you have it when you don’t and don’t have it when you do – something all screening suffers from to some extent), but can lead to you being offered treatment which may well be worse than the disease. This is discussed further in the excellent The Norm Chronicles, by Michael Blastland and David Spiegelhalter, which questions whether, overall, screening is particularly effective in saving lives.

Effective in preventing death? Perhaps not. But effective in increasing retirement income? Almost certainly.

The latest Association of British Insurers (ABI) facts and figures on the UK annuity market suggest that enhanced annuities have grown in popularity, to 24% in 2012 from 2% in 2003. There is scope to make further large increases in these figures if more people can be persuaded to have themselves screened for some of the most common undiagnosed conditions before they retire.

So don’t necessarily accept a standard annuity rate. And consider getting yourself tested first.