Fresh hope for dementia sufferers as diagnosis rates decline by millions of people

Here’s some of the best news I’ve heard recently – dementia rates have dropped ­unexpectedly.

In 2000, people got a diagnosis at an average age of 80.7, but by 2012 that age was 82.4.

Now I know that doesn’t sound like a lot, but in terms of the numbers of people affected it’s huge. Millions.

This new study comes from the US but applies to us equally well. It’s by the National Institute on Ageing and published in JAMA Internal ­Medicine, a journal of world renown.

It included 21,000 people of all races, education and income levels with an average age of 75.

To assess dementia, participants were asked, among other things, to recall 10 nouns immediately and after a delay, to serially subtract seven from 100, and to count backward from 20.


The test is based on extensive research indicating it is a good measure of memory and thinking skills.

Participants were also asked about their education levels, income and health. This dementia decline seems unexpected.

It’s occurred despite an increase in diabetes and the study found this condition can raise the risk of developing dementia by 39%.

More older people today also have cardiovascular risk factors – high levels of blood pressure, blood sugar and cholesterol – all of which increase the risk of dementia.

But more are taking medications for those conditions, so better control of those risk factors may play a role in the dementia decline.

Some studies have found that obesity in middle age increases dementia risk in old age, but in this study obese people had a 3% lower risk of dementia.


Years of education is linked to decreased dementia risk and this study confirmed that too.

The theory is education changes developing brains in a good way, making them more resistant to dementia.

So people who are better educated have brains that are better able to compensate for dementia damage.

Dr Kenneth Langa, a professor of medicine at the University of Michigan, US, thinks much of what’s happening with dementia rates defies explanation.

And Dr Denis Evans, a professor of medicine at Chicago’s Rush University, US, says we should be wary of accepting possible explanations for a decline because the situation is “very complex”.

But despite there being no way for individuals to protect themselves from Alzheimer’s, there seems to be a long-term trend.

Compared with the rate in the early 1990s, Dr Langa estimates there’s been a 25-30% decrease in dementia rates among older Americans.

Now we have to work out what is causing this apparent phenomenon.