It can seem news reports are constantly contradicting each other. One says the number of people with dementia is growing every year, while another claims cases are dropping. We investigate how this can happen...

It was only a couple of weeks ago when the Office for National Statistics (ONS) reported that dementia was the leading cause of death in England and Wales.

With 61,000 deaths attributed to dementia last year, it meant it had overtaken heart disease. The ONS put this down to an increasingly ageing population – age increases your risk of dementia – and improved survival rates for other illnesses.

However, last week, a seemingly contradictory report came out from researchers at the University of Michigan in the US. It claimed the number of seniors in America with dementia was dropping (and given the similarities in diet and lifestyle in the US and UK, you could apply the same ethos to numbers in England and Wales).

So, which is it?

It’s thought that one of the main reasons that dementia cases appear to be rising so quickly is because of the way deaths are being registered. In many cases, dementia is a contributory cause for death, but not necessarily the only cause. So, for example, many people with dementia die from pneumonia, but this can be triggered by challenges caused by dementia (such as difficulty swallowing, which can lead to aspiration pneumonia).

Doctors are being increasingly encouraged to diagnose dementia as early as possible and to include it as an underlying cause on death certificates. It’s why you might hear that someone has died from “complications caused by dementia”.

A number of incentives were put in place in 2013/14 as part of the Prime Minister’s challenge on dementia, including a push to increase the number of dementia diagnoses (and even paying GPs for each dementia diagnosis).

‘Whereas in the past there would have been a certain amount of stigma, or a reluctance to put dementia on death certificates, there is now an actual encouragement to put dementia on death certificates as a leading cause of death,’ says Professor Carol Brayne, director of the Cambridge Institute of Public Health.

‘For someone with severe dementia, who has no ability to function day-to-day and has to be fed, that person would be dying of severe dementia,’ Brayne says. ‘But with somebody who is frail, or who has multiple health problems, doctors would be more likely now – if the dementia has been recognised – to put dementia down as being a contributing factor. Because we are all well aware that people with dementia do die faster than people without dementia.’

However, when you look at the actual figures for dementia, you’ll actually see a steady reduction in cases*, particularly in men, between the years 1990-1993 and 2008-2011.

For example, in 1990-93, the percentage of men aged 80-84 with dementia was about 15% but by 2008-11, it had dropped to 10%. And for women, the percentage of dementia cases in those aged 85-89 was nearly 27%, while in 2008-11 it had dropped to 17%.

It’s thought improvements in general healthcare over the years has made a difference, including improved nutrition in early years, vaccinations, a drop in smoking and various other health factors in comparison to previous generations. Even factors such as increasing numbers of people in higher education have been linked to a reduced dementia risk.

So while it can feel like dementia numbers are snowballing, in reality, the proportion of people with dementia has decreased. It’s just that society has become more aware and more willing to recognise it and diagnose it for what it is.

*Figures taken from the Cognitive Function and Ageing Study from The Lancet.

Source: bbc.co.uk and sciencedaily.com and bbc.co.uk