In his new book " A field Guide to lies" Daniel Levitin reminds us that as thinking and responsible people we always need to carry out a quick plausibility check on the statistics we are shown - especially before repeating them.
This week the BBC ran the following headline "Dementia now leading cause of death" (link) which made me very curious. Some further digging took me to the Dementia UK website and then to the ONS data sets to figure out what exactly was going on.
My conclusion was surprising: This is an indicator that is POSITIVE. It's all good- what is misleading is the spin that's been put on it- does that surprise you? Great- read on, and if you take away nothing else from this then remember that indicators sit within a story - the story here is about policy that's working, people that are living longer and a change to more streamlined reporting... It's all good.
To start with I tried a reality check: could dementia really be a leading cause of death? I was unsure because I was not aware that people actually died from memory loss- unless they got into trouble by stepping into a road or taking double doses of their medications etc. The definition of dementia is " an overall term that describes a wide range of symptoms associated with a decline in memory or other thinking skills severe enough to reduce a person's ability to perform everyday activities. Alzheimer's disease accounts for 60 to 80 percent of cases."
So far then this article was raising some concern in the credibility stakes- it made no sense to me - so I dug deeper...
1) The BBC article
The first two sentences in the BBC article insist Dementa IS a Cause of death and proceeds to make a direct comparison between dementia and heart disease- which does provide a mechanism for death to occur (stopping the heart). So I am wondering whether I am mistaken as to what death actually is- The definition of death in the UK now also includes brain death- as well as loss of biological function. In this context though brain death means the loss of electrical activity in the brain... and the advanced stage of dementia does not cause that- it does however cause memory loss, problems with communication, problems arising from compound medications, and immobility.... Reading further in the article however it seems that Dementia is frequently being listed on the death certificate as a cause of death which seems strange- and the figures also seem to show that twice as many women "die" from Dementia than men. The concluding statement of this article is that no-one survives a diagnosis of Dementia which is then swiftly followed by a list of signs and symptoms of Dementia.
So there are two main questions for me around this article:
- does dementia "cause" death and if so how?
- are they conflating the data between longevity and Dementia? Women live longer and older people will generally have more dementia...
2) Turning to the data
So I turned to Dementia UK - but they say the same as the BBC article so I then went in search of the data published by the ONS mortality team. (ONS data link)
Speaking to the statisticians at the ONS and trawling through the data highlighted a few things:
1) Dementia does not cause death, but there has been a change in reporting since 2011 which puts emphasis on reporting the underlying condition rather than the thing that caused death, so Dementia is listed as the cause of death for a diverse range of associated problems including falls, infections, and strokes.
2) This has also been coupled with a marked increase in longevity (especially in men) as more illnesses and conditions are being successfully treated. Dementia is typically a disease associated with longevity as it usually manifests after the age of 65.
3) There have also been government initiatives on Dementia diagnosis and care: the Prime Minister’s challenges on dementia and the government’s mandate to NHS England includes an agreed ambition that two-thirds of the estimated number of people with Dementia in England should now have a diagnosis.
The increase in Dementia related deaths from all three of these effects has also been associated with a decrease in deaths from falls or other things (because they are now listed as Dementia deaths), so the effect appears enhanced, but it is important to also remember that main causes of death across all age groups is from cancers, and that for youngsters it is still suicide and road accidents.
The BBC article is badly written to the point of being misleading, but applying a reality check has very quickly led to a deeper understanding of what is actually a statistical effect caused by changes in coding the causes of death on death certificates, and greater success in diagnosing Dementia.
The important thing here is to remember that a correct and early Dementia diagnosis can result in more successful care which increases the quality of life for both the sufferer and their relatives.
Ultimately however death is the inevitable result of old age - and we have to die from something eventually. Not all deaths need to be linked to Dementia, but all dementia is a lifelong diagnosis and all Dementia sufferers eventually die...
We can expect these dementia -caused death statistics to rise over the coming years - but it would be a mistake to see this as a negative- when it is in fact a positive indicator showing success in early diagnosis and better end of life care.