The notion of a dementia epidemic has been a big concern in ageing societies across the globe for some time. With the extension of life expectancy it seems to be an inevitable disaster – one of the “greatest enemies of humanity”, according to UK prime minister David Cameron.
Many shocking figures have been published pointing to dramatic increases in dementia prevalence and massive predicted costs and burdens. Yet new evidence seems to suggest otherwise. In a review of dementia occurrence in five studies in the UK, Sweden, Spain and the Netherlands between 2007 and 2013 that used consistent research methods and diagnostic criteria, we found none that supported headlines about dramatic increases in dementia. They report stable or reduced prevalence at specific ages over the past few decades – despite ageing populations.
How to reconcile this relatively optimistic picture with what looks like panic on the part of governments, charities and the mainstream media? One reason is that they fail to recognise the complexity of dementia diagnosis. The main criteria for diagnosing dementia hinge on cognitive decline and an associated deterioration in a person’s ability to carry out day-to-day activities. If there are variations in the recognised boundaries of these criteria either in different countries or during different time periods, this can affect occurrence estimates without changing the fundamentals of the dementia syndrome itself.
Over the past few decades, the diagnostic criteria have indeed changed across the world in parallel with public awareness and perceptions. More people are now diagnosed with very early dementia, for example, though it may or may not progress into more severe forms. The introduction of biomarkers for diagnosis is likely to further expand prevalence by identifying large sections of populations at risk – and is already in its early stages. Such changes will affect different groups of people in different contexts in different ways, but basically we might be counting more people as having dementia due to the use of more inclusive diagnostic criteria.
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Image: “It ought to be lovely to be old, To be full of the peace that comes with experience And wrinkled ripe fulfillment” - D.H. Lawrence
Credit: Sheena876
This article was originally published on The Conversation. Read the original article.
Reproduced courtesy of the University of Cambridge
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