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Dementia numbers set to rise to 1.2 million by 2040

New cases falling but people will live longer with dementia

Adrian O'Dowd

Thursday, 06 July 2017

Experts are predicting that there will be 1.2 million people in England and Wales living with dementia by 2040 – a rise of 57% from 2016 – due to increased life expectancy.

The prediction is made in a study* published online today in The BMJ which says that although the number of newly diagnosed cases of dementia is falling, the overall prevalence will increase substantially as people live longer and deaths from other causes, such as heart disease, continue to decline.

Currently, dementia costs the UK economy an estimated £23 billion a year, but existing forecasts may not be precise because they assume that rates of dementia remain constant.

Therefore, an international team of researchers based at University College London (UCL) and the University of Liverpool, set out to predict the future burden of dementia with more certainty by developing a mathematical model that takes account of disease trends and death rates alongside the effects of increasing life expectancy.

For the study, they used data from 17,906 men and women from the English Longitudinal Study of Ageing (ELSA) - a study that began in 2002 to track the health of a representative sample of the population in England aged 50 and above.

Participants were selected randomly in six waves from 2002 to 2013 and at each wave, tests were carried out to assess memory, verbal fluency and numeracy function, and basic activities of daily living.

Dementia was identified by these assessments as well as by interviews with carers, or by doctor diagnosis.

After taking into account the effect of dropout from the study, the team found the rate of dementia incidence went down by 2.7% per year between 2002 and 2013.

Despite this fall in incidence, the model showed that overall prevalence of dementia was set to increase substantially, mostly because of increased life expectancy.

They calculated that there were currently 767,000 people living with dementia in England and Wales and the number would increase to more than 1.2 million by 2040.

Dr Sara Ahmadi-Abhari, lead author from University College London, said: “The risk of developing dementia at any given age is going down over time, shifting dementia to later years in life. This decline is mainly because of improvements in healthcare and adopting healthier lifestyles.

“Our estimate of 1.2 million people with dementia by 2040 is based on the assumption that the decline in risk of developing dementia continues to the future. If public health efforts fail and the risk of developing dementia does not continue to decline, the growth in numbers of people living with dementia will be much larger, reaching 1.9 million by 2040.”

Professor Eric Brunner, the study’s senior investigator, also from UCL, said: “Our results have significant policy implications in terms of care needs and public spending.”

In a linked editorial,** Emiliano Albanese from the WHO Collaborating Centre for Research and Training in Mental Health, University of Geneva, Switzerland, said: “The results from the ELSA study do confirm that the absolute number of people with dementia will increase substantially in the coming years in England and Wales, as a result of an aging population, and it is these numbers that matter most to policy makers planning future care and services.”

* Ahmadi-Abhari S, Guzman-Castillo M, Bandosz P, et al. Temporal trend in dementia incidence since 2002 and projections for prevalence in England and Wales to 2040: modelling study. BMJ 2017;358:j2856. DOI: 10.1136/bmj.j2856

** Albanese E. Dementia trends in England and Wales. BMJ 2017;358:j3132. doi: 10.1136/bmj.j3132

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