Results from two major cohort studies, led by the University of Cambridge and supported by the Medical Research Council, reveal that the number of people with dementia in the UK is substantially lower than expected because overall prevalence in the 65 and over age group has dropped.

This study provides compelling evidence of a reduction in the prevalence of dementia in the older population over two decades.

Professor Carol Brayne

The two studies provide the first estimate of the change in the number of people live with dementia in the UK, and the new figures give a more accurate picture for those developing policies and planning healthcare services for dementia patients.

The results indicate that overall prevalence has gone down by 1.8 per cent to an estimated 6.5 per cent of the population. Using the current age profiles of the UK, this corresponds to an estimated 670,000 people over the age of 65 living with dementia, a reduction of more than 20 per cent in the number of people projected to have dementia today compared with 20 years ago.

Three geographical areas in Newcastle, Nottingham and Cambridgeshire from the initial MRC Cognitive Function and Ageing Study (CFAS) examined levels of dementia in the population. The latest figures from the follow up study, CFAS II, show that there is variation in the proportion of people with dementia across differing areas of deprivation,  suggesting that health inequalities during life may influence a person’s likelihood of developing dementia.

Prevalence of dementia in women remains higher than men, with 7.7 per cent of women over 65 estimated to have dementia, compared with 4.9 per cent of men. Although the overall prevalence of dementia has fallen, the prevalence of dementia among people living in care homes has increased, from 56 per cent of care home residents twenty years ago, to 70 per cent today.

The study was led by Professor Carol Brayne from the Cambridge Institute of Public Health at Cambridge University. She said: “This study provides compelling evidence of a reduction in the prevalence of dementia in the older population over two decades. Whether or not these gains for the current older population will be borne out in later generations would seem to depend on whether further improvements in primary prevention and effective health care for conditions which increase dementia risk can be achieved, including addressing inequalities.”

Professor Hugh Perry, Chair of the Neurosciences and Mental Health Board at the Medical Research Council said: “This robust and comprehensive study gives us crucial information on the prevalence of dementia in the country. Of course we can’t assume that this reduction will be seen in future studies, therefore the need for us to find ways of preventing and treating dementia is as urgent as ever. We should be very much encouraged by the indication that there may be modifiable environmental factors that play a role in a person’s risk of developing dementia. The knowledge gleaned from the CFAS I and CFAS II studies is a great example of the benefits of long-term investment by the MRC.”

Story adapted from a MRC press release.

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