The findings are the result of two major cohort studies, supported by the Medical Research Council.
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 research was led by Prof Carol Brayne from the Cambridge Institute of Public Health at Cambridge University.
Co-author Prof Antony Arthur from UEA’s school of Nursing Sciences said: “Our study shows that the proportion of people over the age of 65 with dementia is less than it was 20 years ago. Although the prevalence is lower, the actual number of people with dementia will continue to rise as the numbers of people surviving into old age is increasing.
“Most planning for the future need for dementia care services has been based on studies that are now quite old and on the assumption that dementia risk doesn’t change across generations. Ours is one of the few studies able to test whether that assumption is correct.
“Our findings suggest that there are real differences in the health experiences of generations born twenty years apart. Possible contributions to this decline in prevalence is the reduction in cardiovascular disease and the increased education between a cohort of people born prior to the mid-1920s and those born up to the mid-1940s.
“It is very encouraging but we cannot assume that a reduction in prevalence on this scale will be seen in future generations. It is therefore vitally important that we continue to develop and test ways of preventing and treating dementia.”
Prof 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. 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.”
Co-author Dr Fiona Matthews from the MRC Biostatistics Unit presented the findings at the Alzheimer’s Association International Conference in Boston today. The full results of the study are published online today in The Lancet.
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