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Dementia prevalence fell in UK

In the past 20 years there has been a marked decrease in the prevalence of dementia among those aged 65 years or older in the United Kingdom, according to the results of a set of collaborative studies.

"This study provides compelling evidence of a reduction in the prevalence of dementia in the older population over two decades," study researcher Carol Brayne, MD, of the Cambridge Institute of Public Health, University of Cambridge, United Kingdom, said in a press release.

Brayne and colleagues analyzed data from the Medical Research Council's Cognitive Function and Ageing Study (CFAS). The first part of the study (CFAS I) included baseline interviews conducted between 1989 and 1994 with more than 7,000 older adults living in Cambridgeshire, Newcastle and Nottingham. Interviews focused on sociodemographics, lifestyle, health and other factors. A subsample was then assessed for dementia.

From 2008 to 2011, the same key methods were used in a similarly sized cohort (CFAS II), which allowed the researchers to estimate changes in the prevalence of dementia during 2 decades.

Results indicated that if trends had remained the same since 1989, approximately 884,000 adults aged 65 years and older — or 8.3% of the population — would be expected to have dementia. However, the prevalence was significantly lower in CFAS II (670,000, or 6.5% of the population), a 24% reduction in the total number of older adults with dementia.

However, Brayne and colleagues found that dementia rates were higher among women (7.7%; 95% CI, 6.8-8.5) compared with men (4.9%; 95% CI, 4.2-5.7), and the prevalence of dementia increased in care settings from 56% to 70% (OR=1.7; 95% CI, 1-2.9) between CFAS I and CFAS II. Dementia in care settings accounted for approximately 34% of all cases (29% men vs. 36% women).

According to the researchers, the CFAS study serves as a useful surveillance tool for examining changes in dementia and related risk factors.

"Whether or not the gains that we have identified for the present older population will be borne out in later generations will probably depend on whether further improvements in primary prevention and effective health care for disorders that increase the risk of dementia can be achieved, including addressing inequalities," they wrote.

Disclosure: The researchers report no relevant financial disclosures.