Unlike many previous studies, restricted to single sites, this research, funded by the British Medical Research Council, applied a single methodological approach to over thirteen thousand people across five diverse sites. The researchers studied two thousand five hundred people from each site, dividing them into two age groups: those from sixty-five to seventy-four years of age; and those who were seventy-five years of age and older. Dementia incidence, or the number of new cases over a given time, rises with age. However, the study did not support the previous assumption that dementia incidence varied according to sex. The suggestion in the previous literature that incidence may fall again after a certain, critical age, was also not supported by the findings.
There was no convincing evidence of variation across the sites. This puts into question the idea that action to reduce cardiovascular disease will necessarily have an impact on dementia incidence: a proposal that emerged out of previous, single site studies with differing prevalence of cardiovascular disease and other chronic disorders. The results, together with the methodological approach developed for the Medical Research Council's study, will be valuable for the future research on dementia incidence that is needed to inform public health policy.
Citation: Matthews F, Brayne C, Medical Research Council Cognitive Function and Ageing Study Investigators (2005) The incidence of dementia in England and Wales: Findings from the five identical sites of the MRC CFA study. PLoS Med 2(8): e193.
Fiona E Matthews
MRC Biostatistics Unit
University Forvie Site
Cambridge, United Kingdom
PLEASE MENTION PLoS Medicine (www.plosmedicine.org) AS THE SOURCE FOR THESE ARTICLES. THANK YOU.
All works published in PLoS Medicine are open access. Everything is immediately available without cost to anyone, anywhere--to read, download, redistribute, include in databases, and otherwise use--subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.