Is the Prevalence of Dementia Changing?

Dementia in the growing elder population is an important driver of healthcare costs and a matter of societal concern. Some trends might increase dementia prevalence (e.g., longer lifespan, increasing obesity and diabetes, survival after stroke), whereas others might reduce it (e.g., more-effective prevention of cardiovascular disease, improved early-life education). Between 1989 and 1994, researchers estimated dementia prevalence in three geographic areas in England by interviewing a population-based sample of more than 7500 older adults (age, ≥65). Now, investigators report results of an identical survey in a similar sample from the same areas between 2008 and 2011.

The overall prevalence of dementia fell significantly, from 8.3% to 6.5%. I…