In England, the prevalence fell from 8.3% to 6.5% during the past 20 years.

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%. In care facilities, dementia prevalence rose from 58% to 73%; however, the proportion of elders living in such facilities declined from 5% to 3%. In both surveys, dementia prevalence was higher in women than in men in care and community settings.

COMMENT

This rigorous study is a persuasive piece of evidence that, at least in some settings, the prevalence of dementia in elders is declining and might be sensitive to societal efforts to improve education, primary prevention, and healthcare delivery.