This is great news.
60% of Dementia is due to Alzheimers whilst remaining 40% is roughly split between Vascular dementia (dementia due to mini-strokes) and Dementia with lewy bodies (a histopathological finding).<p>Unfortunately Alzheimers is largely a pathological diagnosis (ie. it requires a brain biopsy usually post mortem to diagnose) and I didn't dig up the british study this is largely taken from to see where they thought the decline was coming from but it is very good news and should be welcomed!
One of the most fascinating pieces I read about dementia care was also in the NY Times about life prisoners.<p>(<a href="http://www.nytimes.com/2012/02/26/health/dealing-with-dementia-among-aging-criminals.html?_r=1" rel="nofollow">http://www.nytimes.com/2012/02/26/health/dealing-with-dement...</a>)
Hopefully this is true, I feel like the studies were not thorough enough to conclude conclusively that Dementia is declining, for example the study in Denmark had relatively moderate to small numbers and takes people at different ages (93 and 95, perhaps people with Dementia likely die before 95 for example). The British study seems better, but still 56% of people declining is kind of high.<p>In either case, logically this seems fairly strait forward and these studies do provide some insight, so good news! I hope there's a similar study done in the U.S.
I wonder how much attribution can be given to the thought that many people keep their minds more active now with various forms of entertainment like games, smartphones, books, puzzles, etc.
I strongly distrust this study because of participant "self-selection bias". 80% of approached subjects declined to participate in the tests. There is too much probability, that those people who experience onset of dementia would decide to not participate in such study, especially now, when privacy is getting NSA-ed and all data about you is going to affect your google search, targeting, re-targeting and your insurance rate
It's important to note that none of this decline was attributed to medications which are meant to manage the symptoms. These medications are, IMO, largely useless.