
Dementia Rate Drops Sharply, as Forecast - a5seo
http://www.nytimes.com/2013/07/17/health/study-finds-dip-in-dementia-rates.html
======
robbiep
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).

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!

~~~
pstuart
And possible good news about Alzheimers:

[http://opinionator.blogs.nytimes.com/2012/09/25/bittman-
is-a...](http://opinionator.blogs.nytimes.com/2012/09/25/bittman-is-
alzheimers-type-3-diabetes/)

~~~
ekianjo
This theory that Al Zheimer is due to a form of Diabetes does not have much
support from the key thought leaders currently. [Disclaimer: I worked on Al
Zheimer]. For all we know, it may be a combination of several factors and not
a single one.

~~~
juskrey
Please recall what "key thought leaders" were thinking about cholesterol for
previous 50 years.

~~~
ekianjo
I am not saying they are right. I was just adding comments on what the experts
in the field are thinking about. Besides, there are some clinical trials
ongoing to treat "Brain Diabetes" as a way to fight Al Zheimer but nobody
expects much from them, including investors. It's probably not that simple.

~~~
juskrey
From "investors" word, I assume they are trying to treat it by adding
medications? What about removing carbs? Though, investors would be really
disappointed..

~~~
ekianjo
"Removing carbs"... talk about pseudo-science...

~~~
gambogi
Yeah because dietary modification is no way to treat a disease [1] _cough_ PKU
_cough_

[1]-
[http://en.m.wikipedia.org/wiki/Phenylketonuria#Treatment](http://en.m.wikipedia.org/wiki/Phenylketonuria#Treatment)

------
DanBC
One of the most fascinating pieces I read about dementia care was also in the
NY Times about life prisoners.

([http://www.nytimes.com/2012/02/26/health/dealing-with-
dement...](http://www.nytimes.com/2012/02/26/health/dealing-with-dementia-
among-aging-criminals.html?_r=1))

~~~
thoughtpalette
Wow, that was moving.

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lettergram
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.

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.

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ronnier
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.

~~~
GotAnyMegadeth
Is there any evidence that that affects things either way? (Genuinely curious)

~~~
robbiep
There is absolutely evidence that mental acuity is protective against
Alzheimer's.

From [1] Education > 15 years (cf. <12) has the lowest relative risk (0.48) of
developing Alzheimer's of all investigated interventions

Patterson, C. et al. CMAJ 2008;178:548-556 (for those that can, DOI:
10.1503/cmaj.070796 )

~~~
mzs
That's good, thanks, but it doesn't really address the original question
regarding games for example. Also what if dementia already has some effects
early in life, just more subtle. So for example early stages could be more
difficulty concentrating, variations in attention, or greater difficulty in
internalizing ideas, memorization, or recall. Then those who would later show
typical symptoms of dementia later in life would be more likely to end
education early just because they had more difficulty with it than their
peers.

~~~
robbiep
Hi Mzs, thats a really good question and you're right I don't directly address
it. Basically it's impossible to examine for that at the moment because
'games' etc would rely on a person's recall of, say, how much they did the
cross-word, that sort of thing whereas education is verifiable _and_ , in this
case, statistically meaningful.

Regarding onset of dementia.

There are early-onset dementias that can start from the late 40's to 60s.
These are usually of a genetic variant (For example, 2 copies of ApoE4 gene,
Amyloid Precursor Protein or a presenilin mutation, or Down's syndrome).
Diabetes is a big risk factor as well.

There are also a number of dementias that are of early onset that are not
Alzheimer's such as Frontotemporal dementia and Semantic Dementia which are
awful diseases and it's terrible to watch patients so young with such severe
pathology.

> _Also what if dementia already has some effects early in life, just more
> subtle._

Just to focus on the most common dementia, Alzheimer's - We know that it
_doesn 't_ have more subtle effects early on. When you start to develop it,
you start to develop it. The following things are the features of Alzheimer's,
in order of progression:

\- Memory

o Impaired anterograde episodic memory

o delayed recall of stories

o ‘Sparing’ of Working memory

\- Attentional and executive deficits

o poor concentration

\- Language and Knowledge

o Impaired semantics

\- Visuospatial and perceptual disabilities

But It definitely is not apparent so early for example in people at 20 or 30
years of age.

We know this because brain biopsies from post mortems of young people don't
show the neuronal loss, amyloid plaques and 'tombsones' of Tau protein tangles
on histology which is pathognomonic of the disease.

In fact, Education seems to be so important at preventing the march of the
disease _not_ because higher levels of brain activity somehow decrease
deposition of the characteristic histology findings, but because increased
education increases so-called 'cognitive reserve', meaning that even when the
damage starts to occur, the person is still able to function at such a high
level because the decline in global cognitive capabilities has not yet been so
great that the characteristic signs and symptoms have begun to manifest.

Could you argue cause vs effect with regard to education and cognitive
reserve? Sure, and I haven't examined the data closely enough with regard to
education to know how or if they controlled for it. However I have read
_extensively_ from the original literature with regard to the origins and
pathogenesis of the disease and trust that something that is trumpeted at
being a major factor in delaying the development of AD, by way of the quality
of the reporting literature (Lancet, NEJM, Nature and Nature Medicine) to not
have been missed after extensive peer review over the course of several
decades (?the argument from authority? I feel it is well enough established to
be fact)

~~~
mzs
Thanks, I did not know about the results from biopsies of young and that was a
good point about the quality of data just asking about how much people
remember doing something like puzzles and games. I really enjoy this site
thanks to the thoughtful comments, have a good one.

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solnyshok
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

~~~
leoedin
While I certainly agree with your suggestion that there might be self-
selection bias in play (as commented on in the article), to suggest that the
subjects were concerned about the NSA or Google is ridiculous. The study was
undertaken between 1984 and 1994. Google didn't exist and the vast majority of
the population had no internet access. The idea of electronic data privacy had
probably not even occurred to most approached. I would be surprised if more
than a handful of those approached (all aged above 65 in 1994) even owned a
computer.

Please don't hijack _every_ comment thread with irrelevent complaints about
the NSA.

~~~
solnyshok
Ok, I did not pay attention to the timespan, thought it is much more recent
study. This however, doesn't alter anything, people today are no more willing
to self-reveal fatal/terminal/disabling ilnesses, or even to accept having one
- than 100 years ago

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ExpiredLink
I suspect a statistical error.

~~~
wtallis
Are you suspecting any particular analytic error, or are you just expressing
an unwillingness to believe in the conclusion without regard for the strength
of the evidence?

~~~
ExpiredLink
A drop of more than 25% would be sensational indeed. This is highly
implausible. The article even hints at "methodological problems" in previous
studies. BTW, medical studies in general are known to be prone to
methodological errors.

~~~
pcrh
I work in this area, and I would be inclined to agree with you. The most
likely cause of this result is methodological variance. Even if that can be
formally excluded (which is unlikely), the next most likely reason (alluded to
in the article) is that dementia is one aspect of ageing, and that if people
are healthier for longer then the effects of ageing are less pronounced in the
younger elderly. Thus it would have no impact on the eventual likelihood of
dementia for an individual, just that it might occur later than it otherwise
would.

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dr_
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.

~~~
guhemama2
Some studies show that the medications efficiency is variable, but in college
I did a long term study with elder people with dementia, and guess what was
the conclusion? The ones that did not take meds had bigger cognitive losses,
and the ones that did take meds on _early_ dementia stages had a smaller loss.

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crucifiction
Unleaded gasoline.

~~~
ams6110
Leaded gasoline potentially affected at most a few generations in the 20th
century. Do we see a spike in dementia correlated with the years that leaded
gasoline was used?

~~~
Spooky23
Just conjecture -- but the ww2 generation would have had the most lifetime
exposure to leaded gasoline. They're dying off in increasing numbers.

Subsequent generations may have had less exposure due to suburbanization and
the banning of leaded gas.

