
Dementia rates 'higher near busy roads' - steve_w
http://www.bbc.co.uk/news/health-38506735
======
amai
It is not pollution, it is the noise and the low quality of sleep that causes
dementia. Good sleep quality is important so the glymphatic system that cleans
the brain of garbage while sleeping can work well. See this recent article:
[https://www.scientificamerican.com/article/nedergaard-how-
th...](https://www.scientificamerican.com/article/nedergaard-how-the-brain-
dumps-its-trash-video/)

~~~
Reason077
_It is not pollution_

PM2.5 particles from vehicle emissions are small enough to penetrate the
blood-brain barrier and have been shown to end up in brain tissue.

Even if it isn't a direct cause of dementia, air pollution contributes to
cardiovascular diseases which are themselves risk factors for dementia.

~~~
pasbesoin
I'll add my speculative observation to the mix: Pollution aggravates my
allergies, and when I'm having an allergic reaction, I have poorer sleep.

I suspect this result may be reflective of multiple factors that remain to be
associated, qualified, and quantified with respect to this overall
correlation.

------
awjr
In terms of pollution I'm assuming we are talking about NOx, PM2.5, and PM10.
However it would be useful to understand if lead, banned in most countries
around 2000, impacts dementia and whether this is now beginning to show itself
within this study.

~~~
lostlogin
My favourite lead and violence link -
[http://motherjones.com/environment/2016/02/lead-exposure-
gas...](http://motherjones.com/environment/2016/02/lead-exposure-gasoline-
crime-increase-children-health)

~~~
awjr
That's a brilliant article.

~~~
Retric
In the end there are huge range of causes that all impact these statistics.

For example, the rise of video games which may be a stronger explanation. One
way to test this is if their are dips in violence around the release of GTA or
other ultra popular games. With the method of action simply being fewer human
interactions.

That said, the indirect evidence is even low levels of environmental lead
contamination are significant over a population. Which suggests other things
may cause similar issues without people noticing. EX: mad as a hatter

~~~
lostlogin
The correlation matches the phasing out dates in various places. The dates
lead were discontinued weren't the same everywhere. Edit: how would games
explain the geographic distribution? Areas with heavy lead contamination seem
to have more of the effects, although no mention is made of game
console/computer prevalence in any of the lead articles.

~~~
Retric
ED: This is in terms of the New York City drop in violence around 1993.

The data is just not as clear as your suggesting. After controlling for
various things there is a percentage of the variation that links back to lead
levels, but that does not mean it's the only or even the strongest impact in
the raw data. Further, lead usage is linked to other things and as such is not
completely independent.

PS: Remember, people move so lifetime exposure get's really hard to track
accurately without regular blood tests.

~~~
lostlogin
I'm struggling to find the other article that covers a broader geographic
area, it was posted here last year. This one is a ok
[http://www.bbc.com/news/magazine-27067615](http://www.bbc.com/news/magazine-27067615)

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Pica_soO
Could there be some guarding reflex, that detects irregular sound or the
absence of regular sounds and jump starts the sleeping mammal if predator
presence is detected?

[https://dash.harvard.edu/bitstream/handle/1/5342191/Acerbi%2...](https://dash.harvard.edu/bitstream/handle/1/5342191/Acerbi%20and%20Nunn%20AB.pdf?sequence=1)

[http://the.sleep.ru/lib/NeurosciBiobehavRev_2008_dolphins.pd...](http://the.sleep.ru/lib/NeurosciBiobehavRev_2008_dolphins.pdf)

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epalmer
Hum. I live maybe 3000 feet from very busy road. Luckily there is forest
between my home and the road. From the article it would seem that my "risk
factor" is nil.

At 63 I am starting to think more about dementia risk factors.

~~~
wil421
I wouldnt worry too much. My grandfather has dementia symptoms and he's 90.
You could have another 30 years.

One advice after watching him is to never quit your hobbies until you
abosolutely have to. His mental decline was sharp after giving up hobbies he
had for 40 years.

~~~
epalmer
I don't worry too much. Just try to pay attention to what researchers are
saying and controlling what I can with my lifestyle.

I work still and will continue to work till at least 67.

I'm a developer and development manager so I get to challenge my brain
routinely at work. I consume nuts, lots of and a variety of tea, a little
chocolate and some red wine to help with polyphenols [1]. Oh and Omega 3 fatty
acid sources. I am actively getting my weight under control.

I play puzzles, board games and other things to stimulate my brain.

[1]
[https://www.researchgate.net/publication/308945733_Nutrition...](https://www.researchgate.net/publication/308945733_Nutrition_for_the_ageing_brain_towards_evidence_for_an_optimal_diet)

~~~
wil421
As a 30 year old I think of the same. I'm trying to not spend the next 30
years being sedentary in a office.

I'm trying to pick of all kinds of outdoor hobbies I can do year around.

~~~
epalmer
I've been sedentary most of my life. That has turned out to be not so good for
my health. I do go workout now about 5 times a week. Been doing that for 3+
years.

I think your strategy of finding outside hobbies can be a real benefit.

------
unclebucknasty
There is a correlation between living near busy (noisy) roads and sleep
deprivation and also between sleep deprivation and dementia.

Seems like a possible mechanism that didn't appear to be explored.

~~~
tunap
My initial thought follows this line. Even if a subject doesn't experience
actual sleep deprivation, the constant external stimuli are still omni-
present, regardless of how well the conscious mind tunes them out. Perhaps
sub+consciously parts of the brain never get any rest, even while sleeping?

I know I feel less refreshed if I fall asleep and media or traffic outside is
constant. A hotel room facing a freeway often leaves me waking unrefreshed,
which can be partially mitigated if the room's fan blower is left on for
continuous, monotonous white noise masking.

~~~
unclebucknasty
Yeah, it can disturb your all-important REM sleep without causing you to fully
awaken, so you're not aware that your sleep has been disturbed. You're just
not as refreshed by morning.

Interesting about the fan blower. My wife started using that to prevent our
young kids from being awakened by normal household noise. It reminded me of
something I'd read years ago about people who worked in server rooms losing
hearing sensitivity in the range of the constant low-level hum. Not sure how
much exposure was required, but I encouraged her to use it sparingly.

~~~
dpark
I wonder if that's permanent hearing loss or temporary desensitization. It's
not hard to imagine that the brain eventually starts to tune out a constant
60db server hum without any mechanical or permanent hearing loss.

------
rollthehard6
Easy to imagine vascular dementia rates being higher due to air pollution,
would be interesting to see if rates of non-vascular dementia, such as
Alzheimer's are also higher.

~~~
onion2k
It's equally easy to imagine that people who have a brain chemistry that makes
them value things like quicker access to transport or a faster pace of life
that makes them want to live in the centre of a city are also more susceptible
to dementia though. This research has highlighted an interesting correlation
that's worth studying, it's not _necessarily_ showing that pollution is the
cause.

~~~
DaiPlusPlus
[https://www.eurekalert.org/pub_releases/2017-01/pho-
lnm01031...](https://www.eurekalert.org/pub_releases/2017-01/pho-
lnm010317.php)

According to the press-release, a difference in distance of only 50m from a
high-traffic road creates an observable 7% difference in dementia risk.

I'd say it's very easy to both live in a city centre and live 50m away from a
major road.

------
dvh
Shouldn't car mechanics also have higher dementia rate?

~~~
viraptor
General car mechanics probably not. I don't think they spend that much time
next to running (and not just idling) engines. But I like that train of
thought... how about professional drivers - truck, bus, taxi?

~~~
mymythisisthis
Truckers die early [http://www.truckinginfo.com/article/story/2012/07/fmcsa-
answ...](http://www.truckinginfo.com/article/story/2012/07/fmcsa-answers-
questions-about-driver-life-expectancy-statistics.aspx)

------
martincmartin
Has the study been replicated? If not, we can't know whether it was a
statistical fluke, bad methodology, or some other oversight in the experiment.

(I know they do statistical tests, but they often use the wrong tests.)

[https://en.wikipedia.org/wiki/Replication_crisis](https://en.wikipedia.org/wiki/Replication_crisis)

------
philfrasty
I was wondering lately why noise-cancelling technology is not used inside
residential-buildings? Is there such a big difference between making this
technology work inside my Bose-headphones vs an apartment? Street-noise seems
pretty predictable and steady from afar.

edit: bad bad grammar

~~~
warcode
ANC/R works by sending out the opposite waveform of the noise, at about the
same volume. It does not remove noise.

Passive noise control through insulation is the best solution for residential
buildings.

~~~
Naritai
I have long wanted to investigate advanced methods of reducing noise
transmission between rooms; it seems to me that's a area that will clearly
need improvement if we really expect cities of the future to be towers and
condos instead of standalone houses. But you're correct that whatever solution
does exist won't look / act like noise-canceling headphones.

~~~
Tharkun
I think that's an area that would benefit less from investigating and more
from acting. But for some reason people think a room that's 20cm wider is
"better" than one with sound-proofed walls.

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conductr
Perhaps a correlation to people who live busier/more stressful lives in
general.

------
stewbrew
Are there any educated, rich people with a healthy lifestyle living within 200
m of a busy road around? I would be interested in your stance on this.

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finid
A study like that need to be conducted in New York City (USA), especially in
Manhattan and Brooklyn.

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chatwinra
Can't read the article because it's behind a paywall (sigh).

Any indication of how the researchers defined a 'major road'? Was it purely
size or done by traffic throughput over time? Or did they be use air pollution
/ noise measurements instead?

~~~
abstractbeliefs
[https://archive.fo/CCg3d](https://archive.fo/CCg3d)

------
stuaxo
Is it possible to filter out particulates in the home?

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nrjdhsbsid
Ehhhh I feel like the researchers took 5000 variables and threw them at the
wall to see what sticks.

Living near busy roads is usually cheaper... And I doubt people with dementia
are locking down C level positions

~~~
awjr
The study specifically adjusts for poverty/lifestyle.

~~~
reddytowns
But what proof is there that their adjustments covered every possible cause? I
would suggest this is by definition impossible, since if we knew every
possible cause for dementia, we would not need to do the study.

~~~
dpark
They obviously didn't cover every possible cause nor should they be expected
to. With that logic no one could ever do an empirical study.

~~~
reddytowns
True, but there should be some rationale as to why they assume that
normalization wrt the cofactors they've chosen are sufficient to provide for
their conclusions.

Simply seemingly randomly choosing cofactors and then shrugging it off as good
enough to draw conclusions from is sloppy. Typical, yes, but mean you
shouldn't be skeptical of their conclusions, no.

~~~
dpark
Your specific concern was about socioeconomic status and because they answered
that you now call it a random cofactor. Come on. You're not giving meaningful
criticism. You're just being negative.

