
A Medical Mystery of the Best Kind: Major Diseases Are in Decline - suprgeek
http://www.nytimes.com/2016/07/10/upshot/a-medical-mystery-of-the-best-kind-major-diseases-are-in-decline.html
======
magila
On the other hand, autoimmune diseases have been increasing in prevalence over
the last century. While these diseases are rarely immediately fatal, in severe
cases they can have a major impact on quality of life. Onset often occurs in
early adulthood so the cost of treatment over a lifetime can be extremely
high. The usual treatment, immunosuppressive therapy, also has serious risks
of its own.

While there has been much progress on finding new treatments, their scope has
been limited to new and creative ways of suppressing the immune system. There
are a multitude of theories which attempt to explain the causes of autoimmune
diseases, but we seem to be quite far from truly understanding them.

~~~
alexandercrohde
Absolutely. I wish this article wouldn't speak so generally when I hear
consistent articles about major spikes in:

\- Autoimmune issues (especially allergies) \- Obesity (particularly in
children) and diabetes \- Autism \- Depression, ADD, and similar disorders

~~~
PhasmaFelis
> _Autism - Depression, ADD, and similar disorders_

My personal impression is that the rise of mental conditions is an increase in
diagnosis, not occurrence. An awful lot of people who, just a few decades ago,
would have been dismissed as lazy, stupid, whiny, or the all-purpose "crazy"
are actually starting to receive recognition and treatment. That's a good
thing.

~~~
OvidNaso
The increase in suicide rates seems to be evidence against this hypothesis.

~~~
lsc
are suicide rates going up overall? all I can find, back to the 1950s, is that
the rate has gone up and down with no clear upwards or downwards trend over
those years (2010 rates are slightly below 1950s rates)

[http://www.infoplease.com/ipa/A0779940.html](http://www.infoplease.com/ipa/A0779940.html)

~~~
satai
For CZ we have stats up-to 1870s:
[https://www.czso.cz/csu/czso/sebevrazdy_zaj](https://www.czso.cz/csu/czso/sebevrazdy_zaj)

(link in czech - sorry. First image, brown line is relative suicidal rate that
is probably a good metric for comparison.)

------
mrfusion
I always wondered if the removal of lead in gasoline could account for a lot
of this. Especially the dementia drop.

~~~
SCAQTony
It is never one thing; your lead assessment is probably a serious contender
among other pollutants. Then there is better hygiene via food handlers,
stiffer USDA rules, cleaner water, less smoking and second hand smoke, more
people exercising too.

~~~
JacksonGariety
Smoking rates are only decreasing in developed nations. Globally it's
increasing by ~1% each year.

~~~
Ensorceled
The study is talking about wealthy (e.g. developed) nations this doesn't
apply.

~~~
JacksonGariety
I was just replying to his comment. It's a "mainstream" idea that people like
to repeat, but it's simply untrue.

It's like a stock phrase: "Smoking is actually going down, you know! People
really _are_ getting smarter/healthier/happier/whatever."

It's just false.

------
lordnacho
Speculation:

\- People have become more aware of the risk factors, and behave accordingly.
Awareness would be connected to prevalence but have a lagged effect.

\- Deadly diseases cause evolutionary responses. Perhaps a disproportionate
number of people with predisposition to these illnesses passed away before
having offspring.

\- Reporting bias? While an illness looms large in the minds of the medical
community, doctors are more likely to either wrongly attribute to the illness
(false positive), or do false negatives less often.

\- Highly speculative: combined effects are non-linear. I don't know what they
use to do these studies, but typically you hear something along the lines of
"for every x, there's m*x effect", which makes things sounds nice and linear.
Maybe better prevention and better treatment does better than either on its
own summed up, and so you won't be able to find the "reason" by splitting into
each feature.

~~~
tlrobinson
I don't think you'd see any significant evolutionary responses in the
timeframes the article is talking about (<100 years or 4 generations)

~~~
Swizec
Haven't studies shown that high stress (like concentration camp) has immediate
effect on next generation's DNA? That would indicate that it's at least
potentially possible for evolutionary adaptation to work pretty fast.

~~~
bhouston
That isn'y evolution if it is epigenetic, it would be another type of
adaption, Lamarckian really:
[https://en.wikipedia.org/wiki/Lamarckism#Epigenetic_Lamarcki...](https://en.wikipedia.org/wiki/Lamarckism#Epigenetic_Lamarckism)

~~~
coltonv
This is incorrect. Evolution is simply change over generations by natural
selection. the mechanism by which that happens, be it DNA or epigenetics or
whatever, is not strict

~~~
aroch
Yes/no... It has to be heritable beyond a single reproductive cycle. Which
isn't the case with all epi markers.

------
sgt101
wow - I have no clue (obviously) but possible reasons :

\- better home heating (less open fires, more heated bedrooms)

\- increased time from atmospheric nuclear bomb testing (and the various
dispersals of plutonium in the 60's and 70's)

\- better nutrition in general

\- higher genetic diversity in breeding populations; not many peoples
grandparents all come from the same village in the developed world now

\- less pollution in the west; import of finished goods rather than local
manufacturing

~~~
ekianjo
> increased time from atmospheric nuclear bomb testing (and the various
> dispersals of plutonium in the 60's and 70's)

Ambient radioactivity, under a certain threshold (which is disputed) has
actually shown some positive effects. If I remember correctly, folks living in
naturally more radioactive areas have been showing lower cancer rates vs the
average.

~~~
daveguy
This is a great big citation needed. Come on, you can't "if I remember
correctly" a statement like "some radiation is good for you."

~~~
alejohausner
OK, I'll supply a citation, which argues the opposite. See the Wikipedia page
on "radiation hormesis". Scroll down to "cobalt 60 exposure".

TL,DR: Many apartments in Taiwan were radioactive, because the steel in the
structure had been mixed in with 60Co. Residents got big doses of gamma rays.
And yet they didn't get much cancer! It turns out that no, gamma rays are not
good for you; rather, most residents were young, biasing the sample (few young
people get cancer). The study didn't account for this bias.

------
ktRolster
This is weird:

    
    
      >Until the late 1930s, stomach cancer was 
      >the No. 1 cause of cancer deaths in the 
      >United States.

~~~
_mhr_
I found a chart showing the prevalence of multiple forms of cancer over time:
[http://i52.tinypic.com/r9euci.jpg](http://i52.tinypic.com/r9euci.jpg).

~~~
SilasX
Weird. Why would lung cancer go the opposite direction as smoking prevalence?
I understand the dynamic of "cancer only kills people who outlive every other
cause of death", but for the discorrelation to be _that_ strong?

~~~
transcranial
The correlation is one of the strongest there is, and indeed, causal --
there's a almost perfect lag time of ~20 years [1].

[1]
[https://en.wikipedia.org/wiki/Lung_cancer#/media/File:Cancer...](https://en.wikipedia.org/wiki/Lung_cancer#/media/File:Cancer_smoking_lung_cancer_correlation_from_NIH.svg)

~~~
SilasX
The graph stops at 1970.

~~~
GFK_of_xmaspast
Are you suggesting that some post-Nixonian mechanism is in play here.

------
sjclemmy
What about widespread use of painkillers? Aspirin, paracetamol and ibuprofen
have become common place over this period. Calming the body's immune response
might have a beneficial effect on overall health.

~~~
autokad
cancer is caused by swelling, thus anything that reduces it will reduce cancer
incidents.

~~~
philippnagel
Cancer is caused by swelling?

~~~
ccallebs
Perhaps he means inflammation. Inflammation has been linked to certain types
of cancers.

~~~
autokad
yes, I meant that, and no - nearly all cancers are linked to inflammation. the
differences are in what causes the inflammation.

~~~
jeffdavis
"linked to" does not mean "caused by".

------
codecamper
I wonder if all the benefits may be coming from people having kids later in
life. You'd think this would lead to more disease, but maybe we are actually
evolving to be longer living and the kids later in life is what is causing it.

~~~
nxzero
Research does show that having kids is correlated to having a longer life
expectancy:

[https://www.psychologytoday.com/blog/iage/201410/having-
chil...](https://www.psychologytoday.com/blog/iage/201410/having-children-
beneficial-living-longer-0)

~~~
allengeorge
Maybe because the kids born in later in life are born to more educated, and
more well-off parents?

------
mrfusion
It mentions statins as something obviously good but is there any evidence
they're actually beneficial? I thought cholesterol was good now?

~~~
rollthehard6
Some doctors and researchers believe the benefit from statins is more to do
with the decrease in inflammation caused by them. Possibly widespread use of
statins has beneficial effects on other disease processes too.

~~~
Gibbon1
Yeah I think there was a large study done comparing a newer cholesterol
lowering drug with statins. The result was the new non-statin drug wasn't
effective at all even though it lowered cholesterol levels.

~~~
mrob
You might be thinking of CETP inhibitors. This class of drug modifies
cholesterol levels to numbers associated with better health, but so far none
of them have conclusively improved health outcomes:

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

Anacetrapib is still in stage III trials so it's too early to consider the
concept a failure, but I think the bad results so far are evidence that
hyperlipidemia is a symptom not a cause of cardiovascular disease, and that
statins have some mechanism of action beyond just modifying cholesterol levels
(eg. anti-inflammatory, as some people have suggested).

~~~
Gibbon1
Yes those drugs. Hard to say conclusively, but the failure of most of CETP
inhibitors is troubling news for the hyperlipidemia theory. Meaning possible
hyperlipidemia has multiple causes and in and of itself isn't bad.

AKA

Cause A results in hyperlipidemia.

Cause B results in hyperlipidemia.

Cause C results in hyperlipidemia and arterial plaques.

Cause D results in hyperlipidemia.

~~~
carbocation
Numerous lines of evidence, including randomized controlled trials, single
gene studies, and Mendelian randomization studies, are not consistent with
your interpretation.

Multiple agents that reduce cholesterol, including ezetemibe and statins,
reduce cardiovascular disease outcomes and death.

Multiple cholesterol-related genes, including HMGCR, LDLR, APOB, PCSK9, and
ANGPTL3, contain variants which influence both LDL cholesterol and the risk
for coronary artery disease, myocardial infarction, and death.

And Mendelian randomization studies that rely upon a dose-response
relationship between genes that influence cholesterol and the cardiovascular
outcomes that they cause have also demonstrated a link between genetically
driven cholesterol levels and hard endpoints.

So, one set of drugs (CETP inhibitors) that don't seem to follow the story are
more likely to be the exception, rather than the rule. Interesting biology
awaits us in the explanation of why the CETP inhibitors don't do what we
imagined they would with hard outcomes.

~~~
Gibbon1
> reduce cardiovascular disease outcomes and death.

Only in small selected populations.

------
raverbashing
The question I guess is not what diseases are in decline, but which ones are
going up

~~~
transcranial
Apparently Parkinson's disease has been on the rise over the past several
disease, some say due to the _decrease_ in smoking. Which is fascinating, as
smoking has been shown to be actually _protective_ against Parkinson's.

~~~
amorphid
Or maybe you die from something smoking related before getting Parkinson's.

~~~
seizethecheese
Or maybe both.

------
robbles
Is it possible that medical advances in the last couple of decades have simply
delayed the deaths of many sufferers? Heart disease and cancer survival rates
are usually qualified with a number of years, given that they are difficult to
fully cure. With a larger aging population just barely hanging on, perhaps an
upswing is just around the corner but hard to see now. i.e. the rate of death
has not actually dropped, the average survival time is longer.

------
lastres0rt
Put bluntly: All of these 'little increases" are starting to add up in big
ways. I'm not that surprised that a decline in one disease is leading to
declines in others. As we all live a little longer, we make each other
healthier as well, being better able to cope with the expanded safety net.

As someone who's seen her grandparents suffer with a cacophony of diseases
right before death? Sometimes, one thing really DOES lead to another.

------
throwwit
The largest extrinsic factor (causally effective), should be the environment's
physiological interaction with cells that have accumulative exposure: the
alimentary system. Lower incidences of alimentary cancers should be the
hallmark result of bans on various carcinogenic additives. The question should
be how low the rates can inherently go based on diet alone, and to then
proceed to narrow down the scope of any further factors.

------
known
Check
[https://en.m.wikipedia.org/wiki/WHO_Model_List_of_Essential_...](https://en.m.wikipedia.org/wiki/WHO_Model_List_of_Essential_Medicines)
and
[https://en.m.wikipedia.org/wiki/List_of_bestselling_drugs](https://en.m.wikipedia.org/wiki/List_of_bestselling_drugs)

------
JoeAltmaier
Is it simply, that fewer people can afford insurance/visit a doctor? So they
die of 'natural causes' and never get diagnosed?

------
nxzero
Curious, if the cause is the decline in cigarette consumption; here's a graph
showing roughly 100 years of data for the topic:

[http://4.bp.blogspot.com/-p4ECPyex_cY/TzSalazW2XI/AAAAAAAAA2...](http://4.bp.blogspot.com/-p4ECPyex_cY/TzSalazW2XI/AAAAAAAAA2o/Wrgj5mSyGHA/s1600/Smoking+1900-2006.JPG)

~~~
jschwartzi
The lines do seem to correlate. In the case of stomach cancer, I'm wondering
if there's a similar correlation between the decline in chewing tobacco and
the decline in stomach cancer. Chew is full of fiberglass and other stuff, and
if you swallow any of the juice you're swallowing that stuff. It's impossible
to clear it all from your mouth after you finish chewing, too.

~~~
DanBC
When smokers give up smoking they start to clear their lungs. They cough up
phlegm. many people swallow that, not spit it out. That increases risk of
mouth, throat, stomach, bladder, and penis cancer.

Tobacco is already pretty harmful.

> Chew is full of fiberglass

No, it isn't.

~~~
sukilot
Why don't active smokers cough up phlegm?

~~~
armitron
Many reasons.

Smoking coats the lungs with a layer of tar and heavy, chronic smokers have
coated their lungs to such an extent where there is drastically reduced lung
area in contact with the environment (and irritants/allergens). The tar acts
like a shield in this case and prevents immune response that can lead to
constriction in the lungs and phlegm production.

Moreover, active smokers have destroyed the cilia in their lungs (which start
to regenerate when one quits smoking) and it's the cilia that do most of the
cleaning and phlegm expulsion. When one quits smoking, he goes through weeks
or months of coughing and increased phlegm production as the cilia start
growing back.

Finally, a lot of active (and ex) smokers _do_ cough up phlegm. The co-factors
of phlegm production are simply too many for a definite answer. You also have
asthmatics and those who suffer from COPD/emphysema.

------
alphaoverlord
One explanation can be expanding criteria and/or earlier diagnosis. Earlier
diagnosis, even with the same treatment efficacy, will lead to records of
improved survival, and expanding criteria of particular diagnoses will often
identify borderline cases that likely don't have the same morbidity and
mortality.

------
triadicmonad
Of course hundreds of probable individual causes can be attributed to this
phenomenon. The Galileo of medicine will be the one who can unify and make the
data sensible without pretending one or two factors caused it all.

------
dmix
Better home food (popularity of brown bread vs white bread), better take out
food (not just McDonald's and diners anymore), and more indoor working
conditions (less exposure to pollution) likely play a big part.

------
artagnon
Our genes are somehow improving in quality (survival longevity, quality of
life, IQ), and this effect is cascading over generations. I don't know if it
can be explained using pure epigenetics, and natural evolution is certainly
too slow to explain this, so there might be mutagens in our everyday
environment that directly modify the DNA sequence. We recognize cigarette
smoke, heavy metals as mutagens, but are there more subtle mutagens that lead
to better DNA?

------
dm03514
Coffee?

------
mrfusion
Interesting about the stomach cancer. Makes me wonder if we should be careful
about limiting antibiotic usage too far? Perhaps everyone should take a course
every five years or so?

~~~
sukilot
What does one have to do with the other?

~~~
Chinjut
From the article: "Until the late 1930s, stomach cancer was the No. 1 cause of
cancer deaths in the United States. Now just 1.8 percent of American cancer
deaths are the result of it. No one really knows why the disease has faded —
perhaps it is because people stopped eating so much food that was preserved by
smoking or salting. Or maybe it was because so many people took antibiotics
that H. pylori, the bacteria that can cause stomach cancer, have been
squelched."

