

Coffee drinking linked to longer life - jonbischke
http://www.cnn.com/2012/05/16/health/coffee-drinking-longer-life/index.html

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ryandvm
My guess is that if you're drinking 6 cups of coffee a day, you've probably
got yourself a nice white collar job - and a lot of the other life lengthening
perks that come along with gainful employment.

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cynicalkane
Like almost everyone else who will comment here, I haven't read the study, but
studies normally statistically control for these sorts of things.

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Cushman
Thanks for that. It's a little annoying that every time a study like this
comes up, somebody jumps in with "Well, did they control for [obvious thing to
control for]?"

You don't become a scientist because you're lazy and stupid. If you're reading
about a study and think there's an obvious reason it's inaccurate, you are
almost certainly wrong. Not that the study is not inaccurate -- many, perhaps
most are -- but the reason is definitely not obvious. It's something that the
authors, people who have spent a lot more time thinking about it than you, and
who are probably smarter and better educated to boot, never figured out.

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cjbprime
Guess what: it looks like the authors didn't control for income (or even just
whether the person has a job!) or intelligence.

I just read the paper; there are many diet and exercise-related controls, and
that's it as far as I can see. I totally agree with the OP that being _the
kind of person who might drink coffee_ probably has a confounding effect on
health. I can't even think of how to try to control it properly.

I don't understand how you get from "most studies are inaccurate" to "but you
shouldn't assume the ones that get reported on in the media are inaccurate in
a way that we can detect". Why not? People who are performing studies that get
picked up by popular media are the _least_ likely people to be performing
their work rigorously, and the most likely to be choosing a sensational
hypothesis that's difficult to measure correctly.

I agree that we might eventually get to a point where the amount of skepticism
and cynicism about scientific results vastly outweighs the number of papers
published with poor experimental design or lack of real statistical
significance. But I don't think we're currently anywhere close!

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Cushman
You make some good points, so I hope this doesn't seem dismissive-- my claim
is not that the study is right. My claim is simply that the editors of the
NEJM decided to publish the study having read it in greater depth than any of
us here would care to, so if I read the CNN article and think there's an
obvious reason it's not true, I can be pretty sure I'm wrong.

Now that being said, I think we're talking at cross purposes. The study found
a link between coffee drinknig and mortality; I misread the GGP as being
critical of that link, where it's actually just a hypothesis which would
explain it. So none of this is really relevant :P

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hogworth
Gosh I hope this doesn't come off as too negative, but what is the point
finding these 'links'?

Science is about trying to explain the world, not looking for random facts.

We learn nothing of substance about coffee, health or anything else from this
article. Yet it has the appearance of being scientific, for example, it
mentions antioxidants.

It wouldn't be fair to label it _pseudoscience_ however it does share some of
the features.

People are starting to learn by now that correlation doesn't imply causation,
but they still think it is suggestive of causation, or makes causation more
probable, or something like that.

To try to dispel that: the fact that coffee drinking correlates positively
with life expectancy is logically consistent with coffee acting to _reduce_
lifespan. More importantly, knowing causes is not very helpful since pretty
much everything causes pretty much everything else.

What is useful is solving problems and trying to explain the world. That's
what people like Newton, Darwin and Einstein were doing.

FWIW my guess is that drinking coffee causes people to eat less food which
might indeed result in greater health, though this doesn't seem like a
fruitful line of enquiry.

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Someone
Do you know on how many centuries of tabulating 'links' Newton, Darwin, and
Einstein built their work? Apart from modesty, there is truth in Newton's
claim about standing on the shoulders of giants.

Also, this is not a random fact. People have argued both ways whether coffe is
healthy or not. If we want doctors to give advice based on facts, we have to,
somehow, figure out who (if anybody) is right there. Barring a clear mechanism
either way, looking for facts is a step towards scientific understanding.

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sma
NPR article on the same study, with link to the study itself,
[http://www.npr.org/blogs/thesalt/2012/05/16/152835058/can-
co...](http://www.npr.org/blogs/thesalt/2012/05/16/152835058/can-coffee-help-
you-live-longer-we-really-want-to-know)

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cjensen
Typical CNN. The study finds an association, so CNN reports a causation.

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sophacles
Did you actually read the article? The only thing that might imply causation
is the word "linked". However that also could imply correlation.

define link: A relationship between two things or situations, esp. where one
thing affects the other

define correlation: A mutual relationship or connection between two or more
things

The definitions are close enough that even amongst the math/science
researchers I work with, the words are frequently used interchangeably.

Everything else in the article talks in terms of "maybe", "plausible",
"associated" and so on. All words that don't imply causation, nor rule it out.
Further, the article is careful to point out that:

 _The explanation for the study findings "might not specifically be the
coffee," Fisher says. "It might be some characteristic of the coffee
drinker."_

I'n all, I found it to be pretty good "science for the layman" reporting - to
the point where I was surprised at how good it was.

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xutopia
I have a slow caffeine metabolism (SNP: rs762551) and according to some
studies this may lead to me to develop heart disease if I drink too much
caffeine.

The fact that I'm a minority and that fast metabolizers might actually benefit
from caffeine says to me that going just on that article might not be a good
idea.

A majority of people might benefit from caffeine, while a minority might have
really dire consequences.

/edit this is all preliminary research so add more weight to "might" that I
use here.

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sophacles
Tangential: I was actually pretty surprised at how good this article was at
not being too hype-filled. It discussed the report in terms that did not imply
causation. It offered potential explanations (with caveats that they were just
speculation), pointed out potential flaws with the stats (2 different places
where unaccounted factors may be the real responsibility), and generally
didn't say "go drink lots of coffee, it will save your life".

So my kudos to the author and editor for being reasonable.

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arethuza
"The spice extends life. The spice expands consciousness..."

Given my dependence on coffee I'm probably going to end up floating in a tank
of the stuff a few thousand years from now.

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pixie_
Obviously this is because coffee makes you super alert. People on coffee don't
get in as many traffic accidents, and also defuse bombs better.

