
Exercise Tied to Lower Risk for Some Types of Cancer - hvo
http://well.blogs.nytimes.com/2016/05/18/exercise-tied-to-lower-risk-for-13-types-of-cancer/?rref=collection%2Fsectioncollection%2Fhealth&action=click&contentCollection=health&region=rank&module=package&version=highlights&contentPlacement=1&pgtype=sectionfront&_r=0
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azdle
I don't have access to the actual paper, but my first thought on this is to
wonder if they factored in the idea that people who specifically exercise are
obviously interested in being healthy and may be doing other things that are
"healthy" that would affect whether they get cancer or not.

I wonder if it'd be possible to get data on people who are active, but not for
the reason of being healthy, things like working construction, and compare
that to see if it's the activity itself or just the mentality that comes from
wanting to be healthy.

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mrfusion
Here's the problem with your idea though
[http://www.npr.org/templates/story/story.php?storyId=1779251...](http://www.npr.org/templates/story/story.php?storyId=17792517)

It suggests people get more benefits from exercise when they expect it.

I'm curious to hear your thoughts.

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azdle
That's a very interesting experiment, however, at least from how it's
described in that article, I don't think it's anywhere rigiorus enough to draw
any conclusions from.

> One possible explanation is that the process of learning about the amount of
> exercise they were already getting somehow changed the maids' behavior. But
> Langer says that her team surveyed both the women and their managers and
> found no indication that the maids had altered their routines in any way.
> She believes that the change can be explained only by the change in the
> women's mindset.

I think that they're too quick to dismiss a change in behavior. Simply asking
someone (and their managers‽) if they did anything different this month than
they did last month isn't a very reliable way to figure out if there were any
subtle changes in behavior.

I don't know if they were expecting massive conscious changes, but I would be
shocked if suddenly knowing that their daily routine is good for them didn't
change some of the subconscious decisions they were making. Even just simple
things like taking the stairs 10% more than they did before or how they decide
when and how much to eat based on a certain level of hunger. You're still
going to think "I took the stairs sometimes, but took the elevator when I
needed it." or "I ate the same foods that I did before." but maybe you were
taking smaller portions.

Basically what I'm trying to say is that it's very hard to draw hard
quantitative conclusions from vague qualitative assessments.

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seizethecheese
Results from the source study abstract[1]:

" A total of 1.44 million participants (median [range] age, 59 [19-98] years;
57% female) and 186 932 cancers were included. High vs low levels of leisure-
time physical activity were associated with lower risks of 13 cancers:
esophageal adenocarcinoma (HR 0.58, 95% CI 0.37-0.89), liver (HR 0.73, 95% CI
0.55-0.98), lung (HR 0.74, 95% CI 0.71-0.77), kidney (HR 0.77, 95% CI
0.70-0.85), gastric cardia (HR 0.78, 95% CI 0.64-0.95), endometrial (HR 0.79,
95% CI 0.68-0.92), myeloid leukemia (HR 0.80, 95% CI 0.70-0.92), myeloma (HR
0.83, 95% CI 0.72-0.95), colon (HR 0.84, 95% CI 0.77-0.91), head and neck (HR
0.85, 95% CI 0.78-0.93), rectal (HR 0.87, 95% CI 0.80-0.95), bladder (HR 0.87,
95% CI 0.82-0.92), and breast (HR 0.90, 95% CI 0.87-0.93). Body mass index
adjustment modestly attenuated associations for several cancers, but 10 of 13
inverse associations remained statistically significant after this adjustment.
Leisure-time physical activity was associated with higher risks of malignant
melanoma (HR 1.27, 95% CI 1.16-1.40) and prostate cancer (HR 1.05, 95% CI
1.03-1.08). Associations were generally similar between overweight/obese and
normal-weight individuals. Smoking status modified the association for lung
cancer but not other smoking-related cancers."

[1]:
[http://archinte.jamanetwork.com/article.aspx?articleid=25218...](http://archinte.jamanetwork.com/article.aspx?articleid=2521826)

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methodover
Phew, 186 thousand cancers included out of 1.4 million participants? I knew
cancer was not entirely uncommon but... man. That's a lot of unhappy news.
Feels bad to think about.

If it is true that exercising regularly reduces the risk of cancer, I wonder
what the mechanism is? Exercise builds muscle mass, improves lung capacity...
Why would that have anything to do with cancer?

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trhway
>Phew, 186 thousand cancers included out of 1.4 million participants? I knew
cancer was not entirely uncommon but... man. That's a lot of unhappy news.
Feels bad to think about.

2 out of 5 will get cancer during their lifetime.

[http://www.cancer.gov/about-cancer/what-is-
cancer/statistics](http://www.cancer.gov/about-cancer/what-is-
cancer/statistics)

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ekianjo
And close to 50 percent once uou cross the 80s. The biggest factor for cancer
is aging.

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jimrandomh
No. This study is confounded and provides no evidence of anything.

The problem is that people's willingness to exercise depends on their health
as much as or more than their health is affected by exercise. Because this
study did not involve an intervention (it just pooled a bunch of surveys), it
can't distinguish between exercise causing reduced cancer risk, or a third
variable affecting both.

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Someone1234
The same could be said of almost any study that tried to show this. It is
unethical to design the study in the way you're suggesting (i.e. stop people
exercising to see if they get cancer).

They did however:

> Body mass index adjustment modestly attenuated associations for several
> cancers, but 10 of 13 inverse associations remained statistically
> significant after this adjustment.

So even for two thin people, exercise seems to have helped. I legitimately
don't see how you could design a study that you'd be satisfied with.

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jimrandomh
The correct study is one where some participants get an intervention to make
them exercise more, and some are left alone. There's no ethical issue, but
running such a study would be difficult and expensive.

Adjusting for BMI does not solve the problem, because there are many things
besides BMI (unmeasured confounders) which affect both cancer risk and
willingness to exercise.

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ekianjo
And BMI is a pseudo science measure anyway. Its been proven to be a poor
indicator in about every disease many times before.

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aortega
I think it's pretty obvious. I believe that it is not that exercise helps, but
sedentarism is poisonous. A sedentary 40 year old looks and feels 20 years
older than a 40 year old athlete.

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ousta
actually a 40yr old athlete that has already more than 20 year of athlete life
behind will have a body in a much more bad shape than a guy who had regular
walks and healthy diet.

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aortega
I'm talking about a healthy athlete, not one that it's into professional
sports and actually destroys his body or hearth with substance abuse.

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WaBlueKey
Risks are often affected by your genetic makeup, eating and exercising habits,
where you live, what type of work you do, and childhood exposure to harmful
materials. There are other things that influence the risk level.

Personally, staying informed and listening to my body has been my best
medicine, but I'm also aware of my family history with different diseases,
which helps shape my choices.

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cJ0th
It would be interesting to see whether or not one could show that exercise is
tied to higher risk for some types of cancer if they would use the same
methodology analogously.

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ekianjo
This article is poorly written. The term 'tied' is correct in the title since
its an observational study, but then it jumps directly into implying a causal
relationship based on the correlation. Correlation is not causation.

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known
Drink hot water and go for one hour early morning walk;

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fsiefken
why hot water, I read that cold water burns some calories as well?

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ars
> I read that cold water burns some calories as well?

Not very many. An 8oz cup of water at 40F burns 2.1 calories to warm up to
body temperature.

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ekianjo
20 percent less between super active folks and non active ones is not super
convincing. If it diminished the risk by 80 percent instead it would make for
a much better story

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enraged_camel
>>20 percent less between super active folks and non active ones is not super
convincing.

Do you mean "compelling"? Because it should definitely be convincing: it's
well outside the margin of error.

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ekianjo
Yeah, compelling is what I meant.

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birdDadCawww
Not even going to read this but cancer is pure environmental and can be
avoided. some people get exposed to things and it sucks. yeah eat healthy and
move spontaneously.

