On Thu, 21 Jun 2001 21:14:44 -0700, Chas F Brown
<[EMAIL PROTECTED]> wrote:
>
>
>"David C. Ullrich" wrote:
>>
>> On Fri, 15 Jun 2001 15:23:03 +0100, Paul Jones
>> <[EMAIL PROTECTED]> wrote:
>>
>> >"David C. Ullrich" wrote:
>> >>
>> >> But analyzing it this way simply makes no sense. Those
>> >> "trials" you're talking about are _far_ from independent;
>> >> each "trial" is associated with a particular person, and
>> >> there will be a very strong correlation between various
>> >> "trials" for the same person at different hours.
>> >
>> >Okay then, how should it be analysed?
>>
>> I've explained at least twice why I do not believe it
>> is _possible_ to draw the sort of inference you want
>> to draw from the data you've given us. You must
>> be reading _some_ of those posts or you wouldn't
>> keep replying.
>>
>
>Well, although I've agreed with most of your complaints about trying to
>derive any information from the scanty data shown, there is *something*
>we can notice about the data set which has some relevance.
>
>Let's say we look at a sampling of 100 people who have both had heart
>attacks within the last year and have smoked an aspirin an average of
>once a week during that year.
>
>Now, without knowing what the average percentage of people who smoke
>aspirin each year, and the average percentage of people who have heart
>attacks each year without smoking aspirin, these numbers alone would be
>pretty useless.
>
>But if 95% of the people in the data set had their 1 heart attack inside
>of 1 minute after smoking an aspirin, you'd have some reason to further
>examine the hypothesis that, for some segment of the population, smoking
>an aspirin could trigger a heart attack. (Of course it could also be
>that impending heart attacks bring on the desire to smoke aspirin, or
>some other hypothesis that correlates the two phenomena).
>
>One the other hand, one would expect if there were no immediate
>correlation between smoking aspirin and heart attacks, the average time
>between smoking aspirin and heart attack would be more like 1/2 week.
>This would then indicate that it was not particularly worthwhile to
>investigate an immediate link between asprinin smoking and heart
>attacks.
>
>That seems to be the type of correlation that was reported here - some
>distribution of MJ smoking, and its *temporal* correlation with heart
>attacks.
>
>Now, that says exactly nothing about whether MJ use increases or
>decreases the liklihood of having a heart attack in general (it could in
>fact in general *decrease* heart attacks, even in our data set);
That's exactly right. When I say that there's nothing we can conlude
from the data given I didn't mean there's _nothing_ we can conclude,
rather nothing we can conclude _concerning_ the question of
whether smoking increases the risk of a heart attack.
I don't see how we can even quite conclude that the risk of a heart
attack is higher among users immediately after smoking, for various
reasons: I doubt that most users' use is uniformly distributed
during the 24 hours of the day, I have no idea whether heart
attacks are uniformly distributed throuought the day, so it could
well be that the times people tend to smoke are the same as the
times they tend to have heart attacks. Or they tend to smoke
before meals (I knew some people like that years ago in college)
and tend to have heart attacks after meals. Or they tend to
smoke when they start to feel little chest pains, as someone
suggested.
Then even if it _is_ true that a smoker is more likely to
have a heart attack immediately after smoking a joint, that
does _NOT_ show that smoking increases the risk! Could be
as you say that it actually decreases the risk, but regardless
the time immediately after smoking is the riskiest time.
So it seems clear to me that there is _nothing_ we can conclude
about whether smoking increases the risk of a heart attack -
it also seems clear that that is _the_ question of interest
here.
Not that I'm claiming that it _is_ the case that smoking
decreases the risk of heart attack although the hour
immediately afterwards is the riskiest time. I have no
reason to think that's so. Also no reason to think it's
not so: People who assume such a thing is ridiculous
think so because they've classified the world into
Good things and Bad things - actual things in the world
are not that simple:
(i) Aspirin is a Good thing. Good for pain and fever relief,
and actually an aspirin a day helps prevent heart attack
or stroke, I forget which. The reason I forget which is
it's irrelevant to me: For me aspirin is a Very Bad thing,
because of other medical problems.
(ii) Alcohol is a Bad thing. Except for that bit about
how a glass of red wine a day is good for you, in terms
os risk of heart attack or stroke, again I forget which.
Alas, it doesn't follow that a quart of whiskey a day
is good for you.
Given that there _are_ plenty of "legitimate" medical
uses for marijuana and given that the interaction between
the body and chemicals is simply _not_ a matter of some
chemicals Good and some Bad, the idea that smoking
lowers risk of heart attack even though the risk is
greatest immediately afterwards is _not_ a priori
ridiculous. Note again that I'm not saying that that's
so (honest, I'm not even conjecturing that it's so),
my point is just that there are _so_ many essentially
independent _possible_ explanations for the data that
I just don't see how anyone can draw any serious
conclusions from it.
Conclusions regarding whether smoking affects the
risk of heart attack, in any case. Weaker (but
much less interesting) conclusions about correlations
might be possible, but there are _so_ many ways
that a correlation could exist "by accident" that
I don't see why one would care. (Unless one was
planning on blurring the distinction between
correlation and causation for political reasons...)
What I want to know is why alcohol and tobacco are legal:
http://www.drugwarfacts.org/causes.htm
http://www.drugwarfacts.org/addictiv.htm
> but
>instead would say, there is a segment of the population for whom MJ use
>is followed by a high liklihood of a heart attack.
>
>Would those people have had a heart attack anyway? Is this some small
>segment of the population that reacts this way? These questions would
>still remain without any further figures.
>
>Even in the abscence of this data, though, one might want to take some
>precautions during the hour following MJ usage, for those with an
>otherwise high liklihood of heart attack, such as: be near medical
>facilities, etc.
I don't see how the data even _proves_ that this is a sensible
suggestion.
>Cheers - Chas
>
>---------------------------------------------------
>C Brown Systems Designs
>Multimedia Environments for Museums and Theme Parks
>---------------------------------------------------
David C. Ullrich
*********************
"Sometimes you can have access violations all the
time and the program still works." (Michael Caracena,
comp.lang.pascal.delphi.misc 5/1/01)
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