From: altar@beaufort.sfu.ca (Ted Wayn Altar)
Subject: Re: Cure worse than the disease?
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Fri, 8 Jan 1993 06:06:09 GMT

Tim Ikeda writes:

>First, thanks for dropping the anabolic issue. Calciferol operates in
>a tissue-specific, regulatory manner which is quite distinct from
>the sex hormone-derived steriods which are *popularly* refered to
>as "anabolic steroids". "Anabolic" is a context-specific term in much the
>same way that "transposition" suggests "conversion to a different key" for
>a musician and "movement of a block of DNA" to a molecular biologist.

This is good point and one that I tried to make so that we could
move on and then consider whether or not Moon's remarks were
context "appropriate" given that *he* wishes to establish a *new*
contextual understanding of calciferol not as a vitamin but as
a harzardous steroid.  It is not that he wants to preserve the
`status quo ante' with respect to how we view calciferol, but he 
wants to change it.  I don't think there is anything wrong with 
that.  Of course, you are right to suggest that this is not the 
appropriate forum for arguing the highly technical merits for such 
a change.  Maybe it is not even the appropriate forum for even 
reporting that Dr. Moon so wishes to see such a terminological 
change occur.  Ok, I was wrong to have mentioned that issue.


>
>Some other things...
>In section IV of your post, the columns for "female" and "male" of the
>"heart disease" catagory were transposed. (Though millions of men wish
>it wasn't a typo.)

Thanks for the correction Tim.

>
>Also, the data on heart disease was based on populations from
>the period of 1965-1969 whereas the VitD intake data covers
>(I think) the 1970's. Significant lifestyle changes in populations
>occurred between these periods. Like jogging.
>

I agree that significant lifestyle changes have occurred, but
if we partialled out such factors, there is still likely a large
unaccounted for variance which Moon's correlation of vitamin D
and heart disease does appear to account for.


>Drs. Moon, Bandy and Davison noted that during 1969-1970, heart disease
>began to decrease in the US and Canada while in England/Wales and
>Ireland, there was a slow increase. Presently, the male heart disease
>death rate is similar in all these areas (a bit over 500/100K pop.),
>seriously reducing the correlation between femoral fractures in >women and death from heart disease for men. One other major problem
>with the table described, at least as indicator of VitD intake hazard,
>is that the data is not adjusted for lifestyles or ethnicities of
>the countries reported.

No doubt these also are risk factors, but there is no need to
adjust for them if we assume that vitD intake is randomly
distributed within a nation's health policies of supplementation.
Why would you think, for instance, that an increased vitD
consumption is correlated with ethnicity or lifestyle in a manner
that has worked to INFLATE rather then deflate the obtained
correlation of vitD with heart disease?  For example, suppose SES
is correlated negatively with heart disease (which often is the
case) but positively correlated with vitD consumption (i.e., with
affluence comes a greater consumption of dairy products, fish and
vitamin supplements).  If anything, this kind of confound would
work AGAINST Moon finding a relationship between vitD and heart
disease.  To put it another way, the correlation that Moon has 
obtained would be even HIGHER if this SES was in fact a confound 
to be partial it out.

There is, however, no need to partial out every possible factor 
if those factors can reasonably be presumed to be randomly
distributed among the correlated relationship in question.  If a
third factor (say, life style) is in fact correlated with the
predictor (vitD) and criterion (heart disease) variable, that by
itself does not negate the relationship between vitD and heart
disease.  What is important to consider is in what likely
direction and how much this third variable would be expected to
be correlated with vitD and heart disease.  The assumption of
such other known factors being more or less *randomly* unrelated,
or correlated in different directions, with the variables in
question would lead one to therefore expect such influences (should
there be an) upon the obtained correlation between vitD and heart d
disease to more or less cancel out each out.  Unless we have good 
reason to think otherwise, this is a reasonable working assumption 
that occurs in all manner of research quite routinely.


>(Note how a "lower" VitD consumer in Finland

Remember, these figures don't tell us how much calciferol 
a population is actually obtaining from ALL sources,
but only about relatively how much calciferol is being 
added to the food supply.  The assumption is that the
other sources add up to relatively similar levels, but
this is only an assumption.  If, for instance, Finland men
during that period in particular consumed a lot of herring 
and kipper and mackeral, they would indeed be ingesting a 
lot of calciferol.  After all, 100 grams of fried or baked 
herring or kipper contains about 25 ug of calciferole, which 
already over twice the Canadian RDA (12.5 ug) for adults 
in the absence of sunlight.



>still has a high male heart disease rate -- greater than US or Canada).
>(The data for proximal femur fractures in Canada was for the time
>period 1972-1984.)
>

Well, this is a crude correlation since uncertainty exists as to
how much vitamin D is actually being delivered (we have only a 
few ordinal categories being correlated with a continuous 
interval variable, which introduces some slop that can be 
expected to depress the correlation rather than inflate it.
Notwithstanding this uncertainty that would muddy up the
relationship, a pretty strong correlation nevertheless emerges
and one that accounts for about 50% of the variance for male
heart disease.  That's really quite impressive!


>Personally, I would have preferred seeing data that was matched
>by year -- the heart disease data is readily available.

So would I, but I really don't see how in the present case this
can be expected to seriously affect the obtained relationship.

It would be nice to have perfect data, but we live in an
imperfect world where we must make do with the best information
available.  While imperfect (and what data ever is "perfect"), it
is certainly better than having no data at all.

                                Regards,
                                    ted