>From:    Sukie Crandall <[log in to unmask]>
>Karen, thank you so much for posting details about that study
 
You're welcome.  One thing I did want to make sure everyone understood (I'm
sure Sukie knows this) is that what I posted was only a brief summary of
the study - methods, a few pertinent results, and conclusions.  I obviously
couldn't type in the whole paper.  I want to caution everyone NOT TO READ
TOO MUCH into the results and conclusions.  And certainly anyone really
interested should get a copy of the article and read the whole thing.  I
avoided posting any of my personal opinions (I have plenty) about the study
in order to let people draw their own conclusions but everyone should be
aware that one scientific article is not the be all and end all of any
story.  This fact is too often overlooked by those who are not really
familiar with the scientific method and how careful one must be to not
overstate things based on the results you get.
 
>One thing that would be useful to know would how often vets there look for
>the disorder.
 
This was not addressed.
 
>which leads also to the question of how many don't receive medical care
>when ill, a problem which can skew numbers if too high or off-centered.
 
Certainly a good point.  I must also point out that the prevalence figure
of 0.55% was based only on ferrets in the study group which developed the
disease WITHIN THE THREE MONTH PERIOD STATED.  That is, it is not that they
followed all 1274 ferrets over their lifetimes and determined that only 7
(possibly 14) ferrets developed disease.  They also did not have any data
on differences in how these ferrets were kept or their history, such as
diet, exercise, genetics, etc.  Given that whole ferrets can develop the
disease, it is not simply altering that is the necessary and sufficient
cause of adrenal problems.  It certainly appears to be an important factor,
but other things must also have an impact.  In fact, (with the caveat
mentioned above) given that most of those 1274 ferrets were neutered, and
yet so few apparently developed disease, it is not unreasonable to
hypothesize that there are indeed other factors which must come into play.
The method which was chosen to obtain data (owner survey) has some problems
as well.  As the scientists were trusting to the knowledge and honesty of
492 different people, my personal opinion is that the data can't have the
same weight as you would grant to a study done where you can directly
control the environment and make direct observations.  That obviously would
require a great deal more time and money, and this was a way to at least
get a start on the problem, and you can't fault them for doing it the best
way they could.  It should not however be granted more weight than it
deserves.
 
>was especially true for the intact ferrets.  Median is the middle number in
>a series, mean is average, mode is the most common number.  Obviously, if
>the middle age in the series for intact ferrets was only a one year they
>were largely below the ages where adrenal disease occurs.
 
To give an example of median, mean, and mode, consider the following series
of numbers.  1, 3, 3, 3, 3, 3, 7, 9, 10, 15, 20, 50, 100.  The median is
the middle number in the series, which is 7.  The mean of the series is
17.5, and the mode is 3.
 
>necessarily have to be a duplicating one.  If a large comprehensive study
>by vets of late vs.  early neuters found that there is large difference
>between rates for these two groups AND if it found a similar incidence of
>this adrenal disease in the late neuters as they found, then that suggests
>that the lower over-all rate there might simply reflect the absence of
>early neuters.
 
You are saying (I think) that it needs to be determined, for example,
whether a group of early alters ends up with a disease prevalence of say,
25%, while a group of late alters, (kept under the same conditions as the
early alters), has a disease prevalence of only, say, 1%.  Or whether there
is no difference between the two groups at all.  Am I understanding you
correctly?  I think this is very important to know.  Then one can begin
to ask questions about what else contributes to causing disease.
 
>If the difference is not large enough to account for such a
>difference in rates, or if we have more cases of this adrenal problem
>among late neuters in other areas
 
By "other areas" you mean other geographical areas?
 
>Note that I am not an expert by any means so adjust your opinion of my
>comments accordingly, and that I have not yet seen a copy of this study
>so would appreciate one since some of what I mention above may be tackled
>within it.
 
Most vets should be receiving JAVMA.  (If they aren't maybe you should
wonder?) If your vet cannot get a copy for you, and you live near a
university, try the library there.  Even if they don't get the journal,
they can request a copy of the article through inter-library loan.  If all
else fails, those who can't get a copy of the article and want one should
email me privately and I'll give you my address to which you can send a
SASE and I'll mail you back a copy.  I must ask however that you try these
other routes first before doing that.  Thanks.
 
Karen
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==========================================================================
"The snake is an animal. It has a backbone and heart. It has red blood and
drinks water and eats food. It breathes air and feels fear, just like every
other animal in the world. And it's in a body that is the hardest thing for
the average person to understand."
                -- Dave Barker, herpetologist
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If you love ferrets, check out:
http://www.dartmouth.edu/~crassi/index.html
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[Posted in FML issue 2944]