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Peter L Moolhuizen [mailto:email @ redacted] wrote:

> For all of you interested in reading up on research in this 
> area from the
> National Vaccine Information Center.
> http://www.909shot.com/juvenilediabetes.htm

This page appears to be promotional for the work of John Classen.  Classen
has several published papers that indicate associations between viruses and
type 1 DM incidence.  I haven't had a chance to review all of these papers,
but the work that I have had a chance to look at has a serious flaw in it:
it presents a relative risk (RR) of 1.19 for an association between
Hemophilus influenzae B (HiB) vaccine and type 1 DM.  In English, we would
say that someone who has received the HiB vaccine has 1.2 (rounding the RR)
times the risk of developing type 1 DM in a non-random pattern. Classen's
flaw is that he presents no confidence interval for the RR0.  

A relative risk of 1 means that there is no association.  In order to
ascertain statistical significance, it is necessary to give that value some
bounds, typically a 95% confidence interval.  It says that the "true" value
has a probability of being within that range 95% of the time.  In other
words, 5% of the time, we will be in error when we state that value.  When
dealing with relative risk (or odds ratios), if the confidence interval (at
any level of precision) contains the value of 1, it is deemed not
significantly different from 1, and we conclude that there is no
association.  Given the typical sample size in the studies discussed, it is
very unlikely, IMHO, that a relative risk of 1.19 is statistically

All of the other papers I found in a Medline search from 1997 to present
that deal with vaccination and risk of type 1 DM indicate no association
between any known vaccine and onset of DM.

Now it's possible that Classen is correct.  Only time and further research
will tell.  I'm a little concerned (but not much) about Classen's
objectivity because he is the founder and owner of Classen Immunotherapies,
Inc. in Baltimore, MD.  It raises the question of conflict of interest
(note:  I am not accusing him of conflict of interest - only that it raises
the question for me).

Jim Handsfield
mailto:email @ redacted OR
mailto:email @ redacted

The opinions expressed are my own and do not necessarily represent those of
my wife who runs this house and makes more important decisions than I do.
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