[extropy-chat] Vitamin supplementation increases mortality risk

[Hal Finney]

There are several news reports appearing about a recent publication
in the British medical journal The Lancet which suggests that vitamin
supplementation increases mortality risk.  The report is available at
<http://www.thelancet.com/journal/vol364/iss9441/full/llan.364.9441.primary_research.30873.1>
and an interpretation at
<http://www.thelancet.com/journal/vol364/iss9441/full/llan.364.9441.analysis_and_interpretation.30892.1>
See http://www.bugmenot.com for a login and password, or use the free
registration available.  I got cpmmsh/rpmseam from bugmenot.

The new result is a meta-analysis, which means that the researchers did
not actually do any experimentation, but rather went back and combined
the data from numerous reported trials to see if they could derive a
more statistically significant result.  Specifically they were looking
at studies of vitamin and nutrient supplementation to prevent cancer.
Their basic conclusion was that the supplements don't help, with the
possible exception of selenium which had a small protective effect.

However a surprising result of their meta-analysis was that in fact the
supplements (other than selenium) actually increased overall mortality.
This result was statistically significant, barely.

The interpretation and analysis from the 2nd link above is a little more
optimistic.  There are some methodological quirks in the way the research
was done that make the statistical significance a little questionable.
In addition, the researchers only looked at studies where supplements
were being tested against cancer, while their mortality results were from
all-causes mortality.  If they really want to know whether supplements
increase general mortality, they should look at all studies which report
such results, not just cancer studies.

The analysts suggest that this means that the current results should only
be considered preliminary until further work is done.  It will also be
important to identify which particular supplements and dosages are risky.

Hal