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Hello, my
name is Bo Abrahamsen.
I'm a professor at the
University of Southern Denmark
and the Research Center
for Aging and Osteoporosis
in Glostrup Hospital, Copenhagen.
My talk today is Osteoporosis
Calcium and Vitamin D.
And I will try to talk
about some studies
that I think may be familiar to you.
So it may be you'll find you'll
have to go back and perhaps read
the paper in question to fully
understand what I'm getting at,
so maybe one or two places.
I'm not giving a
lot of introduction.
But rather, assume that you may
have already read the papers.
Because they've been really widely
discussed in the past years.
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These are my disclosures.
I'm not speaking on behalf of any
of the organizations listed here
at all.
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As you probably know,
there's difference
in fracture risk in
different parts of the world.
And there's a little bit of a
tendency for fractures to be rarer
the nearer you get to the Equator.
So that would of course drive the
hypothesis that perhaps the lack
of vitamin D in the Northern
and Southern Hemisphere
as you get away from
the Equator would
be one of the reasons
there are more fractures.
So if you look at the
right hand of the slide,
you'll see rates from
the International
Osteoporosis Foundation.
And as you can see, Argentina,
Iceland, and Norway all
have fairly high fracture
rates, whereas Central Africa
and the northern part of Latin
America all have low rates.
And these are the very
sun-rich areas of the world.
But you can also see fairly
high rates of fractures
in the Middle East and in the
European and Asian part of Turkey.
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It's been difficult to show any
convincing effects of vitamin
D supplementation in the general
population on bone mineral density.
As you know, bone mineral
density is an important risk
factor for fracture.
It's not the only one, but
it's a really important one.
And there was a really nice
meta-analysis in The Lancet
this year looking at a number
of intervention trials.
And then on the left part of the
chart showing the mean difference
in numbers on BMD
with supplementation
this is percent change
in lumbar spine BMD.
And as you can see, the
average increase is zero.
If you look at the right
hand, you have the chart,
you have the femoral
neck BMD where there
is a small significant
increase, but of less than 1%.
And you may know that a
standard deviation of BMD
is about 10% or 11%.
And that's the order
of a change that's
needed to reduce
fracture risk by half.
So these are quite small and quite,
perhaps, inconsistent findings.
The authors conclude that this
systematic review provides
very little evidence
of an overall benefit
of vitamin D supplementation
on bone density.
They also conclude that
there's a small BMD
benefit potentially
at the femoral neck.
But they also find signs of
significant publication bias
as assessed by funnel plots.
And you also notice
significant heterogeneity
between studies statistically.
So there's no clear BMD effect in
the general public of vitamin D
supplementation, though
of course as clinicians,
we know that in an individual
patient who is vitamin D deficient,
the response in BMD can be huge.
