Vitamin D supplementation in adolescent female ballet dancers and gymnasts in a 12 month randomised controlled trial in Auckland, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
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Date
2014
Open Access Location
DOI
Authors
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Massey University
Abstract
Aim:
To
examine
the
effects
of
vitamin
D
supplementation
on
the
bone
health
of
female
adolescent
ballet
dancers
and
gymnasts.
Method:
Adolescent
female
ballet
dancers
and
gymnasts
from
Auckland,
New
Zealand
were
recruited
to
a
12
month
randomised
double-‐blind
trial.
Participants
were
supplemented
with
cholecalciferol
50,000
IU
per
month
or
a
placebo.
At
baseline
detailed
dietary
intake
was
collected
by
a
four
day
food
record;
at
baseline
and
12
months
bone
mineral
density
(BMD)
and
content
were
recorded
by
DXA
as
well
as
bone-‐free,
fat-‐free,
lean
body
mass,
percentage
body
fat,
height
and
weight.
At
baseline,
six
months
and
12
months
serum
markers
for
vitamin
D
(oestradiol
and
parathyroid
hormone)
were
collected.
Results:
A
total
of
61
adolescent
girls
were
recruited
at
baseline,
BMD
and
content
by
DXA
was
completed
in
45
girls
and
41
provided
vitamin
D
serum
samples.
Serum
vitamin
D
concentration
was
recorded
for
41
female
ballet
dancers
and
gymnasts
aged
12
to
18
years
was
72
nmol/L
and
remained
adequate
(>50
nmol/L)
in
both
intervention
and
control
groups
for
the
12
month
duration.
There
was
no
significant
difference
between
intervention
and
control
groups
in
bone
mineral
density
and
content
at
any
bone
site
at
12
months.
The
significant
predictors
of
increased
bone
mineral
density
at
baseline
were
older
age
(P=0.002)
higher
bone-‐free,
fat-‐free,
lean
body
mass
(P=0.001)
and
higher
calcium
intake
(P=0.005).
For
higher
bone
mineral
content
the
significant
predictors
at
baseline
were
older
age
(P=0.01)
and
higher
bone-‐
free,
fat-‐free,
lean
body
mass
(P=0.001).
In
all
participants
(n=48)
bone
mineral
density
and
content
increased
significantly
at
12
months
(total
body
BMD
and
content,
areal
BMD,
total
hip
BMD
and
content,
femoral
neck
BMD
and
content
and
lumbar
spine
BMD
and
content).
II
Discussion:
More
than
adequate
baseline
serum
vitamin
D
levels
in
this
adolescent
group
may
explain
the
lack
of
significant
difference
in
any
of
the
bone
measures
between
intervention
and
control
groups.
As
the
age
range
of
the
adolescent
girls
varied
markedly
and
older
age
predicted
both
an
increase
in
BMD
and
content,
it
is
likely
that
there
was
also
bone
accrual
due
to
growth.
The
nil
effect
of
vitamin
D
supplementation
on
bone
measures
was
also
limited
by
the
small
sample
size.
Conclusion:
In
this
study
vitamin
D
supplementation
had
no
effect
on
the
bone
mineral
density
and
content
of
female
adolescent
ballet
dancers
and
gymnasts.
Further
investigations
are
needed
to
examine
vitamin
D
supplementation
on
bone
measures
in
a
large
group
of
adolescent
girls.
Description
Keywords
Teenage ballerinas, Adolescent ballerinas, Female gymnasts, Adolescent gymnasts, Vitamin D in nutrition, Vitamin D supplementation