|dc.description.abstract||Achievement of maximum bone density in early adulthood may
be the key to preventing skeletal fragility in the elderly. The
purpose of this study was to investigate lifestyle and dietary
factors that may relate to bone density in young women.
The study involved two primary components. The first was a
cross-sectional examination of the relationship of selected
lifestyle factors and dietary calcium to bone density in an
experimental population of 101 young women, aged 20 to 35 years.
The second was to investigate the effects of six months of
physical activity and calcium diet supplementation (separately
and combined) on bone density in the same population. Seventy
eight women completed the six-month experimental trial.
Os calcis bone density, the dependent variable measured in
both components of the study, was determined using the GE 9800
CT scanner at the University Hospital, Saskatoon. Three to five
contiguous CT images, each 3 rom in thickness, were computed for
the right os calcis of each subject and the image representing
the most central region of the bone was used for data analysis.
There appeared to be no relationship between height, weight
or age and bone density in the cross-sectional analysis.
Childhood physical activity was a key determinant of bone
density in the study sample. Those subjects who participated in
organized sport or fitness activities as children had significantly higher bone density than those who did not
(�(99)=2.00, £<.05). The classification of childhood physical
activity within a four category criteria (Sometimes Active,
Active, More Active, Very Active) also identified significant
differences in adult bone density (1(3,97)=2.74, £<.05).
Childhood milk consumption, current calcium intake and
current lifestyle factors (e.g. cigarette smoking, coffee
consumption avocational physical activity), considered
separately, did not appear to be significant determinants of
bone density in early adulthood. When cigarette smoking and
current coffee consumption were considered together, there was a
significant difference in bone density between non-smoking
subjects with low daily coffee intake compared to subjects who
smoked cigarettes daily and consumed five or more cups of coffee
per day (�(55)=1.99, £<.05).
The results of the six-month experimental trial indicated
that most young women, aged 20 to 35 years have not begun to
suffer an age-related loss of trabecular bone and may have the
potential to increase trabecular bone density. Sixty-three of
the 78 subjects (80.8%) in the experimental trial maintained or
gained bone density within the trabecular region of the os
calcis over the six month duration of the study.
Over a six-month treatment period, calcium supplementation
and exercise intervention (separately and combined) failed to
generate a significant osteogenic effect in the experimental