Abstract
Osteoporosis is a disease characterised by reduced bone strength and increased risk for
low-trauma fracture. The present thesis reports a series of studies aimed at: (a) assessing
the agreement of estimates of bone-loss measured by two different densitometers;
(b) identifying predictors of long-term bone loss; (c) identifying the optimal timing
of repeat bone mineral density measurement; and, (d) describing the short-term and
long-term impacts of hip fracture on mortality.
Data from the Dubbo Osteoporosis Epidemiological Study found significant discordance
in estimates of bone loss when bone density was measured by two different
densitometers. Weight loss was shown to be a strong predictor of bone loss. Specifically
in men osteocalcin and sex hormone binding globulin were predictors of bone
loss. And, the optimal time to repeat a bone density test was estimated using an individual s
current age and bone density.
In women and men hospitalised following hip fracture, advancing age, being male
and pre-fracture concomitant diseases, were shown to increase the risk of mortality.
And, in long-term follow-up, both women and men following hip fracture were observed
to have an excess of mortality when compared to that expected in the background
population.
These results indicate that the optimal time to repeat a bone density measurement
can be estimated using absolute risk of reaching a treatment threshold, and that the
most serious consequence of osteoporosis, hip fracture is related to increased mortality
in both the short- and long-term period following fracture.