Osteoporosis - The Facts
Osteoporosis is a disease of brittle bones. Loss of bone mineral (calcium) leads to weakening of the skeleton, fragility and bony fractures. In Australia 1 in 2 women and 1 in 5 men aged 70 years and older suffer from osteoporosis.
Frequently patients with osteoporosis present with painless spinal fractures leading to a dowager's hump (curvature of the spine and protruding abdomen). Over many years the spinal deformity may cause ongoing mechanical back pain which is debilitating. Acute back pain in elderly females on the other hand is often the result of a spontaneous vertebral fracture as a consequence of osteoporosis. The syndrome of skeletal deformity, ongoing back pain and resultant lack of mobility is responsible for the high mortality and morbidity associated with the disease (e.g. pneumonia).
Women at risk of osteoporosis are usually post-menopausal, of small body frame with a previous history of smoking, excess alcohol and coffee consumption and lack of exercise.
Recent data has demonstrated that genetic factors may play a key roll in the pathogenesis of osteoporosis. Daughters of mothers with spinal or hip fractures have been demonstrated to have diminished skeletal bone mass (bone calcium).
Bone densitometry, a non-invasive measurement of skeletal bone calcium content, has revolutionised the diagnosis of osteoporosis. It is now no longer necessary to await a final incident fracture, but to measure bone mass in predisposed individuals at risk for osteoporosis.
Patients with bone densitometric measurements in the lower range of normal can now be diagnosed prior to developing osteoporosis and treated appropriately (calcium, hormone replacement therapy).
Calcium is a mineral found predominantly in our skeleton. It acts as a calcium bank in order to allow adequate calcium homeostasis.
Calcium accrual into the skeleton commences in infant life and is maximised in the pubertal years. Optimal calcium intake is therefore essential during this period.
Other important roles of calcium are to:
Daily calcium requirements are usually provided by adequate dietary calcium intake.
Recommended daily intake of calcium includes:
In the event of a calcium deficiency state (decreased dietary intake, malabsorption or increased loss) calcium requirements are met by skeletal calcium release leading to a negative calcium balance. Over a prolonged period of time this may predispose to osteoporosis.