Clinical: Clinical Review - Osteoporosis.(Disease/Disorder overview)

Contributed by Professor John A Kanis, professor emeritus in metabolic bone diseases, and director of WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield, and Dr Eugene McCloskey, reader in adult bone disease, University of Sheffield

Section 1 Epidemiology and aetiology

Epidemiology

The clinical significance of osteoporosis lies in the fractures that arise. In the UK, osteoporosis results in more than 200,000 fractures each year, causing severe pain and disability to individuals at an annual cost to the NHS of over pounds 1.73 billion.

More than one-third of adult women and one in five men will sustain one or more osteoporotic fractures in their lifetime. Common sites of fracture include the vertebral bodies, distal radius, proximal femur and the proximal humerus.

Hip fractures alone account for more than 20 per cent of orthopaedic bed occupancy in the UK, and the majority of the direct health service cost of osteoporosis.

Approximately 50 per cent of patients suffering a hip fracture can no longer live independently and 20 per cent die within 12 months of the fracture.

Fractures in patients aged over 60 years account for more than two million hospital bed days in England each year. This exceeds the bed occupancy attributable to diabetes, IHD, heart failure or COPD. The ageing of the UK population will double the number of osteoporotic fractures over the next 50 years if changes are not made in present practice.

Already, the admission rate for hip fractures has increased in England by 2.1 per cent per year since 1999, while hospital bed days have increased by 5.9 per cent a year.

Aetiology

The most common cause of osteoporosis arises from estrogen deficiency that begins some years before the time of menopause. The skeleton comprises approximately 20 per cent trabecular bone and 80 per cent cortical bone and undergoes a continual process of resorption and formation, governed by the activity of bone cells in bone remodelling units.

Approximately 10 per cent of the adult skeleton is remodelled every year.

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