What are the clinical features of osteoporosis?

Essentially these are pathological fractures - fractures that result from trauma that would not normally cause a bone to break. In principle, fractures may occur anywhere. In practice, the three most common types of fracture are:

• Colles' fracture - fracture of the distal part of the radius bone (at the wrist). When this is seen in a middle-aged woman, it should be regarded as due to osteoporosis until proven otherwise.
• Hip fractures - most common in people over 65 years. These are serious with a 20% mortality associated with them in the first three months.
• Vertebral fractures - the vertebrae of the spine are very prone to a type of fracture called a 'wedge fracture', so-called due to their characteristic appearance on spinal X-ray. As vertebrae are mainly trabecular bone, the type which is weakened most readily in osteoporosis, they are prone to collapse under the stress of the body weight going through the spine. Such fractures are associated with a loss of height in the affected individual and a forward curvature of the spine (a kyphosis), often called a 'Dowager's hump). Such fractures can also cause considerable pain. They also can cause irritation to nerves leaving the spine causing a wide variety of problems. Damage to the spinal cord itself, running through the vertebrae is thankfully very uncommon.

Fractures can cause pain and in some cases (e.g. hip fractures) severe disability. The chance of a fracture is greatly increased by factors which increase the risk of falling such as visual problems, stroke, dementia, Parkinson's, old age, cardiovascular disease and drugs (e.g. sedatives).