Osteoporosis is a condition in which the bones become less dense, weaker, and break (fracture) more easily. A loss of bone density is a normal part of ageing, but in some people this loss becomes excessive, leading to an increased risk of fractures following even a minor fall or injury. The spine, wrist and hips are most commonly affected.

Throughout life our bone mass is constantly being formed and lost, with a balance between renewal and loss. Bone mass peaks at about 30 years of age, after which the balance tips towards loss. The fall in oestrogen levels in women around the menopause increases the rate of bone loss and makes women more prone to osteoporosis. Men experience a more steady loss, but by the age of 65–70 years, bone mass declines at the same rate in men and women, so older men can develop osteoporosis.

Only a small proportion of the people with osteoporosis are aware of it; often the first indication is a fracture. Another common sign of osteoporosis is crush fractures of the spine that cause a stooped posture or ‘dowager’s hump’.

In addition to calcium, vitamin D supplements and exercise to help increase bone density, medications that affect bone metabolism are used to treat osteoporosis.