Coloured X-ray of the of a 73 year old female patient with osteoporosis of the spine. The spine has been stabilised with screws and a plate (white). Osteoporosis is characterised by loss of bone density and deterioration of bone tissue, and causes pain and immobility. It is most common in post-menopausal women. It may be prevented by a diet rich in calcium, and regular weight-bearing exercise.