Osteoporosis, a condition characterised by a decrease in bone mass and density, affects one in three women over the age of fifty and one in twelve men. The decrease in bone density associated with osteoporosis greatly increases the risk of hip fracture, a factor which can have a long-term effect on the quality of life of older people and a huge financial impact on the health system.

While osteoporosis is usually not diagnosed until later in life, predisposing risk factors can be present from an early age. Similarly, positive steps can be taken at all stages of life to increase and maintain bone health, thus offsetting the occurrence of osteoporosis in later life.

Risk Factors for Osteoporosis
• Previous fragility fracture: a fragility fracture occurs when somebody falls from a standing height or less and suffers a fracture as a result.
• Prolonged corticosteroid therapy: prolonged use is considered to be a period of three months or more. This figure is cumulative, that is, three months' corticosteroid use over a lifetime.
• Medical conditions such as liver or thyroid disease, diseases which result in malabsorption (e.g. coeliac disease, inflammatory bowel disease), alcoholism, rheumatoid arthritis.
• Family history of osteoporosis
• A low body mass index: less than 19kg/m2
• A period of prolonged immobilisation
• Radiographic evidence of vertebral deformity or osteopaenia
• Untreated hypogonadism (early menopause or hysterectomy), secondary amenorrhoea, primary hypogonadism in women; primary or secondary hypogonadism in men. As Eileen Relihan notes, "Sex hormones are intrinsically linked to osteoporosis."

Corticosteroid Use and Osteoporosis
Long-term use of corticosteroids increases the risk of osteoporosis and fracture by:
• Decreasing absorption of calcium and increasing urinary excretion
• Affecting the sex hormones
• Decreasing muscle mass
• Decreasing osteoblast activity, leading to decreased bone formation
• Affecting growth hormones and growth factors.

Patients taking a daily dose of 5mg or more of prednisolone for over three months should be treated with a bisphosphonate. It is recommended that treatment with bisphosphonate be commenced at the time of commencing corticosteroid.

High dose inhalers may also have an impact on bone density but not to the same extent as oral steroids.

Bone Mineral Density and Tests for Osteoporosis
Bone Mineral Density (BMD) is the single most important determinant of fracture risk. Peak bone mass is established in the fourth decade of a person's life, after which there is a gradual age-related decline. This is accelerated in women after the menopause.

To reach a diagnosis of osteoporosis, an individual's BMD is compared by means of standard deviation units - T scores - with that of a healthy young adult woman. Osteoporosis is diagnosed with a T score of -2.5 or less. Osteopaenia is indicated with a T score of between -1 and -2.49. DEXA (dual energy absorptiometry) scanning is the principal means used to measure BMD and sequential BMD measurements may be taken to monitor the efficacy of intervention and to aid further patient compliance.

Steps to Reduce the Risk of Osteoporosis
Increasing BMD in early life and maintaining it reduces the risk of osteoporosis. Lifestyle measures which can encourage bone health at all stages of life include:
• Cessation of smoking - smoking decreases the levels of oestrogen in the system and smokers tend to have earlier menopause and lower body weight.
• Reduction of alcohol intake
• Performing regular weight-bearing and strength-enhancing exercise - running and walking are particularly effective.
• Increasing levels of calcium and Vitamin D in the diet - the recommended daily intake of calcium is 800mg.

Alongside pharmacological intervention, patients with osteoporosis should also be encouraged to increase weight-bearing physical activity, to increase calcium and vitamin D intake and to assess and modify their environment to decrease the risk of injury which may lead to fractures.

Further information on treatments for osteoporosis is contained in the article Medical Management of Osteoporosis

Related articles:
Medical Management of Osteoporosis
Medicines and Falls
Preventing Falls in the Elderly
Useful Websites: Osteoporosis and Falls Prevention

This article was prepared by Julie Cronin and is based on the ICCPE live learning course Preventing Falls in the Elderly, given by Eileen Relihan.