Osteo Update

Introduction

Osteoporosis is a condition that causes bones to become thin and weak.

It occurs more commonly in old age as bone loss increases. The bones become fragile and more likely to break (fracture) - particularly those of the spine, wrist, and hips.

Bones are repaired and reinforced by a range of proteins and minerals, which are absorbed from the bloodstream. Changes in hormone levels affect the strength of the bones. For example, the female hormone oestrogen offers some protection against osteoporosis. However after the menopause, oestrogen levels fall, often causing the bones to thin quickly.

Symptoms

The early warning signs of osteoporosis may include joint pains, and having difficulty standing or sitting up straight. Often, however, there is no warning before a minor fall or sudden impact causes a bone fracture.

Fractured bones in the elderly can be serious because the bone is no longer able to repair itself effectively. Such injuries may lead to arthritis or long-term problems with mobility.

Causes

Bones are at their strongest in early adult life. However, after the age of around 35, bone loss increases very gradually as part of the natural ageing process.

Women are at greater risk of developing osteoporosis than men. This is due to the decrease in the hormone oestrogen after the menopause.

Women are at greater risk of developing osteoporosis when they have:

• an early menopause (before the age of 45),
• a hysterectomy before the age of 45, particularly when the ovaries are also removed, or
• when periods are absent for a long time (more than 6 months) as a result of over-exercising, or over-dieting.

The male hormone testosterone also helps to keep the bones healthy. Men continue to produce this hormone into old age, but the risk of osteoporosis is increased in individuals with low levels of testosterone.

Other risk factors include:

• race - Caucasian or Asian races are at greater risk than African-Caribbean
• a family history of osteoporosis, particularly a history of hip fracture in a parent
• a previous fragility fracture (fracturing a bone after only a minor accident)
• long-term immobility (eg confined to bed)
• a very low body mass index (a way of combining weight and height measurements)
• excessive alcohol consumption or smoking
• low levels of vitamin D or dietary calcium

Some medicines and disorders can increase your risk including:

• long-term use of corticosteroids (medicines sometimes used to treat severe allergies or inflammation)
• long-term use of heparin (used to thin the blood)
• aromatase inhibitors (used in the treatment of breast cancer in women)
• overactive thyroid disorders (eg hyperthyroidism)
• rheumatoid arthritis
• digestive disorders that affect nutrient absorption, such as Crohn's Disease, chronic liver disease, or coeliac disease
• a disorder of calcium metabolism (hyperparathyroidism)
• other conditions, such as kidney disease and ankylosing spondylitis

Diagnosis

Osteoporosis is not often diagnosed until the first fracture occurs. An X-ray cannot reliably measure bone density but is useful to identify spinal factures. A bone density scan, called a dual energy X-ray absorptiometry (DEXA) scan, is used to measure the density of bones and compare this to a normal range. This test measures the likely strength of bones and the risk or fracture.

Treatment

Your doctor may prescribe the following medicines to help prevent fractures and increase your bone density:

• Bisphosphonates or strontium ranelate
• Calcium and vitamin D supplements
• Calcitonin
• Selective oestrogen receptor modulators (SERM)

Hormone replacement therapy (HRT) is a prescription-only treatment that relieves symptoms of the menopause by restoring hormones to a premenopausal level. HRT has also been shown to reduce osteoporosis, but is unlikely to be prescribed to treat or prevent the condition.

Complications

Broken wrists, hips and spinal bones are the most common fractures in people with osteoporosis. Hip replacements are often needed following hip fractures, but there is still a risk that people will have reduced mobility or independence even after treatment. Although osteoporosis does not directly shorten life expectancy, the decrease in mobility is a common reason for admitting people to nursing homes, where full-time care can be given.

Prevention

Lifestyle factors, such as diet and exercise, can influence bones status. Following a healthy lifestyle throughout life is the best way to delay the onset of osteoporosis, and slow the rate at which bones become fragile.

Recommendations include:

• regular weight bearing exercise
• eating a healthy diet that contains plenty of calcium
• quit smoking
• limit alcohol intake

Useful Links

Age Concern www.ageconcern.org.uk

National Osteoporosis Society www.nos.org.uk

Arthritis Care www.arthritiscare.org.uk

Help the Aged www.helptheaged.org.uk

NHS Choices - osteoporosis