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Osteoporosis: the disease of the 21st century?

Tim Melville
BSc(Tech)(Hons)
Health Service Liaison Manager
National Osteoporosis Society
Camerton, Bath
E:t.melville@nos.org.uk
W:www.nos.org.uk

The bones in our skeleton are made of a thick outer shell and a strong inner mesh filled with collagen (protein), calcium salts and other minerals. The inside looks like honeycomb, with blood vessels and bone marrow in the spaces between bone. Osteoporosis occurs when the holes between bone become bigger, making it fragile and liable to break easily. Osteoporosis usually affects the whole skeleton, but it most commonly causes fractures to bone in the wrist, spine and hip.

Bone is alive and constantly changing. Bone is broken down by cells called osteoclasts and replaced by bone-building cells (a process known as resorption) called osteoblasts. This process of renewal is called bone turnover. Where there is an imbalance and turnover exceeds resorption the bone deteriorates, and over a prolonged period this can lead to osteoporosis.

The following are facts and figures related to osteoporosis:

  • One in three women and one in 12 men over the age of 50 in the UK has osteoporosis.(1,2)
  • Every three minutes someone fractures a bone due to osteoporosis.(3)
  • An estimated three million people in the UK have osteoporosis.(3)
  • Each year in the UK, osteoporosis causes over 70,000 hip fractures, 50,000 wrist fractures and 40,000 spinal fractures.(1)
  • 240,000 osteoporotic fractures (including those from other sites) are treated by the NHS each year.(1)
  • Osteoporosis costs the NHS and government over £1.7b each year(1) - that's £5m each day.

Who is at risk of getting osteoporosis?
Everyone is potentially at risk of developing osteoporosis because of bone loss that occurs as we get older, and because the population is living longer, but there are also many other risk factors.
For women:

  • Lack of oestrogen, caused by early menopause (before the age of 45), or early hysterectomy (before the age of 45), particularly when both ovaries are removed (oophorectomy).
  • Missing periods for six months or more (excluding pregnancy) as a result of overexercising or overdieting.

For men:

  • Low levels of the male hormone testosterone (hypogonadism).

For men and women:

  • Long-term use of high-dose corticosteroid tablets (for conditions such as arthritis and asthma).
  • Close family history of osteoporosis (mother or father), particularly if your mother suffered a hip fracture.
  • Other medical conditions such as Cushing's ­syndrome and liver and thyroid problems.
  • Malabsorption problems (coeliac disease, Crohn's disease, gastric surgery).
  • Long-term immobility.
  • Heavy drinking.
  • Smoking.

If patients have one or more of these risk factors they are at increased risk of developing osteoporosis. If a patient has already had a broken bone after a minor bump or fall (fragility fracture) they may already have osteoporosis and would be advised to talk to their GP.

Does my patient have osteoporosis?
Because patients cannot see or feel their bone getting thinner they will probably be unaware of any problems with their bone health. Osteoporosis is a silent disease, and for most people the first sign that something is wrong is when they break a bone, often in the wrist or spine after a minor incident, although not all fractures are due to osteoporosis.
 
How to diagnose osteoporosis?
A normal X-ray of bone cannot reliably measure bone density but is useful to identify spinal fractures, explain back pain, height loss or kyphosis.

A bone density scan, called a dual energy X-ray absorptiometry (DXA) scan, is used to measure the density of bones and compare this with a normal range. This test is currently the most accurate and reliable means of assessing the strength of your bones and your risk of fracture. The Royal College of Physicians clinical guidelines advise which patients should be referred for a DXA scan, as shown in Figure 1.(4)

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Population-wide approach

Is osteoporosis preventable?
Genes determine the potential height and strength of an individual's skeleton, but lifestyle factors can influence the amount of bone they invest in the bone "bank" during their youth and how much is saved in later life.

"Bone-friendly" diet
Healthy bones need a well-balanced diet, incorporating minerals and vitamins from different food groups.  Ensure that diets are rich in calcium. The best sources of calcium are milk and dairy products, such as cheese and yogurt. Nondairy sources of calcium include green leafy vegetables, baked beans, bony fish and dried fruit.

Regular, weight-bearing exercise
Like muscles, bones suffer if they are not used. They need regular weight-bearing exercise, exerting a loading impact that stretches and contracts the muscles, stimulating the bone. Good bone-building exercises include running, skipping, aerobics, tennis and even brisk walking. Exercising at least three times a week for a minimum of 20 minutes improves bone health. If a patient hasn't exercised for a while, they should consult their GP or practice nurse before embarking on an exercise regime.

What else can patients do to reduce their risk of getting osteoporosis?
Smoking has a toxic effect on bone, so stopping is beneficial. Smoking can also cause women to have an early menopause and may increase the risk of hip fracture in later life.

Drinking too much alcohol is damaging to bone turnover. Alcohol intake should be limited to a maximum of 21 units per week for men and 14 units for women.
 
Selective case finding
In the absence of current evidence to support a population-wide screening strategy, a selective case-finding strategy has been recommended by all national and international collaborations to examine this issue.(4-6) With the selective case-finding strategy, patients are identified by the presence of strong risk factors, scanned and treated.
 
Recommendation
Peak adult bone mass is under genetic control.(7) However, a number of factors, from conception to skeletal maturity, determine the extent to which this genetic potential is achieved. These include: hormonal status; weight-bearing physical activity; and nutritional status and lifestyle attributes such as smoking and alcohol intake. Many of these factors also influence the rate of bone loss in later life. Preventive strategies should focus on modifying these factors.

Primary care organisations have an opportunity to integrate health promotion and healthcare at the individual and population level thanks to their links with other agencies. On the basis of clinical and cost-effectiveness, it is recommended that lifestyle measures to develop and maintain bone health throughout life are included in health promotion activities, while a selective case-finding approach is adopted to target individuals at high absolute risk of fracture.

Those at highest risk and where treatment can be most effectively targeted are:

  • Residents of nursing and residential homes and the "free-range" frail elderly.
  • Patients who have sustained a previous fragility fracture.
  • Patients on doses of oral steroids of 5mg or more for longer than three months.(1)

Treatments
The Royal College of Physicians clinical guidelines for prevention and treatment of osteoporosis should be followed to help decide which of the following treatments should be used and what lifestyle advice should be given.(4)

For people who have been diagnosed with osteoporosis there are a range of treatments available. The most common treatments include:

Bisphosphonates - nonhormonal drugs that help maintain bone density and reduce fracture rates.

Calcium and vitamin D supplements - can be of benefit for older people to reduce the risk of hip fracture. Hormone replacement therapy (HRT) - oestrogen replacement for women during menopause, which helps maintain bone density and reduces fracture rates for the duration of therapy.

Selective oestrogen receptor modulators (SERMs) - drugs that act in a similar way to oestrogen, helping to maintain bone density and reduce fracture rates, specifically of the spine.

Testosterone therapy - testosterone replacement for men with low testosterone levels to help maintain bone density.

Osteoporosis set to be the disease of the 21st century?
The number of osteoporotic fractures is increasing as the population ages. The International Osteoporosis Foundation estimates suggest that osteoporotic hip fractures alone will increase by 135% in the next 50 years.(8) This will make osteoporosis the highest user of bed-days in the NHS. Osteoporosis can be prevented and treated and should never be neglected.

References

  1. Torgerson DJ, Iglesias CP, Reid DM. The economics of fracture prevention. In: Barlow DH, Francis RM, Miles A, editors. The effective management of osteoporosis. London: Aesculapius Medical Press; 2001. p. 111-21.
  2. Cooper C. Epidemiology of ­osteoporosis. Osteoporosis Int 1999;Suppl 2:S2-8.
  3. National Osteoporosis Society ­estimated figure.
  4. Royal College of Physicians. Osteoporosis: clinical guidelines for prevention and treatment. London: RCP; 1999.
  5. Kanis JA, Delmas P, Burckhardt P, Cooper C, Torgerson D. Guidelines for diagnosis and management of osteoporosis. The European Foundation for Osteoporosis and Bone Disease. Osteoporosis Int 1997;7(4):390-406.
  6. WHO. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. Geneva: WHO; 1994.
  7. Ralston SH. Osteoporosis. BMJ 1997;315:469-72.
  8. European Commission, Industrial Relations and Social Affairs Directorate. Report on osteoporosis in the European Community. Belgium: EC; 1998. p. 16-7.

Resources
The National Osteoporosis Society Helpline is staffed by six ­osteoporosis nurses, offering information and support on all aspects of ­osteoporosis. You can email a question to the osteoporosis nurses at nurses@nos.org.uk.Your question will be answered within 10 working days. Please bear in mind that we cannot guarantee confidentiality when ­corresponding by email
If you would prefer to speak to an osteoporosis nurse, please call the NOS ­confidential helpline on 0845 4500230. The helpline is open Monday 10am to 5pm and Tuesday to Friday 9.30am to 5pm. The helpline is not open Bank Holidays or between Christmas and New Year
For further ­information or the NOS's Primary Care Strategy for Osteoporosis and Falls, email hsl@nos.org.uk

Further reading
Primary care for osteoporosis and falls. Available from the National Osteoporosis Society

Woolf AD, Dixon A St J. Osteoporosis: a clinical guide. London: Martin Dunitz; 1998

Royal College of Physicians and Bone and Tooth Society of Great Britain. Osteoporosis: clinical guidelines for prevention and treatment. Update on ­pharmacological interventions and an algorithm for management. London:RCP; 2000