| A-Z of Osteoporosis |

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A-Z OF OSTEOPOROSIS
Osteoporosis literally means porous bones. It is a condition in which bone tissue is reduced and the micro-architecture of bone is disrupted. This leads to an increased risk of fracture which usually involves the spine, hip or wrist. The World Health Organisation (WHO) defines osteoporosis as a systemic skeletal disease, characterised by low bone mass and micro-architectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture.

It is a myth that osteoporosis is a normal part of aging and that only women are susceptible. We now know that this disease can also affect young people as well as men.

Osteoporosis is called the silent disease because it progresses undetected for many years and the first sign of this disease is usually a fracture. Spinal fractures may be painless, but often result in severe back pain for several weeks. Compression fractures of the spine occur because the weakened bone collapses under the body's weight. This causes a loss of height and increased curvature of the spine (Dowager's hump).

The majority of hip fractures is also the result of osteoporosis and can be a devastating consequence – resulting in institutionalisation, reduced functional capacity and even death. Hip fracture rates in South African Caucasians are similar to those in Europe and the USA.


Some Fast Facts About Osteoporosis
More than one-third of women over the age of 50 and nearly half of those over age 70 are affected by this disease.

Osteoporosis in men is on the increase, and one in 5 men will develop this disease.

In most cases the patient is 50-70 years old before osteoporosis is diagnosed- it can however, affect women and some men in their mid – thirties or even earlier.

Without appropriate preventative therapy, one out of every three White and Asian post-menopausal women will have a spine fracture.

A woman's risk of sustaining a hip fracture is equal to the combined risk of developing breast, uterine and ovarian cancer.

Up to 20% of hip fracture victims die within one year; 15-25% will require institutionalisation and less than half will regain full functional capability,

In developed countries, spinal osteoporosis is 6 times, and hip fractures 2-3 times more common in women than men – in developing countries, including South Africa, the incidence of hip fractures in men approximates that of women. Although less common in blacks, osteoporosis occurs in all population groups and recent evidence suggests that its prevalence is increasing.

Although treatable, the prevention of osteoporosis is much more effective. This requires an understanding of predictive factors so that the likelihood of osteoporosis may be judged, an awareness of methods to measure bone mass, a knowledge of lifestyle adaptations and drugs available to prevent further bone loss.

Recent advances in treatment options have resulted in a 50-70% reduction in the rate of osteoporotic fractures.

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Who Is At Risk?
Osteoporosis can be divided into two types: primary and secondary osteoporosis. Primary osteoporosis is the more common. Secondary osteoporosis is usually the result of an identifiable agent or disease process that causes the bone loss.

Although the exact cause of primary osteoporosis is not always clear, a number of risk factors are known to increase the chances of developing this disease.

Remember - an individual may have these risk factors and not develop osteoporosis. Conversely, many people may have no apparent risk factors and develop osteoporotic fractures.

RISK FACTORS FOR OSTEOPOROTIC FRACTURES
(A) DECREASED BONE STRENGTH
(i) Genetic Factors
Elderly females
Family history of osteoporosis
White, Asian and Mixed - race origin
Excessive leanness

(ii) Lifestyle Factors
Alcohol abuse
Heavy smoking
Malnutrtion
Sedentary lifestyle
Chronic immobilisation
Excessive exercise plus low energy intake

(iii) Diseases/Drugs
Hormonal disorders (Cushing's; hypogonadism; hyperthyroidism; type I diabetes).
Malignant diseases (e.g myeloma; solid tumours)
Gut disorders (e.g. Gastrectomy; inflammatory bowel disease; malabsorption syndromes)
Collagen disorders (e.g. Rheumatoid arthritis; osteogenesis imperfecta; Marfan syndrome)
Eating disorders (anorexia nervosa; bulimia)
Drugs (e.g. cortisone; anti-convulsants; anti-coagulants; excessive thyroid hormone)

(iv) Aging Factors
Premature menopause
Osteoblast(bone building cell) incompetence
Negative calcium balance resulting in overproduction of parathyroid hormone

(B) INCREASED PROPENSITY TO FALL
Mental impairment*
Institutionalisation
Gait and balance disorders*
Weakness and immobility
Visual impairment
Environmental hazards/accidents
History of falls

* Increased by alcohol and drugs like sedatives, anti-depressants, antihypertensive drugs and anti-diabetes agents.

Gender, Age and Race
The peak bone mass of women, which is reached at 25-30 years, is usually about 10-25% less than that of men. After peak bone mass is reached, bone mass gradually declines in both women and men. Because of the rapid bone loss during the menopause, osteoporosis occurs more frequently in women than in men, who have no well defined “andropause”- men lose sex hormones (testosterone) at a much slower rate.

Although osteoporosis is not a normal part of aging, the likelihood of developing this disease and associated fractures becomes greater the longer you live.

South African White, Asian and Coloured populations are at higher risk to develop osteoporosis than Blacks. Current research is under way to determine why.

Heredity
Genetic factors play an important role in achieving adult peak bone mass. This is apparent in females where those with mothers suffering from spinal osteoporosis, tend to have lower bone densities.

Peak bone mass can however be influenced by calcium intake, exercise, hormonal factors and general health.

Body Build
Short, small framed individuals with low body weight have less bone to lose than larger, big boned women.
Fat tissue is an important source of oestrogen production- petite women often have lower blood levels of this bone protective hormone.

Reproductive History
The female sex hormone, oestrogen, protects against bone loss. A premature menopause (before age 45), whether spontaneous, or surgically induced markedly increases the risk of osteoporosis.

Not breast feeding also appears to incur additional risk, whereas pregnancy with its accompanying high levels of oestrogen actually protects against bone loss. A rare form of pregnancy-induced osteoporosis is however, well documented

A decrease in testosterone levels of men can also result in bone loss and osteoporotic fractures. Up to 30% of men with osteoporosis have low testosterone levels.

Diet
A variety of nutritional factors influence bone health and a balanced diet containing adequate calories, minerals, vitamins and other nutrients is required to build and maintain strong bones. Sufficient calories, protein and Vitamin C are required for normal collagen synthesis.

Excessive phosphorous, protein and salt intake may enhance the excretion of calcium in the urine.

Caffeine has still to be proven harmful to bone.

Calcium is probably the most important nutrient needed for a healthy skeleton- especially in children, pregnant or lactating women and the elderly.

Calcium is important for bone, muscle, heart, nerve and blood cells to function normally. We lose calcium in urine and stools every day. It is therefore important to balance this loss with an adequate intake of calcium. If there is more calcium loss than intake, calcium gets released from bones and a longstanding depletion can lead to a decrease in bone mass.

Lack of exercise
Mechanical muscle-pull on bone is the only physiological way to stimulate bone formation. Immobilisation causes a dramatic decrease in bone tissue and 20-40% of bone mass can be lost within a 2 year period. Weight bearing exercises like walking, jogging, dancing etc. are important to prevent bone loss.

Over- training in both men and women can also lead to bone loss.

Alcohol
Studies have shown that the intake of 1 alcoholic drink per day in women and 2 per day in men should not be exceeded as this can lead to osteoporosis.

Chronic alcoholism is associated with significant bone-loss in nearly 50% of cases and alcohol has a direct toxic effect on bone.

Smoking
Women who smoke tend to have lower blood levels of oestrogen, a lower body mass and tend to go through an earlier menopause than non-smokers. Bone mass in smokers is generally 15-25% lower than non-smokers.

Medications
The long-term (more than 6 months) use of glucocorticoids (e.g. cortisone used for treating asthma, eczema, arthritis etc) is and important cause of osteoporosis.

Other drugs known to negatively influence bone formation include anti-epileptic agents, certain diuretics, anti-coagulants, immuno-suppressive drugs and aluminium-containing antacids. Patients on thyroid hormone replacement therapy should have there hormone levels checked regularly since excess thyroid hormone can also result in bone loss.

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HOW DO I KNOW I AM AT RISK?
The treatment of advanced osteoporosis is difficult and the real key to the management of this disease is prevention. It is therefore extremely important to identify, sooner rather than later, those individuals who are at risk. Osteoporosis is a silent disease with no symptoms until a fracture occurs- to wait for symptoms is therefore too late. What can be done to predict future fractures?

1. Clinical Risk Factor Assessment
Those risk factors which may predispose to the development have already been discussed and we mention the more important ones again:

•Advanced age
•Premature menopause (before 45 years)
•Other causes of low sex hormone levels in men and women
•Long term cortisone use
•Previous fracture after minimal trauma
•Alcohol or tobacco abuse
•Certain hormonal, intestinal or malignant diseases
•Excessive leanness
•A strong family history of osteoporosis
•Malnutrition, poor calcium intake and eating disorder (e.g. anorexia, bulimia)

Although the predictive value of a clinical risk factor is not accurate (i.e. individuals without risk factors may develop osteoporosis), it provides clear indications for further investigations (e.g. bone mass measurement).

2. Bone Mass Measurement
A low bone mass is strongly associated with the development of fractures and bone mass measurement is currently the best predictor of fractures. Bone mass measurements should always form part of a comprehensive programme of medical management, preferably done by a knowledgeable physician.

Routine screening of bone mass without any indication is cost- ineffective and not recommended.

Indications for Bone Mass Measurement:
(i) Presence of disorders known to be bad for your bones
• Early menopause; other causes of low sex hormones
• Hormonal, gut malignant, nutritional/eating disorders
• Bone toxic drugs

(ii) X-ray evidence of low bone mass or fracture

(iii) History of non-traumatic fractures

(iv) When there needs to be decided whether to start/continue with hormone replacement therapy or not

(v) Presence of strong historic factors e.g.
• Family history of osteoporosis
• Excessive leanness
• Alcohol abuse
• Heavy smoking

Techniques available to measure bone mass and fractures include:
•Dual-Energy X-ray Absorptiometry (DEXA)
•X-ray energy is passed through the spine, hip other part of the skeleton. It is precise, accurate and painless.
•Computerised Tomography
•The so-called CT accurately measures spinal bones mass. To date it cannot measure hip bone mass. Compared to DEXA, the radiation dose is higher and the measurement less reproducible.

Other Methods:
•X-rays- Although essential to detect fractures and deformities, it is not accurate enough to detect bone loss. Up to 40% of bone loss needs to occur before it is detected on X-rays. The converse also happens where falsely positive findings for osteoporosis occur in about 25% of cases.

• Single Photon Absorptiometry (SPA) - Measures bone in the wrist and forearm; this is useful but does not always provide accurate information about bone density in other sites.

• Ultrasound- Measurements of the heel bone or shin have much potential, but at present the technique is not recommended to confirm a diagnosis of osteoporosis or to follow up response to therapy.

3. Biochemical assessment
Biochemical tests done on blood and urine samples to assess bone turnover (the chewing away as well as the forming of new bone), are available to identify those at risk of rapid bone loss or fracture. They are also used to assess the response to therapy.

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HOW CAN I PREVENT OSTEOPOROSIS?
Preventive measures aim to ensure maximum accumulation of bone tissue during skeletal growth and maturation as well as reducing bone loss after the skeleton matures.

Approaches therefore differ during each life stage. Adolescence and young adulthood are the times to build skeletal reserve; midlife provides the opportunity to preserve bone mass and assure bone health in future years. In later life, those who may already have developed osteoporosis can take measures to prevent further bone loss and fractures.

Certain risk factors which predispose to the developing of osteoporosis cannot be altered- you cannot change your gender, race or age. You can still however do much to prevent further bone loss.

Lifestyle Changes
There are 4 main areas in which you can help maintain healthy bones:
•Balanced diet rich in calcium/ calcium supplements
•Regular weight-bearing exercise
•Stop smoking
•Decrease alcohol intake and avoid bone toxic drugs

Diet
A balanced diet containing adequate calories, minerals and vitamins is required to maintain bone health. Sufficient calories, protein, and vitamin C will ensure normal collagen synthesis.

An adequate Calcium intake is probably the most important bone building mineral.

It is a well known fact that the diet of most individuals in western countries like South- Africa, contain insufficient calcium to maintain a positive calcium balance.

Reasons for limited consumption include a distaste for dairy products, fear of calories and fats (although skim milk actually contains slightly more calcium than full cream milk), true milk allergy (rare in adults) and lactose intolerance which occurs frequently in the elderly, Blacks and Asians. Fermented lactose products like cheese and yoghurt are however tolerated by most.