Osteoporosis: a disease on the rise

Osteoporosis is a disease that makes bones porous or brittle which can cause them to break or fracture more easily than healthy bones.

One in 5 men and 1 in 2 women over the age of 50 will develop a fracture due to osteoporosis in their lifetime and the disease can also affect children. If you have one osteoporotic fracture you are twice as likely to have another and the older you are, the more likely you are to develop the disease.

While osteoporosis is a chronic disease affecting a third of postmenopausal women (over the age of 50) in Europe, it is the fractures and resulting disability as a result of osteoporosis that cause the most damage.

Worldwide, osteoporosis causes more than 8.9 million fractures a year, resulting in an osteoporotic fracture every 3 seconds.

Nearly one in five women who have had a hip fracture end up in a nursing home and approximately 20 per cent will die as a result of their fracture. Therefore there is a very high level of moratlity associated with the disease particularly among older men who tend to suffer osteoporotic fractures at older ages than women.  In 2010, the number of deaths as a result of osteoporotic fractures in the EU was an estimated 43,000.

According to the Irish Osteoporosis Society, 20 per cent of people over the age of 60 who fracture a hip will die within 6-12 months due to the secondary complications of osteoporosis. Half of people over 60 who fracture a hip, will no longer be able to dress, wash or walk unassisted and only 30 per cent will regain their independence.

RISK FACTORS

Hormones play a key role in osteoporosis and while everyone is potentially at risk, one of the risk factors is simply being female. This is because women start off with less bone than men so they can afford to lose less. Usually for a period of two to five years after the menopause women can lose bone quite quickly as a result of having less oestrogen. Bone is a living tissue so it is constantly being re made. In healthy adults there is  a balance between bone being made and being broken down.Once you withdraw oestrogen that balance becomes upset, so you break down more bone than you make. The same is true of testosterone in men, where testosterone deficiency can make them susceptible to osteoporosis but women are more at risk.

The body’s delicate hormone balance can also become upset in younger female athletes who over exercise to the point where their periods stop and also in anorexia nervosa, which is partly nutritional but also partly due to hormonal abnormalities as a result of an eating disorder.

About 70 per cent of bone density and fracture risk is determined by genetics so family history is very important. It is recommended that post menopausal women with a family history of osteoporosis should get their bone denisty checked.

Additional risk factors for osteoporosis include smoking and excessive alcohol intake. Both smoking and alcohol are directly toxic to bone.

Certain medications such as steroids and hormonal medication used to treat breast and prostate cancer, can also increase your risk of developping osteoporosis.

People with medical conditions that affect the body’s ability to absorb nutrients, such as bowel diseases like Chrohn’s disease, those with rheumatoid arthritis and people with poor calcium and vitamin D intake in their diet and who are very immobile, are also at an increased risk of osteoporosis.

SIGNS AND SYMPTOMS

The most common symptom of osteoporosis is a bone fracture following a simple fall. A simple fall is one where you fall from a standing height. So if you break a bone following a fall from a standing height, that is considered a fragility fracture and can be a sign of osteoporosis. If this happens you should be screened for the disease.

Another symptom of osteoporosis is a loss of height which is commonly seen in older women who have sustained a vertrebal or spinal fracture. Only a third of these fractures cause pain or symptoms so it can go unnoticed until a loss of height is seen. Older women can also become more stooped and their tummies can stick out a bit more as a result of the spinal fracture, these are all signs of osteoporosis.

DIAGNOSIS

The main test for diagnosing osteoporosis is called a DXA (dual energy X-ray absorptiometry) scan.  It is a type of x-ray that that measures the density of bone. Scans are normally carried out in women over the age of 65, men over the age of 70, and postmenopausal women under the age of 65 who have other risk factors for the disease.

A DXA scan is usually taken of the spine and hips and is the best way to predict your risk of fracture as it measures the calcium content of bone, but it doesn’t directly measure the strength of the bone .

TREATMENT

Before a doctor prescribes medication for osteoporosis, he or she will try and reverse the risk factors. For example if you smoke you should quit and if you drink heavily you should stop drinking. You should also advise take plenty of weight bearing excercise, which is excercise during which you put your foot to the ground,  such as walking as opposed to swimming or cycling.

Walking has two effects. It strengthens leg muscles which are essentially a form of scaffolding around the bones and every time you put your foot to the ground it creates a small impact through the bones which helps stimulate the production of healthy bone. Did you know that due to the lack of gravity, astronauts have a high risk of osteoporosis as their bone density drops very quickly in space?

As well as attempting to cut out risk factors people with osteoporosis will be advised to maximise their dietary intake of calcium and vitamin D, which are essential for bone health.

Postmenopausal women and men over 50 should be eating 1200 milligrams (mg) of calcium a day. A glass of milk contains 300 mg as does a matchbox size piece of hard cheese.  A standard portion of yogurt contains between 250 and 300 mg of calcium. Other sources of calcium include bread, breakfast cereals and fortified orange juice.  For people who don’t mind taking diary it is not too diffiuclt to get to 1200 mg through diet alone. However if you don’t take diary it is real challenge and calcium supplements may be required.

MEDICATION

We have got a reasonable choice of drugs at the moment to treat osteoporosis and these are broken down into two types; those that effectively stop the breakdown of bone, and those that can build and reduce bone breakdown at the same time.

The drugs which stop the breakdown of bone are called bisphosphonates which come in oral and injectable forms. Other drugs which help stimulate the production of bone are called anabolic agents. One of these is can be given orally, and another by a self administered injection once a day for two years.

However the first line treatment for most patients is correcting the calcium intake through diet and possibly a calcium supplement, and the use of an oral bisphosphonate.

There has been some controvery in recent years over the use of bisphosphonates as some studies suggest that they may cause a condition called osteo necrosis of the jaw (ONJ) . However this is extremely rare. According to the Irish Osteoporosis Society the incidence of ONJ with bisphosphonates used in the treatment of osteoporosis is less than one in 100,000.

It is also important to note that one fracture is prevented for every 30 to 50 patients prescribed a bisphosphonate. Therefore over 2,000 people will avoid a fracture for every one potential case of ONJ, so the benefits far outweigh the risks.

BONE HEALTH

It is possible to reduce your risk of developing osteoporosis and it is also possible to reduce the risk of fracture in a patient who has the disease, if it is detected early enough.

The general advice for people who want to maintain their bone health is to not smoke, not to drink more than the recommended limits, eat a diet rich in calcium and take plenty of weight bearing exercise.

FUTURE

It is interesting to note that osteoporosis has been described as a paediatric disease that presents in a geriatric population. One of the big concerns about the likely explosion in prevalence of osteoporosis over the next few decades is the fact that children are less active. They are also drinking carbonated or sugary drinks at the expense of milk and are more sedentary, spending more time inside on computer games rather than running outside in the sun.

By 2050, the worldwide incidence of hip fracture in men is projected to increase by 310 per cent and 240 per cent in women so there is a real fear that we are simply storing up trouble for the future.

USEFUL RESOURCES

Irish Odtroporosis Society

[ irishosteoporosis.ie ]

Osteoporosis Canada

[ osteoporosis.ca/osteoporosis-and-you/nutrition/calculate-my-calcium/ ]

International Osteoporosis Foundation

[ iofbonehealth.org ]

Dr Ronan Kavanagh, Consultant Rheumatologist at the Galway Clinic in Galway.