Osteoporosis

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. Like other organs in our body, they are constantly changing. Throughout childhood and as young adults bones grow in strength and in size. Around the age of 30, bones reach their peak strength and then naturally becomes weaker with age.

"Brittle bones" or "porous bones" (osteoporosis) is a condition in which bones become fragile. It occurs when the spaces in the bone become bigger, making it fragile and liable to break easily. If left untreated, it can progress painlessly until a bone breaks. These broken bones, or fractures, occur typically in the hip, spine, and wrist.

A hip fracture almost always requires hospitalization and major surgery. It can impair a person's ability to walk unassisted and may cause prolonged or permanent disability or even death. Spinal or vertebral fractures also have serious consequences, including loss of height, severe back pain, and deformity.

Genetic Influence

Your genes determine the potential strength of your bones but lifestyle factors can influence the amount of bone you invest in your bone "bank" during your youth and how much you save in later life. Therefore, family history of osteoporosis is an important risk factor. Other risk factors include:

• Advanced age: bone loss occurs as we get older
• History of bone fracture
• A small thin frame: the bone mass is reduced
• Removal of the ovaries: female hormones estrogen helps protect women against bone loss
• Early menopause
• Low calcium diet
• Lack of exercise
• Eating disordes
• Medications like steroids (for conditions such as arthritis and asthma) or anticonvulsants (for treating epilepsy)
• Missing periods for six months or more as a result of over-exercising or over-dieting
• Alcohol and smoking
• Long-term immobility (bed-ridden)

Diagnosis

Osteoporosis is a silent disease, because you cannot see or feel your bone getting thinner. Therefore, you will probably be quite unaware of any problems with your bone health until a lot of bone has been lost. 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 accident.

Osteoporosis is diagnosed by doing a bone density scan using a densitometer. A small amounts of x-ray is used to produce images of the spine and the hip. The x-ray is composed of two energy levels which are absorbed differently by the bones in the body. The technical term is "dual energy x-ray absorptiometry" (DEXA). A computer is able to determine from these differences how much bone mineral is present. The amount of the bone mineral relates directly to bone strength. This test is currently the most accurate and reliable means of assessing the strength of your bones and your risk or fracture.

The bone densitometer is a large examination table. You will be asked to lie on your back. The test is painless and typically takes a few minutes. The test is very safe, even though x-rays are used. The amount absorbed by you is only 10% of what you receive from a chest x-ray. The test compares your bone mineral density (BMD) to that of a "young adult" at peak bone strength. It also compares your results to people of your same age , called "age-matched". This information, along with other factors helps doctors gauge your risk of osteoporosis.

Prevention

Healthy bones need a well-balanced diet, incorporating minerals and vitamins from different food groups. You especially need to ensure that your diet is rich in calcium. The best sources of calcium are milk and dairy products such as cheese and yogurt. Non-dairy sources of calcium include green leafy vegetables, baked beans, bony fish and dried fruit.

• Take regular, weight-bearing exercise.
  Like muscles and other parts of the body, bones suffer if they are not used. They need regular weight-bearing exercise that exerts a loading impact and stretches and contracts the muscles, stimulating bone to strengthen. Good bone building exercises include running, skipping, aerobics, tennis, even brisk walking. Try to exercise at least three times a week for a minimum for 20 minutes. If you haven't exercised for a while, start gently and check with your doctor if you have another health problem and are worried about exercising.
  
• If you are a smoker - give up! Smoking has a toxic effect on bone in men and women. It can cause women to have an early menopause and may increase the risk of hip fracture in later life. Stopping smoking will benefit your bones and your general health and fitness.
• Watch what you drink! Drinking too much alcohol is damaging to bone turnover. It would be wise to limit your alcohol intake.

Treatment

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

• Bisphosphonates are non hormonal drugs, which 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) is oestrogen replacement for women at the menopause, which help maintain bone density and reduce fracture rates for the duration of therapy.
  
• Selective Estrogen Receptor Modulators (SERMs) are drugs which act in a similar way to oestrogen on the bone, helping to maintain bone density and reduce fracture rates specifically at the spine.