Calcium the key to reducing risk

Despite affecting one in three women and one in 12 men, osteoporosis is still an unseen danger and can be difficult to diagnose, but there are ways to minimise the risks and treat the symptoms. VICKY SWAIN reports.
In the medical world, prevention is usually better than cure, and with osteoporosis the case is the same. Hard to initially diagnose, it most commonly affects women, but itís a myth that men are unaffected Ė low testosterone levels can have the same damaging effects as low oestrogen levels in women.

One of the most important starting points to help combat the onset of osteoporosis in later life is a calcium-rich diet during adolescence, which will help to ensure healthy bones are formed at the outset.

Approximately ten per cent of bone in the body is replaced every year. When more bone is reabsorbed back into the body than new bone is created it means bones become thinner and are more liable to fracture. Bone mass usually peaks by the age of 30. Following that, the level gradually drops at the rate of around one per cent every year, with a higher drop for women during the first few years after the menopause.

There are three types of primary osteoporosis Ė Type I, which is postmenopausal and caused by a lack of the female hormone oestrogen; Type II, which is due to age; and Idiopathic, which affects younger people and for which a cause has yet to be identified.

Added to this there is secondary osteoporosis, which can be the result of a number of factors Ė hormonal, owing to an over-active thyroid; underproduction of sex hormones or over-production of natural steroids; digestive problems which limit the absorption of nutrients in food; arthritis and joint disease; cancer and malignant disease; and some medications, including steroids.

The most important message for doctors to pass on to their patients is that itís better to prevent the onset of osteoporosis before it becomes a problem because of the difficulties in diagnosis

Although osteoporosis can affect anyone, certain groups of people are naturally in a higher risk category. These include females, older people, those experiencing the menopause before the age of 45, people with low sex hormone levels often due to excessive weight loss or exercise, smokers and those with a family history of the condition.

However, whatever the cause, preserving and increasing bone density is the main aim of any treatment for osteoporosis. Bones need a continuous supply of calcium and vitamin D combined with vitamin C and nutrients obtained from a healthy diet.

There are also a number of medicines well suited to the treatment of the condition including Hormone Replacement Therapy (HRT); Calcitonin, administered as a nasal spray or injection under the skin; bisphosphonates; and selective oestrogen receptor modulators, like raloxifene.

But there are drawbacks to each.

Bisphosphonates can be used to stop the progression of osteoporosis and can even reverse the problem by helping calcium to form on the bone. But they are not easily absorbed into the body and need to be taken with fluid and at regular intervals between meals.

Calcitonin is a hormone, which can only be used for a limited amount of time and has shown to be less effective than other drugs.

HRT offers the greatest protection from osteoporosis, but carries the added health risks of breast cancer and deep vein thrombosis (DVT). Raloxifene behaves in a similar way to HRT, but itís less effective in preventing osteoporosis and carries a higher risk of DVT.

In addition, for men, there is testosterone therapy, which involves the replacement of low levels of testosterone that will help maintain bone density.

There are other measures, which are also useful in lessening the effects of osteoporosis.

Ensuring thereís sufficient calcium in the diet is important either through the consumption of foods like dairy products and nuts or through dietary supplements. Vitamin D, the main source of which is through exposure to sunlight, but also found in milk, cereals and eggs, is also a vital part of a diet that counteracts the likelihood of developing osteoporosis.

In some countries fluoride has also been used to combat the disease, but although evidence shows that bone mass increases with its use, there has been no evidence to suggest that it works in the long term to prevent fractures.

The most important message for doctors to pass on to their patients though, is that itís better to prevent the onset of osteoporosis before it becomes a problem because of the difficulties in diagnosing it.

While a normal x-ray canít reliably measure bone density it can identify spinal fractures common in sufferers. However, a dual energy x-ray absorptiometry (DXA) scan can measure the density of bones and compare this to a normal range. This test is currently the most accurate and reliable means of assessing the strength of bones and the risk of fracture.

Bone densitometry is also an essential tool in osteoporosis management. Densitometry helps with diagnosis, fracture risk assessment and monitoring response to therapy. It can be used to categorise patients as normal, osteopenic, or osteoporotic following World Health Organisation (WHO) classifications.

The patientís T-score, a comparison to bone density in a young adult, is the critical variable in diagnosis. Usually, both femurs and the spine are assessed, with the diagnosis made using the lowest T-score and patient examination, in addition to the T-score, is vital in diagnosing osteoporosis.

Hospitals in Middle East have the latest detection facilities

EMore and more hospitals in the Middle East are waking up to the need to detect and treat osteoporosis. The Al-Zahra Hospital in Sharjah, UAE, for example, offers two of the latest state-of-the-art ways to gain the most accurate and widely accepted methods of bone mass measurement.

DEXA BONE DENSITOMETRY

Dual Energy X-ray absorptiometry (DEXA) is recognised to be the gold standard for bone mass measurement.

It is a fast, convenient and extremely precise method to evaluate bone mass and monitor response to therapy.

It measures bone density in the spine, hip and the forearm Ė the sites commonly predisposed to fractures.

The procedure, of course, causes no pain or discomfort, and its radiation exposure is clinically insignificant. The other advantage is that no special preparation is required.

ULTRASOUND BONE DENSITOMETRY

Bone mass can also be measured using ultrasonography Ė the same technique used during pregnancy to monitor foetal development.

In this case the heel bone provides the ideal site for a precise quantitative assessment of bone health. The test is quick and simple, and also avoids exposure to ionising radiation.

Fracture risk assessment Bone Mineral Density (BMD) is the strongest tool to predict fracture risk, increasing rapidly as BMD decreases.

Femur BMD is recognised as the strongest predictor of femur fracture risk, which has the highest morbidity, mortality and cost of all osteoporotic fractures. A decrease of one standard deviation (SD) in femur BMD corresponds to a threefold increase in femur fracture risk. In comparison, a one SD decrease in spine BMD corresponds to double the increase in spine fracture risk.

Monitoring changes in BMD, patients often return for bone density tests every one to three years, depending on the expected rate of loss and their clinical situation. BMD may increase over time as a response to therapy, or it may decrease with disease progression or poor response to therapy.

By ensuring precise measurements of the BMD are taken, changes can be easily detected ensuring the patient receives the best possible care throughout their treatment.

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