Osteoporosis can have a severe impact on women's health but there are ways to prevent its onset, writes Dr Muiris Houston, Medical Correspondent

Half of all women will have suffered a fracture as a result of osteoporosis by the time they are 70. If it is a hip fracture, they are twice as likely to die in the following two years compared to healthy women.

For those who survive, significant disability will be experienced by many to the point where they will have to leave their homes and live in institutions. Are we doing enough to prevent this common and predominantly female disease?

What is it?

Osteoporosis is commonly referred to as thinning of the bones.

The World Health Organisation defines osteoporosis as a bone density that is significantly below the average for the young healthy female population. We achieve our peak bone mass as young adults; by the time women are in their late 30's there is some bone loss.

However, women lose bone at a rate of three to five per cent for the first post-menopausal years, so that osteoporosis is most common after age 50. By 75, about 40 per cent of women will have osteoporosis.

What are its effects?

Osteoporosis can affect any bone in the body causing pain, height reduction and loss of mobility, but it is the frequency with which it causes fractures in the wrist, hip and spine that impacts most on women's health. Almost half of all women will have experienced an osteoporotic fracture by the time they are 70.

Bone is in a constant state of flux between manufacture and breakdown.

As a woman gets older, however, the breakdown of bone is greater, leading to thinner bones which are prone to fracture even from relatively minor falls.

Hip fracture is a particular cause of disability in the aged. Statistics predicting a 135 per cent increase in the number of hip fractures in the EU in the next 50 years show the importance of osteoporosis as a public health issue.

A recent study by the Health Research Board and the Department of Public Health Medicine in UCD showed the devastating effect of hip fracture on a person's quality of life. One hundred and six women admitted to St Vincent's Hospital, Dublin with a fractured hip were followed up two years later.

Compared with a group of women of similar age in good health, the women with a hip fracture were:

a. More than twice as likely to die during the two years;

b. Three times more likely to have to leave their homes and live in institutions;

c. Less mobile - 60 per cent of hip fracture patients were unable to walk 100 yards unaided;

d. More dependent on others for help with feeding, dressing, bathing and toileting.

Some 50 per cent of women were unable to look after themselves properly as a direct result of a hip fracture.

The principal author of the study, Dr Peadar Kirke, says that hip fractures will become more common as the number of older population increased and pointed to the importance of implementing public health strategies to prevent these injuries in older people. Figures from the ESRI show the economic impact of hip fractures. The cost per patient to the health service was £2,353 in 1998, with an average hospital stay of 15 days for treatment.

Can we prevent osteoporosis?

There are generally two types of medical prevention: primary, in which a disease is completely prevented by early intervention and secondary, where the disease is already established but early intervention can arrest its progress and reduce complications.

The primary prevention of osteoporosis is outlined in the accompanying panel and is relevant to women of all ages.

Screening those "at risk" of osteoporosis is another obvious intervention which should offer preventive benefits.

Reliable scanning for osteoporosis is available using a DEXA unit [Dual Energy X-Ray Absorbitometry] and there is a need to ensure a proper geographic spread of such units throughout the State.

There are only 36 scanners in the State at present, most of which do not offer a service to public patients according to Prof Moira O'Brien, president of the Irish Osteoporosis Society.

In response to local need, several group general practices have purchased DEXA units and offer an invaluable service to their communities.

The scanners offer a measurement of bone mineral density, \ which is directly linked to the risk of future fractures.

There is a group of patients for whom secondary prevention could ideally be initiated, but who currently slip through the healthcare net.

Women attending fracture clinics could be offered follow- up assessment for osteoporosis, including a density measurement.

Dr Robert Coughlan, consultant rheumatologist at Merlin Park Regional Hospital in Galway, is determined to bridge the gap between fracture clinics and the detection of osteoporosis.

He has just completed a study of 176 women over 50 who attended with fractures at the hospital over a seven week period.

When their bone densities were measured, 58 per cent were found to need osteoporosis treatment. Dr Coughlan reckons this equates to a prevalence of osteoporosis of about 30 per cent in women over 50.

"The purpose of our initiative was to show the proportion of patients with low trauma fractures who can be treated to prevent further fractures."

How do our osteoporosis services compare internationally?

In 1998, the EU made eight key recommendations based on the premise that all governments should adopt an osteoporosis prevention programme as a major governmental health policy.

The recommendations covered the funding of screening programmes, the reimbursement of proven treatment and financial support for osteoporosis research.

A 2001 audit of these recommendations by the European Parliament showed little progress had been made; in particular, no government has made osteoporosis a health priority. However, last November's National Health Strategy has promised additional facilities for the management of falls, fractures and osteoporosis treatment.

Treatment Options:

Lifestyle advice applied to all patients.

The first step in drug treatment is the prescription of 800 units of Vitamin D and 1,000 microgrammes of calcium per day. Women in the first post-menopausal decade are suitable candidates for oestrogen therapy, either in the form of hormone replacement therapy \ or a drug called raloxifene.

For patients over the age of 60, the usual therapy is with drugs called biphosphanates, which have been proven to reduce fractures by increasing the patient's bone density.

With an ageing population, osteoporosis is set to become an even greater cause of disease within the next 25 years.

By following good lifestyle advice, women have a genuine opportunity to prevent disability and ensure their continuing independence.

But we also need an equitable screening programme to pick up all women at increased risk of osteoporosis and its sometimes devastating consequences.