Most people regard bone as solid and inanimate. In fact, bone tissue is destroyed and replenished throughout adult life, with bone mass reaching a peak around the mid thirties. After that our bone mass steadily declines at a rate of almost 1% per year - i.e. our bone gets thinner. Women's hormonal changes during and after the menopause accelerate the rate at which bone is destroyed, leading to thinner bone which is more prone to fracture and crushing. This thinning of the bone is called osteoporosis, a word which literally means "porous bones".

The bones most at risk are the spine, hip and wrist. Osteoporosis in the spine is the most common, where collapse of the bones causes pain and loss of height. Hip fractures are considered to be the most dangerous because they often lead to loss of mobility. Other bones which may break include the pelvis, thigh and upper arm.

Incidence

After reaching the age of 50, more than 50% of women and over 10% of men will suffer an osteoporosis-related fracture in their lifetime. More hospital beds are used in the NHS for hip fracture patients alone than those with breast cancer or heart attacks. Most of the NHS expenditure is on treating the consequences of osteoporosis, such as back pain and broken bones, rather than the disease itself, Osteoporosis also has a high social cost, since sufferers may become housebound and dependent on others.

Risk Factors

Research to date has managed to pinpoint some risk factors to identify those people (predominantly women) most likely to develop osteoporosis. Females are particularly susceptible if they have had an early menopause (before age 45) or surgical removal of the ovaries. Other risk factors include:

· Sedentary lifestyle
· Confinement to bed/wheelchair for long periods
· Low calcium intake and low exposure to sunlight
· Family history of osteoporosis
· Small, thin build
· Steroid treatment (e.g. prednisolone tablets)
· Asian/Northern European origin
· Smoking
· Excessive alcohol intake

What can we do?

We obviously cannot change factors inherited from our parents, but we can change our lifestyles to make us less likely to develop osteoporosis. This is particularly important in adolescence and early adulthood, so that we can maximise our bone density at its peak such that our bones have more strength to support us for the rest of our lives. But it is never too late; we can -

· Take more exercise. Bone is a living tissue, and will strengthen when pressure is put onto it by working muscles (walking or climbing stairs, for example).

· Change diet to feed our bones with calcium (especially during breastfeeding or the menopause, when calcium may be drained from the body). Good calcium foods include milk (which may be skimmed), cheese, yoghurt, tinned salmon/sardines, dark green leafy vegetables.

· Try to get some sunlight exposure (just a few minutes a day) since the skin can make Vitamin D which helps to absorb calcium and strengthen bones.

· Stop smoking and cut down alcohol intake, so as not to interfere with hormone production and calcium metabolism.

Hormone Replacement Therapy

Women after the menopause lose bone at a higher rate than before, due to an imbalance of female hormones. Studies have shown that Hormone Replacement Therapy (HRT) can prevent rapid bone loss, but it should only be taken under medical supervision following a satisfactory examination.

HRT is not suitable for every woman, and the advantages and disadvantages in each individual case should be discussed with a doctor. Various forms of HRT (tablets, skin patches, implants) are available, and a woman may need to try several before finding one which suits her. A small minority of men develop osteoporosis due to a deficiency of male hormones, for which they can also have replacement therapy.

Treatments for Osteoporosis

Other treatments have been developed for women who cannot (or would prefer not to) have HRT, and these drugs are suitable also for many men with osteoporosis. The most commonly prescribed products are bisphosphonates which are non-hormonal and usually taken as tablets. They improve bone mass and reduce the rate of subsequent fractures, particularly in the spine.

Calcium and Vitamin D supplements can also be useful, particularly in older patients for whom HRT may not be appropriate, and are sometimes combined with bisphosphonates. These treatments might also prevent the osteoporosis which often develops as a side effect of steroids such as prednisolone tablets. A variety of other therapies (including calcitonin nasal spray and fluoride tablets) are still being studied or are used only following specialist advice.

The need for more research

With longer life expectancy, the already high incidence of osteoporosis is on the increase. To ensure that suffering is kept to a minimum in years to come a huge amount of research is needed in this vital area. Broadly speaking, the research falls into four categories: ·

To achieve greater understanding of the disease itself ·
To discover how existing methods of treatment and prevention actually work, eliminate side effects and discover alternative forms of treatment.
To develop a simple and inexpensive screening process which can be used by all women, so that those at risk can be identified early enough for treatment to be truly effective. (Various methods of measuring bone density are currently available but because these are expensive, not readily accessible and not totally reliable they are not in widespread use. Sufferers, therefore, are often not identified until they have their first fracture.) ·
To determine ways in which individuals can help themselves and reduce their potential for osteoporosis (e.g. exercise regimes).