The Health Blog

As a simple definition, osteoporosis is a condition in which bone becomes so fragile and brittle that it breaks comparatively easily. Bone is a living, changing thing, containing two main types of cells called, confusingly, ‘osteoclasts’ and ‘osteoblasts’. All through our lives, the osteoclasts wear away microscopic craters in the bone, and then the osteoblasts fill these craters with newly formed bone, exactly matching the space dissolved away by the osteoclasts. That way, bone is constantly renewed — a sort of repair-and-maintenance system. Oestrogen is thought to reduce the rate at which osteoclasts dissolve bone, and to increase the rate at which osteoblasts build it up. Once oestrogen levels fall, the osteoclasts dissolve the tiny craters at a faster rate than before, while the osteoblasts don’t replace the bone so efficiently. Eventually, the bone becomes less dense and strong, and more liable to fracture.

Bone is built up during childhood and teenage years, and reaches a peak content (called ‘peak bone mass’) in the early twenties. For the next 15 years or so, the bones thicken and strengthen, but then from about the age of 35 onwards, bone mass starts to fall gradually. In a man it continues in -this gradual fall for the rest of his life, and a man of 90 can expect to have lost about 25 per cent of his total quantity of bone. In women, however, bone density drops dramatically in the years immediately after the menopause — about 3-5 per cent every year in the vertebrae of women who have had a natural menopause, and as high as 7-9 per cent in the vertebrae of women who have had an early oophorectomy. (The hip joint loses bone density at a slightly lower rate.) To lose bone at about 3 per cent a year may not seem much, but if you get a calculator, start with 100 (to represent the amount of bone you have at the menopause), then subtract 3 per cent from that figure, then 3 per cent again from the next figure, you will find that after doing this seven times you get a figure of 80. In other words, after losing 3 per cent of your bone every year for seven years, you are left with just 80 per cent of what you had at the start of the menopause – and you are probably still only in your fifties. Many women lose bone mass at a faster rate than 3 per cent, and sometimes for as long as 15 or 20 years; it is not unusual for them to end up having lost one-third or even half of their bone mass by about the age of 70. No wonder fractures occur!

Bones are not solid things, like an iron bar, as this would make them very heavy. Each bone contains an outer shell of ‘cortical’ bone, which is strong, compact and dense, and an inner area of ‘trabecular’ bone, which is brittle and fragile. The bones that are most vulnerable to fracture in osteoporosis are those that have a higher proportion of trabecular bone, such as the hip joints and the vertebrae of the spine.

Trabecular bone is made up of tiny vertical pillars, joined together with horizontal cross-ties, giving it strength with the minimum of weight. In osteoporosis, as the osteoclasts wear away bone faster than the osteoblasts can build it up again, these pillars and cross-ties lose their connections with each other, and the bone therefore loses its strength. Eventually, it becomes so fragile that it can fracture while you are doing such everyday things as lifting a casserole out of the oven, opening a stuck window, putting shopping bags into the boot of the car, doing up the back zip of a dress, or even coughing, laughing or sneezing.

The main component of bone is calcium, which is held in a soft substance called collagen; as collagen levels fall, so do die levels of the calcium held within it. Oestrogen helps the body to absorb calcium effectively, making it available to the osteoblasts, and as oestrogen levels fall after the menopause, so calcium is stored less effectively. Much of it is just excreted in the urine instead of being used to build bone.

As oestrogen is needed to get the ‘bone building’ balance right, and as it also helps the body to absorb calcium and preserve collagen, you can see why oestrogen therapy is so effective in preventing osteoporosis. It can’t rebuild damaged bone, but it can help prevent further bone loss. It has been said of HRT that it ‘stops osteoporosis in its tracks’, because oestrogen therapy at any stage after the menopause halts bone loss.

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The health care costs of abdominal, vaginal and laparoscopically assisted hysterectomies are comparable. However the reduced recovery time of the latter approach promises considerable benefits to women, their families and employers.

An economic evaluation that compared the costs of abdominal hysterectomy and endometrial resection in England for the four months up to and including surgery, found total costs for the former were nearly twice that of the latter. The authors suggested, however, this was not the end of the story:

Given the fact that a subgroup of women requires re-treatment due to resection failure and that this study considers a relatively short period of follow-up, the long-term costs and benefits of endometrial resection need to be evaluated before widespread diffusion is justified.

The all-up cost of an abdominal hysterectomy in Australia in 1993 was about $5000, and for a vaginal hysterectomy it was considerably less at $3550. The cost of a laparoscopically assisted hysterectomy was about $5700, of which almost $1200 was for disposable instruments. Women who do not have private health insurance and whose hysterectomy is carried out in a public hospital ca*n expect to pay nothing. Women with private health insurance can expect to pay $500 or more, regardless of whether they attend a public or private hospital. Their payment will depend on their level of insurance and the fees charged by their surgeon and anaesthetist. Uninsured patients having a hysterectomy in a private hospital face payments of $2500 to $3000.

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It is now believed that benzodiazepine exerts an inhibitory effect on the transmission of signals between nerves, so that there is a slowing down in the relay of signals between nerve cells and hence the person becomes less excitable and more relaxed. Benzodiazepine competes with a naturally occurring chemical in the nerve endings known as GABA (gamma amino butyric acid).

It appears to displace GABA off these nerve endings, which increases the amount of freely available GABA. GABA is known to inhibit transmission of impulses between nerve cells.

There are two main kinds of benzodiazepine, the long acting and the short acting. By long action, we mean that once the drug is absorbed into the body it stays active for a long time and can be detected in the body after many days. The drug is eliminated from the body by two mechanisms, either destroyed by metabolism in the liver or excreted by the kidneys in the urine. The faster the metabolism, the shorter the half-life of the drug, which is the time taken for half of the drug in the body to be eliminated. This elimination phase can be much longer in older people than in younger people because their kidneys are not normally so efficient. The long acting hypnotic drugs have a long half-life and can sustain sleep longer, but they may give a hangover feeling the next morning;

people who take these drugs often complain that they feel like a zombie the following morning. If this drug is taken nightly and regularly, it tends to accumulate in the body. One of the longer

acting drugs is Flurazepam, commonly known as Dalmane, and its half-life is nearly 80 hours. This is rarely prescribed in Australia now.

The short acting benzodiazepine has a short half-life and is eliminated from the body much more quickly, usually within a few hours. It can initiate sleep more easily, but may not be as effective in sustaining sleep. There is very little hangover feeling in the morning and accumulation of the drug in the body is less likely even if taken regularly. A common short acting drug is Temazepam, which is marketed in Australia as Euhypnos or Normison; its half-life is 5.8 hours.

Health authorities all over the world have now recognized the abuse of benzodiazepines. They have found that they are addictive. As the number of deaths from barbiturates fell, it became apparent that quite a large number of people suffer from the distressing effects of dependence on benzodiazepines. In Australia alone there are about 6.5 million prescriptions for benzodiazepines written each year, and there are only 15 million people here.

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