Osteoporosis has been recognized as a problem, deserving of research attention and medical treatment, since about 1980. One in three women develop osteoporosis or ‘brittle bone’ disease. This means that bones break easily because the skeleton has become fragile.
Age-related osteoporosis is caused by gradual loss of bone mineral; this is a normal process, and is not a disease caused by infection. As bone mineral is lost, the bones do not shrink in size but become fragile and porous – ‘osteoporosis’ means porous bone.
From mid-life onward, the skeleton slowly loses bone mineral. If this bone loss is combined with less than average bone mineral density before the menopause, then osteoporotic fractures become increasingly likely as the years go by. However, you can off-set this loss with exercise that stimulates increased bone formation, to improve your BMD. It is never too late to take steps to reduce your risk of fracture, by making sure your lifestyle includes small amounts of regular bone-friendly physical activity and a bone-friendly diet.
The silent condition
Unfortunately, a fracture is often the first sign of osteoporosis. Osteoporotic fractures can occur very easily; changing a stiff gear in the car can be enough to break a brittle bone.
Understanding your bones
Bones should be used regularly or they will deteriorate, like muscles do if they are not used.
The skeleton is a support structure that is alive and responds to challenging loads.
The normal ‘loading’ for the skeleton is the pull of working muscles on your bones and the force of gravity acting on your body weight.
Bones need a variety of brief, frequent loads every day to maintain their strength.
Bones need to be loaded a bit more than usual to improve their strength.
The bones that make up your skeleton are made from living tissue, which renews itself continuously throughout your life. If your skeleton is to do this effectively and remain strong, it needs regular stimulation from physical activities.
Bone is made of a calcium mineral, which gives bone its hardness and whiteness. This calcium mineral is embedded in a protein mesh of collagen, which is gristly and makes bone slightly bendy. Bone tissue is not completely solid, but has a honeycomb structure inside a thick solid outer age layer. This efficient design maximises strength, without being too heavy.
The honeycomb structure of bone provides a huge surface area which is lined with bone cells. These cells continually renew the bone substance in a systematic cycle of breakdown and rebuilding, called bone turnover. This process ensures that minute fractures are repaired and the bone is kept strong. This remodelling allows bone to gain strength in response to increased load, or to lose it if loads become less.
How bone changes with age
During your early years, your body of the skeleton is complete by the time accumulates bone. Up to and during you are 30 years old. It is still possible, adolescence, bones grow rapidly. Most of however, to achieve improvements in your skeleton is in place by the end of BMD after this age if you change from a your teenage years and the consolidation sedentary lifestyle to a more active one.
Some women lose very little bone as they grow older but others can lose a lot, particularly in the first few years after the menopause because of the fall in oestrogen levels that occurs when menstruation ceases. The result is a loss of bone mineral over the next few years of up to five per cent each year. Fortunately, this loss later slows down to a rate of about one per cent a year. Even so, the bone can eventually become so porous that fractures happen very easily. During the postmenopausal years, oestrogen levels are low, and vary from one woman to another. This variation in oestrogen levels may go some way toward explaining why some women are more vulnerable to osteoporosis than others.
Are you at risk?
There are a number of factors that increase your risk of developing osteoporosis. Many of them are genetically programmed so you cannot do anything about them, but it does help to be forewarned. There are other factors you can do something about. Your lifestyle is very important and you may need to change only a few aspects of your life to reduce your chances of developing osteoporosis. If you think you might be at risk, see your doctor to arrange a DXA bone scan and, if necessary, seek treatment to prevent fractures occurring later. The main risk factors which you cannot change are:
Women are at greater risk than men because they have smaller bones which contain less mineral. Oestrogen is important for bone health in women, and oestrogen levels fall at the menopause.
If you have relatives, particularly your mother or a grandmother, who have suffered from osteoporosis you are more likely to do so.
Small, slight women are at greater risk than large women, because they have smaller bones and lower BMD. Women of tall, thin build are also more vulnerable because of the long thin shape of the end of their hip bone. This is where almost half of all hip fractures occur.
Early menopause or hysterectomy
Women who have stopped menstruating before 45 years of age or have had a hysterectomy before this age are at greater than average risk of developing osteoporosis. This is the case even if the ovaries were not removed. If j^ou take hormone replacement therapy from the time of the surgery, your risk of osteoporosis is reduced because the oestrogen is replaced but you are protected only for as long as you take HRT Other drugs which prevent bone loss are available also.
For genetic reasons, black women of African descent have a ten per cent lower risk of osteoporotic fracture than white women of Caucasian descent. Asian women are somewhere in between.
Occasionally the thyroid gland becomes overactive, causing hyperactivity, or underactive, causing lethargy. It is difficult to adjust treatment to get the hormone levels exactly right. Too much thyroid hormone leads to some loss of bone.
A number of diseases are treated or managed with cortico-steroids, including rheumatoid arthritis, Crohn’s disease and severe asthma. Unfortunately, a common side effect is a weakening of the skeleton.
Gut or kidney conditions
Diseases in which absorption of calcium is difficult or too much calcium is lost in the urine threaten calcium stores and lead to loss of bone.
A history of eating disorders
Failure to eat a normal, balanced diet by young women leads to bone loss which is associated with hormonal disturbances, loss of menstrual periods and extreme
Whether oral contraceptives have any effect on bones is a common concern. Contraceptive pills are a form of HRT taken to override the natural pattern of hormonal release that leads to ovulation and potential pregnancy. They contain oestrogen and inhibit a woman’s own oestrogen production. There is currently no evidence to show that taking oral contraception has long-term implications for the skeleton. thinness. Diagnoses of osteoporosis can occur, therefore, in young women. Even after periods have resumed and body weight is back to normal, BMD may not return to previous levels. This loss of bone is likely to persist into middle age, leading to increased risk of fracture.
The weak spots
The bones that are most likely to fracture due to osteoporosis are the wrist, spine and hip. Many of these fractures follow a fall, so maintaining good control of balance is important. You can live with fragile bones if you manage to avoid subjecting them to high impact.
Fracture of the hip is a risk for women late in life which can cause a great deal of misery. Admission to hospital and major surgery to pin the broken ends of the bone together is often needed, and although this is usually a successful operation, many older victims never fully recover their mobility and independence.
Trying to open a stuck window or turning a key in a stiff lock can be enough to cause a vertebral fracture if your spine is osteoporotic. Signs that you might already have spinal osteoporosis are height loss and curvature of the spine. Once a vertebra has collapsed, there is, at present, no way of rebuilding it. If several vertebrae collapse, the curvature of the spine can lead to health problems. For example, respiratory diseases can develop because there is not enough room in the chest for the lungs.
The most common cause of a fractured wrist is when you reach out and use your hand to take the impact of a fall. A broken wrist is not a disaster but it can be very painful; it may not heal in exactly the right position and can cause long-term discomfort. A wrist fracture is a warning that you might have osteoporosis and that it is time to take action to prevent any more serious fractures from occuring.
Smoking has been shown to increase the risk of fracture and the more cigarettes smoked each day, the greater the risk. If you smoke, then the best thing you can do for your bones is to give it up. Your skeleton will recover to some extent and your health will benefit in many ways. Try also to avoid passive smoking.
Prevention & treatment
If you have been diagnosed with osteoporosis or think you may be at high risk, then there are a number of drugs that your doctor can prescribe. The most widely used are various forms of HRT, but other drugs have also been developed that produce similar benefits for the skeleton. You will need to discuss the options with your doctor to determine which is right for you. Since one of the major reasons for bone loss is the fall in oestrogen levels after the menopause, restoring these levels with HRT prevents further loss. HRT can also increase BMD over a period of years, especially in the spine. Although HRT and other drug treatments are useful to postmenopausal women, they do not suit everyone and there can be side effects.
The importance of exercise
Whether you choose to take a drug treatment or not, you can further improve your BMD and reduce your fracture risk by making adjustments to your lifestyle. Research has shown that women who took part in regular exercise as well as starting HRT improved their BMD more than women who either exercised only or took HRT only.
Reducing your risk
There are several steps you can take to look after your bones and to ensure that you go into the menopause in the best possible health. These steps will also help to maintain your BMD after the menopause.
Feed your bones
Because the skeleton is largely made up of calcium salts, and as it acts as a reserve for calcium, it is important that your daily intake of calcium is sufficient. The amount recommended by The Department of Health is 700 mg daily. A pint of skimmed milk contains this much. If you eat a balanced diet, you shouldn’t need to take calcium supplements. But if you can’t eat dairy products, or need to take a supplement for other reasons, choose one carefully: some contain more calcium than others, so compare the labels on different brands before vou buv.
Vitamin D is essential for bone health and for helping you to absorb calcium from your food. The amounts of vitamin D needed are small and the body can build up stores which last for a few weeks. There are two sources of vitamin D: your diet and exposure to the sun.
Your skin can make vitamin D provided it is exposed to ultraviolet light from the sun. Half an hour three times a week of summer sun on your face and hands is recommended – this is below the amount likely to cause sunburn or skin cancer.
In northern winters the sun is too weak to be effective so it is vital to get enough in your diet. Eating fatty fish once a week would supply your requirements, but if you do not like it, then choose a supplement, but do not overdose yourself: too much is toxic.
You also need plenty of fresh fruit and vegetables which contain other vitamins and minerals essential for bone health.
Calcium The richest sources of calcium are milk, cheese and yogurt. Bread, dark green vegetables, almonds and tinned sardines also contain calcium. Some brands of orange juice and most breakfast cereals have added calcium. Mineral water can often contain calcium—but for all foods check the list on the packet as the amounts vary.
Vitamin D Fish and seafood are good sources, as are fish liver oils. Milk and breakfast cereals are often fortified with vitamin D.
Maintain a healthy body weight
The bigger your bones are, the stronger they are, and the heavier you are, the denser your bones are, but this is not an excuse to eat too much! It is, however, very important to realize that dieting to lose weight is not good for your bones.
Weight loss has been associated with bone loss at all ages in adult life. Women who weigh more than 70 kg are unlikely to have an osteoporotic fracture, but clearly if you are not tall there are health reasons why you should not weigh this much. If you are within the healthy weight limits for your height, you shouldn’t go on a weight-loss diet unless your doctor recommends it.
Take some exercise
Active women have half the risk of fracture compared to those who do not take any exercise. Physical activity reduces the risk by improving both BMD and balance so that falls are less likely. Not all exercise is beneficial for your bones, however. Research has shown that the best kind of exercise for your bones is brief bouts of activity that ‘load’ the skeleton.
Choosing the right kind of exercise
Endurance activities such as swimming or cycling are excellent forms of exercise for many reasons, but unfortunately they do not improve your bone health. Activities that provide a short sharp increase in skeletal loading are highly effective for your bones, provided they are more challenging than your normal activities. The good news is that only a few loadings are needed to have an effect; about 50 per day. More than that does not achieve further improvement. This means that you can find time to improve your bone health without having to embark on a lengthy regimen. Regularly taking the stairs instead of the elevator might do it.
Just one minute of jumping or skipping is useful, if it is right for you. It is important to realize, however, that these activities can prove dangerous for women with undiagnosed osteoporosis. They are therefore safe only for healthy premenopausal women.
Effective bone-loading depends on the force of gravity acting on your body, and on any weight you lift, as well as the pull of muscles on your bones as you exercise. This can be achieved in many ways and dynamic resistance exercises are usually safe for everyone, including older women.