Osteoporosis is a disorder that causes bones to lack mineral content and become brittle. The bones literally become porous and appear sponge-like under the microscope. Sufferers experience frequent fractures, and the condition can be both disabling and painful. It is much more common in women than in men, and is often seen as a disease of old age, being sadly very common among elderly women.
But it is not simply a disease of old age. An often-forgotten category of sufferers are people with eating disorders, particularly anorexia nervosa. Malnutrition and hormonal problems in anorexics can lead to the problem developing early in life -- the author has had osteoporosis since her teens and is now disabled. Sadly, awareness of osteoporosis in general, and especially osteoporosis in younger people with eating problems, is not as high in the medical profession as it should be, meaning that many sufferers remain undiagnosed and untreated until severe disability results.
One of the most frequently affected areas is the spine. Individual vertebrae become crushed out of shape because they are so fragile, giving the sufferer a characteristic loss of height and hunch-backed appearance (kyphosis). This in turn can lead to other problems since the organs of the chest and abdomen can be compressed. Breathing problems are a frequent result, as the lungs become crushed. A distorted and damaged spine is painful, disabling and disfiguring.
Other frequent effects of osteoporosis include hip and wrist fractures. Major fractures can be particularly hazardous in very frail patients such as the elderly and the severely underweight anorexic, and can even lead to death, usually caused by infections that the body is too weak to fight. A badly malnourished body may not be capable of repairing a fracture properly, leading to permanent disability.
Pain and disability that result from osteoporosis can greatly impair the sufferer's quality of life, and often lead to psychological difficulties such as depression. Since depression is almost universal among eating disorder sufferers, this can create a vicious circle that reinforces the eating disorder.
Among all this doom and gloom, the good news is that osteoporosis is largely preventable, and treatments now exist that can minimise the damage and suffering in patients who already have it. Both prevention and treatment depend on good nutrition, however, so it is of the utmost importance to bring the eating disorder under control. The longer that the patient continues in a malnourished state, the greater the risk of osteoporosis.
Bones are not just dead lumps of mineral material -- they are complex living tissues with their own needs for energy and oxygen, just like any other bodily organ. The framework of the bone consists of the mineral hydroxyapatite, which is made by special cells called osteoblasts from the raw materials calcium and phosphate, which are obtained from the diet. But even this mineral framework of the bones is ever-changing: all the time, old bone is recycled by cells called osteoclasts and replaced by the action of osteoblasts. There is a constant turnover of bone minerals in the body, which is vital to the maintenance of the skeleton, and is also vital for repairs when bones are damaged. The gaps in the mineral framework are filled with many types of specialist cells with different functions, and with protein structures to strengthen the bones. Like any other organ, the bones will not function properly if the patient is not taking in the nutrition and raw materials that they need.
The skeleton is also the body's main store of calcium. Calcium is used in many different parts of the body and is a vital part of a healthy diet. If the diet is deficient in calcium, then calcium is stripped out of bone to fulfil the body's immediate needs. Correct processing of calcium in the body also requires other body systems to be functioning -- most notably, adequate nutritional intake (calories and protein) is needed to power the cells that maintain the bones, and also hormones, which are chemical messengers produced in other parts of the body, play a vital role in maintaining healthy bones. Extra demands are placed upon the body when it is repairing a fracture, and fractures will not heal properly if the body is malnourished.
The major hormones involved in bone maintenance are the sex hormones testosterone (in males) and estrogen (in females). When malnutrition exceeds a certain level, the body stops producing adequate amounts of these hormones; in women this is accompanied by amenorrhea, the loss of periods. This effect is so much a part of anorexia that it is used as a major diagnostic symptom. Another group of substances that is vital to bone health is the D vitamins, which facilitate the transport and usage of calcium within the body.
A malnourished eating disorder sufferer is likely to suffer a quadruple assault on their bone health due to the factors described in the previous section:
This series of deficiencies has a pronounced effect on bone health. Osteoporosis can develop quite rapidly (over a period of months) even in a previously healthy adult if malnutrition is acute. Even the milder types of malnutrition seen in an eating disorder sufferer who is not severely underweight can lead to osteoporosis over a few years, and the effects of malnutrition on a growing adolescent's bones can be particularly destructive. Since anorexia quite commonly begins during early adolescence, this poses a special risk that a healthy bone density will never be attained, and young anorexics may develop osteoporosis in their teens or twenties. Once it develops, it is only partially reversible at best, and commonly becomes more severe over time.
Anyone who experiences malnutrition for a prolonged period is at risk of developing either osteopenia (a milder loss of bone mineral density) or full-blown osteoporosis. The extent of the problem will depend upon both the severity and duration of the malnutrition, and sufficient malnutrition may occur without extreme weight loss. In female eating-disorder patients, amenorrhea is a good predictor of risk, where it is typically considered by specialists that six months or more without regular periods necessitates preventative action.
Osteopenia and osteoporosis cannot be detected reliably on a conventional x-ray, nor by blood tests. Many patients are not diagnosed until the osteoporosis is far advanced and fractures are occurring. For treatment to be effective it is important that the condition be diagnosed as early as possible, and for this an imaging technique called DEXA (Dual Energy X-ray Absorptiometry) is employed. DEXA scanners are now quite commonly found in major hospitals, and produce a direct measurement of bone mineral density (BMD).
A DEXA scan is normally performed on the lower spine and/or the hip, these being the two areas that tend to be most indicative of osteoporosis. The process is not intrusive or painful. The measurements obtained from the scan are compared with normal values taking into account the sex, age, height and weight of the patient to give a relative indication of BMD compared to an average population. The statistics from the scan can be used to assess the severity of osteoporosis and the risk of fractures, and to decide upon the most appropriate course of treatment.
Follow-up scans may be performed at intervals of a few years to assess the progress of the disease and the patient's response to treatment. DEXA scans are relatively expensive, and some health authorities can be reluctant to pay for them, so the patient may have to take an assertive stance in asking for the appropriate treatment. In cases where a GP is reluctant to refer a patient directly for a scan, it can be helpful to ask for a referral to an orthopedic consultant (or, in some hospitals, a rheumatologist) who has a particular interest in, and knowledge of, osteoporosis. Some health authorities have dedicated osteoporosis clinics staffed by specialist nurses and physiotherapists, and overseen by a consultant.
Treatment may involve specialists from a variety of disciplines, especially where fractures have occurred. In addition to treatment of fractures, treatments may be aimed at physical rehabilitation, fracture prevention, pain control and of course trying to slow down or even partially reverse the underlying process of bone depletion.
Where malnutrition has contributed to the development of osteoporosis, this must be treated if at all possible, as all further treatments for osteoporosis will only be of limited benefit if malnutrition continues. Of course, not all eating-disorder patients can make a full or rapid recovery from their disorder, and in many cases treatment has to be regarded as an exercise in damage limitation.
Calcium Supplements are of benefit whenever there is any doubt about the adequacy of the patient's dietary calcium intake, and are widely prescribed even to osteoporosis sufferers who are not malnourished. They can also be bought over-the-counter. A range of different formulations are available, including chewable and soluble tablets. Calcium supplements rarely cause any significant side-effects, though some people find high doses produce a degree of nausea. In this case a different formulation may be preferable. Some formulations are more readily absorbed than others, especially when taken without food or with a digestive system damaged by an eating disorder: organic formulations such as calcium lactate-gluconate may be absorbed better than inorganic formulations such as calcium carbonate, and soluble formulations are often better absorbed than solid formulations.
Vitamin D Supplements are also of value if there is any doubt about the patient's dietary intake. These may be combined with a calcium supplement, or be part of a multivitamin supplement. Again these may be prescribed or can be bought over-the-counter.
Sex Hormone Treatments are a usual first-line treatment, since low estrogen levels (in women) play such a large part in the development of osteoporosis. For post-menopausal women, Hormone Replacement Therapy (HRT) is normally used. In younger women with amenorrhea, HRT may still be used although a Combined Oral Contraceptive (COC, or "the Pill") is a possible alternative, especially if contraception is also required, and may even cause natural periods to restart if the underlying malnutrition has been corrected. For longer-term therapy, HRT is safer and produces fewer undesirable side-effects than the Pill, especially in patients older than about 35 years.
A minority of patients may have contra-indications to sex hormone treatment. Most notable of these are a history of breast cancer or thromboembolic disease. For such patients, other treatments will have to be tried, but for the majority of osteoporotic patients, HRT remains the preferred first-line treatment.
Some anorexics have emotional issues concerning menstruation and find the state of amenorrhea comforting. Such patients may be reluctant to accept any sex hormone treatment that produces a monthly bleed, as with the COC or monthly-cycle HRT. There may also be medical reasons why periods should be avoided, particularly if the patient remains very malnourished and/or anemic. For these patients, there exist two options: non-cyclic HRT which produces no bleeds at all, and long-cycle HRT that only produces a bleed every 3 or 6 months typically. Although such regimes are normally used only once periods become scarce or absent in the process of the menopause, it is reasonable to argue that a patient with long-term amenorrhea can be treated the same way, and this type of treatment is becoming increasingly well-recognised for osteoporotic patients with or without an eating disorder.
Calcitonin is another hormone involved in the metabolism of calcium, and unlike the sex hormones it is applicable to patients of both sexes and can often be given to patients who have contra-indications to sex hormone treatment. Side-effects can sometimes be a problem, and this treatment is used less often than the others.
Bisphosphonates are a class of non-hormonal drug that affect bone metabolism. They work by binding to the crystals of hydroxyapatite in the bones, where they reduce the ability of osteoclasts to break down bone minerals, without impairing the bone-building properties of osteoblasts. For this reason they effectively increase bone mineral density and can actually partially reverse the course of osteoporosis when used properly in conjunction with other treatments. They do have considerable side-effects and are not tolerated by all patients, but when proven osteoporosis exists they can be of considerable value.
There are a number of different bisphosphonate drugs available for the treatment of osteoporosis, most of which are taken orally. Side-effects on the digestive system, such as nausea and heartburn, are quite common. As an alternative for patients who find these effects unacceptable, there is one bisphosphonate drug, sodium pamidronate, which is given intravenously and is beginning to find use in severe osteoporosis (it is more commonly used for bone cancers). Clinical trials have found this to be very effective, although it carries a significant risk of allergic side-effects and cannot be tolerated by all patients.
If you think you might be at risk of osteoporosis, contact your doctor in the first instance. Since many general practitioners are not well-versed in the treatment of osteoporosis, especially when it is caused by an eating disorder, it is advisable to ask for a referral to a consultant with a special interest in the disease.
It is also well worth contacting the National Osteoporosis Society (see Links and Resources page) for more detailed information about living with osteoporosis. They operate a national helpline as well as a number of local groups for sufferers, and produce a series of informative booklets dealing with different aspects of the condition. Their orientation is primarily towards the needs of older people with osteoporosis, although they do have some resources available for younger people with eating disorders.
Finally, the authors are always interested to receive feedback and comments on this website, and will provide further information and help to the best of their ability. Contact EDSHED@dawnmist.demon.co.uk