Osteoporosis or decreased bone density is one of the many serious complications facing any individual that suffers or has suffered from an eating disorder.
There has been a marked increase in eating disorders in the last decade, however it is difficult to determine the true extent of the disease due to the secretive nature of this disease. In the mildest form, there may be prolonged periods of fasting, restricted food intake, bingeing, purging, a marked preoccupation with food and a distorted body image. Anorexia and bulimia are severe forms of eating disorders.

Anorexia and Bulimia are now more frequently recognised both in the general population and among athletes. Studies have shown that symptoms of eating disorders and weight control are more prevalent in female athletes, compared to non-athletes. However males can also be affected by anorexia and bulimia, which can affect their levels of testosterone, which will affect bone. Individuals with eating disorders often strive for perfection.
Bone is a living tissue and is constantly being broken down and renewed by the body in response to many factors.  Bones need adequate calories, especially protein to lay down the supports for the bone and calcium to harden these supports. In order to absorb calcium from the gut, the body needs vitamin D3. Normal hormones are also needed and, finally, bone requires appropriate weight bearing exercise. The Irish Osteoporosis Society recommends 30 minutes a day of weight bearing exercise for adults, which can be broken into individual sets of 5 to 10 minutes.

Amenorrhea is a very common feature of anorexia and results in the loss of periods for 3-6 months due to over-training and/or inadequate calories for the amount of exercise. amenorrhea is associated with hypothalamic dysfunction, an abnormality of the gland that controls hormones, including sex hormones with low levels of oestrogen.
Amenorrhea as a result of anorexia seems to have a higher detrimental bone loss affect, than exercise related amenorrhea. The longer the loss of periods, the more bone that is lost, therefore the higher the risk of fracture. Irrespective of the cause, amenorrhea places a person at risk of developing osteopenia and/or osteoporosis at an early age.

Patients of all age groups, including teenagers, have been diagnosed with fractured vertebrae (where bones in the spine have collapsed) due to anorexia and amenorrhea. The crucial years for laying down healthy bone are the pre-puberty and the teenage years. Therefore it is essential that people with these conditions seek help as soon as possible. These disorders are commonly due to psychological, biological and social pressures.

Eating disorders and amenorrhea can cause high levels of cortisol, which will also affect bone. Studies have shown that depression is also common in both groups. It is very difficult to determine the amount of people with eating disorder due to the secretive nature of this disease.

In the case of eating disorders, inadequate food/calorific intake and poor intake of calcium and vitamin D3 lead to decreased bone density and possible osteopenia/osteoporosis. This is worsened by a decrease in the hormones oestrogen in females and testosterone in males, which typically accompany eating disorders. Many who have eating disorders may over exercise or do not exercise at all, both of these increase the risk of developing osteoporosis.
Bone is constantly being removed and replaced, however when a person has osteoporosis, the amount of bone that is removed is more than the amount which is replaced. When a person has a low caloric intake and increased dietary fiber intake, this can reduce sex hormone levels and decrease the amount of oestrogen which affects bone. This is why vegans and vegetarians who do not have regular periods and do not take the daily amount of calcium, vitamin D3 and protein are higher risk to develop this silent disease.

Results of DXA scans done on people with eating disorders have shown 19 year olds with bones the equivalent of 60-90 year olds.

Oestrogen deficiency has a significant effect on bone mass, even in the presence of adequate calcium intake and physical activity. Therefore if a person begins to take the daily amount of calcium and vitamin D, but does not address the eating disorder they could still run into problems.


In the treatment of those who have decreased bone density/osteopenia/osteoporosis as a result of an eating disorder, it is necessary to both increase the daily intake of food/calories and to supplement as appropriate calcium and Vitamin D intake. Each case should be treated individually and often the replacement of hormones is also needed in the form of the pill (or HRT) in females. Adequate weight bearing exercise is also essential.

Often the realization of the consequences of their eating disorder by the sufferers can encourage recovery. No one wants to end up with their body deformed by spinal fractures and becoming wheelchair bound, especially when it can be avoided.

If you have had or do have an eating disorder, please get a DXA scan as soon as possible, as osteoporosis is a silent disease and you will not know you have it.


A DXA scan is painless, it is similar to a regular X-ray and usually only takes about 10 minutes.

Explanation of results

Q: What is a T score?

A: A T-score compares the patient’s results with the mean peak bone mass (thickness of bones) of a large number of normal females and males between the ages of 20-40.

Q: What is a Z score result:

A: A Z score compares the patients score with their own age group, this should only be used in the diagnosis of the spine in children and adolescents, under 21. Their bone age should also be compared to their chronological age by x –raying the bones of their non dominant hand.

Q: Can you explain the T-score reading?

A: The IOS has broken up the scores in the Osteopenia range to make it easier for people to know exactly where they are on the scale.

Mild Osteopenia T-score = -1 to -1.49
Mod Osteopenia T-score = -1.5 to -1.9
Marked Osteopenia T-score = -2 to -2.49
Osteoporosis T-score = Greater than -2.5 Or  a low trauma fracture (broken bone from a trip and fall from a standing position or less) is also considered to be osteoporosis unless proved otherwise.
Research shows that most fractures (broken bones) occur within a T score of -1.5 to -2.49 which is the moderate to marked Osteopenia range.

All individual vertebrae levels should be looked, at as well as both hip areas. A diagnosis should not be made on the total average of either the spine or hips.

If a person has developed a hump due to osteoporosis or lost height, a DXA scan will typically show that the person also has osteoporosis in their lower spine. In some cases, an LVA DXA (Lateral Vertebral Assessment) is usually recommended, as this will show if the shape of the bones in this area is compressed due to an osteoporosis fracture. If the DXA machine does not have the LVA software, a lateral x-ray of the thoracic spine (area where hump is) is recommended.

A person may have arthritis Osteophytes or extra bony spurs of their lumbar spine which will give a false higher bone density reading. A DXA scan only measures the four lumbar vertebrae (bones in lower back = Lumbar 1, Lumbar 2, Lumbar 3 and Lumbar 4) and one or both hips (both hips are recommended). It is not typical but a person can have osteoporosis in their upper back and not in their lower back.

The most important fact to take away is that the earlier a person is diagnosed, the better the results.

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