Bone Density: A belated Part 2

Way back in December 2012, I posted Bone Density, Osteopenia, Osteoporosis, and Fractures: Part 1. I never got around to posting Part 2 because I was hoping that some more relevant information would come forward. It hasn’t. Nevertheless, I am posting Part 2 now, even if it doesn’t add a lot of new information to the discussion, because I think it is an important topic. It is important because low bone density is a problem for many individuals with MECP2 Duplication syndrome, this problem often remains hidden until it manifests in fractures or other serious problems, and it is basically irreversible.

Bone density

This figure indicates some of the factors that can lead to low bone density for individuals with MECP2 Duplication Syndrome.

First, there appears to be a direct effect of the syndrome that leads to poor bone development even before birth. While a lot more needs to be learned about this. researchers have found this in studying MECP2 Duplication Syndrome lab mice. The mechanism still remains unclear.

Second, the syndrome also has an indirect effect. Weightbearining and exercise play important parts in the development of bones during childhood and continue to play a part in maintaining bones. Low muscle tone and limited activity mean there is less to stimulate bone development.

Third, children with disabilities rarely get as much outdoor time or sun exposure as other children do. This may result in their bodies manufacturing less vitamin D and, in turn, low levels of vitamin D further interfere with healthy bine development and maintenance.

Fourth, children with disabilities, especially those with limited activity are at greater risk for nutritional issues. As a result, they may hay have lower vitamin D and calcium intake. Feeding challenges can make it difficult to maintain a well balanced diet, and while caloric requirements tend to be low be low due to lack of exercise and muscle mass, this can make it more difficult to ensure adequate intake of vitamins and minerals since these requirements do not reduce in proportion to the reduction in total caloric requirements.

Finally, many of the medications commonly used by individuals with MECP2 duplication syndrome, also can lead to loss of bone density. This is true for many anticonvulsants, Gastric reflux medications, and steroids.

The role of anticonvulsant medication in causing “anticonvulsant rickets” has been well known at least since the 1960s. Many new anticonvulsants have become available since then but these also appear to cause bone loss and increase the risk of fractures.

Some of the antacids used to address gastroesophageal reflux also have been associated with calcium depletion. These proton-pump inhibitors may have little impact for short-term use, but long-term use, especially in patients with other risk factors, may play an important negative role.

Steroids also have negative effects on bone density when used over long periods of time. They decrease absorption of calcium and increase the excretion of calcium.

A Hidden Problem

Families and physicians caring for a medically fragile child or adult are already swamped with other challenges, and the bone density issue is likely to go entirely unnoticed until a fracture or other major problem forces it into their awareness. Sadly, it is pretty much impossible to correct bone density loss at that stage. Usually, the best we can hope to achieve is to slow down further loss of minerals from the bones. So the best thing to do is to identify any problem early and  try to prevent it from getting worse.

So, what can be done?

Families of children our adults with MECP2 Duplication Syndrome should talk to their doctors about possible bone density issues. While MECP2 Duplication Syndrome in itself appears to confer some risk, each of the other factors described above adds to that risk. The more factors that apply, the more important it is to try to prevent bone density loss.

A bone-density scan (bone densiometry or DXA Scan)is probably a good idea. It is non-invasive and uses a very small amount of x-ray compared to typical x-ray procedures.

While there is little available information about the use of supplements to prevent bone demineralization in children or adults with MECP2 Duplication Syndrome. Calcium and vitamin D supplementation are likely to be helpful, especially if medications (such as anticonvulsants) that promote demineralization are being used. This possibility should be explored with the physician to determine if it is appropriate and, if so, appropriate doses. Bloodwork may be required.

Of course, good sources of calcium and vitamin D in the diet can play a very important role. A dietician or nutritionist may be very helpful to determine the best ways to ensure that there is adequate intake of vitamin D and high quality calcium (calcium in an easily absorbable form.

While many children and adults with MECP2 Duplication Syndrome have impairments that limit activity and weightbearing, it is important maximize movement and weightbearing within each individual’s limits.

Vibration and other kinds of stimulation have been suggested as ways to compensate for limited activity levels. Research has not generally shown support for vibration helping with bone density. However, more study is needed to determine if it may play a useful role for those with extremely low activity levels.

The use of drugs that limit bone loss or that can actually improve bone mass may be considered in some cases. However, these drugs can create their own challenges in people who are already taking other medications and have complex health issues.As a result the potential risks and benefits need to be carefully considered.

Of course, while medication can lead to loss of bone density, these medications may be vital to the individual. Nevertheless, this side effect is among a number of reasons why medications should be discontinued if they do not produce a clear benefit, and dosages should be kept to the smallest effective dose.

 

 

 

 

 

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One response to “Bone Density: A belated Part 2

  1. Amy Morrison Baker

    Thanks, Dick! The vibration element is very interesting.

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