Bone health in children and young people with epilepsy treated with anti
epileptic drugs (AEDs)
Dear Twin Registry Member,
We would like to invite your twins and/or their siblings to participate in our study looking at bone health and antiepileptic drugs (AEDs). We are looking for twin pairs and siblings aged 5-18 years, who are the same
gender, and where one child is taking anti-epileptic medicine (AEDs) and one isn’t. The children would be
willing to participate in a study on bone health with a one-off assessment of bone mass, bone strength and
muscle power. The purpose of the study is to understand how the use of this medication may affect the bone
health of young people.
Why is this study important?
Our previous research in adults has shown that people taking AEDs were possibly at risk of lower bone mineral
density (BMD), which increases the risk of broken bones (fractures) with a simple injury. There is also evidence
that those adults who started their AED treatment before the age of 18 had lower BMD than someone who
started in adulthood.
We aim to look at a group of children and young people taking AEDs and compare them to a twin or same-sex
sibling who isn’t taking AEDs to see if those taking the AEDs have lower BMD. We hope this will help us work out
if this is an issue for young people, and if so, how we can help young people on AEDs maximise their bone health
so they are not at increased risk of broken bones.
This is a pilot study involving around 30 twin or sibling pairs, which aims to get an idea of whether this is a
significant issue. We hope this pilot study will lead to larger, longer term studies looking at bone health outcomes
in these young people.
What would my children be asked to do if I decided to let them participate?
Your children will have a bone health assessment in the Bone and Mineral Service at the Royal Melbourne
Hospital. The assessment will take around 4 hours and will be completed on a single day.
The bone health assessment involves completing the following:
(1) Questionnaire
We will ask you to complete two questionnaires about your children’s medical history, fracture history, nature
of the epilepsy, seizure frequency, dosage and length of AED use (if applicable) as well as asking about your
children’s activity levels.
(2) Bone Mineral Density DXA (dual-energy x-ray absorptiometry) Scan and Peripheral Quantitative
Computerised Tomography (pQCT).
We will ask your children to have two different types of bone density scans. Both scans involve the use of
ionizing radiation and your children will be exposed to a low dose of radiation.
These scans are simple tests which do not involve the use of needles or other invasive procedures. Your
children will need to lie on their back and a “scanner” will be positioned overhead. They will not feel anything
from the scanner as it moves overhead.
(3) Bone age Xray
To assist in interpretation of the bone density, your children will have an Xray of the wrist, which will allow us
to make an estimation of your children’s physical maturation. The thickness of bones in the hand can also be
assessed as another measure of bone health.
(4) Blood test
We will take a small sample of blood which will be tested for Vitamin D, blood cell counts, hormones and
markers of bone turnover.
(5) Strength and balance tests.
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This is done using a hand held meter, which we will ask your children to squeeze as hard as they can so we
can record their grip strength. We will also test your children’s strength by asking them to complete some
jumping tests on a special plate on the floor. The same plate can test your children’s balance.
What are the benefits for my children?
We cannot promise that your children will receive any benefits from this project. However, the bone mineral
density test is not currently standard care for young people on AEDs and if the results show your children may
have a lower bone mineral density we will contact you and arrange for your children to have appropriate followup.
If any of your children’s test results are outside normal ranges; for example if your child is low in Vitamin D, we
will also let you know so you can follow up with your family doctor.
What are the risks?
The DXA, pQCT and x-rays of your children’s body and hand involve exposure to a very small amount of
radiation. As part of everyday living, everyone is exposed to naturally occurring background radiation and
receives a dose of about 2 millisieverts (mSv) each year. The effective dose from all these x-rays is about 0.013
mSv. At this dose level, no harmful effects of radiation have been demonstrated, as any effect is too small to
measure. The risk is believed to be minimal.
If you are under the age of 18 years, you (or your children) should inform us of any other studies that you have
participated in that involve the use of radiation.
It is possible your children may feel some discomfort during the blood test. They may feel a sting when the
needle is put in their arm to take the blood. We can use a cream to numb the skin before the blood is taken. It is
possible there may be some bruising, swelling or bleeding where the needle enters the skin. Some people can
feel a little light-headed when blood is taken.
What if I want to withdraw from the study later on?
You are under no obligation to be part of the study, and should you decide to participate, you are free to withdraw
from the study at any time.
If you would like more information about the study, please return the accompanying response letter to the
Australian Twin Registry and you will be sent further information.
Thank you for considering our study,
Yours sincerely,
Prof John Wark
Dr Peter Simm
Head, Bone and Mineral Service
Paediatric Endocrinologist
Royal Melbourne Hospital
Royal Children’s Hospital Melbourne
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