What is it about?

Multiple sclerosis (MS) is a progressively disabling disease caused by damage to nerves in the brain and spinal cord. This damage is caused by the body’s own immune system attacking myelin, which is the material providing the insulation necessary for nerves to function. We believe that some types of exposure can trigger this process. This study addressed the question of whether an injury to the brain, indicated by a diagnosis of concussion, could be one of the triggers of the disease process that results in MS. We used information collected routinely in hospitals to assess if concussion from birth to age 10 years or between 11 and 20 years was associated with an MS diagnosis after age 20 years. We also looked at other injuries at these ages (broken arm and leg bones) to make sure any associations are specific to concussion. There was no association of broken arms and legs with MS. Concussion between ages 11 and 20 years, but not younger ages, was associated with a greater risk of having MS after age 20 years. The risk for MS was greater is teenagers had concussion more than once. The duration between concussion and an MS diagnosis was often more than 10 years.

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Why is it important?

This was the first study to demonstrate convincingly that head injuries that cause inflammation in the brain may lead to development of MS. This is likely to be one of several causes of MS. The teenage years seem to represent ages when exposures are particularly important. In some people, we suspect that the inflammation triggers the immune response that continues, leading to worsening nerve damage and ultimately a diagnosis of MS. The often-long period between concussion and MS diagnosis indicates that at first, the disease can develop slowly. The vast majority of teenagers who suffer a head injury, will not go on to develop MS, as genetic susceptibility and other factors are also required.


Rereading this paper reminded me how much it has influenced our subsequent research. We have focused on the teenage years as a particularly important time, when exposures connected with future MS may have the greatest influence. We also consider the long period between an exposure that causes the disease process to begin and an eventual diagnosis.

scott montgomery
Orebro Universitet

Read the Original

This page is a summary of: Concussion in adolescence and risk of multiple sclerosis, Annals of Neurology, September 2017, Wiley,
DOI: 10.1002/ana.25036.
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