Head Trauma in Adolescence is Associated with Multiple Sclerosis Risk

Multiple sclerosis (MS) is a progressive, debilitating disease in which the body's immune system attacks the fatty layer that insulates some nerves, leading to permanent nerve damage. Based on studies in animals, there has been a suspicion that trauma to the central nervous system may be a risk factor for the development of MS. Now a Swedish study provides new evidence that repeated concussions during adolescence are associated with increase the risk of MS later in life. (Sweden keeps particularly good medical records on all its citizens, making comprehensive population studies possible).

The study's authors examined the records of all Swedes who had been diagnosed with MS since 1964 - over 7,000 people in all. Then they looked at the number of concussions each person with MS had had during adolescence, comparing it to the number of concussions in 10 other people without MS matched for age, gender, and county of residence. The key finding was that persons who had had two or more concussions during adolescence were more than twice as likely to develop MS as persons who had not had any concussions.

No one knows yet how concussions might trigger the development of MS, if indeed they do. One theory is that damage to central nervous system might lead to the release of nervous tissue breakdown products that cause the immune system to attack neural tissue. But that remains to be tested.