A new study published in the Annals of Neurology found a link between head trauma in adolescence, particularly if repeated, with a raised risk of later developing multiple sclerosis. The link may be due to the initiation of an autoimmune process in the central nervous system.

In the analysis of 7292 patients from Sweden with multiple sclerosis who were each matched with 10 people without the condition, one diagnosed concussion in adolescence was associated with a 22% increased likelihood of developing multiple sclerosis. More than one concussion was associated with a greater than twofold increased likelihood.

“This is yet another reason to protect adolescents from head injury, particularly where they are at risk of repeated trauma, including from sports-related injuries,” said Prof. Scott Montgomery, lead author of the study.