PARIS—Head trauma in adolescence, particularly if it is repeated, is associated with an increased risk of subsequent multiple sclerosis (MS), according to data described at the Seventh Joint ECTRIMS-ACTRIMS Meeting. The increased risk may result from the initiation of an autoimmune process in the CNS. This finding underscores the importance of protecting young people from head injuries, according to the researchers.
Previous studies have suggested an association between head trauma and MS risk, but they have had methodologic limitations such as retrospective data collection and small study populations. Tomas Olsson, MD, Professor of Clinical Neuroscience and Senior Physician at Karolinska Institutet in Stockholm, and colleagues used prospectively recorded data to assess whether concussion in childhood or adolescence is associated with subsequent MS risk.
The investigators used the national Swedish Patient and MS registers to identify all diagnoses of MS up to 2012 among people born in 1964 (when the Patient Register was established) or later. They identified 7,292 patients with MS and matched each with 10 people without MS by sex, year of birth, age or vital status at MS diagnosis, and region of residence. This matching resulted in a study population of 80,212. Diagnoses of concussion and control diagnoses of broken limb bones were identified using the Patient Register from birth to age 10 or from age 11 to 20. Dr. Olsson and colleagues used conditional logistic regression to examine associations between broken bones, concussions, and MS.
Concussion in adolescence was associated with an increased risk of MS, producing adjusted odds ratios of 1.22 for one diagnosis of concussion and 2.33 for more than one diagnosis of concussion, compared with none. No notable association with MS was observed for concussion in childhood, or for broken limb bones in childhood or in adolescence.