Trauma and multiple sclerosis: A population-based cohort study from Olmsted County, Minnesota

Utilizing the Olmsted County, Minnesota, population-based records-linkage resource at Mayo Clinic, we identified an incidence and a prevalence cohort with multiple sclerosis (MS), a head injury cohort, and a lumbar disk surgery cohort to evaluate the association between mechanical trauma and MS onset or exacerbation. The MS cohorts consisted of 225 incidence cases (1905 to 1991) and 164 prevalence cases (December 1, 1991) of definite MS in the population of Olmsted County. We assessed the effect of mechanical trauma in the form of spinal injury or extremity fracture with regard to precipitation of MS or exacerbation of an existing neurologic deficit. Fifty-four episodes of trauma, as defined, occurred among 39 MS prevalence cases; most occurred 10 years or more after the onset of disease and were associated with existing MS-related disability. We compared the final disability status of the groups with and without trauma. We found no correlation between the occurrence of peripheral fractures and the onset of MS, exacerbation of MS, or final disability due to MS in the prevalence cohort. In a cohort of 819 head injury cases from the Olmsted County population, none developed MS within 6 months of the trauma. In a lumbar disk surgery cohort of 942 local residents, there were five with MS, but onset of MS had preceded the spinal surgery in four of the five. Thus, we found no association of head injury and spinal disk surgery with onset of MS.