Trauma and multiple sclerosis.

The belief that trauma may precede or exacerbate multiple sclerosis (MS) has come primarily from anecdotal reports and case series that provide no rates and no basis for critical comparison. Each year in the United States, approximately 10,000 persons develop MS. A high proportion of the estimated 250,000 prevalence cases have one or more exacerbations, whereas one-third (or 83,000,000 persons in the United States) suffer a memorable injury; therefore, when trauma precedes MS onset or exacerbation, coincidence, as well as causal association, must be considered. For many patients, MS disability may have precipitated an injury, rather than follow one. Two major prospective cohort studies of MS indicate that physical trauma is not responsible for onset or exacerbation. A prospective cohort of patients with MS followed for eight years at the University of Arizona has failed to demonstrate an association between physical trauma and exacerbation. At the Mayo Clinic, cohorts identified in the Olmsted County, Minnesota population with MS, head injury (819), and lumbar disk surgery (942) demonstrated no correlation between onset or exacerbation of MS. Thus, on the basis of credible epidemiological studies, and particularly the studies of cohorts with MS and with trauma, there is no indication that either onset or exacerbation of MS is the result of physical trauma.