Medical history and multiple sclerosis: A population-based incident case-control study

Background: Consistent evidence regarding the potential role of medical history in multiple sclerosis (MS) etiology is lacking. Objective: The association of medical history variables, that is, head injury and 9 autoimmune diseases with MS onset was investigated. Methods: This was a population-based incident case-control study in Iran with 547 incident cases and 1,057 general population controls (August 7, 2013 - February 17, 2015). Multiple logistic regression models were used for estimating the adjusted ORs. Results: Lifetime history of head trauma was not significantly associated with risk of MS after adjustment for well-known confounders (OR 1.24 [0.93-1.66, p = 0.14]). Similarly, there was no statistically significant association between cumulative numbers of head injury and MS (OR 1.02 [0.90-1.15, p = 0.79]). A history of autoimmune disease did not increase the risk of MS (p > 0.1). Similarly, the cumulative number of autoimmune diseases is not significantly associated with the risk of MS (p > 0.70). Conclusion: Lifetime histories of head trauma as well as 9 investigated autoimmune diseases are not associated with increased risk of MS.