Infectious mononucleosis and risk for multiple sclerosis: A meta-analysis

Objective To characterize the association between infectious mononucleosis (IM), a frequent clinical manifestation of primary Epstein–Barr virus infection after childhood, and the risk for multiple sclerosis (MS). Methods We conducted a systematic review and meta‐analysis of case–control and cohort studies of IM and MS. Results The combined relative risk of MS after IM from 14 studies was 2.3 (95% confidence interval, 1.7–3.0; p < 10−8). Potential sources of heterogeneity (ie, study design, MS definition, and latitude) barely influenced our results. Interpretation We conclude that Epstein–Barr virus infection manifesting as IM in adolescents and young adults is a risk factor for MS. Ann Neurol 2006; 59:499–503