Associations between infectious mononucleosis and cancer: record-linkage studies.

Infection with Epstein-Barr virus (EBV) followed by infectious mononucleosis (IM) is now considered to be a risk factor for Hodgkin's disease (HD). It is less clear whether EBV infection and IM are associated with an increased risk of cancer generally. We used a longstanding record-linkage dataset in Oxford (years 1963-1998), and a more recent record-linkage dataset covering England (1999-2005), to compare rate ratios for cancer between people admitted to hospital for IM and a reference cohort. In the Oxford cohort, there was an increased risk of subsequent HD [rate ratio (RR) 6.0, 95% confidence interval (CI) 2.4-12.5] but not of other cancers combined (RR 0.85, 95% CI 0.57-1.23). In the England cohort, there were increased risks of HD (RR 3.2, 95% CI 1.2-7.0), non-Hodgkin's lymphoma (RR 5.6, 95% CI 2.9-9.8), and oropharyngeal cancer (RR 5.4, 95% CI 1.1-16.2), but no significant overall risk of cancer when lymphomas were excluded (RR 1.01, 95% CI 0.71-1.41). We confirm an association between IM and lymphoma; but the risk, if any, of cancer more generally is likely to be small.