Hepatitis C virus and risk of non-Hodgkin lymphoma in British Columbia, Canada.

We investigated Hepatitis C virus (HCV) seropositivity and the risk of non-Hodgkin lymphoma (NHL) in a population-based case-control study in British Columbia, Canada. Cases were aged 20-79, diagnosed between March 2000 and February 2004, and resident in greater Vancouver or Victoria. Cases with HIV or a prior transplant were excluded. Controls were chosen from the Client Registry of the British Columbia (BC) Ministry of Health, and were age/sex/region frequency matched to cases. Antibodies for HCV were measured in 795 cases and 697 control subjects. HCV seropositivity was 2.4% in cases and 0.7% in controls [odds ratio (OR) = 2.6, 95% confidence interval (CI) = 0.9-7.4]. A significantly elevated risk was observed for B-cell lymphoma (OR = 2.9, 95%CI = 1.0-8.6). The highest risks were associated with diffuse large B-cell lymphoma (OR = 7.3, 95%CI = 2.1-25.0) and marginal zone lymphoma (OR = 6.1, 95%CI = 1.1-33.9). Our results provide further evidence that HCV infection contributes to NHL risk.