Autoimmune and Chronic Infl ammatory Disorders and Risk of Non-Hodgkin Lymphoma by Subtype

Background: Some autoimmune and chronic infl ammatory disorders are associated with increased risks of non- Hodgkin lymphoma (NHL). Because different NHL subtypes develop at different stages of lymphocyte differentiation, associations of autoimmune and infl ammatory disorders with specifi c NHL subtypes could lead to a better understanding of lym-phomagenic mechanisms. Methods: In a population-based case – control study in Denmark and Sweden, 3055 NHL patients and 3187 matched control subjects were asked about their history of autoimmune and chronic infl ammatory dis-orders, markers of severity, and treatment. Logistic regres-sion with adjustment for study matching factors was used to calculate odds ratios (ORs) and 95 % confi dence intervals (CIs) for NHL overall and for NHL subtypes. Results: Risks of all NHL were increased in association with rheumatoi