Background: Non-Hodgkin lymphoma is the seventh most commonly diagnosed malignant condition world-wide, and its incidence has increased markedly in recent decades. Blood transfusions have been implicated as a possible risk factor for non-Hodgkin lymphoma.
Objective: To determine whether blood transfusions are associated with an elevated risk for non-Hodgkin lymphoma.
Design: Population-based, nested case–control study.
Setting: Nationwide cohort in Sweden.
Patients: 361 patients with non-Hodgkin lymphoma and 705 matched controls, nested within a population-based cohort of 96 795 patients at risk for blood transfusion between 1970 and 1983. Prospectively collected information on exposure was retrieved from computerized transfusion registries.
Measurements: Odds ratios obtained from conditional logistic regression models were used as measures of relative risks.
Results: No association was found between blood transfusions and the risk for non-Hodgkin lymphoma when patients who had received transfusions were compared with patients who had not received transfusions (odds ratio, 0.93 [95% CI, 0.71 to 1.23]). A reduction in risk was seen among persons who received transfusion of blood without leukocyte depletion (odds ratio, 0.72 [CI, 0.53 to 0.97]). Risk was not related to number of transfusions, and no interaction was seen with latency after transfusion.
Conclusion: The findings in this study do not support previous observations of an association between blood transfusions and the risk for non-Hodgkin lymphoma.