title: Blood transfusion and non-Hodgkin lymphoma: lack of association.
abstract: BACKGROUND
  Non-Hodgkin lymphoma is the seventh most commonly diagnosed malignant condition worldwide, 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.
  
  
  METHODS
  Population-based, nested case-control study.
  
  
  METHODS
  Nationwide cohort in Sweden.
  
  
  METHODS
  361 patients with non-Hodgkin lymphoma and 705 matched controls, nested within a population-based cohort of 96795 patients at risk for blood transfusion between 1970 and 1983. Prospectively collected information on exposure was retrieved from computerized transfusion registries.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  The findings in this study do not support previous observations of an association between blood transfusions and the risk for non-Hodgkin lymphoma.
authors.affiliation: Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Adami
authors.forename: O
authors.initials: O
authors.lastname: Nyrén
authors.forename: R
authors.initials: R
authors.lastname: Bergström
authors.forename: A
authors.initials: A
authors.lastname: Ekbom
authors.forename: J K
authors.initials: JK
authors.lastname: McLaughlin
authors.forename: C
authors.initials: C
authors.lastname: Högman
authors.forename: J F
authors.initials: JF
authors.lastname: Fraumeni
authors.forename: B
authors.initials: B
authors.lastname: Glimelius
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000209:etiology*; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D016017:Odds Ratio; D012042:Registries; D012306:Risk; D013548:Sweden; D065227:Transfusion Reaction