Flood transfusions and risk of non-Hodgkin's lymphoma subtypes and chroniclymphocytic leukemia

Allogeneic blood transfusion has been suggested as a risk factor for non-Ho dgkin's lymphoma (NHL), possibly specific to certain NHL subtypes, or chron ic lymphocytic leukemia (CLL). Self-reported transfusion history and risk o f NHL subtypes and CLL were examined in a cohort of 37,934 older Iowa women , using data from a questionnaire mailed in 1986. Through 1997, 229 cases o f NHL and 57 cases of CLL in the cohort were identified through linkage to the Iowa Surveillance, Epidemiology and End Results Cancer Registry. Women who reported ever receiving a blood transfusion were at increased risk for all NHLs [age adjusted relative risk (RR), 1.6; 95% confidence interval (CI ), 1.2-2.1). On the basis of the Working Formulation classification, blood transfusion was positively associated with low-grade NHL (RR, 2.7; 95% CI, 1.7-4.5) but not with intermediate-grade NHL (RR, 1.1; 95% CI, 0.7-1.6); th ere were only 8 cases of high-grade NHL. Blood transfusion was positively a ssociated with follicular (RR, 2.8; 95% CI, 1.6-5.1) and small lymphocytic (RR, 3.4; 95% CI, 1.5-7.9) NHL subtypes but not with diffuse NHL (RR, 1.0; 95% CI, 0.7-1.5). There was also a positive association with CLL (RR, 1.7; 95% CI, 1.0-3.0). Finally, transfusion was associated with nodal (RR, 1.8; 95% CI, 1.3-2.5) but not extranodal (RR, 1.2; 95% CI, 0.7-2.1) NHL. Further adjustment for marital status, farm residence, diabetes, alcohol use, smok ing, and red meat and fruit consumption did not alter these associations. I n conclusion, prior blood transfusion was associated with NHL and CLL, and the strongest associations were seen for low-grade NHL, particularly follic ular and small lymphocytic NHL.