[Note: Non-Hodgkin lymphoma, sometimes called just lymphoma, is a large group of cancers that start in cells of the lymph system, which is part of the body’s immune system. They represent 90% of all lymphomas.]
Objective: As factors that alter the immune system have been implicated in non-Hodgkin lymphoma (NHL) etiology, it is of interest to explore the association between vaccination and risk of NHL.
Results of few epidemiologic studies conducted thus far are inconsistent, and only one has examined the association by histologic subtype.
Subjects: A population-based, case-control study of 387 patients with NHL and 535 controls conducted in Nebraska between 1999 and 2002.
Methods: Information on vaccination for tetanus, polio, influenza, smallpox, and tuberculosis, as well as important environmental factors, was collected by telephone interview. Risk was estimated by odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for confounders.
Results: We found that NHL risk was inversely associated with ever receiving a polio (OR = 0.59, CI = 0.40-0.87) or smallpox (OR = 0.71, CI = 0.51-0.98) vaccination and positively associated with influenza vaccination (OR = 1.53, CI = 1.14-2.06). [Note: an OR of 1.0 would represent no difference in risk. The OR of 0.59 for those who received a polio shot would indicate a 41% lower risk of developing lymphoma; and the OR of 1.53 for those who ever received a flu shot would indicate a 53% greater risk of lymphoma.]
No significant association was found for tetanus or tuberculosis vaccination. The patterns of association were similar between men and women. Analysis by histologic subtypes showed that polio vaccination was associated with a lower risk of follicular (OR = 0.54, CI = 0.31-0.92) and chronic lymphocytic leukemia/small lymphocytic lymphomas (OR = 0.29, CI = 0.12-0.69) and smallpox vaccination was associated with a lower risk of marginal zone lymphoma (OR = 0.41, CI = 0.19-0.88).
In contrast, ever receiving an influenza vaccination was associated with a higher risk of follicular (OR = 1.98, CI = 1.23-3.18) and diffuse large B cell lymphomas (OR = 1.88, CI = 1.13-3.12). [The OR of 1.98 would indicate a 98% greater risk, and the OR of 1.88 an 88% greater risk.]
Conclusion: Risk of NHL is inversely associated with polio and smallpox vaccination and positively associated with influenza vaccination. These associations appear to differ by histologic subtype.
Source: Cancer Causes & Control, Jul 2009;20(5):517-523. PMID: 19011978, by Lankes HA, Fought AJ, Evens AM, Weisenburger DD, Chiu BC. Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. [E-mail: email@example.com]