American Journal of Epidemiology Advance Access originally published online on July 8, 2008
American Journal of Epidemiology 2008 168(5):471-480; doi:10.1093/aje/kwn160
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Type 2 Diabetes Mellitus and Risk of Non-Hodgkin Lymphoma: A Systematic Review and Meta-Analysis
1 Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA
2 Department of Epidemiology, Harvard School of Public Health, Boston, MA
Correspondence to Dr. Chun Chao, Department of Research and Evaluation, Southern California Permanente Medical Group, 100 South Los Robles Avenue, Suite 201, Pasadena, CA 91101-2453 (e-mail: chun.r.chao{at}kp.org).
Received for publication February 19, 2008. Accepted for publication May 8, 2008.
Type 2 diabetes mellitus is associated with altered immune function and chronic inflammation. Both of these immune conditions are implicated in the pathogenesis of non-Hodgkin lymphoma. The authors performed a systematic review to summarize findings from the current literature on the association between history of type 2 diabetes mellitus and risk of non-Hodgkin lymphoma. Ten case-control studies and three prospective cohort studies were included in this review. Meta-analysis found that a history of type 2 diabetes mellitus was positively associated with overall non-Hodgkin lymphoma risk. However, there was significant heterogeneity between studies. Study design was an important source of heterogeneity. The rate ratio between type 2 diabetes mellitus and non-Hodgkin lymphoma was found to be 1.18 (95% confidence interval: 0.99, 1.42) among case-control studies and 1.79 (95% confidence interval: 1.30, 2.47) among the prospective cohort studies. Weaknesses were identified in some of the included studies in the areas of case and control selection, measurement of covariates and non-Hodgkin lymphoma, and confounding control. Although a positive association between type 2 diabetes mellitus and risk of non-Hodgkin lymphoma was suggested, the evidence is inconclusive because of methodological limitations of the included case-control studies. More prospective studies with improved control of confounding are needed to confirm these findings.
diabetes mellitus; diabetes mellitus, type 2; lymphoma; lymphoma, non-Hodgkin; meta-analysis
Abbreviations: CI, confidence interval; RR, rate ratio; TNF-
, tumor necrosis factor-