Physical Activity and Risk of Lymphoma:A Meta-Analysis

<p>Background: Physical activity has a protective effect on some types of cancer. The aim of the present meta-analysis was to explore the literature on the association between physical activity and risk of lymphoma.</p><p>Methods: A meta-analysis was conducted for cohort and case-control studies examining the association between self-reported physical activity and risk of lymphoma. Depending on statistical heterogeneity, a random or fixed effects model was used to estimate the summary OR and corresponding 95% confidence interval (CI).</p><p>Results: Seven case-control studies and 5 cohort studies were included. When data from both study designs were combined, no significant influence of physical activity on risk of lymphoma was found (pooled OR 0.90; 95% CI: 0.79-1.02; P = 0.10). Subgroup analysis revealed a significant protective influence of physical activity on risk of lymphoma in case-control studies (pooled OR 0.81; 95% CI: 0.68-0.96; P = 0.02). In contrast, cohort studies, which have a higher level of evidence than case-control studies, confirm the results of the primary meta-analysis (pooled OR = 1.02; 95% CI: 0.88-1.19; P = 0.76). A subsequent subgroup analysis found no significant differences between results for Hodgkin lymphoma and non-Hodgkin lymphoma (chi(2) = 0.16; P = 0.69), nor between results for recreational and occupational activities (chi(2) = 1.01; P = 0.31).</p><p>Conclusions: Epidemiologic research indicates no significant influence of physical activity on risk of lymphoma.</p><p>Impact: Future research should examine the association between sedentary behavior and risk of lymphoma and investigate the dose-response and timing effect of physical activity on risk of lymphoma. (c) 2013 AACR.</p>