The more physical activity, the lower the risk of lymphoma – study

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High levels of physical activity may reduce the risk of lymphoma, according to a review/meta-analysis.

Guiniver A. Davis, MD, MPH, from the Jurawinski-Hamilton Cancer Center, Canada, and colleagues conducted a systematic review/meta-analysis of the literature to examine the association between physical activity and lymphoma occurrence. Eighteen studies (nine cohort, nine case-control) were included in the final analysis.

The researchers found that for all lymphomas, comparing the highest and lowest activity categories, physical activity was protective (relative risk 0.89; 95% confidence interval 0.81–0.98). In sensitivity analyses, the effect persisted in case-control studies (relative risk 0.82; 95% confidence interval 0.71 to 0.96) but not in cohort studies (relative risk 0.95; 95% confidence interval 0.84 to 1.07).

Subgroup analyses demonstrated a protective effect of physical activity in non-Hodgkin lymphoma but not in Hodgkin lymphoma. A protective effect was demonstrated in a dose-response analysis: a 1 percent risk reduction per three metabolic equivalent hours of exercise per week (relative risk 0.99; 95 percent confidence interval 0.98 to 1.00; P = 0.034).

“The dose-response analysis supports these findings with a linear reduction in incidence observed with increasing physical activity for everyday purposes,” the authors write.