Physical activity and pancreatic cancer risk: A systematic review

Background: Physical activity has been associated with a lower risk for pancreatic cancer in several studies, but the overall epidemiologic evidence is not consistent. We therefore did a systematic review to evaluate the association between physical activity and pancreatic cancer risk. Methods: We searched MEDLINE and EMBASE through April 2008 and examined the reference lists of the retrieved articles. We excluded studies that relied on job titles as surrogate measures for physical activity. We used a random-effects model to pool study-specific risk estimates comparing the highest versus the lowest category of physical activity. Results: Total physical activity (occupational and leisure time) was not significantly associated with risk for pancreatic cancer [4 prospective studies; summary 0.53-1.091. A decreased risk for pancreatic cancer was observed for occupational physical activity (3 prospective studies; relative risk, 0.75; 95% CI, 0.58-0.96) but not for leisure-time physical activity (14 prospective studies; relative risk, 0.94; 95% CI, 0.83-1.05). No association was found with light physical activity (2 prospective studies; relative risk, 1.01; 95% CI, 0.77-1.34), moderate physical activity (6 prospective studies; relative risk, 0.83; 95% CI, 0.58-1.18), or vigorous physical activity (7 prospective studies; relative risk, 0.94; 95% CI, 0.80-1.12). Conclusions: This systematic review does not provide strong evidence for an association between physical activity and risk for pancreatic cancer.