Physical activity, energy restriction, and the risk of pancreatic cancer: a prospective study in the Netherlands.

BACKGROUND Because of their influence on insulin concentrations, we hypothesized that both physical activity and energy restriction may reduce the risk of pancreatic cancer. OBJECTIVE We examined the associations between physical activity, proxies for energy restriction, and pancreatic cancer risk. DESIGN The Netherlands Cohort Study consisted of 120,852 individuals who completed a baseline questionnaire in 1986. After 13.3 y of follow-up, 408 cases were available for analysis. Self-reported information on physical activity was collected. Three indicators were used as proxies for energy restriction: father's employment status during the Economic Depression (1932-1940) and place of residence during the World War II years (1940-1944) and the Hunger winter (1944-1945). RESULTS For past sports activities, we observed a significantly decreased risk of pancreatic cancer (HR: 0.80; 95% CI: 0.64, 0.99). Proxies for energy restriction were not related to pancreatic cancer risk. When the results for energy restriction were stratified by height, a significant multiplicative interaction was observed for the Economic Depression period (P = 0.002). Shorter individuals (height less than the sex-specific median adult height) with an unemployed father during the Economic Depression period had a significantly lower cancer risk (HR: 0.31; 95% CI: 0.14, 0.66) than did taller individuals with an employed father. No significant interactions were observed for exposure to energy restriction during the World War II years and the Hunger winter. CONCLUSIONS Our results suggest a modestly decreased risk of pancreatic cancer associated with past sports activity. With respect to proxies for energy restriction, our findings suggest that shorter individuals exposed to energy restriction during adolescence may have a reduced risk, whereas taller individuals may not.