A prospective study of fruits, vegetables, and risk of endometrial cancer.

Case-control studies support a lower risk of endometrial cancer associated with greater vegetable consumption but not fruit consumption. One prospective study suggested an inverse association with fruits and vegetables combined. The authors examined associations for vegetables and fruits separately among women in the American Cancer Society's Cancer Prevention Study II Nutrition Cohort. After exclusions, 41,400 postmenopausal women completed a questionnaire on diet, lifestyle, and medical history at baseline in 1992-1993. Information on diet was updated in 1999; historical dietary information from 1982 was also available. The authors identified 435 eligible cases of endometrial cancer through 2003. In multivariate models, neither fruit consumption (top quintile vs. bottom: rate ratio (RR) = 1.24, 95% confidence interval (CI): 0.90, 1.70; p-trend = 0.30) nor vegetable consumption (RR = 1.21, 95% CI: 0.89, 1.65; p-trend = 0.24) at baseline was associated with risk. Results were similar when diet was cumulatively updated. Only among women who had never used hormone replacement therapy was the risk of endometrial cancer lower in the highest (vs. lowest) tertile of fruit (RR = 0.75, 95% CI: 0.52, 1.07; p-interaction = 0.03, p-trend = 0.11) or vegetable (RR = 0.80, 95% CI: 0.57, 1.13; p-interaction = 0.01, p-trend = 0.29) consumption. This prospective study does not support an association between vegetable or fruit consumption and endometrial cancer.