Dietary intake of energy and animal foods and endometrial cancer incidence. The Iowa women's health study.

To assess the relations of dietary intake of energy and animal foods to endometrial cancer risk, dietary analyses were performed using data from a prospective cohort study of over 23,000 postmenopausal Iowa women who responded to a mailed questionnaire in 1986 and were followed through the end of 1992 for cancer incidence and total mortality. Usual intakes of 127 food items were measured by a semiquantitative food frequency questionnaire. After 7 years of follow-up, 216 incident endometrial cancer cases had been ascertained. There was no statistically significant association of dietary intake of energy and most animal foods with endometrial cancer incidence over the 7-year follow-up period. Stratified analyses, however, suggested that intake of energy from plant foods may be inversely associated with endometrial cancer risk in the latter years of follow-up (trend test, p = 0.03), while high intake of energy and foods from animal sources related to slightly, but not statistically significantly, elevated risks of this cancer in the earlier years of follow-up. The only significant dose-response relation observed in food group analyses was for processed meat and fish, for which a significant 50% excess risk of endometrial cancer was found among women in the highest versus the lowest tertile of intake. This study suggests that dietary intake of energy and most animal foods is not related to or is only weakly related to the risk of endometrial cancer among postmenopausal US women.