Dietary fat, fiber, and carbohydrate intake in relation to risk of endometrial cancer.

BACKGROUND: Macronutrients such as fat and fiber have been hypothesized to play a role in the etiology of endometrial cancer.
METHODS: To investigate these associations, the authors analyzed data from the Nurses' Health Study. From 1980 to 2006, 669 invasive adenocarcinoma cases were identified over 1.3 million person-years of follow-up. Dietary intake was assessed in 1980 and updated every 2-4 years. Cox proportional hazard models were used to calculate relative risks (RRs), controlling for total energy and other risk factors.
RESULTS: Overall, the authors found no significant associations between most dietary factors and endometrial cancer risk. Total fat was associated with a borderline significant decreased risk (top vs. bottom quintile RR = 0.78; 95% CI = 0.60-0.99; P(trend) = 0.18). Findings for animal fat were similar. No inverse associations between dietary fibers and cancer risk were observed. Cereal fiber was modestly positively associated with risk (top vs. bottom quintile RR = 1.38, 95% CI = 1.07-1.79; P(trend) = 0.05). The inverse association with animal fat intake and a positive association with carbohydrate intake were observed among premenopausal but not among postmenopausal women.
CONCLUSIONS: In this large prospective study, no overall association was observed between dietary fat, fiber, and carbohydrates with endometrial cancer risk, although several of the relationships may vary by menopausal status. IMPACT: Dietary fat and fiber intake do not seem to play a major role in endometrial cancer etiology overall. However, further evaluation of these associations, particularly in premenopausal women, is needed. ©2011 AACR.