Fat consumption and breast cancer:: preliminary results from the E3N-Epic cohort

Recent reviews have concluded that a high consumption of total, saturated or animal fat could possibly increase the risk of breast cancer. However these results are highly dependent on the type of study; indeed, most of the prospective studies do not support this association. In this paper, we investigated the relationship between fat consumption and breast cancer risk in the E3N-Epic cohort, the French component of the European Prospective Investigation into Cancer and Nutrition. Assessment of fat consumption was based on daily intakes of food items and nutrients using a food frequency questionnaire. Relative risk (RR) estimates were calculated using Cox's proportional hazards model. After an average of 3.4 years of follow-up, 838 cases of incident breast cancer were recorded in a study population of GS 879 women. The mean caloric intake was 2,073 kcal (SD 540), with 37% of calories coming from fat intake. Milk products and vegetable oils were the main sources of fat in the diet. We found a small positive association between fat intake and breast cancer risk. Compared with the lowest, women in the highest quartile of fat intake had a 37% higher risk of breast cancer (RR 1.37, CI95% = 0.99-1.89. There was no detectable association between fatty acids or food items contributing to fat intake and breast cancer risk. These analyses suggest there is a need for longer follow-up time to increase statistical power and confirm these tendencies.