Lower Breast Cancer Risk among Women following the World Cancer Research Fund and American Institute for Cancer Research Lifestyle Recommendations: EpiGEICAM Case-Control Study

Background According to the World Cancer Research Fund and the American Institute of Cancer Research (WCRF/AICR) one in four cancer cases could be prevented through a healthy diet, weight control and physical activity. Objective To explore the association between the WCRF/AICR recommendations and risk of breast cancer. Methods During the period 2006 to 2011 we recruited 973 incident cases of breast cancer and 973 controls from 17 Spanish Regions. We constructed a score based on 9 of the WCRF/AICR recommendations for cancer prevention:: 1) Maintain adequate body weight; 2) Be physically active; 3) Limit the intake of high density foods; 4) Eat mostly plant foods; 5) Limit the intake of animal foods; 6) Limit alcohol intake; 7) Limit salt and salt preserved food intake; 8) Meet nutritional needs through diet; S1) Breastfeed infants exclusively up to 6 months. We explored its association with BC by menopausal status and by intrinsic tumor subtypes (ER +/PR+ & HER2-; HER2+; ER&PR-&HER2-) using conditional and multinomial logistic models respectively. Results Our results point to a linear association between the degree of noncompliance and breast cancer risk. Taking women who met 6 or more recommendations as reference, those meeting less than 3 showed a three-fold excess risk (OR=2.98(CI95%:1.59-5.59)), especially for postmenopausal women (OR=3.60(CI95%:1.24; 10.47)) and ER+/PR+&HER2- (OR=3.60 (CI95%:1.84; 7.05)) and HER2+ (OR=4.23(CI95%:1.66;10.78)) tumors. Noncompliance of recommendations regarding the consumption of foods and drinks that promote weight gain in premenopausal women (OR=2.24(CI95%:1.18;4.28); p for interaction=0.014) and triple negative tumors (OR=2.93(CI95%:1.12-7.63)); the intake of plant foods in postmenopausal women (OR=2.35(CI95%:1.24;4.44)) and triple negative tumors (OR=3.48(CI95%:1.468.31)); and the alcohol consumption in ER+/PR+& HER2-tumors (OR=1.52 (CI95%: 1.06-2.19)) showed the strongest associations. Conclusion Breast cancer prevention might be possible by following the World Cancer Research Fund and the American Institute of Cancer Research recommendations, even in settings like Spain, where a high percentage of women already comply with many of them.