Objective: We investigated the association between adherence to the recommendations of the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and breast cancer (BC) risk in the Cancer de Màma (CAMA) study in a Mexican population.
Design: Population-based case-control study.
Subjects: Incident BC cases (n 1000) and controls (n 1074) matched on age, region and health-care system were recruited.
Setting: In-person interviews were conducted to assess BC risk factors and habitual diet was assessed with an FFQ. Conformity to the WCRF/AICR recommendations was evaluated through a score incorporating seven WCRF/AICR components (body fatness, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks and breast-feeding), with high scores indicating adherence to the WCRF/AICR recommendations.
Results: No statistically significant associations between WCRF/AICR score and risk of BC were observed. After excluding BMI from the WCRF/AICR score, the top quartile was associated with a decreased BC risk overall, with ORQ4-Q1=0.68 (95% CI 0.49, 0.92, P trend=0.03), and among postmenopausal women, with ORQ4-Q1=0.60 (95% CI 0.39, 0.94, P trend=0.03). Inverse associations were observed between BMI and risk of BC overall and among premenopausal women, with OR=0.57 (95% CI 0.42, 0.76, P trend <0.01) and 0.48 (95% CI 0.31, 0.73, P trend<0.01), respectively. Physical activity level was inversely associated with BC risk.
Conclusions: The WCRF/AICR index was not related with BC risk in the CAMA study. A combination of six components excluding BMI showed strong protective associations, particularly in postmenopausal women. Further prospective studies are required to clarify the role of adherence to WCRF/AICR recommendations, particularly with respect to BMI, in the Mexican population.
Keywords: Breast cancer; Diet; Mexican women; Physical activity; Weight management.