Gardeazabal, IRomanos-Nanclares, AMartinez-Gonzalez, Miguel AngelCastelló Pastor, AdelaSánchez-Bayona, RPerez-Gomez, BeatrizRazquin, CAramendia-Beitia, J MPollan-Santamaria, MarinaToledo, E2020-09-292020-09-292020-02-24Public Health Nutr. 2020 Feb 24:1-12.1368-9800http://hdl.handle.net/20.500.12105/11079OBJECTIVE: Due to the growing interest in the role of dietary patterns (DPs) on chronic diseases, we assessed the association between a posteriori identified DPs in the Seguimiento Universidad de Navarra (SUN) Project - a prospective cohort study in a Mediterranean country - and breast cancer (BC) risk. DESIGN: DPs were ascertained through a principal component analysis based on 31 predefined food groups. BC cases were initially identified through self-report or, if deceased, from death certificates or by notification by the next kin. Women reporting BC were asked to provide a copy of their medical report and diagnoses for confirmation purposes. We fitted Cox regression models to assess the association between adherence to the identified DPs and BC risk. SETTING: Spanish university graduates. PARTICIPANTS: We included 10 713 young and middle-aged - mainly premenopausal - women. RESULTS: After a median follow-up of 10·3 years, we identified 100 confirmed and 168 probable incident BC cases. We described two major DPs: 'Western dietary pattern' (WDP) and 'Mediterranean dietary pattern' (MDP). A higher adherence to a WDP was associated with an increased risk of overall BC (multivariable-adjusted HR for confirmed BC Q4 v. Q1 1·70; 95 % CI 0·93, 3·12; P for trend = 0·045). Contrarily, adherence to a MDP was inversely associated with premenopausal BC (multivariable-adjusted HR Q4 v. Q1 0·33; 95 % CI 0·12, 0·91). No significant associations were observed for postmenopausal BC. CONCLUSIONS: Whereas a higher adherence to the WDP may increase the risk of BC, a higher adherence to the MDP may decrease the risk of premenopausal BC.engSMURhttp://creativecommons.org/licenses/by-nc-nd/4.0/Mediterranean dietary patternWestern dietary patternBreast cancerSUN ProjectCohort studyBreast NeoplasmsDiet, MediterraneanDiet, WesternFemaleFollow-Up StudiesHumansIncidenceMiddle AgedProspective StudiesSpainAttribution-NonCommercial-NoDerivatives 4.0 Internacional320907231-1210.1017/S13689800190038351475-2727Public health nutritionopen access