Long-term weight change and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study Ellingjord Dale, Merete Sánchez Pérez, María José Long-term weight change Breast cancer Cohort study The coordination of EPIC is financially supported by the European Commission (DG-SANCO) and the International Agency for Research on Cancer. The national cohorts are supported by the Danish Cancer Society (Kræftens Bekæmpelse) (Denmark), German Cancer Aid (Deutsche Krebshilfe), German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), Federal Ministry of Education and Research (Bundesministerium fu¨ r Bildung und Forschung, BMBF) (Germany), Associazione Italiana per la Ricerca sul Cancro-AIRC-Italy and National Research Council (Italy), Swedish Cancer Society (Cancerfonden), Swedish Research Council (Vetenskapsra° det), County Councils of Ska°ne and Va¨sterbotten (Sweden), Cancer Research UK (14136 to EPIC-Norfolk; C570/ A16491 and C8221/A19170 to EPIC-Oxford), Medical Research Council (1000143 to EPIC-Norfolk; MR/M012190/1 to EPICOxford) (UK). Infrastructure support for the Department of Epidemiology and Biostatistics at Imperial College London (UK) was provided by the NIHR Imperial Biomedical Research Centre (BRC). The funders had no role in the design and conduct of the study; the collection, analysis and interpretation of the data; or the preparation, review and approval of the manuscript; or in the decision to submit the manuscript for publication. Background: The role of obesity and weight change in breast-cancer development is complex and incompletely understood. We investigated long-term weight change and breast-cancer risk by body mass index (BMI) at age 20 years, menopausal status, hormone replacement therapy (HRT) and hormone-receptor status. Methods: Using data on weight collected at three different time points from women who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, we investigated the association between weight change from age 20 years until middle adulthood and risk of breast cancer. Results: In total, 150 257 women with a median age of 51 years at cohort entry were followed for an average of 14 years (standard deviation¼3.9) during which 6532 breast-cancer cases occurred. Compared with women with stable weight (62.5 kg), long-term weight gain >10 kg was positively associated with postmenopausal breast-cancer risk in women who were lean at age 20 [hazard ratio (HR)¼1.42; 95% confidence interval 1.22–1.65] in ever HRT users (HR¼1.23; 1.04–1.44), in never HRT users (HR¼1.40; 1.16–1.68) and in oestrogen-and-progesterone-receptor-positive (ERþPRþ) breast cancer (HR¼1.46; 1.15–1.85). Conclusion: Long-term weight gain was positively associated with postmenopausal breast cancer in women who were lean at age 20, both in HRT ever users and non-users, and hormone-receptor-positive breast cancer. 2022-02-08T07:37:20Z 2022-02-08T07:37:20Z 2021-03-23 info:eu-repo/semantics/article Merete Ellingjord-Dale... [et al.]. Long-term weight change and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, International Journal of Epidemiology, Volume 50, Issue 6, December 2021, Pages 1914–1926, [https://doi.org/10.1093/ije/dyab032] http://hdl.handle.net/10481/72704 10.1093/ije/dyab032 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España Oxford University Press