Adiposity, hormone replacement therapy use and breast cancer risk by age and hormone receptor status: A large prospective cohort study

Rebecca Ritte, Annekatrin Lukanova, Franco Berrino, Laure Dossus, Anne Tjønneland, Anja Olsen, Thure F. Overvad, Kim Overvad, Françoise Clavel-Chapelon, Agnès Fournier, Guy Fagherazzi, Sabine Rohrmann, Birgit Teucher, Heiner Boeing, Krasimira Aleksandrova, Antonia Trichopoulou, Pagona Lagiou, Dimitrios Trichopoulos, Domenico Palli, Sabina SieriSalvatore Panico, Rosario Tumino, Paolo Vineis, José R. Quirós, Genevieve Buckland, Maria José Sánchez, Pilar Amiano, María Dolores Chirlaque, Eva Ardanaz, Malin Sund, Per Lenner, Bas Bueno-de-Mesquita, Carla H. van Gils, Petra H.M. Peeters, Sanda Krum-Hansen, Inger T. Gram, Eiliv Lund, Kay Tee Khaw, Nick Wareham, Naomi E. Allen, Timothy J. Key, Isabelle Romieu, Sabina Rinaldi, Afshan Siddiq, David Cox, Elio Riboli, Rudolf Kaaks*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

98 Citations (Scopus)


Introduction: Associations of hormone-receptor positive breast cancer with excess adiposity are reasonably well characterized; however, uncertainty remains regarding the association of body mass index (BMI) with hormone-receptor negative malignancies, and possible interactions by hormone replacement therapy (HRT) use.Methods: Within the European EPIC cohort, Cox proportional hazards models were used to describe the relationship of BMI, waist and hip circumferences with risk of estrogen-receptor (ER) negative and progesterone-receptor (PR) negative (n = 1,021) and ER+PR+ (n = 3,586) breast tumors within five-year age bands. Among postmenopausal women, the joint effects of BMI and HRT use were analyzed.Results: For risk of ER-PR- tumors, there was no association of BMI across the age bands. However, when analyses were restricted to postmenopausal HRT never users, a positive risk association with BMI (third versus first tertile HR = 1.47 (1.01 to 2.15)) was observed. BMI was inversely associated with ER+PR+ tumors among women aged ≤49 years (per 5 kg/m2 increase, HR = 0.79 (95%CI 0.68 to 0.91)), and positively associated with risk among women ≥65 years (HR = 1.25 (1.16 to 1.34)). Adjusting for BMI, waist and hip circumferences showed no further associations with risks of breast cancer subtypes. Current use of HRT was significantly associated with an increased risk of receptor-negative (HRT current use compared to HRT never use HR: 1.30 (1.05 to 1.62)) and positive tumors (HR: 1.74 (1.56 to 1.95)), although this risk increase was weaker for ER-PR- disease (Phet = 0.035). The association of HRT was significantly stronger in the leaner women (BMI ≤22.5 kg/m2) than for more overweight women (BMI ≥25.9 kg/m2) for, both, ER-PR- (HR: 1.74 (1.15 to 2.63)) and ER+PR+ (HR: 2.33 (1.84 to 2.92)) breast cancer and was not restricted to any particular HRT regime.Conclusions: An elevated BMI may be positively associated with risk of ER-PR- tumors among postmenopausal women who never used HRT. Furthermore, postmenopausal HRT users were at an increased risk of ER-PR- as well as ER+PR+ tumors, especially among leaner women. For hormone-receptor positive tumors, but not for hormone-receptor negative tumors, our study confirms an inverse association of risk with BMI among young women of premenopausal age. Our data provide evidence for a possible role of sex hormones in the etiology of hormone-receptor negative tumors.

Original languageEnglish
Article numberR76
JournalBreast Cancer Research
Issue number3
Publication statusPublished - 14 May 2012
Externally publishedYes


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