gms | German Medical Science

MAINZ//2011: 56. GMDS-Jahrestagung und 6. DGEpi-Jahrestagung

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie e. V.
Deutsche Gesellschaft für Epidemiologie e. V.

26. - 29.09.2011 in Mainz

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An age specific analysis on obesity and breast cancer risk according to estrogen and progesterone receptor status and use of postmenopausal hormone replacement therapy, in the European Prospective Investigation into Cancer and Nutrition

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  • Rebecca James - DKFZ, Heidelberg
  • Annekatrin Lukanova - DKFZ, Heidelberg
  • Laure Dossus - DKFZ, Heidelberg
  • Rudolf Kaaks - DKFZ, Hiedelberg

Mainz//2011. 56. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 6. Jahrestagung der Deutschen Gesellschaft für Epidemiologie (DGEpi). Mainz, 26.-29.09.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11gmds221

doi: 10.3205/11gmds221, urn:nbn:de:0183-11gmds2211

Published: September 20, 2011

© 2011 James et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

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Introduction: Associations of excess adiposity with breast cancer risk are complex and underlying mechanisms remain poorly defined. The effect of obesity, age and hormone replacement therapy (HRT) with risk of hormone receptor (estrogen (ER) and/or progesterone receptor (PR)) defined breast cancer was prospectively analyzed using all female participants with no history of invasive cancer from the EPIC cohort (European Prospective Investigation into Cancer and Nutrition).

Methods: The association of age-bands (<50, 50–55, 55-60, 60-65 and >65 years) and anthropometry (body-mass-index [BMI], waist and hip circumferences) with ER and PR status [ER-positive (n=5634), ER-negative (n=1369), PR-positive (n=3735), PR-negative (n=2044)] were assessed using competing risk analysis within Cox proportional hazards models stratified by age and study centre and adjusted for height.

Results: Among women less than 50 years of age, BMI showed a similar inverse risk association for ER-positive (per 5 unit increase HR=0.84[95%CI 0.74-0.95]) and ER-negative (HR=0.88[95%CI 0.73-1.05];Phet=0.67) tumors. Among women reporting never use of HRT at baseline, the negative risk association of BMI grew weaker across the age bands until reaching a direct risk association among women aged 65 years and older with both ER-positive (HR=1.23[1.14-1.33]) and ER-negative (HR=1.14[0.95-1.39];Phet=0.72) breast cancer. Irrespective of BMI and age-band, current users of HRT had a higher relative risk of both ER-positive and ER-negative breast cancer, however, within current HRT users an inverse relationship was observed with increasing BMI.

Conclusion: Our results show that among women older than 65 years and who are never uses of HRT, increases in BMI are associated with a risk of both hormone receptor positive and negative tumors. The direct association of BMI with ER-negative tumors was masked by an inverse risk association of BMI with ER-negative tumors in current HRT users. The gradual transition from obesity’s protective effect before menopause to the adipose tissue derived estrogens expressing cancer-promoting action is evident in both ER-positive and -negative tumors. This suggests that in addition to the late-stage affects on growth promotion of tumors, estrogens may also play an important role in earlier evolutionary stages of breast cancer development.