Previous studies that have examined the relationship between body size and incidence of breast cancer suggest that taller women are at increased risk regardless of whether they have reached menopause, and that obesity is associated with a reduced risk of breast cancer in premenopausal women and an increased risk in postmenopausal women, although results of studies on abdominal fat are equivocal. Hormone replacement therapy (HRT) has also been shown to significantly increase the risk of breast cancer in earlier studies.
In order to estimate the relative risk of breast cancer in relation to general and abdominal obesity and evaluate whether HRT plays a role in this relationship, a study was conducted by Petra H. Lahmann, Ph.D. of the German Institute of Human Nutrition in Potsdam-Rehbrücke, Germany. The study was based on the European Prospective Investigation into Cancer and Nutrition (EPIC), a large prospective cohort study coordinated by Dr. Elio Riboli at the International Agency for Research on Cancer (IARC-WHO), Lyon, France. Researchers examined measurements of height, weight, body mass index (BMI), and waist and hip circumference from 73,542 premenopausal and 103,344 postmenopausal women from nine European countries. During 4.7 years of follow-up, 1,879 invasive breast cancers were identified.
Results showed that body size was more strongly associated with breast cancer risk in postmenopausal women than premenopausal women. Height was linked to breast cancer risk in both groups, but more significantly in postmenopausal women. The reasons for this are not well understood, but may be explained by factors that influence both bone growth and breast cancer, such as birth weight, diet, infection, energy balance and insulin-like growth factors. In postmenopausal women, obesity was linked to increase risk of breast cancer in women who were not using HRT, while those on HRT with a low BMI had an increased risk. In terms of fat distribution, hip circumference was a strong predictor of postmenopausal breast cancer in women not using HRT, but waist circumference, controlled for overall body fat (BMI), was not significantly related to increased breast cancer risk, neither in post- nor in premenopausal women.
The authors conclude: "Overweight is one of the few modifiable breast cancer risk factors and thus an important measure for breast cancer prevention and prognosis."
Article: "Body Size and Breast Cancer Risk: Findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)," Petra H. Lahmann, Kurt Hoffmann, Naomi Allen, Carla H. van Gils, Kay-Tee Khaw, Bertrand Tehard, Franco Berrino, Anne Tjønneland, Janne Bigaard, Anja Olsen, Kim Overvad, Françoise Clavel-Chapelon, Gabriele Nagel, Heiner Boeing, Dimitrios Trichopoulos, George Economou, George Bellos, Domenico Palli, Rosario Tumino, Salvatore Panico, Carlotta Sacerdote, Vittorio Krogh, Petra HM Peeters, H Bas Bueno-de-Mesquita, Eiliv Lund, Eva Ardanaz, Pilar Amiano, Guillem Pera, José R. Quirós, Carmen Martínez, María J. Tormo, Elisabet Wirfält, Göran Berglund, Göran Hallmans, Timothy J. Key, Gillian Reeves, Sheila Bingham, Teresa Norat, Carine Biessy, Rudolf Kaaks, Elio Riboli, International Journal of Cancer; Published Online: May 17, 2004 (DOI: 10.1002/ijc.20315).
About the International Journal of Cancer
The International Journal of Cancer, the Official Journal of the International Union Against Cancer (UICC), has long been established as a leading publication for original papers and review articles on the spectrum of topics germane to experimental and clinical cancer research. The International Journal of Cancer concentrates on the fundamental studies that have relevance to the understanding and effective treatment of human cancer. This resource is distinctive for publishing epidemiological studies from all over the world, to a magnitude not instituted anywhere else in oncology-related literature.
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International Journal of Cancer