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Journal of Cancer Epidemiology
Volume 2013 (2013), Article ID 754815, 13 pages
http://dx.doi.org/10.1155/2013/754815
Research Article

Body Fat and Breast Cancer Risk in Postmenopausal Women: A Longitudinal Study

1Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA
2Karmanos Cancer Center, Department of Surgery, Wayne State University School of Medicine, Detroit, MI 48201, USA
3Department of Social Sciences and Health Policy, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
4Department of Social and Preventive Medicine, University at Buffalo, Buffalo, NY 14214, USA
5Department of Public Health Sciences, University of California Davis, Davis, CA 95616, USA
6Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ 85724, USA
7Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, NC 27127, USA

Received 19 February 2013; Revised 14 March 2013; Accepted 14 March 2013

Academic Editor: P. Vineis

Copyright © 2013 Thomas E. Rohan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Associations between anthropometric indices of obesity and breast cancer risk may fail to capture the true relationship between excess body fat and risk. We used dual-energy-X-ray-absorptiometry- (DXA-) derived measures of body fat obtained in the Women’s Health Initiative to examine the association between body fat and breast cancer risk; we compared these risk estimates with those for conventional anthropometric measurements. The study included 10,960 postmenopausal women aged 50–79 years at recruitment, with baseline DXA measurements and no history of breast cancer. During followup (median: 12.9 years), 503 incident breast cancer cases were diagnosed. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. All baseline DXA-derived body fat measures showed strong positive associations with breast cancer risk. The multivariable-adjusted HR for the uppermost quintile level (versus lowest) ranged from 1.53 (95% CI 1.14–2.07) for fat mass of the right leg to 2.05 (1.50–2.79) for fat mass of the trunk. Anthropometric indices (categorized by quintiles) of obesity (BMI (1.97, 1.45–2.68), waist circumference (1.97, 1.46–2.65), and waist : hip ratio (1.91, 1.41–2.58)) were all strongly, positively associated with risk and did not differ from DXA-derived measures in prediction of risk.