American Journal of Epidemiology Advance Access originally published online on December 7, 2005
American Journal of Epidemiology 2006 163(2):101-107; doi:10.1093/aje/kwj017
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Original Contribution |
Association of Overweight with Breast Cancer Survival
1 Department of Medicine, Center for Health Services Research, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN
2 Department of Epidemiology, School of Public Health, University of California at Los Angeles, Los Angeles, CA
3 Department of Epidemiology, Shanghai Cancer Institute, Shanghai, China
Correspondence to Dr. Xiao-Ou Shu, Vanderbilt University Center for Health Services Research, Medical Center East, Suite 6000, Nashville, TN 37232-8300 (e-mail: Xiao-Ou.Shu{at}Vanderbilt.edu).
The authors investigated the association between overweight at the time of or soon after cancer diagnosis and survival in a cohort of 1,455 breast cancer patients aged 25–64 years. The patients were recruited into the Shanghai Breast Cancer Study (Shanghai, China), a population-based case-control study, between August 1996 and March 1998. The median follow-up time for this cohort was 5.1 years (1996–2002) after breast cancer diagnosis, and 240 deaths were identified. Being overweight at cancer diagnosis or soon afterward, as measured by body mass index (BMI; weight (kg)/height (m)2), was associated with poorer overall survival and disease-free survival. Five-year survival rates were 86.5%, 83.8%, and 80.1% for subjects whose BMIs were <23.0, 23.0–24.9, and 
25.0, respectively (p = 0.02); the corresponding 5-year disease-free survival rates were 81.9%, 78.1%, and 76.6% (p = 0.05). The inverse association between BMI and survival persisted after adjustment for age at diagnosis and other known prognostic factors for breast cancer, including disease stage. The authors found neither waist:hip ratio nor waist circumference to be independently associated with overall survival or disease-free survival. These results suggest that excess weight may be an independent predictor of breast cancer survival among Chinese women.
body mass index; body weight; breast neoplasms; mortality; survival; waist-hip ratio
Abbreviations: BMI, body mass index; CI, confidence interval; ER, estrogen receptor; HR, hazard ratio; PR, progesterone receptor; TNM, tumor-node-metastasis