title: Impact of very low physical activity, BMI, and comorbidities on mortality among breast cancer survivors.
abstract: The purpose of this study was to examine post-diagnosis BMI, very low physical activity, and comorbidities, as predictors of breast cancer-specific and all-cause mortality. Data from three female US breast cancer survivor cohorts were harmonized in the After Breast Cancer Pooling Project (n = 9513). Delayed entry Cox proportional hazards models were used to examine the impact of three post-diagnosis lifestyle factors: body mass index (BMI), select comorbidities (diabetes only, hypertension only, or both), and very low physical activity (defined as physical activity <1.5 MET h/week) in individual models and together in multivariate models for breast cancer and all-cause mortality. For breast cancer mortality, the individual lifestyle models demonstrated a significant association with very low physical activity but not with the selected comorbidities or BMI. In the model that included all three lifestyle variables, very low physical activity was associated with a 22 % increased risk of breast cancer mortality (HR 1.22, 95 % CI 1.05, 1.42). For all-cause mortality, the three individual models demonstrated significant associations for all three lifestyle predictors. In the combined model, the strength and significance of the association of comorbidities (both hypertension and diabetes versus neither: HR 2.16, 95 % CI 1.79, 2.60) and very low physical activity (HR 1.35, 95 % CI 1.22, 1.51) remained unchanged, but the association with obesity was completely attenuated. These data indicate that after active treatment, very low physical activity, consistent with a sedentary lifestyle (and comorbidities for all-cause mortality), may account for the increased risk of mortality, with higher BMI, that is seen in other studies.
authors: Cancer Prevention and Control Program, Division of Population Science, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, 92093-0901, USA.|Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA.
authors: Sandahl H
authors: SH
authors: Nelson
authors: Cancer Prevention and Control Program, Division of Population Science, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, 92093-0901, USA.|Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA.
authors: Catherine R
authors: CR
authors: Marinac
authors: Cancer Prevention and Control Program, Division of Population Science, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, 92093-0901, USA.|Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA.
authors: Ruth E
authors: RE
authors: Patterson
authors: Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
authors: Sarah J
authors: SJ
authors: Nechuta
authors: Cancer Prevention and Control Program, Division of Population Science, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, 92093-0901, USA.
authors: Shirley W
authors: SW
authors: Flatt
authors: Division of Research, Kaiser Permanente, Oakland, CA, USA.
authors: Bette J
authors: BJ
authors: Caan
authors: Division of Research, Kaiser Permanente, Oakland, CA, USA.
authors: Marilyn L
authors: ML
authors: Kwan
authors: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
authors: Elizabeth M
authors: EM
authors: Poole
authors: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.|Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
authors: Wendy Y
authors: WY
authors: Chen
authors: Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
authors: Xiao-ou
authors: XO
authors: Shu
authors: Cancer Prevention and Control Program, Division of Population Science, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, 92093-0901, USA. jppierce@ucsd.edu.|Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA. jppierce@ucsd.edu.
authors: John P
authors: JP
authors: Pierce
mesh_terms: D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D009765:Obesity / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D016016:Proportional Hazards Models; D012307:Risk Factors; D057185:Sedentary Behavior; D017741:Survivors
keywords: Body mass index; Diabetes; Lifestyle factors; Obesity; Sedentary behavior