Beyond recreational physical activity: examining occupational and household activity, transportation activity, and sedentary behavior in relation to postmenopausal breast cancer risk.
OBJECTIVE
We prospectively examined nonrecreational physical activity and sedentary behavior in relation to breast cancer risk among 97 039 postmenopausal women in the National Institutes of Health-AARP Diet and Health Study.


METHODS
We identified 2866 invasive and 570 in situ breast cancer cases recorded between 1996 and 2003 and used Cox proportional hazards regression to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs).


RESULTS
Routine activity during the day at work or at home that included heavy lifting or carrying versus mostly sitting was associated with reduced risk of invasive breast cancer (RR = 0.62; 95% CI = 0.42, 0.91; P(trend) = .024).


CONCLUSIONS
Routine activity during the day at work or home may be related to reduced invasive breast cancer risk. Domains outside of recreation time may be attractive targets for increasing physical activity and reducing sedentary behavior among postmenopausal women.
George
Stephanie M
SM
Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA. materess@mail.nih.gov
Irwin
Melinda L
ML
Matthews
Charles E
CE
Mayne
Susan T
ST
Gail
Mitchell H
MH
Moore
Steven C
SC
Albanes
Demetrius
D
Ballard-Barbash
Rachel
R
Hollenbeck
Albert R
AR
Schatzkin
Arthur
A
Leitzmann
Michael F
MF
D000367:Age Factors; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016001:Confidence Intervals; D015444:Exercise; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D017698:Postmenopause; D016016:Proportional Hazards Models; D011998:Recreation; D012306:Risk; D012307:Risk Factors; D057185:Sedentary Behavior; D013997:Time Factors; D014186:Transportation / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology; D017132:Workplace / Q000706:statistics & numerical data