Past recreational physical activity, body size, and all-cause mortality following breast cancer diagnosis: results from the Breast Cancer Family Registry.
Few studies have considered the joint association of body mass index (BMI) and physical activity, two modifiable factors, with all-cause mortality after breast cancer diagnosis. Women diagnosed with invasive breast cancer (n = 4,153) between 1991 and 2000 were enrolled in the Breast Cancer Family Registry through population-based sampling in Northern California, USA; Ontario, Canada; and Melbourne and Sydney, Australia. During a median follow-up of 7.8 years, 725 deaths occurred. Baseline questionnaires assessed moderate and vigorous recreational physical activity and BMI prior to diagnosis. Associations with all-cause mortality were assessed using Cox proportional hazards regression, adjusting for established prognostic factors. Compared with no physical activity, any recreational activity during the 3 years prior to diagnosis was associated with a 34% lower risk of death [hazard ratio (HR) = 0.66, 95% confidence interval (CI): 0.51-0.85] for women with estrogen receptor (ER)-positive tumors, but not those with ER-negative tumors; this association did not appear to differ by race/ethnicity or BMI. Lifetime physical activity was not associated with all-cause mortality. BMI was positively associated with all-cause mortality for women diagnosed at age > or =50 years with ER-positive tumors (compared with normal-weight women, HR for overweight = 1.39, 95% CI: 0.90-2.15; HR for obese = 1.77, 95% CI: 1.11-2.82). BMI associations did not appear to differ by race/ethnicity. Our findings suggest that physical activity and BMI exert independent effects on overall mortality after breast cancer.
Keegan
Theresa H M
TH
Northern California Cancer Center, 2201 Walnut Ave, Suite 300, Fremont, CA 94536, USA. Theresa.keegan@nccc.org
Milne
Roger L
RL
Andrulis
Irene L
IL
Chang
Ellen T
ET
Sangaramoorthy
Meera
M
Phillips
Kelly-Anne
KA
Giles
Graham G
GG
Goodwin
Pamela J
PJ
Apicella
Carmel
C
Hopper
John L
JL
Whittemore
Alice S
AS
John
Esther M
EM
D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D015992:Body Mass Index; D049628:Body Size; D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000401:mortality* / Q000503:physiopathology; D002140:California / Q000453:epidemiology; D002648:Child; D015444:Exercise; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D016013:Likelihood Functions; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010375:Pedigree; D011379:Prognosis; D016016:Proportional Hazards Models; D011960:Receptors, Estrogen / Q000032:analysis; D011998:Recreation; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
D011960:Receptors, Estrogen