Body mass index before and after breast cancer diagnosis: associations with all-cause, breast cancer, and cardiovascular disease mortality.
BACKGROUND
Factors related to improving outcomes in breast cancer survivors are of increasing public health significance. We examined postdiagnosis weight change in relation to mortality risk in a cohort of breast cancer survivors.


METHODS
We analyzed data from a cohort of 3,993 women with ages 20 to 79 years living in New Hampshire, Massachusetts, or Wisconsin with invasive nonmetastatic breast cancers diagnosed in 1988 to 1999 identified through state registries. Participants completed a structured telephone interview 1 to 2 years after diagnosis and returned a mailed follow-up questionnaire in 1998 to 2001 that addressed postdiagnosis weight and other factors. Vital status information was obtained from the National Death Index through December 2005. Hazard ratios and 95% confidence intervals were estimated from Cox proportional hazards models and adjusted for prediagnosis weight, age, stage, smoking, physical activity, and other important covariates.


RESULTS
During an average 6.3 years of follow-up from the postdiagnosis questionnaire, we identified 421 total deaths, including 121 deaths from breast cancer and 95 deaths from cardiovascular disease. Increasing postdiagnosis weight gain and weight loss were each associated with greater all-cause mortality. Among women who gained weight after breast cancer diagnosis, each 5-kg gain was associated with a 12% increase in all-cause mortality (P = 0.004), a 13% increase in breast cancer-specific mortality (P = 0.01), and a 19% increase in cardiovascular disease mortality (P = 0.04). Associations with breast cancer mortality were not modified by prediagnosis menopausal status, cigarette smoking, or body mass index.


CONCLUSIONS
These findings suggest that efforts to minimize weight gain after a breast cancer diagnosis may improve survival.
Nichols
Hazel B
HB
Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. hnichols@jhsph.edu
Trentham-Dietz
Amy
A
Egan
Kathleen M
KM
Titus-Ernstoff
Linda
L
Holmes
Michelle D
MD
Bersch
Andrew J
AJ
Holick
Crystal N
CN
Hampton
John M
JM
Stampfer
Meir J
MJ
Willett
Walter C
WC
Newcomb
Polly A
PA
D015992:Body Mass Index; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000401:mortality*; D002318:Cardiovascular Diseases / Q000401:mortality*; D002423:Cause of Death; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009513:New Hampshire / Q000453:epidemiology; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D011795:Surveys and Questionnaires; D017741:Survivors; D014922:Wisconsin / Q000453:epidemiology