School of Social Development and Public Policy, Beijing Normal University, Beijing, China.
HealthPartners Institute, Minneapolis, Minnesota.
Department of Applied Health Science, School of Public Health, Indiana University Bloomington, Bloomington, Indiana.
Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
Albert Einstein College of Medicine, Bronx, New York.
Veterans Affairs Palo Alto Health Care System, Palo Alto, California.
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California.
Department of Social Sciences and Health Policy, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina.
Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California.
Division of Research, Kaiser Permanente, Oakland, California.
Department of Public Health Sciences, University of California Davis, Davis, California.
Department of Family, Population, and Preventive Medicine, Stony Brook University School of Medicine, Stony Brook, New York.
Memorial Cancer Institute, Memorial Health Care System, Florida International University, Hollywood, Florida.
Department of Epidemiology and Biostatistics, School of Public Health, Indiana University Bloomington, Bloomington, Indiana.
Few previous studies investigating depression before the diagnosis of breast cancer and breast cancer-specific mortality have examined depression measured at more than 1 time point. This study investigated the effect of depression (combining depressive symptoms alone with antidepressant use) measured at 2 time points before the diagnosis of breast cancer on all-cause mortality and breast cancer-specific mortality among older postmenopausal women.
A large prospective cohort, the Women's Health Initiative, was used. The study included 3095 women with incident breast cancer who had measures of depressive symptoms and antidepressant use before their diagnosis at the baseline and at year 3. Multivariate Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) between depression at the baseline, depression at year 3, and combinations of depression at these time points and all-cause mortality and breast cancer-specific mortality.
Depression at year 3 before a breast cancer diagnosis was associated with higher all-cause mortality after adjustments for multiple covariates (HR, 1.35; 95% confidence interval [CI], 1.02-1.78). There was no statistically significant association of baseline depression and all-cause mortality or breast cancer-specific mortality whether or not depression was also present at year 3. In women with late-stage (regional- or distant-stage) breast cancer, newly developed depression at year 3 was significantly associated with both all-cause mortality (HR, 2.00; 95% CI, 1.13-3.56) and breast cancer-specific mortality (HR, 2.42; 95% CI, 1.24-4.70).
Women with newly developed depression before the diagnosis of breast cancer had a modestly but significantly increased risk for death from any cause and for death from breast cancer at a late stage.