title: Multivitamin use and breast cancer outcomes in women with early-stage breast cancer: the Life After Cancer Epidemiology study.
abstract: Little is known about the relation of multivitamin use to breast cancer outcomes. 2,236 women diagnosed from 1997 to 2000 with early-stage breast cancer (Stage I ≥ 1 cm, II, or IIIA) were enrolled about 2 years post-diagnosis, primarily from the Kaiser Permanente Northern California Cancer Registry (83%). Multivitamin use pre-diagnosis and post-diagnosis was assessed via mailed questionnaire. Outcomes were ascertained yearly by self-report and verified by medical record review. Delayed-entry Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for sociodemographic, tumor, and lifestyle factors. Overall, 54 and 72% of the cohort reported using multivitamins pre- and post-diagnosis, respectively. A total of 380 recurrences, 212 breast cancer deaths, and 396 total deaths were confirmed. Compared to never use, multivitamin use after diagnosis was not associated with any outcome (recurrence HR = 0.92; 95% CI: 0.71, 1.20; total mortality HR = 0.92; 95% CI: 0.71, 1.19). Compared to never use, persistent use of multivitamins from pre- to post-diagnosis was associated with a non-significant decreased risk of recurrence (HR = 0.76; 95% CI: 0.54, 1.06) and total mortality (HR = 0.79; 95% CI: 0.56, 1.12). The protective associations were limited to women who had been treated by radiation only (P for trend = 0.048 and 0.083 for recurrence and total mortality, respectively) and both radiation and chemotherapy (P for trend = 0.015 and 0.095 for recurrence and total mortality, respectively). In stratified analyses, women who consistently used multivitamins before and after diagnosis and ate more fruits/vegetables (P for trend = 0.008) and were more physically active (P for trend = 0.034) had better overall survival. Multivitamin use along with practice of other health-promoting behaviors may be beneficial in improving breast cancer outcomes in select groups of survivors.
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, CA 94612, USA. Marilyn.L.Kwan@kp.org
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Kwan
authors.forename: Heather
authors.initials: H
authors.lastname: Greenlee
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Lee
authors.forename: Adrienne
authors.initials: A
authors.lastname: Castillo
authors.forename: Erica P
authors.initials: EP
authors.lastname: Gunderson
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Habel
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Kushi
authors.forename: Carol
authors.initials: C
authors.lastname: Sweeney
authors.forename: Emily K
authors.initials: EK
authors.lastname: Tam
authors.forename: Bette J
authors.initials: BJ
authors.lastname: Caan
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000401:mortality* / Q000473:pathology; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D009367:Neoplasm Staging; D012307:Risk Factors; D016019:Survival Analysis; D017741:Survivors; D014815:Vitamins
chemical_list: D014815:Vitamins