title: Circulating 25-hydroxyvitamin D and postmenopausal breast cancer survival: Influence of tumor characteristics and lifestyle factors?
abstract: We previously reported that lower post-diagnostic circulating 25-hydroxyvitamin D [25(OH)D] concentrations were associated with higher risk of overall mortality and distant disease in stage I-IV postmenopausal breast cancer survivors. This association was now re-examined in an extended dataset to investigate potential effect modification by tumor characteristics and lifestyle factors. A prospective cohort study was conducted in Germany including 2,177 incident stage I-IV postmenopausal breast cancer patients aged 50-74 years. Patients were diagnosed between 2001 and 2005 and median follow-up time was 5.3 years. Cox proportional hazards models were stratified by age at diagnosis, study center and season of blood collection and adjusted for other prognostic factors. A meta-analysis of studies on circulating 25(OH)D and mortality in breast cancer patients was performed to summarize evidence. Lower concentrations of 25(OH)D were significantly associated with higher risk of overall mortality [hazard ratio (HR) lowest vs. highest tertile = 1.86; 95% confidence interval (CI): 1.22, 2.82; p-trend = 0.002] and distant disease (HR = 1.76; 95% CI: 1.24, 2.49; p-trend = 0.003) in stage I-IIIa but not in stage IIIb-IV breast cancer patients. No significant interaction by lifestyle factors was observed (all p-interaction > 0.05). The meta-analysis yielded significant associations with overall and breast cancer-specific mortality (lowest vs. highest quantile: HR = 1.52; 95% CI: 1.22, 1.88 and HR = 1.74; 95% CI: 1.23, 2.40, respectively). In conclusion, post-diagnostic circulating 25(OH)D concentrations were associated with overall mortality and distant disease in stage I-IIIa postmenopausal breast cancer patients. This association was not strongly modified by lifestyle factors.
authors.affiliation: Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Health Evidence, Radboud university medical center, Nijmegen, The Netherlands.
authors.forename: Alina
authors.initials: A
authors.lastname: Vrieling
authors.forename: Petra
authors.initials: P
authors.lastname: Seibold
authors.forename: Theron S
authors.initials: TS
authors.lastname: Johnson
authors.forename: Judith
authors.initials: J
authors.lastname: Heinz
authors.forename: Nadia
authors.initials: N
authors.lastname: Obi
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Dieter
authors.initials: D
authors.lastname: Flesch-Janys
authors.forename: Jenny
authors.initials: J
authors.lastname: Chang-Claude
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000097:blood* / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009367:Neoplasm Staging; D017698:Postmenopause / Q000097:blood; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D013534:Survival; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25(OH)D; breast neoplasms; mortality; recurrence; vitamin D