Circulating 25‐hydroxyvitamin D and postmenopausal breast cancer survival: Influence of tumor characteristics and lifestyle factors?

• Published in: International journal of cancer Vol. 134; no. 12; pp. 2972 - 2983
• Main Authors: Vrieling, Alina, Seibold, Petra, Johnson, Theron S., Heinz, Judith, Obi, Nadia, Kaaks, Rudolf, Flesch‐Janys, Dieter, Chang‐Claude, Jenny
• Format: Journal Article
• Language: English
• Published: Hoboken, NJ Wiley-Blackwell 15.06.2014; Wiley Subscription Services, Inc
• Subjects: 25(OH)D; Aged; Biological and medical sciences; Breast cancer; breast neoplasms; Breast Neoplasms - blood; Breast Neoplasms - mortality; Cancer; Cohort Studies; Confidence intervals; Female; Germany - epidemiology; Gynecology. Andrology. Obstetrics; Humans; Life Style; Lifestyles; Mammary gland diseases; Medical prognosis; Medical research; Medical sciences; Middle Aged; Mortality; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Neoplasm Staging; Postmenopause - blood; Prospective Studies; recurrence; Risk; Risk Factors; Survival; Tumors; vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Women; Germany; Relapse; Breast disease; Steroid hormone; Mortality; Breast tumor; breast neoplasms; Calcitriol; Breast cancer; Malignant tumor; Epidemiology; Survival; recurrence; Mammary gland diseases; Cancerology; Vitamin D; Cholecalciferol(25-hydroxy); Postmenopause; 25(OH)D; Cancer; Life style; mortality; vitamin D
• ISSN: 0020-7136; 1097-0215; 1097-0215
• DOI: 10.1002/ijc.28628

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. What's new? Reduced circulating concentrations of 25‐hydroxyvitamin D may be associated with increased mortality among breast cancer patients. In this study, which examined data on 2,177 postmenopausal women with breast cancer, the association between 25‐hydroxyvitamin D and mortality was found to differ based on tumor characteristics. Lower post‐diagnostic circulating 25‐hydroxyvitamin D concentrations were associated with increased mortality in stage I‐IIIa patients but not in stage IIIb‐IV patients. In contrast, the association between 25‐hydroxyvitamin D and mortality did not strongly differ based on lifestyle factors.