Low levels of vitamin D appear to be associated with worse survival in women with breast cancer.
Association of Serum Level of Vitamin D at Diagnosis With Breast Cancer Survival: A Case-Cohort Analysis in the Pathways Study
Authors: Yao, S. et. al.
Source: JAMA Oncol, doi:10.1001/jamaoncol.2016.4188
Many studies have evaluated the links between serum levels of vitamin D (25-hydroxyvitamin D, or 25OHD) and breast cancer outcomes. The results have been inconsistent. This group sought to determine associations between 25OHD levels and breast cancer features and outcomes.
The Kaiser Permanente Northern California system oversees a database of women who are being evaluated over time to study factors associated with breast cancer diagnosis and survival. Subjects from this database were chosen for the study. Women who agreed to participate provided blood samples for 25OHD soon after enrollment. There were over 1600 subjects. They were followed regularly for 8 years. Serum 25OHD levels were evaluated and links to breast cancer features and outcomes were investigated.
Lower serum 25OHD levels were associated with higher body mass index (BMI), sedentary lifestyle, African American ethnicity, Hispanic ethnicity, cigarette smoking and younger age. Higher 25OHD levels were associated with lower breast cancer stage. Higher 25OHD levels were also associated with superior overall survival. Overall survival, recurrence-free survival, breast cancer-specific survival and ipsilateral disease free survival were all significantly associated with higher 25OHD levels among premenopausal women.
The investigators demonstrated that serum vitamin D levels were associated with breast cancer stage and survival. However, they cautioned that serum 25OHD levels are affected by many things, including breast cancer and breast cancer therapies. Therefore, the assessment of a woman’s 25OHD level must be considered in light of environmental and physiological influences. Nonetheless, the study does contribute to the body of knowledge that low vitamin D levels are associated with poor breast cancer outcomes — specifically, in premenopausal women.