Comparison of 25-hydroxyvitamin D levels in breast cancer patients and control group: a cross-sectional study

Abstract

To assess serum vitamin D levels in patients with breast cancer and compare them against control patients without the disease, testing the hypothesis that patients with breast cancer have lower serum levels of the hormone than patients without the cancer. A total of 101 treatment-naïve patients diagnosed with breast cancer at the Mastology Outpatient Clinic of the Department of Obstetrics and Gynecology of the Irmandade da Santa Casa de São Paulo (ISCMSP), and 100 control patients without the disease at the Endocrinologic Gynecology Outpatient Clinic of the same institution were selected. Serum vitamin D levels for the two groups were compared. Mean serum vitamin D level was 23.85 ng/dL in the breast cancer group versus 28.19 ng/dL in the control group, where this difference proved statistically significant on Student´s t-test (p=0.002). Patient age was a confounding bias, where no correlation between serum level and age was evident on the scatter plot. Patients with breast cancer had lower serum Vitamin D levels than patients without the cancer. However, longitudinal studies should be conducted to determine whether a causal relationship exists between these variables.