Low baseline vitamin D levels increase the risk of bone metastases among females with breast cancer - Hospital based cohort study.

ABSTRACT

BACKGROUND: Serum vitamin D (Vit-D) has been linked to the development of breast cancer (BC); however, their effect on pathological features and outcomes is undetermined. The purpose of this study was to examine the prognostic significance of baseline Vit-D levels and their effect on clinical outcomes. METHODS: We evaluated baseline serum Vit-D levels and baseline clinic-pathological features of female patients with non-metastatic BC between October 2018 and December 2019. A low Vit-D level was described as less than 30 nanogram per liter (ng/l). Patients were observed for a median of 24 months. To evaluate relationships between qualitative variables, the chi-square test was used. The Kaplan-Meier technique was used for survival analysis, and the log-rank test was used to compare the two survival curves. Correlation analysis was also used to examine the link between Vit-D levels and clinical outcomes. RESULTS: The eligibility criteria were fulfilled by 221 patients. The median age of onset was (50.7). The median Vit-D level was (23.1 ng/l) with a range of (4-46 ng/l). Approximately half of the patients (56.5%) had Vit-D levels < 30 ng/l, with HER2 positive and triple negative (TNBC) patients having a greater proportion of low Vit-D levels (p = <0.001). Patients with low baseline Vit-D levels had a larger tumor size, more positive lymph nodes, and were diagnosed at a later stage. Following follow-up, Vit-D deficiency was associated with a significantly increased risk of bone metastases (HR 3.37, 95% CI 1.32-8.59, p = 0.006), and Vit-D levels were significantly correlated with disease-free survival (DFS) and overall survival (OS) (r = 0.850, r = 0.573, p < 0.00, p < 0.001, respectively). CONCLUSIONS: Low serum Vit-D is associated with advanced stage and adverse characteristics. It is more prevalent in HER-2 positive and TNBC patients; it increases the chance of bone metastases, and has a significant correlation with DFS and OS.