Vitamin D deficiency and its association with fatigue and quality of life in advanced cancer patients under palliative care: A cross-sectional study

Background: A normal vitamin D status is required for bones and muscles to maintain their function and structure, but it also contributes to the functional integrity of other multiple physiologic systems in the body. Aim: To assess the relationship of Vitamin D deficiency with health-related quality-of-life issues, fatigue, and physical functioning in advanced cancer patients. Design: This is a cross-sectional study. Patients/settings: Adults under palliative care, having a locally advanced or metastatic or inoperable solid cancer. Results: Among 30 patients in palliative care with advanced solid cancer, 90% were vitamin D deficient. Serum Vitamin D concentration was positively correlated with patient-reported absence of fatigue (s = 0.49), and physical and functional well-being (s = 0.44 and s = 0.41, respectively, p < 0.01). Fatigue was the symptom with the highest median impact on their lives and was the only one associated with serum vitamin D (p = 0.031), with lower fatigue in patients with vitamin D concentrations in the third tertile. There was no evidence of a direct association between health-related quality of life and vitamin D status. Conclusion: The 90% frequency of advanced cancer patients with vitamin D deficiency, together with the positive correlation of vitamin D status with the absence of fatigue and improved physical and functional well-being, points to vitamin D supplementation as a potential therapy to enhance the patient's quality of life.