Relationship Between Vitamin D Status, Pain Severity, and Functional Disability in Chronic Low Back Pain

Background Chronic low back pain is a leading cause of disability worldwide and is frequently categorized as a chronic non-specific musculoskeletal condition. Vitamin D deficiency is highly prevalent in the Indian population and has been postulated to contribute to musculoskeletal pain and functional impairment, although existing evidence remains inconsistent and inconclusive. Objectives The primary objective of this study was to evaluate the relationship between serum vitamin D levels and chronic low back pain. Secondary objectives included assessment of the association between serum vitamin D levels, pain severity, and functional disability among affected patients. Methods This was a hospital-based observational cross-sectional study conducted at a single tertiary care center. Adult patients presenting with chronic low back pain of more than 12 weeks' duration were enrolled after meeting predefined inclusion and exclusion criteria. Serum 25-hydroxyvitamin D levels were measured and categorized according to standard reference ranges. Pain severity was assessed using the Numeric Pain Rating Scale, and functional disability was evaluated using the modified Oswestry Disability Questionnaire. Statistical analysis was performed to determine associations between vitamin D status, pain intensity, and functional disability, with significance set at an appropriate confidence level. Results A high prevalence of vitamin D deficiency and insufficiency was observed among patients with chronic low back pain. Lower serum vitamin D levels were significantly associated with increased pain severity and higher disability scores. Patients with deficient vitamin D levels demonstrated greater functional impairment compared to those with sufficient levels. No statistically significant correlations were identified between serum vitamin D concentration, pain intensity, and functional disability scores. Conclusions Vitamin D deficiency is common among patients with chronic low back pain and is significantly associated with greater pain severity and functional disability. These findings suggest that assessment of vitamin D status may be clinically relevant in the evaluation of patients presenting with chronic low back pain, particularly in regions with a high prevalence of hypovitaminosis D.