Association of serum vitamin D levels with clinical severity and recovery duration in cervical dizziness.

BACKGROUND

Cervical dizziness (CD) is associated with altered cervical musculoskeletal and proprioceptive input, leading to impaired sensorimotor integration and balance control. Vitamin D deficiency has been linked to musculoskeletal pain, muscle dysfunction, and impaired postural stability; however, its role in CD remains unclear.

METHODS

This prospective observational study included 210 patients diagnosed with CD. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured at baseline, and participants were categorized into deficiency (< 20 ng/mL), insufficiency (20-29 ng/mL), and sufficiency (≥ 30 ng/mL) groups. All patients received a standardized multimodal cervical rehabilitation program, with vitamin D supplementation provided to the deficient and insufficient groups. Clinical outcomes were assessed using the Neck Disability Index (NDI), Dizziness Handicap Inventory (DHI), and Vertigo Dizziness Imbalance questionnaires (VDI-SS and VDI-QOL). Associations between vitamin D levels, baseline symptom severity, and recovery duration were analyzed using correlation, multivariable regression, receiver operating characteristic (ROC) analysis, and partial least squares discriminant analysis (PLS-DA).

RESULTS

Lower serum 25(OH)D levels were significantly associated with higher baseline NDI, DHI, VDI-SS, and VDI-QOL scores (all p < 0.001), indicating greater symptom severity and functional impairment. Serum 25(OH)D levels showed a strong inverse correlation with recovery duration (rho = -0.77, p < 0.001) and remained associated with a longer recovery duration in multivariable linear regression. ROC analysis demonstrated high discriminatory performance for delayed recovery (AUC = 0.937), with an exploratory optimal threshold of ≤ 17 ng/mL. In exploratory PLS-DA, serum 25(OH)D contributed more to group separation than did age, sex, or BMI.

CONCLUSIONS

Lower serum vitamin D levels were associated with greater baseline clinical severity and longer recovery duration in patients with CD. These findings suggest that vitamin D status may be clinically relevant in the assessment of disease severity and recovery in this population. Further prospective controlled studies are required to clarify the clinical significance of this association.