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Efficacy of Vitamin D3 Supplementation in Elevating Circulating 25(OH)D Concentration in Individuals With Chronic Spinal Cord Injury (VitD-SCI): Evidence From a Randomized, Double-Blind, Placebo-Controlled Trial.

  • 2025-01
  • Topics in spinal cord injury rehabilitation 31(4)
    • Anneke Hertig-Godeschalk
    • Martin W G Brinkhof
    • Claudio Perret
    • Anke Scheel-Sailer
    • Joelle L Flueck

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 42
Population
42 individuals living with SCI for at least 3 years and who had insufficient 25(OH)D levels at baseline (7 female, 35 male; age 48 ± 10 years; 32 with paraplegia, 10 with tetraplegia)
Methods
12-month randomized, double-blind, placebo-controlled, superiority clinical trial; participants randomly assigned to placebo, MD intervention (24,000 IU D3 once every 4 weeks), or HD intervention (24,000 IU D3 once every 2 weeks)
Blinding
Double-blind
Duration
12 months

Background

Individuals with spinal cord injury (SCI) are at increased risk for insufficient 25(OH)D levels and associated adverse health outcomes, highlighting the need for vitamin D supplementation. However, the optimal dosing strategy for vitamin D supplementation in this population remains unclear.

Objectives

To evaluate the efficacy of medium-dose (MD) and high-dose (HD) vitamin D3 supplementation in raising 25(OH)D levels above the sufficiency threshold of 75 nmol/L in individuals with SCI.

Methods

A 12-month randomized, double-blind, placebo-controlled, superiority clinical trial was conducted in 42 individuals living with SCI for at least 3 years and who had insufficient 25(OH)D levels at baseline. Participants (7 female, 35 male; age 48 ± 10 years; 32 with paraplegia, 10 with tetraplegia) were randomly assigned to the placebo, MD intervention (24,000 IU D3 once every 4 weeks), or HD intervention (24,000 IU D3 once every 2 weeks) group. Baseline 25(OH)D levels (43 ± 16 nmol/L) did not differ between intervention groups (P = .8).

Results

Supplementation was well tolerated, and 25(OH)D levels remained well below the excess threshold. A dose-response effect on 25(OH)D levels was observed [F(2, 40) = 8.21, P < .001]. In the HD group, 46% of the participants reached sufficient levels. Participants having an incomplete lesion, higher baseline 25(OH)D levels, lower body mass index, supplementation during summer, autumn, or winter, or higher sun scores were more likely to reach sufficient 25(OH)D levels.

Conclusion

Vitamin D3 supplementation effectively increased 25(OH)D concentration to sufficient levels in participants with specific characteristics. Higher supplementation doses are needed to successfully increase 25(OH)D levels in all individuals with chronic SCI.

Research Insights

  • Vitamin D3→Elevated Circulating 25-Hydroxyvitamin D Level

    A dose-response effect on 25(OH)D levels was observed [F(2, 40) = 8.21, P < .001]. In the HD group, 46% of the participants reached sufficient levels.

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    24,000 IU once every 4 weeks (medium-dose) or 24,000 IU once every 2 weeks (high-dose)
  • Vitamin D3→Reduced Risk of Insufficient 25-Hydroxyvitamin D Level

    Vitamin D3 supplementation effectively increased 25(OH)D concentration to sufficient levels in participants with specific characteristics.

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    24,000 IU once every 4 weeks (medium-dose) or 24,000 IU once every 2 weeks (high-dose)

Adverse Events Reported

  • Vitamin D3→Overall tolerability

    Supplementation was well tolerated

    Finding
    Reported
  • Vitamin D3→excess 25(OH)D levels

    25(OH)D levels remained well below the excess threshold

    Finding
    Reported
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