Effectiveness of two vitamin D3 repletion protocols on the vitamin D status of adults with a recent spinal cord injury undergoing inpatient rehabilitation: a prospective case series

Abstract

Study design: Prospective case series.

Objectives: To assess the effectiveness and safety of two vitamin D₃ repletion protocols given to individuals with spinal cord injury (SCI).

Setting: Publicly-funded intensive inpatient rehabilitation center, Montreal, Canada.

Methods: Thirty adults with recent SCI complete or incomplete sensorimotor impairments were recruited upon admission from designated regional SCI trauma centers. Participants with serum 25OHD ≤ 30 nmol/L were given 10,000 IU of weekly and 1000 IU of daily vitamin D₃ for 36.8 ± 11.9 days (higher dose: HD). Subjects with serum 25OHD > 30 nmol/L received 1000 IU of daily vitamin D₃ for 38.2 ± 11.6 days (lower dose: LD). Outcomes were changes in 25OHD levels from baseline to the end of the study period and safety outcomes. Thresholds for vitamin D deficiency, insufficiency and sufficiency were: 25OHD levels ≤30 nmol/L, 30-74 nmol/L, and ≥75 nmol/L.

Results: At baseline, 34 and 66% of participants had serum 25OHD < 30 and >30 nmol/L. Both protocols induced a rise in serum 25OHD with a greater increase in the HD vs. LD regimen (31.4 [95% CI: 16.7, 46.0] vs. 11.7 nmol/L [95% CI: 2.2, 21.2]). None of the participants given the HD remained vitamin D deficient, but only one achieved vitamin D sufficiency. Nearly all individuals on the LD regimen remained vitamin D insufficient with only two reaching vitamin D sufficiency. No adverse effects were observed over the course of the supplementation.

Conclusions: Although 1000 IU of daily vitamin D₃ alone or in combination with weekly 10,000 IU for an average of 37.6 days increased serum 25OHD, they were unsuccessful in improving the impaired vitamin D status during inpatient rehabilitation of individuals with a recent SCI.

Fig. 1

Flowchart of participant selection and retention. The number of subjects at screening, study initiation, follow-up and analysis are presented

Fig. 2

a Serum 25-hydroxyvitamin D levels at baseline and at the end of the follow-up period. Individual 25OHD levels are represented by treatment group with the mean indicated by the straight gray line. The dotted line indicates the cut-point proposed for vitamin D sufficiency (75 nmol/L). Within-group comparisons were made by paired-t test. b Distribution of vitamin D status at baseline and at the end of the follow-up period in each treatment group. Black bar indicates vitamin D deficiency (serum 25OHD < 30 nmol/L); dashed bars indicate vitamin D insufficiency (serum 25OHD 30–74 nmol/L) and white bars indicate vitamin D sufficiency (serum 25OHD ≥ 75 nmol/L). Within-group comparisons were made by χ² test