Vitamin D Supplementation Adjunct to Home-Based Electrical Stimulation Exercise Program Versus Passive Movement Training in Chronic SCI: Individual Results From Trial Under Accrual.

Background: Neurogenic osteoporosis as a result of bone demineralization is a well-known complication after spinal cord injury (SCI). Bone demineralization is a result of the inevitable mechanical unloading of paralyzed limbs and decreased skeletal muscle activity. Objectives: To determine the impact of a home-based electrical stimulation (ES)-induced exercise (Excs) protocol plus 2000 IU oral daily vitamin D (vit D) supplementation compared to passive movement training (PMT) plus 2000 IU oral daily vit D supplementation on bone microarchitectural properties as measured by magnetic resonance imaging (MRI), bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DXA), and biomarkers of bone formation and bone resorption in persons with chronic SCI. Methods: Six men with motor complete SCI ranging from C8 to T10 were randomized into either 9 months of vit D+ES-Excs or vit D+PMT groups. The vit D+ES-Excs group underwent daily supplementation of vit D with 4.5 months of neuromuscular electrical stimulation-resistance training (NMES-RT) followed by 4.5 months of functional electrical stimulation (FES) rowing, twice weekly, using a home-based training approach. MRI, DXA, and blood biomarkers were captured at the beginning of the study (baseline), 4.5 months (post-intervention 1), and 9 months after training (post-intervention 2). Results: The percentage changes indicated that 2 persons in the vit D+ES-Excs group showed decreases in trabecular spacing (28%) and increases in trabecular network (33%-49% at post-intervention 2). This was accompanied by attenuation of BMD loss at the pelvis (3.6%-7.7%), femoral necks (4.5%-8.4%), and knees (10.5%-18.7%). The vit D+ES-Excs group showed increases in leg (5.3%) to total body lean mass and decreases in biomarkers of bone resorption (7.0%-23.5%). Similar changes were not demonstrated following 9 months of vit D+PMT. Conclusion: Home-based training with 9 months of vit D+ES exercise demonstrated the safety and practicability in mitigating deleterious changes in bone health in persons with chronic SCI. This is concomitant with increased leg lean mass and decreased circulating biomarkers of bone resorption in persons with SCI.