Acute Suppression of Bone Turnover With Calcium Infusion in Persons With Spinal Cord Injury

AbstractBackground: Some people with chronic spinal cord injury (SCI) have low vitamin D levels and secondary hyperparathyroidism.Objective: To determine whether, and to what extent, an acute calcium infusion decreased levels of N-telopeptide (NTx), a marker of osteoclastic activity, in individuals with chronic SCI.Study Design: Case series.Subjects: Eight men with chronic SCI. A relatively low serum 25 hydroxyvitamin D concentration (25[OH]D ≤20 ng/mL) and/or a high parathyroid hormone (PTH) (>55 pg/mL) was a prerequisite for study inclusion.Methods: Calcium gluconate bolus 0.025 mmol elemental calcium/kg over 20 minutes followed by a constant infusion of 0.025 mmol/kg per hour for 6 hours was infused; blood samples were collected every 2 hours for measurement of serum total calcium, creatinine, NTx, and PTH.Results: All results are expressed as means (± SDs). Baseline serum 25-hydroxyvitamin D level was 14.5 ± 3.5 ng/mL (range: 10.2-19.6 ng/mL); PTH, 70 ± 25 pg/mL (range: 37-100 pg/mL); and NTx, 21 ± 7 ...