Bone loss and bone turnover in acute and chronic spinal cord injured patients

OBJECTIVE: To investigate bone loss and the rate of bone turnover in individuals with spinal cord injury (SCI), and to compare the results with those healthy controls.

METHODS: This cross-sectional, controlled study was performed between January and December 2005, in the Istanbul Physical Medicine and Rehabilitation Training Hospital, Istanbul, Turkey. Forty-eight patients with SCI were included in the study. The control group consisted of 47 age and sex matched healthy subjects. Bone density was measured at the proximal hip region by dual-energy X-ray absorptiometry. Serum levels of osteocalcin (OC) and C telopeptide of type 1 collagen (CTX) were measured.

RESULTS: Femur neck and femur total bone mineral density values in the SCI patients and control group were 0.894 (0.188), 0.911 (0.185), and 0.994 (0.116), 1.063 (0.132) (p<0.03, p<0.000). Serum levels of OC and CTX were significantly increased in patients (p<0.015, p<0.000). Femur bone density in both neck and total regions showed a significant decrease in the SCI patients with longer injury duration (p<0.001, p<0.000). Serum CTX levels were markedly elevated in the first year of SCI. However, serum OC level showed no difference for the injury duration.

CONCLUSION: Significant bone loss was found at the proximal hip in SCI patients. Serum biochemical markers were also significantly higher in the patient group than the healthy controls. The bone density was lower in the long-standing SCI patients, although serum CTX levels were higher in the first 12 months after injury.