From July, 2018 to December, 2019, totally 135 patients with spinal cord injury were enrolled. They were assessed with American Spinal Injury Association Impairment Scale (AIS). β-collagen type I C-terminal telopeptide (β-CTX), total N-terminal propeptide of type I precollagen (TP1NP), 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH), serum calcium and serum phosphorus were measured. The level of TP1NP, β-CTX, 25(OH)D and PTH among clinical characteristics (gender, age, disease course, AIS grade and so on) were analyzed.

The levels of β-CTX and 25(OH)D were lower in women than in men (|t| > 2.044, P < 0.01). There was difference in the level of 25(OH)D among different ages (F = 3.156, P < 0.05). The levels of β-CTX and TP1NP increased in the first four months after spinal cord injury, and decreased then; while the level of PTH decreased in the first four months, and increased then (P < 0.001). The level of β-CTX was lower in patients of AIS D than in patients of AIS A and C (t >2.679, P < 0.05). The level of TP1NP was higher in paraplegics than in quadriplegics (Z = -2.035, P < 0.05). The level of β-CTX was higher in patients with fractures or surgeries involving bone than in patients without fractures or surgeries involving bone (t = 2.169, P < 0.05). There was no difference in all the bone metabolism markers between patients with and without lower extremity motor function (t < 0.839, Z < 1.822, P > 0.05). The ratio of 25(OH)D deficience was 85.19%.

Bone conversion was active in the first four months after spinal cord injury, and decreased gradually then, which may be related to fractures of spine or surgeries involving spine after injury. The effect of spinal cord injury on bone metabolism markers is not clear. Most of patients with spinal cord injury were lack of vitamin D.