Bone Abstracts

Objective: Biochemical assessment of teenage patients with adolescent idiopathic scoliosis (AIS).

Methods: Blood sampling from 120 patients with AIS aged 12–17 years. The patients all had significant scoliosis and blood samples were taken a few days or weeks before they underwent scoliosis surgery. Serum 25-hydroxy-vitamin D (25-OHD), calcium, phosphate, alkaline phosphatase and parathyroid hormone (PTH) were measured. Patients with a 25-OHD level below 25 nmol/l were classified as deficient in line with current UK guidance.

Results: The 25-OHD levels ranged between 8 and 150 nmol/l. The median level was 45 nmol/l. The mean level was 51 nmol/l (S.D.=28). 21 patients (17%) were vitamin D deficient, 47 patients (39%) were vitamin D insufficient meaning that 56% of the AIS patients had inadequate vitamin D levels.

PTH was significantly higher for individuals with vitamin D below 50 nmol/l when compared with individuals with vitamin D above 50 nmol/l (one-way ANOVA P<0.001).

Conclusion: Vitamin D deficiency is common among patients with AIS. Both vitamin D deficiency and insufficiency were associated with higher PTH levels in this population indicating that metabolic bone disease may play a role in the aetiology of this scoliosis. Patients should be assessed and treated for vitamin D Deficiency before scoliosis surgery.