There is an association between adolescent idiopathic scoliosis (AIS) and low bone mass which has been reported to be a significant prognostic factor for curve progression. Given that dietary calcium (Ca) intake and serum Vit-D levels were also low in AIS, we therefore propose a randomized double-blinded placebo-controlled trial to evaluate if daily [500mg Ca + 800 IU Vit-D] can improve bone health and prevent curve progression in AIS. Immature AIS girls with Cobb angle 10-20 degrees will be randomized either to the Treatment or Placebo group with 3-year of treatment. The main outcome measures for evaluation for those who have completed the 3-year treatment and have reached skeletal maturity at the end of 3-year treatment include: (1) percentage of patients with increase in Cobb angle≥6 degrees and (2) percentage of patients who require bracing. Bone measurements using advanced image acquisition technology(HR-pQCT) to assess bone health will also be evaluated.

This study investigates if calcium (Ca) plus Vitamin D (Vit-D) supplementation can prevent curve progression and improve bone health in early Adolescent Idiopathic Scoliosis (AIS) during pubertal growth.

AIS is a prevalent three-dimensional spinal deformity mainly affecting girls at puberty. It can lead to serious complications including spine degeneration, cardiopulmonary compromise, grossly deformed torso and psychosocial disorders. Current treatments are far from being satisfactory, with bracing being lengthy and physically demanding and surgery being a major invasive procedure.

There is an association between AIS and low bone mass which has been reported to be a significant prognostic factor for curve progression. Given that dietary calcium intake and serum Vit-D levels were also low in AIS, we therefore propose a randomized double-blinded placebo-controlled trial to evaluate if daily [500mg Ca + 800 IU Vit-D] can improve bone health and prevent curve progression. Immature AIS girls with Cobb angle 10-20 degrees will be randomized either to the Treatment or Placebo group with 3-year of treatment. The main outcome measures for evaluation for those who have completed the 3-year treatment and have reached skeletal maturity at the end of 3-year treatment include: (1) percentage of patients with increase in Cobb angle≥6 degrees and (2) percentage of patients who require bracing. Bone measurements using advanced image acquisition technology (HR-pQCT) to assess bone health will also be evaluated.

Inclusion Criteria:

1. girls with diagnosis of AIS confirmed after detailed clinical and radiological assessment and
2. between 10 to 14 years old and
3. Risser between 0 to 2 and
4. pre-menarche or < 1 year post-menarche and
5. Cobb angle between 10° to 20 ° and
6. no prior bracing or other treatment for scoliosis and
7. no prior treatment for bone health

Exclusion Criteria:

1. scoliosis with any known etiology such as congenital scoliosis, neuromuscular scoliosis, scoliosis of metabolic etiology, scoliosis with skeletal dysplasia or

2. patients with known endocrine and connective tissue abnormalities, or

3. patients with eating disorders or gastrointestinal malabsorption disorders or any disorders that are known to affect calcium or bone metabolism or

4. prior treatment for bone health before being recruited into the study or

5. patient currently taking medication that affects bone metabolism eg steroid or

6. patient with contra-indications for calcium and Vit-D supplementation:

   1. history of hypersensitivity to the active or placebo tablets
   2. history of renal diseases and renal calculi (nephrolithiasis)
   3. diseases and/or conditions resulting in hypercalcaemia and/or hypercalciuria
   4. hypervitaminosis D