A six years longitudinal cohort study on the changes in bone density and bone quality up to peak bone mass in adolescent idiopathic scoliosis (AIS) with and without 2 years of Calcium and Vit-D supplementation

Abstract

Adolescent idiopathic scoliosis (AIS) is associated with osteopenia which could persist into adulthood affecting attainment of Peak Bone Mass thus resulting in osteoporosis in late adulthood. We previously reported a randomized double-blinded placebo-controlled trial(the Cal study) showing significant bone health improvement with 2-year calcium(Ca)+Vit-D supplementation for AIS girls. This study addressed the important issue whether bone health improvement from the initial 2-year Ca+Vit-D supplementation could persist as subjects approached towards Peak Bone Mass at 6-year ie after 4-year of supplement discontinuation. This was an extension of the Cal study on AIS girls (11–14 years old, mean age=12.9 years, Tanner stage<IV) with femoral neck aBMD Z-score<0 and Cobb angle≥15∘. 330 subjects were randomized to Group1(placebo), Group2(600mgCa+400-IU-Vit-D3/day) or Group3(600mgCa+800-IU-Vit-D3/day) for 2-year supplementation after which supplementation was stopped. Investigations at baseline, 2-year and 6-year included High-resolution Peripheral Quantitative Computed Tomography(HR-pQCT) at distal radius and Dual Energy X-ray Absorptiometry(DXA) at both hips. 270(81.8%) subjects completed 2-year supplementation when changes in left femoral neck aBMD, trabecular vBMD, Trabecular BV/TV, Trabecular Number and Trabecular Separation indicated significant bone health improvement with Ca+Vit-D supplementation(p<0.05). At 6-year(mean age=19.2 years), no between-group difference on bone parameters was noted except increase in Cortical Thickness being greater only in Group3 than in Group1. After 4-year supplement discontinuation, the treatment effect from the initial 2-year supplementation mostly dissipated indicating the need of continued supplementation in AIS girls to sustain therapeutic improvement on bone health as subjects approach towards Peak Bone Mass.