ICCBH2017 Oral Communications (1) (26 abstracts)
1Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong, Hong Kong; 2SH Ho Scoliosis Research Laboratory, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong; 3Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, Hong Kong; 4The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
Objectives: Adolescent Idiopathic Scoliosis (AIS) is associated with low bone mass. This study aimed at evaluating the therapeutic effect and its determinants of Ca+Vit-D supplementation in improving bone strength and preventing curve progression in AIS.
Methods: This was a randomized double-blinded placebo-controlled trial recruiting AIS girls (1114 years old, Tanner stage<IV) with femoral neck BMDZ-scores<0 and Cobb angle≥15°. 330 subjects were randomized to Group 1 (placebo), Group 2 (600 mgCalcium+400 IUVit-D3/day) or Group 3 (600 mgCalcium+800 IUVit-D3/day) for 2-year treatment. Investigations at baseline and 2-year included: (1) Finite Element Analysis (FEA) on HR-pQCT at distal radius, (2)serum 25(OH)Vit-D assay and (3) dietary calcium intake. The SRS guideline was followed for the Latest Follow-up analysis on curve progression defined as Cobb increase≥6°. P-value<0.05 was considered statistically significant.
Results: 270 (81.8%) subjects completed the study. At 2-year, the increases in FEA parameters were significantly greater in the Treatment Group (Table1).
At the Latest Follow-up (N=132), 21·7% in Group 3 and 24·4% in Group 2 progressed as compared with 46·7% in Group 1 (P=0.012, 0.032). Within-group logistic regression analysis showed in Group 3, increase in FEA parameters of failure load and apparent modulus were significant protective factors against curve progression (P=0.043 & 0.034 respectively).
For those with baseline serum 25(OH)Vit-D≤50 nmol/l (N=103), 16.2% progressed in Group 3 as compared with 48.6% in Group 1 (P=0.003). For those with 25(OH)Vit-D>50 nmol/l (N=29), no difference on curve progression was noted. For those with baseline dietary calcium intake≤1000 mg/day (N=109), 19.0% progressed in Group 3 as compared with 54.3% in Group 1 (P=0.001). For those with calcium intake>1000 mg/day (N=23), no difference on curve progression was noted.
Changes from baseline to 2-year§ mean ± SD | p | ||||
Gp 1 N=91 | Gp 2 N=91 | Gp 3 N=88 | Gp 1 Vs Gp 2 | Gp 1 Vs Gp 3 | |
Serum 25(OH)VitD (nmol/l) # | 6.3 ± 15.3 | 20.4 ± 19.6 | 28.0 ± 23.3 | <0.001^ | <0.001^ |
Gp 1 | Gp 2 | Gp 3 | |||
N=83 | N=78 | N=72 | |||
FEA: stiffness (kN/mm) # | 13455 ± 4670 | 15786 ± 5701 | 16520 ± 5563 | 0.048^ | 0.001^ |
FEA: failure load (N) # | 533 ± 193 | 622 ± 243 | 658 ± 252 | 0.094 | 0.002^ |
FEA: apparent modulus (MPa) # | 465 ± 220 | 591 ± 353 | 588 ± 289 | 0.020^ | 0.028^ |
§: Changes from baseline to 2-year refers to the parameter at 2-year minus that at baseline. | |||||
#: P-value from ANCOVA ^: P-value < 0.05. |
Conclusion: The results of this study provide strong evidences that calcium+Vit-D supplementation can improve bone strength in AIS. Its therapeutic effect on preventing curve progression is correlated with increase in FEA parameters, low baseline 25(OH)Vit-D level and low baseline dietary calcium intake.
Funding Source Pfizer Inc (IIRGrant:WI174540). (ClinicalTrials.gov-Identifier: NCT01103115).
Disclosure: The authors declared no competing interests.