Bone Abstracts

Introduction: The effect of vitamin D± calcium supplementation in children has traditionally been assessed using growth parameters, biochemical markers and radiographs.

Objectives: To evaluate the utility of Bone Health Index (BHI), obtained using automated hand radiogrammetry, in assessing treatment effect in children participating in a vitamin D supplementation trial.

Methods: In this double-blind placebo-controlled trial, Afghan children (n=3,046) aged 1 to 11 months were randomised to receive six doses of oral vitamin D3 (100,000 IU) or placebo every three months for 18 months. Main outcome variables included 25-hydroxyvitamin D (25OHD), dietary calcium, growth and Thacher rickets severity scores. 25OHD was measured in 120 random subjects (60 per group) at 5 time points. Of the 641 knee and wrist radiographs obtained from a random subset at study completion, 565 wrist radiographs were available for BHI assessment using BoneXpert version 3.0. Groups were compared using linear regression adjusting for covariates where appropriate.

Results: 92% (522, male=291) of the images were analysable. The placebo (n=258) and vitamin D (n=264) groups had similar demographics at baseline. Three months after treatment end (in summer months), placebo and vitamin D groups had comparable 25OHD levels (median 47.5 (40.5 to 55.6) nmol/l vs 50.9 (45.1 to 57.4) nmol/l, P=0.2), rickets prevalence (Thacher score >1.5, n=12 each), height velocity (10.8±3.1 vs 10.5±3.0 cm/year, P=0.47) and height z scores (−2.1±1.1 vs −2.1±1.0, P=0.60). Afghan children had a lower mean BHI SDS (−0.35 males, −0.26 female) compared to zero (healthy French reference). There was no significant difference in BHI SDS between placebo and vitamin D groups (−0.30 vs −0.31; P=0.81), or between children with and without rickets (−0.64 vs −0.30; P=0.70). When adjusted for height z score, BHI SDS correlated positively with calcium intake (r=0.67, P<0.05). The correlation between BHI SDS and Thacher score was not significant.

Conclusion: Both cohorts were, by enlarge, vitamin D sufficient at study completion and did not differ in BHI SDS or Thacher score. Our data indicate that metacarpal geometry is associated with dietary calcium intake.

Disclosure: The authors declared no competing interests.