Bone Abstracts

Aim: To evaluate progression of bone mineral density (BMD) and bone mineral content (BMC) during pubertal development and influence of body composition and vitamin D on BMD and BMC in children and adolescents.

Materials and methods: This cross-sectional study was part of an ongoing health survey of Delhi school children. Total 1905 apparently healthy school children (835 boys; and 1070 girls) in the age group of 6–17 years were studied. After brief history, tailored clinical examination and anthropometry, blood samples were collected for measurement of serum 25-hydroxy vitamin D (S.25VitD) and parathyroid hormone (iPTH). Whole body DXA scans were performed (GE Lunar Prodigy scanner). Fat mass index (FMI) was calculated.

Results: The mean age of subjects was 13.27±2.48 years while mean FMI was 5.59±3.1 kg/sqM. Vitamin D deficiency (VDD; S.25Vit D <20 ng/ml) was present in 96.8% subjects. BMD and BMC increased progressively with progression of puberty in both boys and girls but maximum gain was observed from pubertal stages 2 to 4 while no significant gain in BMD or BMC was seen between pubertal stages 4 and 5. Boys showed higher percentage rise in BMD from stages 1 to 5 in comparison to girls. FMI did not show any significant correlation with S.25VitD or iPTH but showed significant positive correlation with total body bone mineral content (TBMC; r=0.40, P≤0.001), lumber spine BMD (LSBMD; r=0.11, P≤0.001) and with femoral neck BMD (FNBMD; r=0.13, P≤0.001). Similarly, total lean mass also showed positive correlation with TBMC, LSBMD and FNBMD in all subjects as well in all pubertal groups. S.25VitD was also positively correlated with TBMC (r=0.13, P≤0.001), LSBMD (r=0.15, P≤0.001) and FNBMD (r=0.06, P=0.006).

Conclusion: BMD progressively increases during pubertal development with maximum gain occurring between pubertal stages 2 and 4 with non-significant change between stages 4–5.