Correlation between bone mineral density measured by peripheral and central dual energy X-ray absorptiometry in healthy Indian children and adolescents aged 10-18 years.

There are few large-scale studies on the utility of peripheral dual energy X-ray absorptiometry (pDXA) in children. As central dual energy X-ray absorptiometry (cDXA) equipment is not commonly available in the developing world, we assessed the correlation of bone mineral density (BMD) with cDXA and pDXA in children to determine the optimal Z-score thresholds of pDXA for predicting two predefined Z-score cutoffs (≤-1, ≤-2) of cDXA in 844 subjects (441 boys, 403 girls) aged 10-18 years. The BMD of antero-posterior lumbar spine (L1-L4), proximal femur and forearm was measured by cDXA, while the peripheral BMD of forearm and calcaneus was estimated using pDXA. The correlation was statistically significant at all sites (p<0.01). The coefficients ranged from 0.56 to 0.79 in boys and 0.17 to 0.32 in girls. A significant positive correlation was observed between BMD by pDXA and cDXA in Indian children, with a strong gender difference in both the extent of correlation and the ability of peripheral BMD to predict central BMD.