Bone Abstracts

Objectives: To generate pediatric reference values for calcaneal bone mineral density (BMD) in healthy 2–10 years old Swedish children.

Methods: Dual energy X-ray absorptiometry (DXA) in combination with a laser measurement of the heel thickness, DXL Calscan (Demetech AB), measures bone mass in the calcaneus and an apparent density (BMAD) is calculated. Healthy, Swedish children were included. The left foot was scanned in 117, 2-year-old; 110, 4-year-old; and 107, 7-year-old children using the DXL technique. Half of the children were boys. More than 35% of the children from each age group were followed for another 2 years. Height and weight were determined annually and questionnaires concerning general health were completed at every visit.

Results: The mean BMD in the 2-year-old was 0.170±0.003 g/cm², in the 4-year-old 0.221±0.003 g/cm² and in the 7-year-old 0.296±0.005 g/cm². The 7-year-old girls had a significantly higher BMD than the boys (P=0.026) but there were no significant gender differences in the calcaneal BMD in 2- and 4-year-old. BMD was significantly correlated with age (P<0.001, r=0.78). A weaker correlation was found between BMAD and age (P<0.001, r=0.23). Based on the data from the 2-year follow-up; a total of 645 (328 girls/317 boys) measurements, reference curves (mean±2 S.D.) were produced for calcaneal BMD in girls and boys aged 2–10 years according to age and height.

Conclusion: Calcaneus can be an alternative for measurements when other bone mass measurement techniques are not possible to use. Gender differences are present in the calcaneal BMD at an early age. This study presents gender specific calcaneal BMD reference curves for children 2–10 years of age. These data will be valuable in future research and for evaluating the bone health in children with different disorders.