Bone Abstracts

Objectives: Bone mass development in childhood and adolescence is crucial for peak bone mass (PBM) and low PBM may lead to osteoporosis later in life. The stability of bone mineral status through childhood and adolescence is known as tracking. The objective of this study is to determine the degree of tracking according to bone mass from pre-puberty into puberty in healthy Danish children.

Methods: 190 healthy Danish children (97 boys) with mean age 9.25 years (range 8.0–11.1 years) at baseline (2008) were followed for 7 years. Whole body DXA-scan and anthropometric measurements were performed three times in 2008, 2010 and 2015 respectively. Children were aged 14–17 years at the last follow-up and all were pubertal according to self-assessed tanner-stage. Z-scores were calculated for all three bone parameters (Total Body Less Head (TBLH) Bone Mineral Content (BMC), TBLH Bone Mineral Density (BMD) and TBLH Bone Area (BA)) adjusted for sex and age.

Results: We found the correlation between TBLH BMC Z-score at baseline and at the last follow up to be 0.79 (CI 0.73–0.84). The correlation between Z-score TBLH BMD and TBLH BA were comparable (BMD 0.77 (CI 0.71;0.82) and BA 0.81 (CI 0.75;0.85)). For TBLH BMC and BMD we found a higher correlation coefficient for girls than boys (ex. TBLH BMC 2008–2015 girls: 0.86 (CI 0.79;0.90), boys: 0.71 (CI 0.60;0.80)). Dividing the participants into quintiles depending on Z-scores in 2008 respectively 2015 we found that 85–87% were in the same quintile or the neighbour quintile at follow up. No one moved from the lowest to the highest quintile or opposite.

Conclusion: We found a high degree of tracking in bone mass (TBLH BMC, BMD and BA) in children from 8 to 17 years. The strong tracking may be useful in early identification of individuals at risk of osteoporosis later in life.

The study has been supported by the Danish Foundation TrygFonden

Disclosure: The authors declared no competing interests.