Objectives: We have previously shown bone density tracks strongly from age 8 to 16¹. This longitudinal study aimed to describe tracking of bone measures between 8 and 25 years.

Material and Methods: A total of 197 participants were followed from age 16 to 25 and 99 participants from age 8 to 25. Outcomes measured were bone mineral content (BMC), bone mineral density (BMD) and bone mineral apparent density (BMAD) at the spine, hip and total body. Other factors measured were anthropometrics, inhaled corticosteroids (ICS) use, history of being breastfed,  fitness (PWC₁₇₀), lean mass (LM) and fat mass (FM) (by Dual-energy X-ray absorptiometry).  We examined the partial correlation between each bone measure at ages 8 and 25 and ages 16 and 25. Logistic regression was used to determine factors predicting deviation from tracking.

Result: There was moderate to strong tracking of bone measures from age 8 to 25 (correlation coefficient (r): males, 0.39-0.68; females, 0.59-0.88) and stronger tracking from age 16 to 25 (males, 0.81-0.86; females, 0.84-0.91) after adjustment for change in body size. Increased LM and PWC_170, strenuous exercise at age 16 were associated with a positive and increased FM with a negative deviation of spine and hip BMD from age 16 to 25. LM and FM change was associated with deviation from tracking from age 8 to 25 in males.

Conclusion:  DXA measures track from childhood to young adulthood, especially in females. Males appear to have greater likelihood of deviating from tracking. Bone measures in early childhood could be used to predict people at higher risk of achieving low peak bone mass, potentially leading to osteoporosis in later life. Reducing body fat and improving fitness in childhood might be effective strategies to improve bone density in adulthood.