Serum bone turnover markers were associated with bone mass in late prepuberty and early puberty.

Aim: To analyse the association between bone turnover markers and bone mass in children and young adults.

Methods: This descriptive study followed 132 children (68 boys/64 girls) from Malmö, Sweden, as controls in a school-based intervention study (2000-2017). Height, weight, Tanner stage and bone mass were measured annually from ages 8 to 15 years, with follow-ups at 19 and 23 years of age. Serum markers for bone formation (bone-specific alkaline phosphatase (bALP), N-terminal propeptide of collagen type 1 (PINP), osteocalcin) and resorption (C-terminal telopeptide crosslinks (CTX), tartrate-resistant acid phosphatase (TRAcP 5b)) were collected at ages 9.9 ± 0.6 (mean ± SD) (n = 78), 12.0 ± 0.6 (n = 64), 14.9 ± 0.8 (n = 52), 18.8 ± 0.3 (n = 34) and 23.3 ± 0.6 years (n = 56).

Results: Compared to girls, boys showed higher bone turnover markers at ages 15, 19 and 23 years (all p < 0.05). At 10 years of age (Tanner stage 1 and 2), bALP and TRAcP 5b correlated with current bone mass (adjusted for age and sex), while bALP, PINP, osteocalcin and CTX correlated with bone mass change over the next 2 years (adjusted for age, sex and interval) (all p < 0.05).

Conclusion: Bone turnover markers in early Tanner stages predicted both current bone mass and subsequent bone mass changes.