Contribution of bone turnover markers to bone mass in pubertal boys and girls

Background and aims: The association between bone turnover markers and bone mass in adolescence is not clear. We aimed to evaluate the associations between bone turnover markers and bone mineral content (BMC), density (BMD) and area (BMA). Subjects: A total of 56 adolescents (25 boys, 12.5-17.5 years) participated in the study. Methods: Bone mass and physical activity (PA) were measured using dual energy X-ray absorptiometry and accelerometers. Osteocalcin and amino-terminal propeptide of type I procollagen (PINP), as markers of bone formation, and beta-isomer of the C-terminal telopeptide of type I collagen, as marker of bone resorption were also measured. Sexual maturation, weight, height and average PA were considered as confounders. Results: Positive correlations (Pearson) were observed among the three bone turnover markers (r=0.7-0.9). Stepwise multiple linear regression analyses showed that PINP was strong and negatively associated with BMC, BMD and BMA in girls, explaining 24.9% of the variance in BMC, 25.6% in BMD and 16.3% in BMA. Conclusion: PINP is a strong predictor of bone related variables in pubertal girls.