Serum Procollagen Type I N-Terminal Propeptide and Osteocalcin Levels in Korean Children and Adolescents

PURPOSE: Bone markers can be useful for the diagnosis and treatment of skeletal diseases in children and adolescents. Owing to high skeletal growth velocity and rapid bone turnover, children and adolescents have higher bone marker levels than adults. Thus, a valid age- and sex-specific reference should be established for pediatric populations living in similar environments. We aimed to assess the associations of procollagen type I N-terminal propeptide (P1NP) and osteocalcin with age and sex in a group of healthy Korean children and adolescents. MATERIALS AND METHODS: The participants (290 boys and 290 girls, age range 0–18 years) were Korean outpatients. Serum P1NP and osteocalcin levels were measured in control materials and patient samples by electrochemiluminescence immunoassay using an automated Cobas e411 analyzer. RESULTS: Significant age-dependent variations in bone marker levels were observed in both sexes (p<0.001). The highest P1NP levels were observed during the first year of life; thereafter, levels decreased until puberty. There was no postnatal peak for osteocalcin; however, its levels remained higher than the adult reference range throughout childhood. Significant differences were observed between boys and girls (p<0.05), especially between the ages of 12 and 17 years. Cobas e411 results for P1NP showed satisfactory precision and linearity. CONCLUSION: We established reference data for P1NP and osteocalcin levels in healthy Korean children and adolescents, as the first and only study of these parameters in pre-adulthood in Korea. Cobas e411-quantified bone markers may be useful for determining bone metabolism indices.