Reference intervals in Danish children and adolescents for bone turnover markers carboxy-terminal cross-linked telopeptide of type I collagen (?-CTX), pro-collagen type I N-terminal propeptide (PINP), osteocalcin (OC) and bone-specific alkaline phosphatase (bone ALP)

Bone turnover markers (BTM) are gaining ground in clinical practice but to fully use their potential there is a need for establishing valid reference intervals (RI). Consequently, the purpose of study was establish general RI as well suggested carboxy-terminal cross-linked telopeptide type I collagen (?-CTX), pro-collagen N-terminal propeptide (PINP), osteocalcin (OC) and bone-specific alkaline phosphatase (bone ALP) children adolescents. BTM were measured on Danish adolescents participating CHAMPS-study DK. A total 762 participants included (8–18 years, 50.4% girls) contributing 1410 visits. The calculated based 2-years age spans. Participants with biochemical signs metabolic bone disease excluded. differences between groups clearly reflect changes growth an initial increase BTM, greatest boys, subsequent decrease most pronounced girls. ?-CTX PINP affected by these changes, compared OC ALP. 95% vitamin D insufficiency no which did not markedly alter RI. ?-CTX, PINP, ALP varies sex. resorption formation processes mostly changes. We suggest set clinically applicable four heighten usefulness generalizability