Age related changes in CTX type bone biomarkers are differently affected by calcium status

Abstract

The influence of Calcium nutritional status (CaS) on biomarkers (BM) of normal bone development became recently recognized as a vacancy area in paediatric research. In this study a comparative analysis of the influence of CaS on the age‐linked changes of two different types of CTX markers was afforded. Basal urine samples of 160, both sex, healthy children 6 to 9 years old, normal according to body mass index (BMI by NCHS), were collected. CTXs α and βwere determined by ELISA (Nordic Bioscience Diagnostic, Denmark); calcium/creatinine ratio (Ca/C) was measured as estimator of Ca status: <0, 07 deficient (D); 0,07–0,15, adequate (A); >0,15 high (H). Analyzed as a function of age, and grouping data according CaS, neither significant influence of age nor of CaS was detected over βCTX along the frame of ages of the study. However, CaS modified α CTX evolution so that the although changes linked to age were not founded in D, the decreasing in values with age was similar in A and H groups. The slope of the curves αCTX vs. age was very similar for both (y= −1,6071x + 50,214) but the correlation coefficients(R2) were 0,5432 and 0,9643 respectively. Both CTX molecules,αα‐CTX and ββ‐CTX‐, reflect bone metabolic activity and bone remodelling but only the new biomarker &[alpha&[alpha]‐CTX responds to Ca status and appears appropriate for studies related to bone problems due to calcium inadequacy in paediatric patients.