Establishment of reference intervals for bone turnover markers in healthy Chinese older adults

Background: Reference ranges for bone turnover markers (BTMs) are still lacking in the healthy Chinese population. Aim: To establish reference intervals for BTMs and to investigate the correlations between BTMs and bone mineral density (BMD) in Chinese older adults. Subjects and methods: A community-based cross-sectional study was conducted among 2511 Chinese subjects aged over 50 yrs residing in Zhenjiang, Southeast China. Reference intervals for BTMs ( i.e. procollagen type I N-terminal propeptide, P1NP; ss cross-linked C-terminal telopeptide of type I collagen, ss- CTX) were calculated as the central 95% range of all measurements in Chinese older adults. Results: The reference intervals of P1NP, ss-CTX and P1NP/ss-CTX were 15.8-119.9 ng/ mL, 0.041-0.675 ng/mL and 49.9-1261.5 for females and 13.6-111.4 ng/mL, 0.038-0.627 ng/mL and 41.0-1269.1 for males, respectively. In the multiple linear regression analysis, only ss- CTX was negatively associated with BMD after adjusting for age and body mass index (BMI) in both sex-stratified groups (all p <.05). Conclusion: This study established age- and sex-specific reference intervals for BTMs in a large sample of healthy Chinese participants >= 50 and < 80 years of age and explored the correlations between BTMs and BMD, which provides an effective reference for the assessment of bone turnover in the clinical practice of osteoporosis.