Osteocalcin and its forms across the lifespan in adult men

Authors

Cassandra Smith
Sarah Voisin
Ahmed Al Saedi
Steven Phu
Tara Brennan-Speranza
Lewan Parker
Nir Eynon
Danielle Hiam
Xu Yan
David Scott
Lauren C. Blekkenhorst, Edith Cowan UniversityFollow
Joshua R. Lewis, Edith Cowan UniversityFollow
Ego Seeman
Elizabeth Byrnes
Leon Flicker
Gustavo Duque
Bu B. Yeap
Itamar Levinger

Document Type

Journal Article

Publication Title

Bone

Publisher

Elsevier

School

School of Medical and Health Sciences

RAS ID

31419

Comments

Smith, C., Voisin, S., Al Saedi, A., Phu, S., Brennan-Speranza, T., Parker, L., ... Levinger, I. (2020). Osteocalcin and its forms across the lifespan in adult men. Bone, 130, Article 115085. https://doi.org/10.1016/j.bone.2019.115085

Abstract

Purpose: Osteocalcin (OC), an osteoblast-specific secreted protein expressed by mature osteoblasts, is used in clinical practice and in research as a marker of bone turnover. The carboxylated (cOC) and undercarboxylated (ucOC) forms may have a different biological function but age-specific reference ranges for these components are not established. Given the different physiological roles, development of reference ranges may help to identify people at risk for bone disease. Methods: Blood was collected in the morning after an overnight fast from 236 adult men (18 to 92 years old) free of diabetes, antiresorptive, warfarin or glucocorticoid use. Serum was analyzed for total osteocalcin (tOC) and the ucOC fraction using the hydroxyapatite binding method. cOC, ucOC/tOC and cOC/tOC ratios were calculated. Reference intervals were established by polynomial quantile regression analysis. Results: The normal ranges for young men (≤30 years) were: tOC 17.9–56.8 ng/mL, ucOC 7.1–22.0 ng/mL, cOC 8.51–40.3 ng/mL (2.5th to 97.5th quantiles). Aging was associated with a “U” shaped pattern for tOC, cOC and ucOC levels. ucOC/tOC ratio was higher, while cOC/tOC ratio was lower in men of advanced age. Age explained ∼31%, while body mass index explained ∼4%, of the variance in the ratios. Conclusions: We have defined normal reference ranges for the OC forms in Australian men and demonstrated that the OC ratios may be better measures, than the absolute values, to identify the age-related changes on OC in men. These ratios may be incorporated into future research and clinical trials, and their associations with prediction of events, such as fracture or diabetes risk, should be determined.

DOI

10.1016/j.bone.2019.115085

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