A cross-sectional study of osteocalcin and body fat measures among obese adolescents

Carine M. Lenders, Phillip D.K. Lee, Henry A. Feldman, Darrell M. Wilson, Stephanie H. Abrams, Stephen E. Gitelman, William J. Klish, Marcia S. Wertz, George A. Taylor, Richard T. Alongi, Tai C. Chen, Michael F. Holick

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Osteocalcin (OCN), a marker of osteoblast activity, has been implicated in the regulation of energy metabolism by the skeleton and thus may affect body fat measures. Objective: To examine the relationships of OCN to body fat measures and whether they vary according to markers of energy and vitamin D metabolism. Design and Methods: Data were obtained from 58 obese adolescents aged 13-17.9 years (38 females, 8 black or African-American). Total fat mass (FM) [dual X-ray absorptiometry (DXA)] and visceral adipose tissue (VAT) [computerized axial tomography (CT)] were calculated. Blood tests included leptin, OCN, 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), thyroid function tests, and triglycerides. Markers of glucose metabolism were obtained from fasting and OGTT samples. Results and Conclusions: Adolescents with 25(OH)D <20 ng mL-1 were considered deficient (n = 17/58); none had high PTH (PTH ≥ 65 pg mL-1). OCN was associated with lower VAT (-84.27 ± 33.89 mm2) and BMI (-0.10 ± 0.05 kg m-2), not FM (P = 0.597) in a core model including age, sex, race, geographic latitude, summer, height z-score, and tanner stage. Adding 25(OH)D deficiency and PTH attenuated the inverse association of OCN to VAT. There was a significant interaction of OCN and 25(OH)D deficiency on FM (0.37 ± 0.18 kg, P = 0.041) and BMI (0.28 ± 0.10 kg m-2, P = 0.007) in this adjusted model, which was further explained by leptin. Adding A1C to the core model modified the relationship of OCN to VAT (-93.08 ± 35.05 mm 2, P = 0.011), which was further explained by HOMA-IR. In summary, these findings provide initial evidence for a relationship between OCN and body fat measures that is dependent on energy metabolism and vitamin D status among obese adolescents.

Original languageEnglish (US)
Pages (from-to)808-814
Number of pages7
JournalObesity
Volume21
Issue number4
DOIs
StatePublished - Apr 1 2013
Externally publishedYes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Nutrition and Dietetics

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    Lenders, C. M., Lee, P. D. K., Feldman, H. A., Wilson, D. M., Abrams, S. H., Gitelman, S. E., Klish, W. J., Wertz, M. S., Taylor, G. A., Alongi, R. T., Chen, T. C., & Holick, M. F. (2013). A cross-sectional study of osteocalcin and body fat measures among obese adolescents. Obesity, 21(4), 808-814. https://doi.org/10.1002/oby.20131