A cross‐sectional study of osteocalcin and body fat measures among obese adolescents12. (25th May 2013)

• Record Type: Journal Article
• Authors: Lenders, Carine M.; Lee, Phillip D.K.; Feldman, Henry A.; Wilson, Darrell M.; Abrams, Stephanie H.; Gitelman, Stephen E.; Klish, William J.; Wertz, Marcia S.; Taylor, George A.; Alongi, Richard T.; Chen, Tai C.; Holick, Michael F.
• Is Part Of: Obesity. Volume 21:Number 4(2013:Apr.)
• Page Start: 808
• Page End: 814
• Publication Date: 2013-05-25
• Subjects: Obesity -- Periodicals; 616.398005
• DOI: 10.1002/oby.20131
• Languages: English
• ISSNs: 1930-7381

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="abs1-0" sec-type="section"> <p>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.</p> </sec> <sec id="abs1-1" sec-type="section"> <title>Objective:</title> <p>To examine the relationships of OCN to body fat measures and whether they vary according to markers of energy and vitamin D metabolism.</p> </sec> <sec id="abs1-2" sec-type="section"> <title>Design and Methods:</title> <p>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.</p> </sec> <sec id="abs1-3" sec-type="section"> <title>Results and Conclusions:</title> <p>Adolescents with 25(OH)D <20 ng mL<sup>−1</sup> were considered deficient (<italic>n</italic> = 17/58); none had high PTH (PTH ≥ 65 pg mL<sup>−1</sup>). OCN was associated with lower VAT (−84.27 ± 33.89 mm<sup>2</sup>) and BMI (−0.10 ± 0.05 kg m<sup>−2</sup>), not FM (<italic>P</italic> = 0.597) in a core model including age, sex, race, geographic latitude, summer, height <italic>z</italic>‐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, <italic>P</italic> = 0.041) and BMI (0.28 ± 0.10 kg m<sup>−2</sup>, <italic>P</italic> = 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<sup>2</sup>, <italic>P</italic> = 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.</p> </sec> </abstract>