Department of Health Sciences, University of Jyväskylä, FIN-40014 Jyväskylä, Finland.
J Clin Endocrinol Metab. 2012 Nov;97(11):4106-14. doi: 10.1210/jc.2012-2045. Epub 2012 Sep 4.
The skeleton is recognized as an important player in energy metabolism through its interactions with other tissues. Whether the association of osteocalcin with glucose metabolism is age dependent has not been fully addressed.
The objective of the study was to examine the age-specific association between different forms of osteocalcin and glucose and adipokines.
This was a family-based study across three generations.
The study was conducted at a university laboratory.
Sixty-four daughter-premenopausal mother-maternal grandmother trios participated in the study.
Fasting plasma glucose and insulin concentrations, serum total (tOC), carboxylated (cOC), and uncarboxylated (ucOC = tOC - cOC) osteocalcin, leptin, and adiponectin levels, and fat masses were assessed. Generalized estimating equations (GEE) model was used to assess the associations of bone biomarkers with glucose metabolism variables and adipokines.
No significant difference in insulin was found between generations, whereas glucose and leptin increased with age. Levels of tOC, cOC, and ucOC were highest in girls and lowest in mothers (P < 0.01). Grandmothers had higher leptin and adiponectin than mothers and girls. Despite the differences in insulin and glucose between the low and high homeostasis model assessment insulin resistance index (HOMA-IR) groups within generations, no significant differences in tOC, cOC, and ucOC were found. Compared with their low HOMA-IR counterparts, the high HOMA-IR group had significantly higher leptin and lower adiponectin in mothers and grandmothers. The tOC, cOC, and ucOC levels did not correlate with HOMA-IR, leptin, or adiponectin when the three generations were evaluated together, but when separated by generation, leptin was inversely correlated with tOC (P = 0.003) and cOC (P = 0.047) in mothers and with ucOC in grandmothers (P = 0.042).
Osteocalcin, glucose, and adipokines change with age but in a noncommensurate manner. We infer that the association between osteocalcin and glucose metabolism is minor and age specific in nondiabetic women. Leptin, however, strongly correlated with insulin resistance independently of fat masses, suggesting that obesity, as a metabolic disorder risk factor, affects glucose metabolism, partly through the role of leptin.
骨骼通过与其他组织的相互作用被认为是能量代谢的重要参与者。然而，骨钙素与葡萄糖代谢的关联是否与年龄有关尚未得到充分解决。
本研究旨在研究不同形式的骨钙素与葡萄糖和脂肪因子之间的年龄特异性关联。
这是一项跨三代人的基于家庭的研究。
研究在大学实验室进行。
64 名女儿-绝经前母亲-祖母三代女性参与了研究。
评估空腹血浆葡萄糖和胰岛素浓度、血清总（tOC）、羧化（cOC）和未羧化（ucOC=tOC-cOC）骨钙素、瘦素和脂联素水平以及脂肪量。使用广义估计方程（GEE）模型评估骨生物标志物与葡萄糖代谢变量和脂肪因子的关联。
各代之间的胰岛素无显著差异，而葡萄糖和瘦素随年龄增长而增加。tOC、cOC 和 ucOC 水平在女孩中最高，在母亲中最低（P<0.01）。祖母的瘦素和脂联素水平高于母亲和女孩。尽管各代内低和高稳态模型评估胰岛素抵抗指数（HOMA-IR）组之间的胰岛素和葡萄糖存在差异，但 tOC、cOC 和 ucOC 无显著差异。与低 HOMA-IR 对照组相比，高 HOMA-IR 组母亲和祖母的瘦素水平较高，脂联素水平较低。当三代人一起评估时，tOC、cOC 和 ucOC 水平与 HOMA-IR、瘦素或脂联素均无相关性，但按代分开时，母亲的 tOC（P=0.003）和 cOC（P=0.047）与瘦素呈负相关，而祖母的 ucOC 与瘦素呈负相关（P=0.042）。
骨钙素、葡萄糖和脂肪因子随年龄变化，但不成比例。我们推断，在非糖尿病女性中，骨钙素与葡萄糖代谢的关联较小且具有年龄特异性。然而，瘦素与胰岛素抵抗呈强烈相关性，与脂肪量无关，这表明肥胖作为代谢紊乱的危险因素，通过瘦素的作用部分影响葡萄糖代谢。
