AIMS Osteocalcin, a bone-derived factor, could be a feasible marker for metabolic disorders and adverse cardiovascular outcomes. This study aimed to explore the correlation between serum osteocalcin levels and correct QT interval (QTc) interval prolongation, a risk factor of cardiac morbidity and mortality. METHODS We recruited 1210 subjects (age range: 26-80 years) in communities in Shanghai. Serum osteocalcin levels were determined using an electrochemiluminescence immunoassay. The QTc interval was measured using a 12-lead electrocardiogram and was calculated by the Bazett formula. A prolonged QTc interval was defined as QTc > 440 ms. Visceral fat area (VFA) was assessed by magnetic resonance imaging. A VFA of 80 cm2 was applied as a cut-off point for central obesity. RESULTS Subjects with diabetes, overweight/obesity, or central obesity had significantly lower serum osteocalcin levels than those without (all P < 0.01). In subjects with a normal QTc interval, QTc interval lengthening accompanied decreasing osteocalcin levels (Pfor trend = 0.033), and the decline was more obvious in subjects with a prolonged QTc interval (Pfor trend = 0.022). Serum osteocalcin levels were correlated with the QTc interval (standardized β = -0.082, P = 0.005). Neither diabetes nor overweight/obesity was correlated with the QTc interval, whereas central obesity was positively correlated (P = 0.032). In addition, the correlation between osteocalcin levels and the QTc interval was attenuated when central obesity was included in the model simultaneously (standardized β = -0.075, P = 0.010). Mediation analysis revealed that VFA played a mediating role in the aforementioned correlation, and the estimated percentage of the total effect mediated by VFA was 20.9% (P = 0.007). CONCLUSIONS VFA partially mediated the inverse correlation between the serum osteocalcin levels and QTc interval, suggesting that improving fat metabolism may be a mechanism by which osteocalcin protects against cardiovascular diseases.

中文翻译：

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内脏脂肪区在血清骨钙素水平与QTc间期延长相关性中的中介作用

AIMS 骨钙素是一种骨源性因子，可能是代谢紊乱和不良心血管结局的可行标志物。本研究旨在探讨血清骨钙素水平与正确的 QT 间期 (QTc) 间期延长之间的相关性，QTc 间期延长是心脏发病率和死亡率的危险因素。方法我们在上海市社区招募了1210名受试者（年龄范围：26-80岁）。使用电化学发光免疫测定法测定血清骨钙素水平。QTc 间期使用 12 导联心电图测量并通过 Bazett 公式计算。QTc 间期延长定义为 QTc > 440 ms。通过磁共振成像评估内脏脂肪面积（VFA）。将 80 cm2 的 VFA 作为中心性肥胖的分界点。结果 患有糖尿病、超重/肥胖、或向心性肥胖者的血清骨钙素水平显着低于非肥胖者（均 P < 0.01）。在QTc间期正常的受试者中，QTc间期延长伴随着骨钙素水平的降低（Pfor趋势=0.033），QTc间期延长的受试者下降更为明显（Pfor趋势=0.022）。血清骨钙素水平与 QTc 间期相关（标准化 β = -0.082，P = 0.005）。糖尿病和超重/肥胖均与 QTc 间期无关，而向心性肥胖呈正相关（P = 0.032）。此外，当中心性肥胖同时包含在模型中时，骨钙素水平与 QTc 间期之间的相关性减弱（标准化 β = -0.075，P = 0.010）。中介分析表明，VFA 在上述相关性中起中介作用，VFA 介导的总效应的估计百分比为 20.9%（P = 0.007）。结论 VFA 部分介导了血清骨钙素水平与 QTc 间期的负相关，表明改善脂肪代谢可能是骨钙素预防心血管疾病的一种机制。