Whole-Body and Hepatic Insulin Resistance in Obese Children

BackgroundInsulin resistance may be assessed as whole body or hepatic.ObjectiveTo study factors associated with both types of insulin resistance.MethodsCross-sectional study of 182 obese children. Somatometric measurements were registered, and the following three adiposity indexes were compared: BMI, waist-to-height ratio and visceral adiposity. Whole-body insulin resistance was evaluated using HOMA-IR, with 2.5 as the cut-off point. Hepatic insulin resistance was considered for IGFBP-1 level quartiles 1 to 3 (ResultsThe majority, 73.1%, of obese children had whole-body insulin resistance and hepatic insulin resistance, while 7% did not have either type. HOMA-IR was negatively associated with IGFBP-1 and positively associated with BMI, triglycerides, leptin and mother's BMI. Girls had increased HOMA-IR. IGFBP-1 was negatively associated with waist-to-height ratio, age, leptin, HOMA-IR and IGF-I. We did not find HOMA-IR or IGFBP-1 associated with fatty liver.ConclusionIn school-aged children, BMI is the best metric to predict whole-body insulin resistance, and waist-to-height ratio is the best predictor of hepatic insulin resistance, indicating that central obesity is important for hepatic insulin resistance. The reciprocal negative association of IGFBP-1 and HOMA-IR may represent a strong interaction of the physiological processes of both whole-body and hepatic insulin resistance.

胰岛素抵抗可分为全身型与肝脏型两类进行评估。本研究旨在探讨与两类胰岛素抵抗均相关的影响因素。本研究纳入182名肥胖儿童，采用横断面研究设计。研究人员记录了所有受试者的人体测量学指标，并对三项体脂相关指标进行了对比分析：体重指数（BMI，Body Mass Index）、腰围身高比（waist-to-height ratio）以及内脏脂肪量（visceral adiposity）。全身型胰岛素抵抗采用稳态模型胰岛素抵抗指数（HOMA-IR，Homeostatic Model Assessment for Insulin Resistance）进行评估，判定截断值设定为2.5。肝脏型胰岛素抵抗则以胰岛素样生长因子结合蛋白1（IGFBP-1，Insulin-like Growth Factor Binding Protein 1）水平的第1至3四分位数作为判定依据。研究结果显示，73.1%的肥胖儿童同时存在全身型与肝脏型胰岛素抵抗，另有7%的受试者两类胰岛素抵抗均未发生。HOMA-IR与IGFBP-1呈负相关，与BMI、甘油三酯、瘦素及母亲的体重指数呈正相关；女性受试者的HOMA-IR水平显著升高。IGFBP-1与腰围身高比、年龄、瘦素、HOMA-IR及胰岛素样生长因子I（IGF-I，Insulin-like Growth Factor I）呈负相关。本研究未发现HOMA-IR或IGFBP-1与脂肪肝存在关联。结论：在学龄儿童群体中，BMI是预测全身型胰岛素抵抗的最优指标，而腰围身高比则是肝脏型胰岛素抵抗的最佳预测因子，这提示中心性肥胖与肝脏型胰岛素抵抗的发生发展密切相关。IGFBP-1与HOMA-IR之间的双向负相关关系，可能反映了全身型与肝脏型胰岛素抵抗相关生理过程间存在较强的相互作用。