[The correlations of abdominal adipose tissue with anthropometric and metabolic parameters in obese children by magnetic resonance imaging].

Objective: To explore abdominal fat mass distribution and contents among obese children via magnetic resonance imaging (MRI), and analyze the correlations of abdominal adipose tissue with anthropometric and metabolic parameters. Methods: Cross-sectional study. There were 60 obese children admitted to the Children's Health Care Department and Endocrinology Department at Children's Hospital of Nanjing Medical University from July 2016 to December 2018. Children's gender, age, height, weight, body composition, waist circumference and blood pressure were recorded. The levels of fasting blood glucose, lipids, insulin were measured, and liver ultrasound was performed, and the body mass index Z score (BMI-Z), waist-to-height ratio (WHtR) and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated. In addition, contents of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and total abdominal adipose tissue (TAAT) were calculated according to feedback of abdominal MRI scan images. The associations between the contents of abdominal adipose tissue, physical examination status and metabolic disorders among obese children were analyzed through correlation analysis and regression analysis. Receiver operating characteristic (ROC) curve was used to compare the accuracy of fat mass in different parts of the abdomen in predicting their metabolic disorders. Results: A total of 60 children were enrolled in the study, included 44 boys and 16 girls, with age of (9.2±1.4) years. The contents of SAT, VAT and TAAT among the 60 children were positively associated with BMI-Z (r=0.60, 0.46, 0.59), body fat percentage (r=0.64, 0.67, 0.68) and waist-to-height ratio (r=0.60, 0.57, 0.61) (all P<0.01). Meanwhile, contents of SAT and TAAT were also positively correlated with systolic blood pressure (r=0.47, 0.49), triglyceride (r=0.33, 0.35) and HOMA-IR (r=0.33, 0.28)(all P<0.05). In order to adjust the confounding effects among various variables, regression analysis was applied and the result showed that the body fat percentage (β=0.59, 0.66, 0.65) and waist-to-height ratio (β=0.53, 0.63, 0.59) were most related to abdominal fat contents (all P<0.01), including SAT, VAT and TAAT among obese children. According to ROC, SAT had outstanding evaluation performances for the diagnosis of insulin resistance and metabolic syndrome, while VAT had excellent evaluation performances for non-alcoholic fatty liver disease (area under curve=0.68, 0.69, 0.69, 95%CI 0.54-0.82, 0.55-0.84, 0.53-0.85, P=0.017, 0.014, 0.019). Conclusions: As one of the best indexes, body fat percentage and WHtR can be used to predict the contents of SAT, VAT and TAAT among obese children. With the increase of abdominal SAT or VAT, the risks for insulin resistance, metabolic syndrome and non-alcoholic fatty liver disease would increase. Assessment of abdominal fat and metabolic risks in obese children should combine BMI-Z with waist circumference and body composition analysis.目的： 应用磁共振成像（MRI）探讨肥胖患儿腹部脂肪分布和含量并分析其与体格测量及代谢紊乱的关系。 方法： 横断面研究，选择2016年7月至2018年12月在南京医科大学附属儿童医院儿童保健科及内分泌科就诊的60例肥胖患儿为研究对象，收集患儿性别、年龄，测量身高、体重、体成分、腰围、血压，空腹检查血糖、血脂、胰岛素以及肝脏B超，并计算体质指数Z评分（BMI-Z）、腰围身高比（WHtR）和稳态模型胰岛素抵抗指数（HOMA-IR）；根据腹部MRI扫描图像计算腹部皮下脂肪（SAT）含量、内脏脂肪（VAT）含量及腹部总脂肪（TAAT）含量，采用相关分析、回归分析等分析肥胖患儿腹部脂肪组织含量与体格测评及其代谢紊乱指标的关系，受试者工作特征（ROC）曲线比较腹部不同部位脂肪预测其代谢紊乱的准确性。 结果： 60例患儿中男44例、女16例，年龄（9.2±1.4）岁。肥胖患儿腹部SAT、VAT及TAAT均与其BMI-Z（r=0.60、0.46、0.59）、体脂百分比（r=0.64、0.67、0.68）、WHtR（r=0.60、0.57、0.61）呈显著正相关（均P<0.01）；SAT和TAAT均与收缩压（r=0.47、0.49）、甘油三酯（r=0.33、0.35）、HOMA-IR（r=0.33、0.28）等呈正相关（均P<0.05）。为校正各变量间的混杂干扰作用，回归分析显示，肥胖患儿腹部SAT、VAT及TAAT均与体脂百分比（β=0.59、0.66、0.65）及WHtR（β=0.53、0.63、0.59）相关（均P<0.01）。ROC曲线显示，SAT对胰岛素抵抗、代谢综合征的评估性能更好，VAT则对非酒精性脂肪性肝病的评估性能更好（曲线下面积=0.68、0.69、0.69，95%CI 0.54~0.82、0.55~0.84、0.53~0.85，P=0.017、0.014、0.019）。 结论： 肥胖患儿腹部SAT、VAT及TAAT含量与体脂百分比及WHtR密切相关，随腹部脂肪含量的增加，发生胰岛素抵抗、代谢综合征及非酒精性脂肪性肝病的风险增高，并呈现部位差异。临床评估肥胖患儿腹部脂肪预测代谢风险时，应在BMI-Z基础上，结合腰围和体成分分析。.