儿童青少年腰围身高比与非酒精性脂肪肝病关系的回顾性分析

背景：肥胖是导致儿童青少年人群非酒精性脂肪肝病（NAFLD）发生的重要原因之一，腰围身高比（WHtR）是反映内脏脂肪和评价儿童青少年心血管代谢风险的简单而准确的体格测量指标，但WHtR 与NAFLD的关系研究十分有限。目的：分析儿童青少年WHtR与NAFLD的关系。设计：常规体检数据的回顾性分析。方法：以所有参加上海市闵行区2014至2020年住校学生健康体检的学生为研究对象，将血清ALT水平高于一般人群性别和年龄别第97.5百分位数水平定义为疑似NAFLD（简称NAFLD）。基于全国数据提示心血管代谢风险聚集的WHtR作为切点值，以男孩和女孩WHtR分别≥0.481和≥0.456定义为WHtR升高；以非条件二分类Logistic回归模型，校正年龄、性别等协变量后，分析WHtR升高与NAFLD的关系。通过计算AUC、敏感度、特异度、阳性预测值和阴性预测值，评价WHtR升高对NAFLD的区分效果。主要结局指标：WHtR与NAFLD的关联性。结果：与WHtR正常组相比，NAFLD患病率在 WHtR升高人群中显著升高（16.2% vs 2.3%, P<0.001），且随着年龄的增长呈现上升趋势。在WHtR升高人群中，男孩NAFLD患病率高于女孩（21.6% vs 11.0%，P<0.001），而在WHtR正常人群中男孩和女孩的NAFLD患病率接近（2.3% vs 2.2%， P=0.71）。WHtR升高人群NAFLD的发生风险增加 71%，校正的OR =1.71，95% CI：1.26~2.31，P=0.001。分层分析结果显示WHtR升高分别能增加男孩77%（OR=1.77，95% CI：1.19~2.63，P=0.005）和女孩69% （OR=1.69，95% CI：1.05~2.71，P=0.005）的NAFLD发生风险 。WHtR升高区分NAFLD的AUC为0.73（95% CI：0.71~0.76），敏感度63.2%、特异度83.4%、阳性预测值16.8%和阴性预测值97.7%。结论：儿童青少年WHtR升高与NAFLD的发生独立相关；学校和社区等基层医疗保健机构要重点关注WHtR升高的人群，除了血压、糖脂代谢异常以外，还需特别关注NAFLD的患病情况。

A retrospective analysis of relationship between waist-to-height ratio elevation and non-alcoholic fatty liver disease in children and adolescents

Background：Childhood obesity is one of the leading causes of nonalcoholic fatty liver disease (NAFLD). Waist to height ratio (WHtR) is a physical measurement index reflecting the visceral fat and cardiometabolic risk in children and adolescents, but the relationship between WHtR and NAFLD is unclear. Objective：To investigate the association of WHtR and NAFLD in children and adolescents. Design：Retrospective analysis of children's physical examination data. Methods：Resident students who participated in the 2014 2020 routine annual physical examination in Minhang District, Shanghai were included for the analysis. Suspected NAFLD was defined by the elevation of 97.5 percentile of alanine aminotransferase (ALT) levels according to the age and sex specific reference intervals for the healthy children. Based on the results of the WHtR cut off values proposed for screening cardiometabolic risk in children and adolescents from a national wide data, we defined the WHtR elevation group as WHtR values in boys and girls being equal to or higher than 0.481 and 0.456, respectively. We used unconditional binary logistic regression to assess the association of WHtR and NAFLD after adjustment of age and gender. We used the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value and negative predictive value to assess the ability of WHtR cutoffs in discriminating NAFLD. Main outcome measures：The association of WHtR and NAFLD. Results：Compared with the normal WHtR group, the NAFLD prevalence was significantly higher in WHtR elevation group (16.2% vs 2.3%, P<0.001), and increased with age. The NAFLD rate in boys with elevated WHtR was higher than that in girls (21.6% vs 11.0%，P<0.001), but was similar in both genders with normal WHtR (2.3% vs 2.2%，P=0.71). Elevated WHtR was associated with 71% increase in the risk of NAFLD (adjusted OR=1.71, 95% CI:1.26 2.31，P=0.001), and the association was similar in boys and girls with 77% increase in boys (OR=1.77, 95% CI:1.19 2.63，P=0.005) and 69% increase in girls (OR=1.69,95% CI: 1.05 2.71，P=0.005）. The AUC (95% CI), sensitivity, specificity, positive predictive value and negative predictive value of elevated WHtR for identifying NAFLD were 0.73(0.71 0.76), 63.2%, 83.4%, 16.8%, and 97.7%, respectively. Conclusion：Elevated WHtR is associated with NAFLD in children and adolescents. For the children and adolescent with elevated WHtR, schools and primary health care institutions should pay attention to the NAFLD occurrence in addition to abnormal blood pressure, glucose, and lipids metabolism.