Association of alanine aminotransferase concentration with cardiometabolic risk factors in children and adolescents: the CASPIAN-V cross-sectional study

ABSTRACT BACKGROUND: It has been suggested that the levels of some liver enzymes, and especially alanine aminotransferase (ALT), might be correlatable with cardiometabolic risk factors. We investigated the relationship between ALT concentration and cardiometabolic risk factors among children and adolescents. DESIGN AND SETTING: This nationwide study in Iran was conducted within the framework of the fifth survey of a national surveillance program known as the Childhood and Adolescence Surveillance and PreventIon of Adult Non-communicable disease study (CASPIAN-V). METHODS: The participants comprised 4200 students aged 7-18 years, who were recruited through multi-stage random cluster sampling in 30 provinces in Iran. Physical examinations and laboratory tests were conducted in accordance with standard protocols. RESULTS: Overall, 3843 students (participation rate: 91.5%) completed the survey. Mean ALT levels were significantly higher in individuals with dyslipidemia, in terms of elevated total cholesterol (TC) or LDL-cholesterol or triglycerides (TG), excess weight and dyslipidemia. Some cardiometabolic risk factors were associated with higher levels of ALT, with the following odds ratio (OR) and 95% confidence interval (CI):metabolic syndrome (OR: 1.013; 95% CI: 1.001-1.025); elevated TC (OR: 1.060; 95% CI: 1.039-1.081), elevated LDL (OR: 1.031; 95% CI: 1.016-1.046), elevated TG (OR: 1.056; 95% CI: 1.040-1.072) and dyslipidemia (OR: 1.051; 95% CI: 1.034-1.068). CONCLUSION: This large population-based study revealed that some cardiometabolic risk factors were significantly associated with ALT levels. These findings suggest that an association with fatty liver is an underlying mechanism for development of cardiometabolic risk factors.

**研究背景**：已有研究表明，部分肝脏酶类（尤其是丙氨酸氨基转移酶（alanine aminotransferase, ALT））水平或可与心血管代谢危险因素存在相关性。本研究旨在探讨儿童青少年群体中ALT浓度与心血管代谢危险因素之间的关联。
**研究设计与研究场景**：本研究为伊朗全国性调查，依托于“儿童青少年成人非传染性疾病监测与预防研究”（Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable disease study, CASPIAN-V）国家监测计划第五次调查框架开展。
**研究方法**：研究对象为伊朗30个省份通过多阶段整群随机抽样招募的4200名7~18岁学生。所有受试者均按照标准流程完成体格检查与实验室检测。
**研究结果**：最终共有3843名学生完成本次调查，应答率达91.5%。合并血脂异常（即总胆固醇（total cholesterol, TC）、低密度脂蛋白胆固醇（low-density lipoprotein cholesterol, LDL-C）或甘油三酯（triglycerides, TG）水平升高）、超重个体的平均ALT水平显著升高。多项心血管代谢危险因素与ALT水平升高存在显著关联，对应的比值比（odds ratio, OR）及95%置信区间（confidence interval, CI）分别为：代谢综合征（OR: 1.013; 95% CI: 1.001~1.025）、总胆固醇升高（OR: 1.060; 95% CI: 1.039~1.081）、低密度脂蛋白胆固醇升高（OR: 1.031; 95% CI: 1.016~1.046）、甘油三酯升高（OR: 1.056; 95% CI: 1.040~1.072）以及血脂异常（OR: 1.051; 95% CI: 1.034~1.068）。
**研究结论**：这项基于大规模人群的研究显示，部分心血管代谢危险因素与ALT水平存在显著关联。本研究结果提示，与脂肪肝的关联或是心血管代谢危险因素发生的潜在机制。