Updated reference ranges for aminotransferase levels of Korean children and young adolescents based on the risk factors for metabolic syndrome

Abstract

We investigated the reference values of liver enzymes based on cardiometabolic risks among children and adolescents using the Korea National Health and Nutrition Examination Survey. A total of 8091 subjects aged 10-18 years were included from the data from 2007-2017. Overall, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the AST/ALT ratio varied with sex and age. AST levels tended to decrease with age, but ALT levels had a U-shaped curve, which resulted in a gradual increase in the AST/ALT ratio after age 13. The prevalence of MetS was strongly associated with elevated AST or ALT and a decreased AST/ALT ratio. The prevalence ratios of the development of MetS were also elevated in groups with high levels of AST and ALT and a low AST/ALT ratio. Particularly in the combined ALT and AST/ALT analyses, borderline-high levels also showed a high prevalence ratio of MetS. Liver enzymes were also involved in the increase in the adjusted mean values for each risk factor for MetS. Here, we provided updated reference values for liver enzymes based on the analysis between population-based data and cardiometabolic risk factors; AST, ALT and the AST/ALT ratio might be useful in the early diagnosis and treatment of MetS.

Figure 1

Flow chart of the study population (n = 8091).

Figure 2

The distribution of sex- and age-specific percentiles for levels of AST, ALT, and the AST/ALT ratio in children aged 10–18 years (n = 8091). Each figure represents the distribution of percentile by age of (A) AST percentile of boys, (B) AST percentile of girls, (C) ALT percentile of boys, (D) ALT percentile of girls, (E) AST/ALT ratio percentile of boys and (F) AST/ALT ratio percentile of girls.

Figure 2

The distribution of sex- and age-specific percentiles for levels of AST, ALT, and the AST/ALT ratio in children aged 10–18 years (n = 8091). Each figure represents the distribution of percentile by age of (A) AST percentile of boys, (B) AST percentile of girls, (C) ALT percentile of boys, (D) ALT percentile of girls, (E) AST/ALT ratio percentile of boys and (F) AST/ALT ratio percentile of girls.

Figure 2

The distribution of sex- and age-specific percentiles for levels of AST, ALT, and the AST/ALT ratio in children aged 10–18 years (n = 8091). Each figure represents the distribution of percentile by age of (A) AST percentile of boys, (B) AST percentile of girls, (C) ALT percentile of boys, (D) ALT percentile of girls, (E) AST/ALT ratio percentile of boys and (F) AST/ALT ratio percentile of girls.

Figure 3

The differences in the prevalence of MetS for groups according to levels of AST, and ALT, and the AST/ALT ratio in children aged 10–18 years based on obesity (n = 8091). Subjects were classified as normal (< 85th percentile), overweight (≥ 85 and < 95th percentile), and obese (≥ 95th percentile) according to BMI. (A) The prevalence of MetS was presented according to AST, (B) ALT, and (C) the AST/ALT ratio.

Figure 4

The differences in the number of MetS components for groups according to the levels of AST, and ALT, and the AST/ALT ratio in children aged 10–18 years based on the obesity (n = 8091). Subjects were subdivided into normal (< 85th percentile), overweight (≥ 85 and < 95th percentile), and obese (≥ 95th percentile) groups according to BMI. (A) The number of components of MetS was presented according to AST, (B) ALT, and (C) the AST/ALT ratio.