Elevated plasma concentrations of liver enzymes are used in adults and children as the markers of liver injury. However, the age- and sex-specific effects of adiposity on pediatric liver enzyme concentrations remain unclear.

A study enrolled participants from 2 cohorts of Danish children and adolescents: 1858 from a population-based cohort and 2155 with overweight or obesity.

• The enrolled participants were aged from 6 to 18 years. 
• Both cohorts were subjected to the calculation of Age- and sex-specific percentile curves for fasting plasma concentrations of alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), gamma-glutamyltransferase (GGT), bilirubin, and alkaline phosphatase (ALP).
• 458 participants underwent proton magnetic resonance spectroscopy for Hepatic fat content measurement.

The following observations were made-

• ALT, AST, LDH, and ALP concentration decreased with age in both girls and boys
• GGT and bilirubin were comparable across age groups in girls while showing a slight increase with age in boys. 
• Overweight or obese individuals exhibited higher concentrations of ALT in all age groups. 
• Overweight or obese boys showed an increase in the concentrations of ALT and to a lesser degree GGT, with age. 
• Optimal ALT cut-points for diagnosing hepatic steatosis (liver fat content > 5%) was found to be 24.5 U/L for girls and 34.5 U/L for boys.

Thus it was concluded that the pediatric normal values of liver enzymes changes with both age and sex. Overweight and obesity causes an elevation in biochemical markers of liver damage. Thus it is important to prevent and treat overweight and obesity in children and adolescents. 

Source: The Journal of Clinical Endocrinology & Metabolism, 2020;105(2): 430–442, https://doi.org/10.1210/clinem/dgz010