Hepatic parenchyma changes in obese paediatric patients

Rationale: Non-alcoholic fatty liver disease (NAFLD) is emerging clinical issue in childhood and adolescent age. Present knowledge of NAFLD suggests an important role of genetic and environmental risk factors in the pathogenesis of the disease. Most of the patients are obese, however, NAFLD also occurs in the non-obese group and interestingly, in obese individuals it may be absent. The transabdominal ultrasound examination is the most widely used imaging method for NAFLD screening. Aim: The aim of the study was to assess the impact of paediatric obesity as the main risk factor in NAFLD development. Materials and methods: The degree of steatosis (represented by hepatorenal index) and hepatic parenchyma stiffness (represented by fibrosis liver index) were quantitatively evaluated using ultrasound device in a total of 240 paediatric and adolescent patients divided in subgroups according to age and weight criteria. Results from ultrasound examination were subsequently correlated with anthropometric and laboratory parameters. Results: Hepatorenal index (HRI) and liver fibrosis index (LFI) in healthy term neonates with normal birth weight was significantly lower compared to the control group of healthy normal weight children aged 10–18 years (p <0.001). We did not observe an effect of gender on changes in HRI (p = 0.332) and LFI (p = 0.339) in teenage and adolescent controls. Regardless of gender, normal HRI values in paediatric heathy control group ranged from 1.02–1.23 (10th–90th percentile). The group of obese children aged 10–18 years had HRI and LFI values significantly higher in contrast with healthy normal weight controls. Obese individuals had liver stiffness proportional to BMI (p = 0.005, rs = 0.310), however, the steatosis degree remained unchanged (p = 0.357). Hepatic parenchyma stiffness also increased with waist circumference gain in corpulent patients (p <0.01). Conclusion: Results of this study point to a significant association of obesity and NAFLD in paediatric population. The assessment of HRI and liver stiffness using ultrasound methods have been employed in the diagnosis of early stages of hepatic changes in obese children and adolescent patients at risk of NAFLD development. In addition to the early detection in these changes, ultrasound determination enables non-invasive and real-time assessment of dynamics of the disease and the effect of the administered therapy, which improves control over the disease. Keywords non-alcoholic fatty liver disease, obesity, hepatorenal index, real-time elastography, body roundness index, paediatric age, adolescent age