Identifying the effects of excess weight, metabolic syndrome and insulin resistance on liver stiffness using ultrasound elastography in children

Background. Metabolic syndrome (MetS) and insulin resistance (IR) are known predictors of nonalcoholic fatty liver disease (NAFLD) which is one of the significant comorbidities of obesity. Obese children with MetS and IR are reported to be more likely to have advanced liver fibrosis compared to those without MetS or IR. The aim of this study is to determine the effects of excess weight, MetS and IR on liver fibrosis assessing liver stiffness in children using ultrasound elastography and compare gray scale ultrasonographic findings of hepatic steatosis (HS) with liver fibrosis. Methods. The study group involved 131 overweight/obese children. The control group involved 50 healthy lean children. Groups were adjusted according to body mass index (BMI) and BMI-standard deviation scores (SDS). Liver stiffness measurements which are expressed by shear wave velocity (SWV) were performed for each individual. The study group was further subgrouped as children with MetS and without MetS, with IR and without IR. Results. The mean SWV of liver was 1,07 ± 0,12 m/s in the control group and 1,15 ± 0,51 m/s in the study group. The difference was significant (p=0,047). SWV of liver was weakly correlated with age, BMI, BMI-SDS, Homeostatic Model Assessment-Insulin Resistance and high-density lipoprotein cholesterol. The mean SWV of the liver in the study group for children without MetS was 1,1 ± 0,44 m/s, with MetS was 1,23 ± 0,70 m/s. The difference was not significant (p=0,719). The mean SWV of the liver in the study group for children without IR was 1,02 ± 0,29 m/s, with IR was 1,24 ± 0,61 m/s. The difference was not significant (p=0,101). In multivariate regression analysis, the only independent factor affecting liver stiffness was BMI-SDS (OR:2,584, 95% CI: 1,255- 5,318, p=0,010). Conclusions. Obesity itself, regardless of MetS or IR seems to be the major problem affecting liver stiffness in this study. However, large scale longitudinal studies might clarify this issue.