Overview of screening methods for fatty liver disease in children

Efficacy of Ultrasound for the Detection of Possible Fatty Liver Disease in Children

Pediatric MASLD (previously referred to as NAFLD) incidence has continued to rise along with the obesity pandemic. Pediatric MASLD increases the risk of liver fibrosis and cirrhosis in adulthood. Early detection and intervention can prevent and reduce complications. Liver biopsy remains the gold standard for diagnosis, although imaging modalities are increasingly being used. We performed a retrospective study of 202 children seen in a pediatric gastroenterology clinic with a complaint of abdominal pain, elevated liver enzymes or MASLD, or a combination of the three to evaluate screening methods for MASLD. A total of 134 of the 202 patients included in the study underwent laboratory testing and abdominal ultrasound. Ultrasound images were reviewed with attention to liver size and echotexture by a fellowship-trained pediatric radiologist for liver size and echotexture. Overall, 76.2% of the initial radiology reports correctly identified hepatomegaly based on age and 75.4% of the initial radiology reports correctly described hepatic echogenicity that was consistent with increased hepatic fat deposition. Use of screening ultrasound in concert with other clinical evaluations can be helpful to identify children at risk of MASLD. Utilizing ranges for liver span according to age can help to diagnose hepatomegaly, and understanding how to identify hepatic echogenicity is important for identifying possible hepatic steatosis.

Prediction of Nonalcoholic Fatty Liver Disease by Anthropometric Indices and Bioelectrical Impedance Analysis in Children

Background: Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in children and is associated with obesity. Objectives: To test whether addition of bioelectrical impedance analysis (BIA) parameters to BMI and anthropometric indices improves the prediction performance of NAFLD than BMI z score (BAZ) alone. Methods: This cross-sectional study recruited 933 children 6-12 years of age for anthropometric measure, BIA, and liver ultrasound. Prediction models of the BAZ, anthropometric, and BIA sets were built in children with obesity using machine learning algorithms. Results: Prevalences of NAFLD were 44.4% (59/133) and 20% (12/60) in boys and girls with obesity, respectively. In both sexes, BAZ set performed worst; adding anthropometric indices into the model improved the model performance, whereas BIA parameters were the best approach for predicting NAFLD. The best result in boys achieved had an accuracy of 75.9% and area under receiver operating characteristic curve of 0.854. In girls, the best result achieved had an F-measure score of 0.615, Matthews correlation coefficient of 0.512, and area under precision-recalled curve of 0.697. Conclusion: BIA is a simple and highly precise tool that yields better NAFLD prediction model than anthropometric indices, and much better performance than BAZ. This study suggests BIA as a potential predictor for pediatric NAFLD.

What is the appropriate strategy for diagnosing NAFLD using ultrasonography in obese children?

BACKGROUND

The aim of this study is to identify obese children who are candidates for a potential diagnosis of non-alcoholic fatty liver disease (NAFLD).

METHODS

We enrolled 242 obese children (122 boys and 120 girls) aged 7-16 years who were examined with abdominal ultrasonography in our pediatric obesity clinic. We compared patients in the normal group with those in the NAFLD group (mild disease, moderate to severe disease) and identified the optimal anthropometric parameters among height, weight, body mass index (BMI), waist circumference, hip circumference, waist to height ratio (WHtR), and waist to hip ratio to predict NAFLD using a receiver operating characteristic curve analysis. We also investigated risk factors associated with NAFLD for the anthropometric parameters and the biochemical model using logistic regression.

RESULTS

The high- and low-risk groups for hepatic steatosis relative to a WHtR of 0.56 as the standard point showed significant differences in hepatic steatosis severity grade (P<0.001), BMI (P=0.004), hip circumference (P=0.090), aspartate aminotransferase (P<0.001), alanine aminotransferase (P<0.001), triglycerides (P=0.001), and the triglyceride to high-density lipoprotein (HDL) cholesterol ratio (P=0.006). Risk factors for hepatic steatosis on logistic regression analysis were male sex (odds ratio: 3.68, 95% confidence interval: 1.76-7.70), WHtR >0.56 (2.25, 1.05-4.81), and waist circumference >90th percentile (20.22, 9.21-44.36) in the anthropometric parameter model and elevated alanine aminotransferase levels (boys >25.8 U/L, girls >22.1 U/L) (6.93, 2.52-19.03), hypertriglyceridemia (>110 mg/dL) (3.80, 1.23-11.75), and triglyceride to HDL cholesterol ratio >3 (9.23, 2.95-8.83) in the biochemical parameter model.

CONCLUSION

A diagnostic approach to hepatic steatosis is recommended as part of the proper screening and stratification of risk factors in obese children. WHtR is a simple and convenient method of effectively identifying obese children who are candidates for hepatic steatosis screening.

Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents

OBJECTIVE

To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents.

MATERIALS AND METHODS

This prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard.

RESULTS

The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity).

CONCLUSION

Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies.

Steatosis and steatohepatitis: complex disorders

Non-alcoholic fatty liver disease (NAFLD) which includes steatosis and steatohepatitis, in particular non-alcoholic steatohepatitis (NASH), is a rising health problem world-wide and should be separated from alcoholic steatohepatitis (ASH). NAFLD is regarded as hepatic manifestation of the metabolic syndrome (MetSy), being tightly linked to obesity and type 2 diabetes mellitus (T2DM). Development of steatosis, liver fibrosis and cirrhosis often progresses towards hepatocellular carcinogenesis and frequently results in the indication for liver transplantation, underlining the clinical significance of this disease complex. Work on different murine models and several human patients studies led to the identification of different molecular key players as well as epigenetic factors like miRNAs and SNPs, which have a promoting or protecting function in AFLD/ASH or NAFLD/NASH. To which extent they might be translated into human biology and pathogenesis is still questionable and needs further investigation regarding diagnostic parameters, drug development and a better understanding of the genetic impact. In this review we give an overview about the currently available knowledge and recent findings regarding the development and progression of this disease.

Metabolic syndrome, insulin resistance and Fatty liver in obese Iranian children

BACKGROUND

Obesity is a global epidemic and its morbidities such as metabolic syndrome, insulin resistance, and fatty liver leads to a spectrum of psycho-social and medical consequences.

OBJECTIVES

The objective of this study was to investigate the prevalence of fatty liver in obese Iranian children and its' association with metabolic syndrome and insulin resistance.

PATIENTS AND METHODS

102 obese Iranian children, referred to pediatric clinics from March 2011 to March 2012, were enrolled in this cross-sectional study. All the patients were visited by a pediatric endocrinologist, a pediatric gastroenterologist and an expert radiologist in the evaluation of fatty liver grading.

RESULTS

The grade of fatty liver was higher in older children (P = 0.001). It was also more in taller and heavier children (P = 0.000). The more the BMI was, the more the fatty liver grade was (P = 0.002). Severity of fatty liver according to liver sonography in patient had a positive relationship with waist circumference, hip circumference, serum TG, serum FBS, serum fasting insulin, serum ALT, systolic blood pressure and HOMA index and had a negative correlation with the level of alkaline phosphatase. Severity of fatty liver also had a close relationship with the presence of acanthosis nigricans and HOMA index.

CONCLUSIONS

Prevalence of fatty liver is high in our obese children. It was associated with criteria of metabolic syndrome and insulin resistance, so visceral fat may participate in the pathogenesis of the metabolic syndrome or merely serve as a marker of increased risk for the metabolic complications of obesity.

Histological abnormalities in children with nonalcoholic fatty liver disease and normal or mildly elevated alanine aminotransferase levels

OBJECTIVE

To investigate the histological spectrum of nonalcoholic fatty liver disease (NAFLD) in children with normal, mildly elevated (26-50 U/L boys, 23-44 U/L girls), or elevated (>50 U/L in boys, >44 U/L in girls) serum alanine aminotransferase (ALT) levels.

STUDY DESIGN

The Nonalcoholic Steatohepatitis Clinical Research Network enrolls children aged 5-18 years with NAFLD. We analyzed baseline clinical and histological data from 91 children with suspected NAFLD and normal or mildly elevated ALT and liver biopsy analysis within 180 days of ALT measurement, and compared them with data from 392 children with elevated ALT.

RESULTS

Seventeen of the 91 children with suspected NAFLD (19%) had a normal ALT level, and 74 (81%) had a mildly elevated ALT level. Overall, 45% of the biopsy specimens analyzed had steatosis ≥33%, 22% had grade ≥2 lobular inflammation, 81% had portal inflammation, 29% had ballooned hepatocytes, 35% had "suspicious/borderline" steatohepatitis, 8% had definite nonalcoholic steatohepatitis, 34% had an NAFLD activity score ≥4, and 46% had fibrosis (38% mild/moderate and 8% bridging/cirrhosis). Marked steatosis (50% vs 24%) and fibrosis (54% vs 12%) were significantly more common in the patients with mildly elevated ALT compared with those with normal ALT, with no difference in ballooning, inflammation, or NAFLD activity score ≥4 between the 2 groups. Fibrosis stage 3/4 was seen in none of the children with normal ALT, in 9% of those with mildly elevated ALT, and in 15% of those with elevated ALT.

CONCLUSION

Liver biopsy specimens from children with NAFLD with normal or mildly elevated ALT levels show significant histological abnormalities, including advanced fibrosis in children with mildly elevated ALT. Thus, measurement of ALT may underestimate liver injury in NAFLD. The use of appropriate ALT cutoff levels can help identify children at risk for more severe disease.

Visceral/epicardial adiposity in nonobese and apparently healthy young adults: association with the cardiometabolic profile

OBJECTIVE

We investigate associations of regional adipose tissues with cardiometabolic profile of nonobese and apparently healthy young adults.

METHODS

Four hundred twenty-five nonobese and apparently healthy individuals were assessed for blood pressure and fasting lipid profile, blood glucose and adiponectin. Subcutaneous abdominal adipose tissue (SAT) and ectopic fat depots (visceral abdominal adipose tissue [VAT], epicardial adipose tissue [EAT] and hepatic fat fraction [HFF]) were quantified by magnetic resonance imaging.

RESULTS

According to anthropometric measurements, blood pressure and blood markers, the population (18-35 years, 54% women) had a low cardiometabolic risk. Compared to women, men had more VAT, EAT and HFF, but less SAT. Regional adipose tissues were positively correlated with each other. VAT and EAT carried significant correlations with all markers of cardiometabolic risk, while SAT and HFF correlated variably with these markers. While taking into account age and gender, SAT, VAT and EAT were associated with most cardiometabolic markers, while HFF was only associated with total cholesterol/high-density lipoprotein ratio (TC/HDL-C) and triglycerides (TG). When comparing SAT, VAT and EAT head-to-head, VAT was the only adipose tissue location maintaining significant association with most markers of cardiometabolic risk. Greater VAT (≥50th percentile) was associated with a worse cardiometabolic profile, whether individuals were overweight or normal weight.

CONCLUSION

Even in nonobese and apparently healthy young women and men, accumulation of ectopic visceral adiposity in general, and of VAT in particular, is associated with a worse cardiometabolic profile whether individuals were overweight or normal weight.

Cut-Off Values of Visceral Adiposity to Predict NAFLD in Brazilian Obese Adolescents

Objectives. The present study aimed at determining cut-off points of visceral fat to predict NAFLD and analyzed metabolic disorders of obese adolescents. Methods. Cross-sectional study involved 165 obese adolescents ranged in age from 15 to 19 years. Glycemia, hepatic transaminases, lipid profile, and insulin resistance were analyzed. Visceral and subcutaneous fat were measured by ultrasound and body composition by plesthysmography. Results. The NAFLD adolescents had significantly higher values for body mass, BMI-for-age, BMI, total fat, waist circumference, and visceral fat when compared with non-NAFLD obese adolescents in both genders. Moreover, there were significant positive correlations between visceral fat with the variables BMI-for-age (r = 0.325,), TG (r = 0.277), AST (r = 0.509), ALT (r = 0.519), WC (r = 0.390), and visceral/subcutaneous ratio (r = 0.790) for NAFLD group. Total fat, triglycerides, and visceral fat were the independent predictors to NAFLD. Analysis of the ROC curves revealed cut-off points of visceral fat of 4.47 cm for girls and 4.21 cm for boys. Conclusions. The results may suggest that abdominal ultrasonography procedure may be a safe alternative method of assessing visceral adiposity aiming to be considered to the development of preventive and treatment strategies in obese individuals. This clinial trial is registered with ClinicalTrial.gov (NCT01358773).

What about non-alcoholic fatty liver disease as a new criterion to define metabolic syndrome?

Non-alcoholic fatty liver disease (NAFLD) is currently not a component of the diagnostic criteria for metabolic syndrome (MetS); however, the development of NAFLD has some common mechanisms with the development of MetS, as they share the pathophysiologic basis of insulin resistance. It is also recognized that NAFLD is the hepatic manifestation of MetS. To define MetS, the presence of at least three of the proposed criteria is required, and sometimes it is sufficient to have only one laboratory value, modified by diet or drugs, for the classification of MetS. Ultrasonographically-detected NAFLD (US-NAFLD) is more stable, only changing during the middle- to long-term. Although controversies over MetS continue, and considering that abdominal ultrasonography for diagnosing NAFLD has high specificity and guidelines to modify the natural course of NAFLD by diet composition or lifestyle have not yet been established, why should we not introduce US-NAFLD as a new criterion to define MetS?

Association of Plasma Retinol Binding Protein-4 (RBP4) and Sonographic Grading of Fatty Liver in Obese Iranian Children

BACKGROUND

The prevalence of obesity and its related comorbidities, such as fatty liver, in children is increasing worldwide mostly due to changes in diet and life-style. Many serological markers have been suggested for screening of fatty liver but investigations for finding more reliable factors are still in progress.

OBJECTIVES

This study aimed to investigate the correlation between the level of retinol binding protein-4 (RBP4) in the serum and sonographic grading of fatty-liver severity in obese Iranian children.

PATIENTS AND METHODS

This case-control, double-blind study involved 51 obese children aged between five and 17 years as the case group. In addition, 35 healthy lean children with no liver problems were selected as the control group. Plasma RBP4 (using an ELISA), serum triglycerides (TG), low-density-lipoproteins (LDL), high-density-lipoproteins (HDL), total-cholesterol (Chol), and body mass index (BMI) were measured. Grading the severity of the fatty liver condition was done by an expert radiologist in the case group.

RESULTS

RBP4 levels in obese children (19 482.9 ± 3 302.2 pg/ml) were higher than those found in the lean control group (14 295.68 ± 2 381.3 pg/ml) (P < 0.05). In the obese patients, RBP4 levels showed a significant correlation with the grade of fatty liver and BMI (P < 0.05).

CONCLUSIONS

It was found that the level of RBP4 had a strong correlation with the severity of fatty liver. Therefore, RBP4 may be considered as a useful, noninvasive predictive biomarker of intrahepatic lipid content in obese children prior to using radiological investigations. In particular, abdominal sonography, for the evaluation of intrahepatic lipid content in obese patients, as the sensitivity of a sonography is decreased due to the increased thickness of the abdominal wall as a result of fat deposits.