Pediatric nonalcoholic fatty liver disease: a comprehensive review

Prevalence of Adolescents Meeting Criteria for Metabolic and Bariatric Surgery

BACKGROUND AND OBJECTIVES

The American Academy of Pediatrics endorses metabolic and bariatric surgery (MBS) as a safe and effective treatment of severe obesity in children with class 3 obesity or with class 2 obesity and qualifying comorbidities. The study objective was to determine eligibility and characteristics of adolescents who qualify for MBS based on American Academy of Pediatrics guidelines.

METHODS

This retrospective cohort study analyzed electronic health record data of 603 051 adolescents aged 13 to 17 years between January 1, 2018, and December 31, 2021. Centers for Disease Control and Prevention criteria were used to define obesity classes 2 and 3. Multivariable logistic regression was used to evaluate the factors associated with meeting MBS eligibility criteria.

RESULTS

Of the 603 041 adolescents evaluated, 22.2% had obesity (12.9% class 1, 5.4% class 2, and 3.9% class 3). The most frequently diagnosed comorbid conditions were gastroesophageal reflux disease (3.2%), hypertension (0.5%), and nonalcoholic fatty liver disease (0.5%). Among adolescents with class 2 obesity, 9.1% had 1 or more comorbidities qualifying for MBS, and 4.4% of all adolescents met the eligibility criteria for MBS. In multivariable modeling, males, Black and Hispanic adolescents, and those living in more deprived neighborhoods were more likely to meet MBS eligibility criteria.

CONCLUSIONS

Overall, 1 in 23 adolescents met the eligibility criteria for MBS. Demographic and social determinants were associated with a higher risk for meeting these criteria. The study suggests that the health care system may face challenges in accommodating the demand for MBS among eligible adolescents.

Incidence of Type 2 Diabetes in Children With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Type 2 diabetes (T2D) is a growing problem in children. Children with NAFLD are at potentially high risk for developing T2D; however, the incidence of T2D in this population is unknown. This study aimed to determine the incidence of T2D in children with NAFLD and identify associated risk factors.

METHODS

Children with NAFLD enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network were followed longitudinally. Incidence of T2D was determined by using clinical history and fasting laboratory values. Cumulative incidence curves were developed for time to T2D. A Cox regression multivariable model was constructed using best subsets Akaike's Information Criteria selection.

RESULTS

This study included 892 children with NAFLD and with a mean age of 12.8 years (2.7) followed for 3.8 years (2.3) with a total 3234 person-years at risk. The incidence rate of T2D was 3000 new cases per 100,000 person-years at risk. At baseline, 63 children had T2D, and during follow-up, an additional 97 children developed incident T2D, resulting in a period prevalence of 16.8%. Incident T2D was significantly higher in females versus males (hazard ratio [HR], 1.8 [1.0-2.8]), associated with BMI z-score (HR, 1.8 [1.0-3.0]), and more severe liver histology including steatosis grade (HR, 1.3 [1.0-1.7]), and fibrosis stage (HR, 1.3 [1.0-1.5]).

CONCLUSIONS

Children with NAFLD are at high risk for existing and incident T2D. In addition to known risk factors for T2D (female and BMI z-score), severity of liver histology at the time of NAFLD diagnosis was independently associated with T2D development. Targeted strategies to prevent T2D in children with NAFLD are needed.

Association of Hepatic Steatosis with Adipose and Muscle Mass and Distribution in Children

Background: Pediatric studies have shown associations between hepatic steatosis and total body fat, visceral fat, and lean mass. However, these associations have not been assessed simultaneously, leaving their relative importance unknown. Objective: To evaluate associations between hepatic steatosis and total-body adiposity, visceral adiposity, and lean mass in children. Method: In children at risk for fatty liver, hepatic steatosis, adipose, and lean mass were estimated with magnetic resonance imaging and dual-energy X-ray absorptiometry. Results: Two hundred twenty-seven children with mean age 12.1 years had mean percent body fat of 38.9% and mean liver fat of 8.4%. Liver fat was positively associated with total-body adiposity, visceral adiposity, and lean mass (P < 0.001), and negatively associated with lean mass percentage (P < 0.001). After weight adjustment, liver fat was only positively associated with measures of central adiposity (P < 0.001). Visceral adiposity also had the strongest association with liver fat (P < 0.001). Conclusions: In children, hepatic steatosis is more strongly associated with visceral adiposity than total adiposity, and the association of lean mass is not independent of weight or fat mass. These relationships may help guide the choice of future interventions to target hepatic steatosis.

Correlation between Transient Elastography (Fibroscan®) and Ultrasonographic and Computed Tomographic Grading in Pediatric Nonalcoholic Steatohepatitis

PURPOSE

This study aimed to examine the advantages and usefulness of transient elastography (Fibroscan^®) in diagnosing non-alcoholic steatohepatitis in children and adolescents compared to those of abdominal computed tomography and liver ultrasonography.

METHODS

Forty-six children and adolescent participants aged between 6 and 16 years who underwent transient elastography (Fibroscan^®) as well as liver ultrasonography or abdominal computed tomography were included. Thirty-nine participants underwent liver ultrasonography and 11 underwent computed tomography. The physical measurements, blood test results, presence of metabolic syndrome, and the degree of liver steatosis and liver fibrosis were analyzed, and their correlations with transient elastography (Fibroscan^®), abdominal computed tomography, and liver ultrasonography, as well as the correlations between examinations, were analyzed.

RESULTS

Thirty-six participants (78.3%) were boys, and the mean age was 12.29±2.57 years, with a mean body mass index of 27.88±4.28. In the 46 participants, the mean values for aspartate aminotransferase, alanine aminotransferase, and total bilirubin were 89.87±118.69 IU/L, 138.54±141.79 IU/L, and 0.77±0.61 mg/dL, respectively. Although transient elastography (Fibroscan^®) and abdominal computed tomography grading had a statistically significant positive correlation with aspartate aminotransferase and alanine aminotransferase values, the correlations between the results of grading performed by transient elastography (Fibroscan^®), abdominal computed tomography, and liver ultrasonography were not statistically.

CONCLUSION

We confirmed that each examination was correlated with the results of some blood tests, suggesting the usefulness and possibility of diagnosis and treatment of steatohepatitis mediated by transient elastography (Fibroscan^®) in the department of pediatrics.

Gestational exposure to high fat diets and bisphenol A alters metabolic outcomes in dams and offspring, but produces hepatic steatosis only in dams

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Perinatal development is a critical window for altered, lifelong health trajectory, and evidence supports the role of perinatal programming in chronic metabolic diseases. To examine the impact of diet and bisphenol A (BPA) on the developmental trajectory of NAFLD in offspring, we exposed dams from pre-gestation through lactation to a human-relevant dose of oral BPA coupled with intake of high fat Western or Mediterranean-style diets. We assessed hepatic steatosis by quantifying hepatic triglycerides (TGs) and metabolic health by measuring body weight, relative organ weights, and serum hormone levels in dams and offspring at postnatal day 10 (PND10) and 10-months of age. In dams, consumption of the Western or Mediterranean diet increased hepatic TGs 1.7-2.4-fold, independent of BPA intake. Among offspring, both perinatal diet and BPA exposure had a greater impact on metabolic outcomes than on hepatic steatosis. At PND10, serum leptin levels were elevated 2.6-4.8-fold in pups exposed to the Mediterranean diet, with a trend for sex-specific effects on body and organ weights. At 10-months, sex-specific increases in organ weight and hormone levels were observed in mice perinatally exposed to Western + BPA or Mediterranean + BPA. These findings suggest lifestage-specific interaction of perinatal exposures to experimental diets and BPA on offspring metabolic health without effects on NAFLD later in life. Importantly, alterations in dam phenotype by diet and BPA exposure appear to impact offspring health trajectory, emphasizing the need to define dam diet in assessing effects of environmental exposures on offspring health.

Treatment of type 2 diabetes in children: what are the specific considerations?

Introduction: The number of individuals under 18 years of age with type 2 diabetes is increasing at an alarming rate worldwide. These patients are often characterized by obesity and they often experience a more rapid disease progression than adults with type 2 diabetes. Thus, focus on prevention and management of complications and comorbidities is imperative. With emphasis on weight loss and optimal glycemic control, treatment includes lifestyle changes and pharmacotherapy, which in this patient group is limited to metformin, liraglutide and insulin. In selected cases, bariatric surgery is indicated.Areas covered: This perspective article provides an overview of the literature covering pathophysiology, diagnosis, characteristics and treatment of pediatric type 2 diabetes, and outlines the gaps in our knowledge where further research is needed. The paper draws on both mechanistic studies, large scale intervention trials, epidemiological studies and international consensus statements.Expert opinion: Type 2 diabetes in pediatric patients is an increasing health care problem, and the current treatment strategies do not successfully meet the many challenges and obstacles in this patient group. Treatments must be early, intensive, multifaceted and durable. Also, prevention of obesity and type 2 diabetes in at-risk children should be addressed and prioritized on all levels.

Prevalence of prediabetes and type 2 diabetes in children with obesity and increased transaminases in European German-speaking countries. Analysis of the APV initiative

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), prediabetes and type 2 diabetes mellitus are known to be closely linked with obesity as early as during childhood.

OBJECTIVES

The study aimed to determine the prevalence of prediabetes and T2DM in children with obesity with or without increased transaminases.

METHODS

Data from the observational multicentre (n = 51), cross-sectional Adipositas Patienten Verlaufsbeobachtung registry were analyzed. Mild increase (mild group) was defined by alanine transaminase (ALT) >24 to ≤50 U/L and moderate to severe increase (advanced group) by ALT > 50 U/L. Prediabetes and T2DM were defined according to recent IDF/ISPAD guidelines.

RESULTS

The prevalence of prediabetes and T2DM was 11.9% (95% CI: 11.0-12.8) and 1.4% (95% CI: 1.1-1.7) among all participants (n = 4932; male = 2481; mean age 12.9 ± 2.7 years; BMI-SDS 2.1 ± 0.5; Tanner stage 3.2 ± 1.5). The prevalence of impaired glucose metabolism (prediabetes and T2DM) was 13.8% (95% CI: 12.1-15.4) in the mild, 21.9% (95% CI: 18.8-25.1) in the advanced group, 10.7% (95% CI: 9.4-11.9) in the control group. Mild and advanced groups had greater odds ratios for prediabetes [1.42; 95% CI: 1.17-1.72, 2.26-fold; (1.78-2.86), respectively], the advanced group also for T2DM [2.39 (1.36-4.21)] compared to controls. While an increase in transaminases predominantly affected boys, girls within the advanced group had a higher T2DM prevalence than males (5.4 vs. male 2.1%).

CONCLUSIONS

Children with obesity and increased liver transaminases as surrogates of NAFLD should be screened for T2DM.

Prevalence and risk factors of sonographically detected non alcoholic fatty liver disease in a screening centre in Klang Valley, Malaysia: an observational cross-sectional study

Objectives:

Nonalcoholic fatty liver disease (NAFLD) is a very common liver disorder in Western countries. As of late, it has been found to be prevalent in Asia as well. It is a benign disease unless it develops into necroinflammation and fibrosis. This study was proposed to determine the prevalence and risk factors of sonography-detected NAFLD among Malaysian adults in Klang Valley, West Malaysia.

Study design:

An observational cross-sectional study.

Methods:

The participants were aged between 45 and 75 years who participated in a screening program at the Golden Horses Health Sanctuary in Klang Valley. Lipid profile and anthropometric measurements were collected from the subjects’ medical records. Ultrasound machine and a structured self-administered questionnaire were used as instruments for recruiting data from the subjects. The subjects who consumed alcohol (>140 g/wk for men and >70 g/wk for females), had hepatitis B or C viruses, liver insults, and surgery, and taken lipid-lowering medications were excluded from the study.

Results:

A total of 628 subjects were analyzed, and 235 (37.4%) subjects were diagnosed with definite NAFLD. They comprised 518 (82.5%) Chinese, 92 (14.6%) Malays, and 18 (2.9%) Indians. Peak prevalence of NAFLD was found in 53 to 60 years age group. The higher prevalence of NAFLD was among men (48.3%) than women (27.3%) and among Indians (61.1%) and Malays (51.1%) than among Chinese (34.2%). NAFLD has been found to be strongly correlated with male sex, high body mass index (≥23.0 kg/m²), hypertriglyceridemia, low high-density lipoprotein cholesterol, diabetes mellitus, and hypertension.

Conclusion:

NAFLD is quite common among adults in Malaysian urban population. The prevalence of NAFLD was inordinately high among the 53 to 60 years age group, male sex, Indians, and Malays (as compared with Chinese). Age >60 years, male sex, high body mass index (≥23.0 kg/m²), hypertriglyceridemia, and diabetes mellitus were proven to be risk predictors for NAFLD.

Accuracy of PDFF estimation by magnitude-based and complex-based MRI in children with MR spectroscopy as a reference

PURPOSE

To assess and compare the accuracy of magnitude-based magnetic resonance imaging (MRI-M) and complex-based MRI (MRI-C) for estimating hepatic proton density fat fraction (PDFF) in children, using MR spectroscopy (MRS) as the reference standard. A secondary aim was to assess the agreement between MRI-M and MRI-C.

MATERIALS AND METHODS

This was a HIPAA-compliant, retrospective analysis of data collected in children enrolled in prospective, Institutional Review Board (IRB)-approved studies between 2012 and 2014. Informed consent was obtained from 200 children (ages 8-19 years) who subsequently underwent 3T MR exams that included MRI-M, MRI-C, and T1 -independent, T2 -corrected, single-voxel stimulated echo acquisition mode (STEAM) MRS. Both MRI methods acquired six echoes at low flip angles. T2*-corrected PDFF parametric maps were generated. PDFF values were recorded from regions of interest (ROIs) drawn on the maps in each of the nine Couinaud segments and three ROIs colocalized to the MRS voxel location. Regression analyses assessing agreement with MRS were performed to evaluate the accuracy of each MRI method, and Bland-Altman and intraclass correlation coefficient (ICC) analyses were performed to assess agreement between the MRI methods.

RESULTS

MRI-M and MRI-C PDFF were accurate relative to the colocalized MRS reference standard, with regression intercepts of 0.63% and -0.07%, slopes of 0.998 and 0.975, and proportion-of-explained-variance values (R2 ) of 0.982 and 0.979, respectively. For individual Couinaud segments and for the whole liver averages, Bland-Altman biases between MRI-M and MRI-C were small (ranging from 0.04 to 1.11%) and ICCs were high (≥0.978).

CONCLUSION

Both MRI-M and MRI-C accurately estimated hepatic PDFF in children, and high intermethod agreement was observed.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1641-1647.

Magnetic resonance elastography measured shear stiffness as a biomarker of fibrosis in pediatric nonalcoholic fatty liver disease

Magnetic resonance elastography (MRE) is a promising technique for noninvasive assessment of fibrosis, a major determinant of outcome in nonalcoholic fatty liver disease (NAFLD). However, data in children are limited. The purpose of this study was to determine the accuracy of MRE for the detection of fibrosis and advanced fibrosis in children with NAFLD and to assess agreement between manual and novel automated reading methods. We performed a prospective, multicenter study of two-dimensional (2D) MRE in children with NAFLD. MR elastograms were analyzed manually at two reading centers, and using a new automated technique. Analysis using each approach was done independently. Correlations were determined between MRE analysis methods and fibrosis stage. Thresholds for classifying the presence of fibrosis and of advanced fibrosis were computed and cross-validated. In 90 children with a mean age of 13.1 ± 2.4 years, median hepatic stiffness was 2.35 kPa. Stiffness values derived by each reading center were strongly correlated with each other (r = 0.83). All three analyses were significantly correlated with fibrosis stage (center 1, ρ = 0.53; center 2, ρ = 0.55; and automated analysis, ρ = 0.52; P < 0.001). Overall cross-validated accuracy for detecting any fibrosis was 72.2% for all methods (95% confidence interval [CI], 61.8%-81.1%). Overall cross-validated accuracy for assessing advanced fibrosis was 88.9% (95% CI, 80.5%-94.5%) for center 1, 90.0% (95% CI, 81.9%-95.3%) for center 2, and 86.7% (95% CI, 77.9%-92.9%) for automated analysis.

CONCLUSION

2D MRE can estimate hepatic stiffness in children with NAFLD. Further refinement and validation of automated analysis techniques will be an important step in standardizing MRE. How to best integrate MRE into clinical protocols for the assessment of NAFLD in children will require prospective evaluation. (Hepatology 2017;66:1474-1485).

Imaging Features of Non-Alcoholic Fatty Liver Disease in Children and Adolescents

Non-invasive diagnosis and quantification of liver steatosis is important to overcome limits of liver biopsy, in order to follow up patients during their therapy and to establish a reference standard that can be used in clinical trials and longitudinal studies. Imaging offers several methods in this setting: ultrasound, which is the cheapest technique and easy to perform; magnetic resonance spectroscopy (MRS), which reflects the real content of triglycerides in a specific volume; and proton density fat fraction (PDFF) magnetic resonance, which is a simple method that reflects the distribution of the fat in the whole liver. Other techniques include ultrasound elastography (EUS) and magnetic resonance elastrography (MRE), which can evaluate the progression of non-alcoholic fatty liver disease (NAFLD) into non-alcoholic steato-hepatitis (NASH) and cirrhosis, by quantifying liver fibrosis.

Low and High Birth Weights Are Risk Factors for Nonalcoholic Fatty Liver Disease in Children

OBJECTIVES

To examine the distribution of birth weight in children with nonalcoholic fatty liver disease (NAFLD) compared with the general US population, and to investigate the relationship between birth weight and severity of NAFLD.

STUDY DESIGN

A multicenter, cross-sectional study of children with biopsy-proven NAFLD enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network Database. Birth weight was categorized as low birth weight (LBW), normal birth weight (NBW), or high birth weight (HBW) and compared with the birth weight distribution in the general US population. The severity of liver histology was assessed by birth weight category.

RESULTS

Children with NAFLD (n = 538) had overrepresentation of both LBW and HBW compared with the general US population (LBW, 9.3%; NBW, 75.8%; HBW, 14.9% vs LBW, 6.1%; NBW, 83.5%; HBW 10.5%; P < .0001). Children with HBW had significantly greater odds of having more severe steatosis (OR, 1.82, 95% CI. 1.15-2.88) and nonalcoholic steatohepatitis (OR, 2.03; 95% CI, 1.21-3.40) compared with children with NBW. In addition, children with NAFLD and LBW had significantly greater odds of having advanced fibrosis (OR, 2.23; 95% CI, 1.08-4.62).

CONCLUSION

Birth weight involves maternal and in utero factors that may have long-lasting consequences. Children with both LBW and HBW may be at increased risk for developing NAFLD. Among children with NAFLD, those with LBW or HBW appear to be at increased risk for more severe disease.

Imaging patterns of fatty liver in pediatric patients

Fatty liver can present as focal, diffuse, heterogeneous, and multinodular forms. Being familiar with various patterns of steatosis can enable correct diagnosis. In patients with equivocal findings on ultrasonography, magnetic resonance imaging can be used as a problem solving tool. New techniques are promising for diagnosis and follow-up. We review imaging patterns of steatosis and new quantitative methods such as proton density fat fraction and magnetic resonance elastography for diagnosis of nonalcoholic fatty liver disease in children.

In Children With Nonalcoholic Fatty Liver Disease, Cysteamine Bitartrate Delayed Release Improves Liver Enzymes but Does Not Reduce Disease Activity Scores

BACKGROUND & AIMS

No treatment for nonalcoholic fatty liver disease (NAFLD) has been approved by regulatory agencies. We performed a randomized controlled trial to determine whether 52 weeks of cysteamine bitartrate delayed release (CBDR) reduces the severity of liver disease in children with NAFLD.

METHODS

We performed a double-masked trial of 169 children with NAFLD activity scores of 4 or higher at 10 centers. From June 2012 to January 2014, the patients were assigned randomly to receive CBDR or placebo twice daily (300 mg for patients weighing ≤65 kg, 375 mg for patients weighing >65 to 80 kg, and 450 mg for patients weighing >80 kg) for 52 weeks. The primary outcome from the intention-to-treat analysis was improvement in liver histology over 52 weeks, defined as a decrease in the NAFLD activity score of 2 points or more without worsening fibrosis; patients without biopsy specimens from week 52 (17 in the CBDR group and 6 in the placebo group) were considered nonresponders. We calculated the relative risks (RR) of improvement using a stratified Cochran-Mantel-Haenszel analysis.

RESULTS

There was no significant difference between groups in the primary outcome (28% of children in the CBDR group vs 22% in the placebo group; RR, 1.3; 95% confidence interval [CI], 0.8-2.1; P = .34). However, children receiving CBDR had significant changes in prespecified secondary outcomes: reduced mean levels of alanine aminotransferase (reduction, 53 ± 88 U/L vs 8 ± 77 U/L in the placebo group; P = .02) and aspartate aminotransferase (reduction, 31 ± 52 vs 4 ± 36 U/L in the placebo group; P = .008), and a larger proportion had reduced lobular inflammation (36% in the CBDR group vs 21% in the placebo group; RR, 1.8; 95% CI, 1.1-2.9; P = .03). In a post hoc analysis of children weighing 65 kg or less, those taking CBDR had a 4-fold better chance of histologic improvement (observed in 50% of children in the CBDR group vs 13% in the placebo group; RR, 4.0; 95% CI, 1.3-12.3; P = .005).

CONCLUSIONS

In a randomized trial, we found that 1 year of CBDR did not reduce overall histologic markers of NAFLD compared with placebo in children. Children receiving CBDR, however, had significant reductions in serum aminotransferase levels and lobular inflammation. ClinicalTrials.gov no: NCT01529268.

Prevalence of Prediabetes and Type 2 Diabetes in Children With Nonalcoholic Fatty Liver Disease

IMPORTANCE

Nonalcoholic fatty liver disease (NAFLD) is a major chronic liver disease in children in the United States and is associated with insulin resistance. In adults, NAFLD is also associated with type 2 diabetes. To our knowledge, the prevalence of type 2 diabetes in children with NAFLD is unknown.

OBJECTIVE

To determine the prevalence of type 2 diabetes and prediabetes in children with NAFLD and assess type 2 diabetes and prediabetes as risk factors for nonalcoholic steatohepatitis (NASH).

DESIGN, SETTING, AND PARTICIPANTS

This was a multicenter, cross-sectional study at 12 pediatric clinical centers across the United States participating in the National Institute of Diabetes and Digestive and Kidney Diseases NASH Clinical Research Network. Children younger than 18 years with biopsy-confirmed NAFLD enrolled in the NASH Clinical Research Network.

MAIN OUTCOMES AND MEASURES

The presence of type 2 diabetes and prediabetes as determined by American Diabetes Association screening criteria using clinical history and fasting laboratory values.

RESULTS

There were 675 children with NAFLD included in the study with a mean age of 12.6 years and mean body mass index (calculated as weight in kilograms divided by height in meters squared) of 32.5. Most of the children were boys (480 of 675) and Hispanic (445 of 675).The estimated prevalence of prediabetes was 23.4% (95% CI, 20.2%-26.6%), and the estimated prevalence of type 2 diabetes was 6.5% (95% CI, 4.6%-8.4%). Girls with NAFLD had 1.6 (95% CI, 1.04-2.40) times greater odds of having prediabetes and 5.0 (95% CI, 2.49-9.98) times greater odds of having type 2 diabetes than boys with NAFLD. The prevalence of NASH was higher in those with type 2 diabetes (43.2%) compared with prediabetes (34.2%) or normal glucose (22%) (P < .001). The odds of having NASH were significantly higher in those with prediabetes (OR, 1.9; 95% CI, 1.21-2.9) or type 2 diabetes (OR, 3.1; 95% CI, 1.5-6.2) compared with those with normal glucose.

CONCLUSIONS AND RELEVANCE

In this study, nearly 30% of children with NAFLD also had type 2 diabetes or prediabetes. These children had greater odds of having NASH and thus were at greater long-term risk for adverse hepatic outcomes.

Feasibility of and agreement between MR imaging and spectroscopic estimation of hepatic proton density fat fraction in children with known or suspected nonalcoholic fatty liver disease

PURPOSE

To assess feasibility of and agreement between magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) for estimating hepatic proton density fat fraction (PDFF) in children with known or suspected nonalcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

Children were included in this study from two previous research studies in each of which three MRI and three MRS acquisitions were obtained. Sequence acceptability, and MRI- and MRS-estimated PDFF were evaluated. Agreement of MRI- with MRS-estimated hepatic PDFF was assessed by linear regression and Bland-Altman analysis. Age, sex, BMI-Z score, acquisition time, and artifact score effects on MRI- and MRS-estimated PDFF agreement were assessed by multiple linear regression.

RESULTS

Eighty-six children (61 boys and 25 girls) were included in this study. Slope and intercept from regressing MRS-PDFF on MRI-PDFF were 0.969 and 1.591%, respectively, and the Bland-Altman bias and 95% limits of agreement were 1.17% ± 2.61%. MRI motion artifact score was higher in boys than girls (by 0.21, p = 0.021). Higher BMI-Z score was associated with lower agreement between MRS and MRI (p = 0.045).

CONCLUSION

Hepatic PDFF estimation by both MRI and MRS is feasible, and MRI- and MRS-estimated PDFF agree closely in children with known or suspected NAFLD.

Global publication trends and research hotspots of nonalcoholic fatty liver disease: a bibliometric analysis and systematic review

With the globally increasing prevalence, nonalcoholic fatty liver disease (NAFLD) becomes the predominant cause of chronic liver disease. A global look at the publication trends and the research hotspots of NAFLD are urgently needed to assess the situation of NAFLD research. The global scientific research in the Science Citation Index-Expanded covered articles relevant to NAFLD was retrieved and its bibliometric parameters and research hotspots of NAFLD were systematically evaluated. To sum up, 6356 articles were published in 994 different journals covering 93 SCI subject categories during 1986–2013, in which English was the most predominant language used. Starting from the late 1980s, the publication on NAFLD grew slowly and entered into a highly developing period in the 21st century, especially in the last decade. Besides hepatic steatosis, metabolic syndrome and its combination of symptoms such as obesity, insulin resistance are listed as the top frequent keywords. Bibliometric results suggest that the obviously rapid growth of the articles in recent years appears to be associated with the accelerating incidence of NAFLD and its cofactors such as metabolic syndrome. In addition, epidemiology focusing on comparing different regions and population is attracting ever-growing attention. Meantime, pathology plays an important role in NAFLD research.

Metabolic inflexibility and insulin resistance in obese adolescents with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a comorbidity of childhood obesity.

OBJECTIVE

We examined whole-body substrate metabolism and metabolic characteristics in obese adolescents with vs. without NAFLD.

SUBJECTS

Twelve obese (BMI ≥ 95th percentile) adolescents with and without NAFLD [intrahepatic triglyceride (IHTG) ≥5.0% vs. <5.0%] were pair-matched for race, gender, age and % body fat.

METHODS

Insulin sensitivity (IS) was assessed by a 3-h hyperinsulinemic-euglycemic clamp and whole-body substrate oxidation by indirect calorimetry during fasting and insulin-stimulated conditions.

RESULTS

Adolescents with NAFLD had increased (p < 0.05) abdominal fat, lipids, and liver enzymes compared with those without NAFLD. Fasting glucose concentration was not different between groups, but fasting insulin concentration was higher (p < 0.05) in the NAFLD group compared with those without. Fasting hepatic glucose production and hepatic IS did not differ (p > 0.1) between groups. Adolescents with NAFLD had higher (p < 0.05) fasting glucose oxidation and a tendency for lower fat oxidation. Adolescents with NAFLD had lower (p < 0.05) insulin-stimulated glucose disposal and lower peripheral IS compared with those without NAFLD. Although respiratory quotient (RQ) increased significantly from fasting to insulin-stimulated conditions in both groups (main effect, p < 0.001), the increase in RQ was lower in adolescents with NAFLD vs. those without (interaction, p = 0.037).

CONCLUSION

NAFLD in obese adolescents is associated with adverse cardiometabolic profile, peripheral insulin resistance and metabolic inflexibility.

Paediatric non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFLD) is a progressive disease that encompasses a spectrum of liver diseases, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Data related to survival in children are scarce, but these data firmly associate NAFLD with higher risks of hepatic and non-hepatic morbidities and mortalities compared with the general population. More recently, the association between NAFLD and cardiovascular disease among children has increasingly been recognized. Given that obesity is a major risk factor for the disease, paediatric NAFLD is becoming a global issue, paralleling the dramatic rise in obesity worldwide. NASH, which is more common in obese children, has the potential to advance to liver fibrosis and failure. It is unclear why certain patients undergo such transformation but this susceptibility is likely related to an interaction between a genetically susceptible host and the surrounding environment. Currently, treatment is largely conservative and includes lifestyle modification, attainable through healthy weight reduction via diet and exercise. In this review, current knowledge about NAFLD in children is summarized. This review aims to increase the awareness of the medical community about a hidden public health issue and to identify current gaps in the literature while providing directions for future research.

Accuracy of multiecho magnitude-based MRI (M-MRI) for estimation of hepatic proton density fat fraction (PDFF) in children

PURPOSE

To assess accuracy of magnitude-based magnetic resonance imaging (M-MRI) in children to estimate hepatic proton density fat fraction (PDFF) using two to six echoes, with magnetic resonance spectroscopy (MRS) -measured PDFF as a reference standard.

METHODS

This was an IRB-approved, HIPAA-compliant, single-center, cross-sectional, retrospective analysis of data collected prospectively between 2008 and 2013 in children with known or suspected nonalcoholic fatty liver disease (NAFLD). Two hundred eighty-six children (8-20 [mean 14.2 ± 2.5] years; 182 boys) underwent same-day MRS and M-MRI. Unenhanced two-dimensional axial spoiled gradient-recalled-echo images at six echo times were obtained at 3T after a single low-flip-angle (10°) excitation with ≥ 120-ms recovery time. Hepatic PDFF was estimated using the first two, three, four, five, and all six echoes. For each number of echoes, accuracy of M-MRI to estimate PDFF was assessed by linear regression with MRS-PDFF as reference standard. Accuracy metrics were regression intercept, slope, average bias, and R(2) .

RESULTS

MRS-PDFF ranged from 0.2-40.4% (mean 13.1 ± 9.8%). Using three to six echoes, regression intercept, slope, and average bias were 0.46-0.96%, 0.99-1.01, and 0.57-0.89%, respectively. Using two echoes, these values were 2.98%, 0.97, and 2.72%, respectively. R(2) ranged 0.98-0.99 for all methods.

CONCLUSION

Using three to six echoes, M-MRI has high accuracy for hepatic PDFF estimation in children.

Improvement in nonalcoholic fatty liver disease and metabolic syndrome in adolescents undergoing bariatric surgery

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children. It is linked to obesity and the metabolic syndrome (MS), predisposing to future cirrhosis. The objective of this study was to demonstrate the effects that weight loss achieved with laparoscopic adjustable gastric band (LAGB) has on the metabolic parameters and NAFLD scores of obese adolescents with evidence of fatty liver disease.

METHODS

Adolescents undergoing LAGB were evaluated for NAFLD with evidence of fatty liver on preoperative sonogram, serum biochemistry, or both between 2005 and 2011. Primary endpoint was change in NAFLD scores after LAGB and secondary endpoint change in MS criteria.

RESULTS

Fifty-six out of 155 adolescents had evidence of fatty liver disease at presentation. The group consisted of 17 (30%) male and 39 (70%) females, mean age 16.1 years (range 14-17.8 yr). Preoperative body mass index (BMI) was 48.8 kg/m(2) (±7) dropping to 37.9 kg/m(2) (±8.3) at 12 months and 36.8 kg/m(2) (±8.2) at 24 months. Fifteen (27%) patients met the criteria for MS. When comparing 1-year postsurgery to presurgery, the NAFLD score decreased by an average of .68 (SD = 1.03, P<.01). The 2-year NAFLD score decreased by a mean of .38 (SD = .99, P = .01). The reoperation rate for band/port related complications was 10.7% at 2 years with no mortality. MS rates improved from 27% to 2% at 2 years (P< .01).

CONCLUSIONS

LAGB is a safe and effective operation for obese adolescents with NAFLD. There was significant improvement in NAFLD scores and resolution of MS.

Screening for metabolic and reproductive complications in obese children and adolescents

Childhood obesity is associated with a number of metabolic comorbidities. These include glucose intolerance and type 2 diabetes mellitus, hyperlipidemia, fatty liver disease, and reproductive complications, such as polycystic ovary syndrome. The occurrence of these complications in a child or adolescent may result in progressive health decline at an early age. We, therefore, advocate screening and early diagnosis. This purpose of this review is to outline a rational, evidence-based approach to screening obese children and adolescents for metabolic and reproductive complications. In each section, the aim is to provide the primary care provider with a review of the literature supporting current screening practices. As such, this review is designed to assist the primary care provider in the selection and interpretation of screening tests and to make recommendations regarding the referral of patients for subspecialty care.

Evidence and recommendations for imaging liver fat in children, based on systematic review

BACKGROUND & AIMS

Fatty liver is a common problem in children and increases their risk for cirrhosis, diabetes, and cardiovascular disease. Liver biopsy is the clinical standard for diagnosing and grading fatty liver. However, noninvasive imaging modalities are needed to assess liver fat in children. We performed a systematic review of studies that evaluated imaging liver fat in children.

METHODS

We searched PubMed for original research articles in peer-reviewed journals from January 1, 1982, through December 31, 2012, using the key words "imaging liver fat." Studies included those in English, and those performed in children from birth to 18 years of age. To be eligible for inclusion, studies were required to measure hepatic steatosis via an imaging modality and a quantitative comparator as the reference standard.

RESULTS

We analyzed 9 studies comprising 610 children; 4 studies assessed ultrasonography and 5 studies assessed magnetic resonance imaging (MRI). Ultrasonography was used in the diagnosis of fatty liver with positive predictive values of 47% to 62%. There was not a consistent relationship between ultrasound steatosis score and the reference measurement of hepatic steatosis. Liver fat as measurements by MRI or by spectroscopy varied with the methodologies used. Liver fat measurements by MRI correlated with results from histologic analyses, but sample size did not allow for an assessment of diagnostic accuracy.

CONCLUSIONS

Available evidence does not support the use of ultrasonography for the diagnosis or grading of fatty liver in children. Although MRI is a promising approach, the data are insufficient to make evidence-based recommendations regarding its use in children for the assessment of hepatic steatosis.

Body composition variables as predictors of NAFLD by ultrasound in obese children and adolescents

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a disorder associated with excessive fat accumulation, mainly in the intra-abdominal region. A simple technique to estimate abdominal fat in this region could be useful to assess the presence of NAFLD, in obese subjects who are more vulnerable to this disease. The aim of this cross-sectional study was to verify the reliability of waist circumference and body composition variables to identify the occurrence of NAFLD in obese children and adolescents.

METHODS

Sample was composed of 145 subjects, aged 11 to 17 years. Assessments of waist circumference (WC), trunk fat mass (TFM) and fat mass (FM) by dual-energy X-ray absorptiometry (DXA) and ultrasound for diagnosis of NAFLD and intra-abdominal adipose tissue (IAAT) were used. Correlation between variables was made by Spearman's coefficients; ROC curve parameters (sensitivity, specificity, area under curve) were used to assess the reliability of body composition variables to assess the presence of NAFLD. Statistical significance was set at 5%.

RESULTS

Significant correlations were observed between NAFLD and WC (p = 0.001), TFM (p = 0.002) and IAAT (p = 0.001). The higher values of area under the ROC curve were for WC (AUC = 0.720), TFM (AUC = 0.661) and IAAT (AUC = 0.741).

CONCLUSIONS

Our findings indicated that TFM, IAAT and WC present high potential to identify NAFLD in obese children and adolescents.

Paediatric gastroenterology evaluation of overweight and obese children referred from primary care for suspected non-alcoholic fatty liver disease

BACKGROUND

Screening overweight and obese children for non-alcoholic fatty liver disease (NAFLD) is recommended by paediatric and endocrinology societies. However, gastroenterology societies have called for more data before making a formal recommendation.

AIM

To determine whether the detection of suspected NAFLD in overweight and obese children through screening in primary care and referral to paediatric gastroenterology resulted in a correct diagnosis of NAFLD.

METHODS

Information generated in the clinical evaluation of 347 children identified with suspected NAFLD through screening in primary care and referral to paediatric gastroenterology was captured prospectively. Diagnostic outcomes were reported. The diagnostic performance of two times the upper limit of normal (ULN) for alanine aminotransferase (ALT) was assessed.

RESULTS

Non-alcoholic fatty liver disease was diagnosed in 55% of children identified by screening and referral. Liver disease other than NAFLD was present in 18% of those referred. Autoimmune hepatitis was the most common alternative diagnosis. Children with NAFLD had significantly (P < 0.05) higher screening ALT (98 ± 95) than children with liver disease other than NAFLD (86 ± 74). Advanced fibrosis was present in 11% of children. For the diagnosis of NAFLD, screening ALT two times the clinical ULN had a sensitivity of 57% and a specificity of 71%.

CONCLUSIONS

Screening of overweight and obese children in primary care for NAFLD with referral to paediatric gastroenterology has the potential to identify clinically relevant liver pathology. Consensus is needed on how to value the risk and rewards of screening and referral, to identify children with liver disease in the most appropriate manner.

Magnetic resonance imaging of the pediatric liver: imaging of steatosis, iron deposition, and fibrosis

Traditionally, many diffuse diseases of the liver could only be diagnosed by liver biopsy. Although still considered the gold standard, liver biopsy is limited by its small sample size, invasive nature, and subjectivity of interpretation. There have been significant advances in functional magnetic resonance (MR) imaging of the liver. These advances now provide radiologists with the tools to evaluate the liver at the molecular level, allowing quantification of hepatic fat and iron, and enabling the identification of liver fibrosis at its earliest stages. These methods provide objective measures of diffuse liver processes and aid hepatologists in the diagnosis and management of liver disease.

Role of physical activity in the treatment of nonalcoholic fatty liver disease in children and adolescents

Currently, nonalcoholic fatty liver disease (NAFLD) is the most frequent liver abnormality observed in obese children and adolescents. A strong body of evidence suggests that increased liver fat is significantly associated with visceral adiposity, metabolic syndrome, and insulin resistance in obese children and adolescents. Diet and exercise are generally recommended to treat obese youth with NAFLD as they do not carry side effects and confer multiple cardiometabolic benefits. Studies in adult populations report a beneficial effect of regular physical activity on reducing liver fat. In children and adolescents, available data show that weight loss induced by increasing physical activity and calorie restriction is beneficial to reduce liver fat and associated health risk factors such as insulin resistance and dyslipidemia. Currently, evidence regarding the independent effects of regular exercise alone (e.g., without calorie restriction) on NAFLD are unclear. Additionally, there is no data regarding the optimal exercise regimen (e.g., type, dose, intensity) that should be prescribed for reducing NAFLD in children and adolescents. The purpose of this review is to examine the role of physical activity on NAFLD in children and adolescents.

Pediatric obesity

Childhood obesity is a tremendous burden for children, their families, and society. Obesity prevention remains the ultimate goal but rapid development and deployment of effective nonsurgical treatment options is not currently achievable given the complexity of this disease. Surgical options for adolescent obesity have been proven to be safe and effective and should be offered. The development of stratified protocols of increasing intensity should be individualized for patients based on their disease severity and risk factors. These protocols should be offered in multidisciplinary, cooperative clinical trials to critically evaluate and develop optimal treatment strategies for morbid obesity.

Ultrasonography as a non-invasive tool for detection of nonalcoholic fatty liver disease in overweight/obese Egyptian children

INTRODUCTION

Liver biopsy, although a gold standard in diagnosis of nonalcoholic fatty liver disease (NAFLD), is an invasive and expensive tool.

AIM

To assess the diagnostic accuracy of abdominal ultrasound in detecting NAFLD among a group of overweight/obese children having one or more liver abnormality (clinical hepatomegaly, raised ALT or echogenic liver parenchyma by ultrasound).

METHODS

Seventy-eight overweight/obese children were referred to the Pediatric Hepatology Unit, Cairo University Pediatric Hospital, Egypt, for assessment for hepatic abnormalities. Out of the 78 children, 34 had one or more abnormality in the form of clinical hepatomegaly, raised alanine aminotransferase (ALT) and/or echogenic liver parenchyma by ultrasound. All 34 cases underwent liver biopsy for evaluation for NAFLD.

RESULTS

Histological NAFLD was detected in 15 cases; 8 simple steatosis and 7 nonalcoholic steatohepatitis (NASH). Sonographic evaluation of hepatic parenchymal echogenicity revealed: 11 with grade 1 echogenicity, 12 with grade 2 and 9 with grade 3 while only 2 had normal liver echopattern. Ultrasonography was 100% sensitive and 100% specific in detecting histological NAFLD, while the positive predictive value (PPV) was 47% and negative predictive value (NPV) was 11%. After consolidating the included children into 2 groups: the first including normal and grade 1 echogenicity and the second including grades 2 and 3, the sensitivity of ultrasonography in detecting histological NAFLD was still 100%, while negative predictive value increased to 100% with an accuracy of 82%.

CONCLUSION

We conclude that ultrasonography is an important non invasive tool in assessment for NAFLD. Normal or grade 1 hepatic echogenicity can soundly exclude histological NAFLD and obviates the need for liver biopsy.

US cannot be used to predict the presence or severity of hepatic steatosis in severely obese adolescents

PURPOSE

To evaluate the diagnostic accuracy of ultrasonography (US) for the assessment of hepatic steatosis in severely obese adolescents, with proton magnetic resonance (MR) spectroscopy as the reference standard, and to provide insight on the influence of prevalence on predictive values by calculating positive and negative posttest probabilities.

MATERIALS AND METHODS

This prospective study was institutional review board approved. All participants, and/or their legal representatives, gave written informed consent. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the overall presence of steatosis and for the presence of substantial (moderate to severe) steatosis. Positive and negative posttest probabilities were calculated and plotted against prevalence.

RESULTS

A total of 104 children (47 male, 57 female) were prospectively included. Mean age was 14.5 years (range, 8.3-18.9 years) and mean age-adjusted standard deviation body mass index (BMI) score (BMI z score) was 3.3 (range, 2.6-4.1). The overall prevalence of hepatic steatosis was 46.2% (48 of 104). Sensitivity of US was 85.4% (41 of 48), specificity was 55.4% (31 of 56), PPV was 62.1% (41 of 66), and NPV was 81.6% (31 of 38). The prevalence of substantial steatosis was 15.4% (16 of 104), with US sensitivity of 75.0% (12 of 16) and specificity of 87.5% (77 of 88). PPV was 52.2% (12 of 23) and NPV was 95.1% (77 of 81). Plotting of posttest probabilities against prevalence for both disease degrees demonstrated how disease prevalence influences US accuracy.

CONCLUSION

Positive US results in severely obese adolescents cannot be used to accurately predict the presence and severity of hepatic steatosis, and additional imaging is required. Negative US results exclude the presence of substantial steatosis with acceptable accuracy. Steatosis prevalence differs among specific populations, strongly influencing posttest probabilities.

Assessment and management of obesity in childhood and adolescence

The increased prevalence of obesity in childhood and adolescence highlights the need for effective treatment approaches. Initial assessments of these patients should include taking a careful history (investigating comorbidities, family history and potentially modifiable behaviors) and physical examination with BMI plotted on a BMI-for-age chart. The degree of investigation is dependent on the patient's age and severity of obesity, the findings on history and physical examination, and associated familial risk factors. There are several broad principles of conventional management: management of comorbidities; family involvement; taking a developmentally appropriate approach; the use of a range of behavior change techniques; long-term dietary change; increased physical activity; and decreased sedentary behaviors. Orlistat can be useful as an adjunct to lifestyle changes in severely obese adolescents and metformin can be used in older children and adolescents with clinical insulin resistance. Bariatric surgery should be considered in those who are severely obese, with recognition of the need for management in centers with multidisciplinary weight management teams and for surgery to be performed in tertiary institutions experienced in bariatric surgery. Finally, given the high prevalence and chronic nature of obesity, coordinated models of care for health-service delivery for the management of pediatric obesity are needed.

Assessment and management of obesity in childhood and adolescence

The increased prevalence of obesity in childhood and adolescence highlights the need for effective treatment approaches. Initial assessments of these patients should include taking a careful history (investigating comorbidities, family history and potentially modifiable behaviors) and physical examination with BMI plotted on a BMI-for-age chart. The degree of investigation is dependent on the patient's age and severity of obesity, the findings on history and physical examination, and associated familial risk factors. There are several broad principles of conventional management: management of comorbidities; family involvement; taking a developmentally appropriate approach; the use of a range of behavior change techniques; long-term dietary change; increased physical activity; and decreased sedentary behaviors. Orlistat can be useful as an adjunct to lifestyle changes in severely obese adolescents and metformin can be used in older children and adolescents with clinical insulin resistance. Bariatric surgery should be considered in those who are severely obese, with recognition of the need for management in centers with multidisciplinary weight management teams and for surgery to be performed in tertiary institutions experienced in bariatric surgery. Finally, given the high prevalence and chronic nature of obesity, coordinated models of care for health-service delivery for the management of pediatric obesity are needed.

Pediatric nonalcoholic fatty liver disease, metabolic syndrome and cardiovascular risk

Nonalcoholic fatty liver disease (NAFLD) encompasses a range of liver histology severity and outcomes in the absence of chronic alcohol use. The mildest form is simple steatosis in which triglycerides accumulate within hepatocytes. A more advanced form of NAFLD, non-alcoholic steatohepatitis, includes inflammation and liver cell injury, progressive to cryptogenic cirrhosis. NAFLD has become the most common cause of chronic liver disease in children and adolescents. The recent rise in the prevalence rates of overweight and obesity likely explains the NAFLD epidemic worldwide. NAFLD is strongly associated with abdominal obesity, type 2 diabetes, and dyslipidemia, and most patients have evidence of insulin resistance. Thus, NAFLD shares many features of the metabolic syndrome (MetS), a highly atherogenic condition, and this has stimulated interest in the possible role of NAFLD in the development of atherosclerosis. Accumulating evidence suggests that NAFLD is associated with a significantly greater overall mortality than in the general population, as well as with increased prevalence of cardiovascular disease (CVD), independently of classical atherosclerotic risk factors. Yet, several studies including the pediatric population have reported independent associations between NAFLD and impaired flow-mediated vasodilatation and increased carotid artery intimal medial thickness-two reliable markers of subclinical atherosclerosis-after adjusting for cardiovascular risk factors and MetS. Therefore, the rising prevalence of obesity-related MetS and NAFLD in childhood may lead to a parallel increase in adverse cardiovascular outcomes. In children, the cardiovascular system remains plastic and damage-reversible if early and appropriate interventions are established effectively. Therapeutic goals for NAFLD should address nutrition, physical activity, and avoidance of smoking to prevent not only end-stage liver disease but also CVD.