Fatty liver and its fibrous changes found in simple obesity of children

Review article: epidemiology, pathogenesis and potential treatments of paediatric non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of paediatric liver disease. Similar to NAFLD in adults, NAFLD in children is associated with obesity and insulin resistance and requires liver histology for diagnosis and staging. However, significant histological differences exist between adult and paediatric NAFLD to warrant caution in extrapolation of adult data.

AIM

To review the available data on the epidemiology, pathogenesis, diagnosis and treatment of paediatric NAFLD.

METHODS

Relevant articles were identified by Medline searches using the keywords: nonalcoholic fatty liver disease, steatohepatitis, obesity and children.

RESULTS

The rise in childhood obesity has been accompanied by an increase in paediatric NAFLD. Age, gender and race/ethnicity are significant determinants of risk, and sex hormones, insulin sensitivity and adipocytokines are implicated in the pathogenesis of paediatric NAFLD. There is no consensus for treatment of NAFLD; however, data suggest that diet, exercise and some pharmacological therapies may be of benefit.

CONCLUSIONS

To evaluate and effectively treat paediatric NAFLD, the pathophysiology and natural history of the disease should be clarified and non-invasive methods for screening, diagnosis, and longitudinal assessment developed. Randomized, controlled, double-blind trials of pharmacological therapies in children with biopsy-proven disease are necessary.

Lifestyle intervention and antioxidant therapy in children with nonalcoholic fatty liver disease: a randomized, controlled trial

No proven treatment exists for nonalcoholic fatty liver disease (NAFLD) in children and adolescents. We sought to determine the efficacy of lifestyle intervention with or without antioxidant therapy in pediatric NAFLD. A total of 53 patients (age 5.7-18.8 years, 37 boys) were included. Lifestyle intervention consisting of a diet tailored to the patient's calorie needs, and increased physical activity was prescribed in all. Patients were concomitantly randomized to alpha-tocopherol 600 IU/day plus ascorbic acid 500 mg/day (n = 25) or placebo (n = 28), and treated for 24 months. The study was an extension of a previous study aimed at evaluating the effect of 12-month lifestyle intervention and antioxidant therapy on serum levels of aminotransferases. The primary end point of the present study was change in liver histology on repeated biopsy at 24 months. Secondary end points were changes in body weight, liver enzymes, and insulin sensitivity indices on 2-hour oral glucose tolerance test. The amount of weight lost at 24 months was similar in the placebo and antioxidant groups (-4.75 [range, -16-4.0] versus -5.5 [range, -12.2-0.4] kg, respectively, P = 0.9). A significant improvement occurred in the grade of steatosis, lobular inflammation, and hepatocyte ballooning, and in the NAFLD activity score in both groups. Levels of aminotransferases, triglycerides, cholesterol, fasting glucose, and insulin, and insulin sensitivity indices improved significantly as well. The improvement in all these parameters was not significantly different between the two groups.

CONCLUSION

Lifestyle intervention with diet and increased physical activity induces weight loss and is associated with a significant improvement in liver histology and laboratory abnormalities in pediatric NAFLD. Alpha-tocopherol plus ascorbic acid does not seem to increase the efficacy of lifestyle intervention alone.

Advanced hepatic fibrosis and cirrhosis due to nonalcoholic fatty liver disease in Sri Lankan children: a preliminary report

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases and may progress to advanced hepatic fibrosis and cirrhosis in some patients. Cirrhosis due to NAFLD is considered extremely rare in children in the Asia-Pacific region. We report the characteristics of 5 children with advanced hepatic fibrosis and cirrhosis due to NAFLD. Four of them were obese, and all of them had high alanine transaminase levels and ultrasonographic evidence of fatty liver. None had diabetes mellitus or hyperlipidemia. The calculated HOMA-IR was more than two in all five cases. Liver biopsy showed stage III fibrosis in 2 patients and stage IV fibrosis (cirrhosis) in 3.

Weight gain associated with chronic exposure to chlorpyrifos in rats

OBJECTIVE

This work exposed rats to low levels of the organophosphate insecticide chlorpyrifos and monitored for toxic effects, including weight gain.

METHODS

Rats received either a subcutaneous injection of chlorpyrifos, 5 mg/kg/day, or an equal volume of vehicle daily for 4 months. Subjects were observed for 30 minutes after injection for signs of acute toxicity. Body weights were recorded at baseline, 2 months, 3 months, and 4 months. At the end of the experiment, the weights of hearts, medial lobe of the livers, peri-nephric fat pads, and gastrocnemius muscles were recorded. Effects of chlorpyrifos on adipocyte differentiation in culture were studied. Results were compared using RMANOVA.

RESULTS

No signs of acute cholinergic toxicity were observed after injections in any subject. Rats in the 5 mg/kg group were significantly heavier than those in the control group by 2 months (335.7 +/- 16.7 g vs. 318.6 +/- 15.8 g; p = 0.034). This difference increased at 3 months (350.1 +/- 16.4 g vs. 322.3 +/- 21.3 g p = 0.006) and 4 months (374.4 +/- 22.2 g vs. 340.2 +/- 25.2 g p = 0.006). At 4 months, the weights of the perinephric fat pads were significantly increased in the chlorpyrifos group relative to controls (2.867 + 0.516 vs. 1.130 + 0.171, p = 0.0039). The two groups showed no weight differences between hearts, livers, and gastrocnemius muscles. Chlorpyrifos did not affect adipocyte differentiation in tissue culture.

CONCLUSIONS

Chronic exposure to chlorpyrifos at 5 mg/kg/day caused an increase in rat body weight when compared to controls. This increase was in adipose tissue. Chlorpyrifos did not induce differentiation of adipocytes in culture.

Pediatric obesity: parallels with addiction and treatment recommendations

Rates of pediatric obesity have increased dramatically over the past decade. This trend is especially alarming because obesity is associated with significant medical and psychosocial consequences. It may contribute to cardiovascular, metabolic, and hepatic complications, as well as to psychiatric difficulties. The development of obesity appears to be influenced by a complex array of genetic, metabolic, and neural frameworks, along with behavior, eating habits, and physical activity. Numerous parallels exist between obesity and addictive behaviors, including genetic predisposition, personality, environmental risk factors, and common neurobiological pathways in the brain. Typical treatments for pediatric obesity include behavioral interventions targeting diet or exercise. These treatments have yielded mixed results and typically have been examined in specialty clinic populations, limiting their generalizability. There are limited medication options for overweight children and adolescents, and no approved medical intervention in children younger than 16 years old. Bariatric surgery may be an option for some adolescents, but due to the risks of surgery, it is often seen as a last resort. The parallels between addiction and obesity aid in developing novel interventions for pediatric obesity. Motivational enhancement and cognitive-behavioral strategies used in addiction treatment may prove to be beneficial.

Fatty liver in childhood

A parenchimás szervek – mint például a máj – abnormális zsírfelhalmozódását zsíros átalakulásnak nevezzük. A máj elzsírosodásának hátterében a májsejtek zsírfelvevő és zsírleadó folyamatainak egyensúlyzavara áll, miáltal a felesleges triglicerid felhalmozódik a hepatocytákban. Normál esetben a sejtek kb. 5%-a tartalmaz trigliceridet, zsírmáj esetén ez az érték 50% fölé is emelkedhet. 50% alatt májelzsírosodásról, 50% felett zsírmájról beszélünk. Enyhébb esetben nem feltétlenül okoz sejtműködési zavart, súlyosabb formánál azonban igen, sokszor a sejthalál előfutára. A zsírmáj olyan kórállapotnak tekinthető, mely érzékennyé teszi a májat egyéb toxikus hatásokkal szemben. Nem önálló betegség, legtöbbször valamilyen ártalom, egyéb kórfolyamat kísérő jelensége. Önmagában – bizonyos súlyossági fokig (a fibrosis megjelenéséig) – reverzíbilis károsodást jelent, a kiváltó ok megszűnésekor a máj a felesleges triglicerid-tartalmát leadja. Kezelni az alapfolyamatot kell; még nem ismert olyan specifikus gyógyszer, amely a hepatocytákban lerakódott zsírt csökkenti.

Non-alcoholic fatty-liver disease in pediatric populations

The increasing prevalence of obesity is not only observed in adults. Children are affected by obesity and related diseases, such as chronic liver disease, more frequently than in the past. Nonalcoholic fatty-liver disease is an important cause of chronic liver disease and in the near future will become important worldwide. Considering this phenomenon, it is important for gastroenterologists and hepatologists to be aware of the presence of nonalcoholic fatty-liver disease in pediatric populations and to treat it adequately. This practice will have important benefits for future generations. This review discusses the most important aspects in epidemiology, diagnostics and treatment of nonalcoholic fatty-liver disease in children.

Update on non-alcoholic fatty liver disease in children

Non-alcoholic fatty liver disease (NAFLD) is probably the most common cause of liver disease in the pediatric community. It is closely associated with obesity and insulin resistance. NAFLD may lead to non-alcoholic steatohepatitis (NASH). Although NASH is a prerequisite for the definition of NAFLD in adults and children, distinct differences are often apparent in the extent or location of fat, inflammation and fibrosis. Confirmation of the diagnosis of NAFLD can usually be achieved by imaging studies; however, staging the disease requires a liver biopsy. Current treatment relies on weight loss and exercise, although various insulin-sensitizing agents, antioxidants and medications appear promising. The aim of this review is to summarize what is known about pediatric NAFLD in terms of prevalence, pathogenesis, diagnosis, histology and treatment.

Pediatric nonalcoholic fatty liver disease (NAFLD): a "growing" problem?

Nonalcoholic fatty liver disease (NAFLD) can affect both adults and children. With the current worldwide epidemic of pediatric obesity, pediatric NAFLD is increasingly being diagnosed. It is not exactly identical to NAFLD in adults, and these differences may be due in part to the occurrence of hepatic metabolic derangements typical of NAFLD during periods of active growth (infancy, mid-childhood and puberty). The natural history of pediatric NAFLD is not yet known; however, children with pediatric NAFLD can develop cirrhosis. Although details of disease mechanism in pediatric NAFLD remain unclear, hyperinsulinemia with insulin resistance appears to be critical. Determining the pathogenesis of pediatric NAFLD is likely to enhance our understanding of NAFLD in all age groups and may identify new treatment opportunities. Finding effective ways to prevent pediatric NAFLD is an important issue for children's health.

Non-alcoholic fatty liver disease and childhood obesity

Obesity has emerged as a significant global health problem in the pediatric population. Pediatric liver disease is a serious complication of childhood obesity. Non-alcoholic steatohepatitis (NASH) is an entity in the spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from fat in the liver--simple steatosis, NASH/ steatohepatitis--fat with in.ammation and/or fibrosis to advanced fibrosis and cirrhosis when fat may no longer be present. NASH is associated with obesity, diabetes, insulin resistance (IR), and hypertriglyceridemia. Children get NAFLD, and the incidence of this pediatric liver disease is rising as childhood obesity becomes increasingly prevalent. Although much remains to be learned about pediatric NAFLD, it is already evident that children with NASH risk progressive liver damage, including cirrhosis. Liver biopsy is required for definitive diagnosis, and other causes of fatty liver in childhood must be excluded. Gradual weight loss through increased regular exercise and a low-fat, low-refined carbohydrate diet appears to be effective. Drug treatments are being developed. The important message is that childhood obesity poses important health problems, including but not limited to potentially severe chronic liver disease. Early diagnosis of children who are only overweight is a worthy goal so that strategies to limit obesity can be instituted as early as possible. Identification of genetic risks is important, but management will invariably require changes in environmental factors. In addition to individual treatment, a multifaceted, societal initiative is required for solving the childhood obesity epidemic.

Risk for nonalcoholic fatty liver disease in Hispanic youth with BMI > or =95th percentile

OBJECTIVES

To characterize children at risk for nonalcoholic fatty liver disease (NAFLD) and to explore possible mechanisms underlying the development of NAFLD in Hispanic youth with a body mass index > or =95th percentile.

PATIENTS AND METHODS

Hispanic nonoverweight (n = 475) and overweight (n = 517) children, ages 4 to 19 y, were characterized in terms of body composition (dual-energy x-ray absorptiometry), maturation (Tanner stage), diet (24-h recall), physical activity (accelerometry), fitness (maximal oxygen uptake), and biochemical profile (fasting alanine aminotransferase [ALT], glucose, insulin, and lipids; inflammation markers such as adiponectin, leptin, C-reactive protein, and soluble intercellular adhesion molecule-1; and total antioxidants) using standard laboratory techniques. Risk for NAFLD was defined by fasting serum ALT values >97.5th percentile for age- and sex-specific reference values.

RESULTS

Fasting serum ALT was elevated in 24% of overweight children and in only 4% of nonoverweight children. Therefore, to identify risk factors associated with elevated ALT, the remaining statistical analysis was restricted to the overweight group. The percentage of overweight children with elevated ALT did not differ by sex, age, or Tanner stage. Weight, body mass index, z score, waist-to-hip ratio, fat-free mass, fat mass, and percent truncal fat mass were higher in the overweight children with elevated ALT. Fasting insulin, glucose, and homeostasis model-insulin resistance were higher in the overweight children with elevated ALT, as were triglycerides, total cholesterol, low-density lipoprotein, thyroid-stimulating hormone, and triiodothyronine. Fasting serum leptin, C-reactive protein, and soluble intercellular adhesion molecule-1 were significantly higher and adiponectin was lower in the overweight children with elevated ALT.

CONCLUSIONS

The risk for developing NAFLD was high in the overweight Hispanic children. The proportion of "at risk" children was not influenced by gender, age, or maturation. The risk for elevated ALT was predicted by the severity of obesity, central adiposity, hyperinsulinemia, hypertriglyceridemia, elevated thyroid-stimulating hormone, and systemic inflammation.

Non-alcoholic steatohepatitis in children

Non-alcoholic steatohepatitis (NASH) is an important liver disease in children; it can cause cirrhosis in children. The disease mechanism involves hepatic insulin resistance with hyperinsulinemia and changes in certain adipocytokines and inflammatory mediators. The differential diagnosis of childhood NASH includes metabolic disorders, drug hepatotoxicity, and alcoholic hepatitis in adolescent patients. The histologic features in childhood NASH often differ from those in adults who have NASH. Treatment is gradual weight loss through changes in food intake patterns and increased levels of physical activity; the role of drug treatment of NASH in children is an area of ongoing research.

The association between non-alcoholic fatty liver disease and insulin resistance in 20 obese children and adolescents

AIM

To investigate whether there are correlations between non-alcoholic fatty liver disease (NAFLD) and insulin resistance in obese children. For the first time, we present clinical data of 20 obese children with NAFLD, including an oral glucose tolerance test.

METHODS

Twenty obese children were diagnosed as having NAFLD by abdominal ultrasonography. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (gamma-GT) were reported. Insulin sensitivity was evaluated by oral glucose tolerance test, oral glucose insulin sensitivity (OGIS) and homeostasis is model assessment (HOMA) index. All parameters were compared to 20 obese age- and sex-matched patients without NAFLD.

RESULTS

With 81% the prevalence of insulin resistance according to HOMA or OGIS criteria was high in the NAFLD-patients compared to the other group with 63%. Statistically significant differences between both groups were found for mean serum ALT levels, mean glucose levels after 30, 60 and 90 minutes and mean insulin levels after 60 minutes of the glucose tolerance test.

CONCLUSION

The high prevalence of insulin resistance we found in children with NAFLD confirms the suggestion that there may be an association between insulin resistance and NAFLD in obese children and indicates that markers of insulin sensitivity could be useful screening parameters for NAFLD.

Predictors of non-alcoholic fatty liver disease in obese children

OBJECTIVE

To evaluate predictors of non-alcoholic fatty liver disease (NAFLD) in obese children.

DESIGN

Cross-sectional study.

SUBJECTS

Two hundred and sixty-eight obese children not consuming alcohol and without hepatitis B or C were consecutively studied at an auxology clinic.

MEASUREMENTS

Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, glucose, glucose during oral glucose tolerance testing (OGTT), insulin, insulin during OGTT, insulin resistance as estimated by homeostasis model assessment (HOMA), C-reactive protein (CRP), and systolic and diastolic blood pressure were measured. Fatty liver was diagnosed by ultrasonography using standard criteria. Univariable and multivariable logistic regression was used to evaluate predictors of NAFLD. All predictors except gender and pubertal status were modeled as continuous variables.

RESULTS

NAFLD was detected in 44% of obese children. At univariable analysis, male gender, Z-score of body mass index (BMI) (Z-BMI), ALT, AST, GGT, triglycerides, uric acid, glucose, glucose during OGTT, insulin, insulin during OGTT, HOMA, CRP and systolic blood pressure were predictors of NAFLD, whereas HDL-cholesterol and late-pubertal status were predictors of the normal liver. At multivariable analysis, however, only Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT were independent predictors of NAFLD.

CONCLUSION

Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT are independent predictors of NAFLD in Italian obese children, with most of the prediction explained by ALT and Z-BMI.

Effect of vitamin E on aminotransferase levels and insulin resistance in children with non-alcoholic fatty liver disease

BACKGROUND

Few data are available on the effect of antioxidants in paediatric non-alcoholic fatty liver disease (NAFLD).

AIM

To compare the effect of a nutritional programme alone or combined with alpha-tocopherol and ascorbic acid on alanine aminotransferase (ALT) levels, and insulin resistance (IR) in biopsy-proven NAFLD children.

METHODS

IN a 12-month double-blind placebo study, 90 patients were prescribed a balanced calorie diet (25-30 cal/kg/d), physical exercise, and placebo (group A) or alpha-tocopherol 600 IU/day plus ascorbic acid 500 mg/day (group B). IR was estimated by the homeostasis model assessment (HOMA-IR).

RESULTS

At month 12, ALT (32.67 +/- 8.09 vs. 32.18 +/- 11.39 IU/L; P = NS), HOMA-IR (1.52 +/- 0.66 vs. 1.84 +/- 0.95 IU/L; P = NS), and weight loss (32% vs. 35% of excessive body weight; P = NS) did not differ between the two arms. Among subjects who lost >or=20% of their excessive weight, ALT and body weight percentage changes were significantly related (r(o) = 0.260; P = 0.03). In subjects, who lost more than 1.0 kg, HOMA-IR significantly decreased (2.20 +/- 0.21 to 1.57 +/- 0.13 in group A (P <or= 0.01; -8%); 2.91 +/- 0.24 to 1.88 +/- 0.16 in group B (-32%; P <or= 0.0001)). ALT decreased by 36% (59.13 +/- 4.11 vs. 30.27 +/- 1.46 IU/L; P <or= 0.001), and 42% (68.19 +/- 5.68 vs. 31.92 +/- 1.92 IU/L; P <or= 0.0001). In a multivariate analysis, fasting insulin changes in group A (P = 0.012; F = 7.150).

CONCLUSIONS

Diet and physical exercise in NAFLD children seem to lead to a significant improvement of liver function and glucose metabolism beyond any antioxidant therapy.

Pediatric nonalcoholic fatty liver disease: a critical appraisal of current data and implications for future research

Although population prevalence is very difficult to establish, nonalcoholic fatty liver disease (NAFLD) is probably the most common cause of liver disease in the preadolescent and adolescent age groups. There seems to be an increase in the prevalence of NAFLD, likely related to the dramatic rise in the incidence of obesity during the past 3 decades. Despite an increase in public awareness, overweight/obesity and related conditions, such as NAFLD, remain underdiagnosed by health care providers. Accurate diagnosis and staging of nonalcoholic steatohepatitis (NASH) requires liver biopsy. The development of noninvasive surrogate markers and the advancements in imaging technology will aid in the screening of large populations at risk for NAFLD. Two distinct histological patterns of NASH have been identified in the pediatric population, and discrete clinical and demographic features are observed in children with these 2 patterns. The propensity for NASH to develop in obese, insulin-resistant pubertal boys of Hispanic ethnicity or a non-Hispanic white race may provide clues to the pathogenesis of NAFLD in children. The natural history of pediatric NASH has yet to be defined, but most biopsies in this age group demonstrate some degree of fibrosis. In addition, cirrhosis can be observed in children as young as 10 years. While the optimal treatment of pediatric NAFLD has yet to be determined, lifestyle modification through diet and exercise should be attempted in children diagnosed with NAFLD. A large, multicenter trial of vitamin E and metformin is underway as part of the NASH clinical research network.

Alanine amino transferase concentrations are linked to folate intakes and methylenetetrahydrofolate reductase polymorphism in obese adolescent girls

OBJECTIVE

The objective of this study was to investigate the consequences of low dietary folate intake and the impact of the 677 C-->T methylenetetrahydrofolate reductase (MTHFR) common mutation on liver function in obese adolescents.

METHODS

Fifty-seven obese girls (BMI = 36.1 +/- 6.0 kg/m) aged 14.1 +/- 1.5 years were included before starting a weight reduction program. Dietary intakes for folate were assessed by means of an adapted food frequency questionnaire (n = 50). Liver enzymes, plasma lipids, glucose metabolism parameters, ferritin, homocysteine and erythrocyte folate content were measured in plasma or blood obtained under fasting conditions. The MTHFR 677 C-->T polymorphism, which is associated with decreased enzyme activity, was determined using PCR. Body composition was assessed using dual x-ray absorptiometry.

RESULTS

Twenty-three subjects were heterozygote (CT) for the mutation and 5 were homozygote (TT). An increase in alanine amino transferase (ALT) and ALT/aspartate aminotransferase ratio was associated with the mutation (F = 4.46, P = 0.016 and F = 5.92, P = 0.0049, respectively). Alanine amino transferase was correlated negatively to folate intake (r = -0.32, P = 0.024) (n = 50) and positively to homocysteine concentrations (r = 0.30, P = 0.025). Body composition was similar among the 3 genotypic groups. Ferritin was also correlated to ALT concentrations of the entire group (P = 0.009).

CONCLUSION

Our data suggest that folate intake and the MTHFR polymorphism represent a part of the link between antioxidant status and liver disease in obese adolescent girls.

Food behaviors and other strategies to prevent and treat pediatric overweight

OBJECTIVE

To summarize the evidence for the following six strategies to prevent or treat overweight among children: promoting breastfeeding, promoting physical activity, reducing TV/video viewing, increasing fruit and vegetable consumption, reducing sugar-sweetened drink consumption, and reducing portion sizes.

METHODS

Summarization of the relevant literature including review articles, relevant newly published work, the Institute of Medicine's Report on Preventing Childhood Obesity and the Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity, 2001. This is not a comprehensive review.

RESULTS

Evidence for the association between each strategy and overweight varies. For breastfeeding, physical activity, and TV viewing, there are large review studies. Breastfed children may have a small reduction in risk for overweight. Participation in physical activity may reduce the risk of overweight among school-aged children and adolescents. For preschool- and school-aged children, reducing TV viewing time may reduce their risk of overweight, but most studies report small significant associations. Evidence for an association between each dietary factor and overweight is limited and inconclusive. The biggest gaps in evidence are for the effectiveness of interventions using these strategies. The reviewed interventions based on increasing physical activity (n=7) were effective. Two randomized trials suggest that reducing TV viewing reduces overweight. No intervention studies were found that examined the effectiveness of changing fruit and vegetable consumption, sugar-sweetened drink consumption, or portion sizes. Further clarification of the effect of breastfeeding on obesity is needed.

CONCLUSIONS

These six strategies are reasonable ways to attempt prevention or treatment of overweight in children. Strength of the evidence varies by strategy. The key finding is that more applied research is needed to determine the effectiveness of these and other strategies.

Nonalcoholic fatty liver disease in children

Nonalcoholic fatty liver disease (NAFLD) is likely to reach epidemic proportions in children worldwide in the next decade. NAFLD may be the hepatic aspect of the metabolic syndrome in adults and children. The entire range of liver involvement characterizing NAFLD can occur in children: hepatic macrovesicular steatosis without inflammation, steatosis with inflammation or fibrosis, and cirrhosis. NAFLD may be more severe in children from certain ethnic groups or in association with metabolic disorders characterized by abnormalities in insulin receptor structure and function. Treatment strategies focus on modifying risk factors because specific drug treatments are lacking. Overweight/obesity should be identified as early as possible. Comprehensive clinical management to normalize weight should be instituted immediately to avoid hepatic and nonhepatic complications.

The impact of obesity on severely injured children and adolescents

PURPOSE/BACKGROUND

In conjunction with the obesity epidemic in adults, we are starting to see an increase of obesity in children and adolescents. Obesity has been identified as risk factor for poor outcomes in adult trauma patients, but has not been investigated adequately in younger patients. The purpose of this study was to investigate the impact of obesity on the outcomes of a severely injured population of children and adolescents.

METHODS

Retrospective review of traumatized children (age 6-12) and adolescents (age 13-19) admitted to the intensive care unit (ICU) at an urban, level I trauma center from 1998 to 2003. The trauma registry and ICU database were used for data acquisition. Height and weight were recorded for each patient upon admission to the ICU and used to calculate body mass index (BMI). Patients were categorized as either lean (BMI <95th percentile for age) or obese (BMI > or =95th percentile for age). The two groups were compared regarding admission demographics, vital signs, mechanism of injury, patterns of injury, Injury Severity Score, and operations required. Outcomes evaluated were need for and length of mechanical ventilation, complications, length of hospital and ICU stay, and mortality.

RESULTS

There were 316 pediatric and adolescent trauma patients (262 [83%] lean, mean BMI = 23 kg/m2 and 54 [17%] obese, mean BMI = 33 kg/m2) admitted to the ICU. The lean and obese groups were similar regarding age, sex, mechanism of injury, admission vitals, injury severity, and operations required. Injury patterns were similar, except obese patients had less severe head injuries. Although there was no difference in mortality among obese (15%) and non-obese (9%) patients (P = .39), obese children did have more complications (41% vs 22%, P = .04). In addition, obese patients required longer ICU stays (8 +/- 9 vs 6 +/- 6 days, P = .05) after severe trauma.

CONCLUSIONS

Despite similar admission characteristics and less severe head injuries, obese children and adolescents have more complications and require longer ICU stays than their lean counterparts.

Hormonal and metabolic consequences of childhood obesity

It is apparent that chronic illnesses such as type 2 diabetes and cardiovascular disease originate in childhood. Obesity in childhood and adolescence hastens their development, enhances their rates of progression, increases the risks of severe complications, and if persistent, reduces life expectancy.

Metabolic, hormonal, oxidative, and inflammatory factors in pediatric obesity-related liver disease

OBJECTIVE

To examine the role of metabolic, hormonal, oxidative, and inflammatory factors in pediatric obesity-related liver disease.

STUDY DESIGN

In 50 obese children (age 7 to 14 years) with (n = 20, group 1) or without (n = 30, group 2) hypertransaminasemia and ultrasonographic liver brightness, we studied insulin resistance (fasting glucose/insulin ratio [FGIR]) and serum levels of leptin, iron, transferrin, ferritin, C-reactive protein (CRP), white blood cell (WBC) count, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, C282Y and H63D mutations, and erythrocytic glutathione peroxidase (GPX) activity.

RESULTS

FGIR (6.7 +/- 4.1 vs 9.2 +/- 5.2; P = .02), serum ferritin (88.8 +/- 36.0 vs 39.9 +/- 24.0 ng/mL; P = .0001), serum CRP (5.4 +/- 6.0 vs 1.1 +/- 1.6 mg/dL; P = 0.004), and GPX (8.4 +/- 0.9 vs 5.0 +/- 0.5 U/g Hb; P = .05) were significantly higher and more frequently deranged in group 1 than in group 2. FGIR, ferritin, and CRP values were simultaneously deranged in 41% of the group 1 patients and in none of the group 2 patients ( P = .098). Serum leptin, iron, and transferrin, WBC, TNF-alpha, IL-6, and C282Y and H63D mutations were similar in the 2 groups.

CONCLUSIONS

Insulin resistance, oxidative stress, and low-grade systemic inflammatory status are implicated in pediatric obesity-related liver disease. These findings may be useful in planning pathophysiologically based therapeutic trials for hepatopathic obese children who are unable to follow hypocaloric diets.

Overweight children and adolescents: a clinical report of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition

Childhood overweight and obesity are major health problems with immediate and long-term consequences of staggering magnitude. Despite this, there are few preventive and therapeutic strategies of proven effectiveness available to public health and clinical practitioners. Accruing such evidence is currently and appropriately a health policy priority, but there is an urgent need to intervene even before comprehensive solutions are fully established. The aim of this Clinical Report on Overweight Children and Adolescents is to present information on current understanding of pathogenesis and treatment of overweight and obesity. We report on the epidemiology, molecular biology and medical conditions associated with overweight; on dietary, exercise, behavioral, pharmacological and surgical treatments; and on the primary prevention of overweight in children and adolescents.

Perceptions of health status and play activities in parents of overweight Hispanic toddlers and preschoolers

Childhood overweight among lower socioeconomic, Hispanic children has increased. Interviews regarding health status and play patterns were conducted with 76 predominantly Hispanic mothers of overweight toddlers and preschoolers served by Women, Infants, and Children (WIC). Most participants believed their child was healthy and half were unconcerned about their child's weight. Most parents reported having a safe place to play and access to a playground, although gender differences were found. Access to an outside play area was related to amount of active play activities. Children watched an average of 1.7 hours per day of television. Health professionals must partner with parents to address childhood obesity.

Prolonged hepatitis caused by cytomegalovirus and non-alcoholic steatohepatitis in 16-year-old obese boy

Recently, the prevalence of non-alcoholic steatohepatitis (NASH) has been increasingly reported in patients with type 2 diabetes and obesity. NASH exists not only in adults but also in children. We report on an 16-year-old boy with prolonged hepatitis associated with NASH after cytomegalovirus hepatitis. Increased transaminase levels recovered in parallel to his weight reduction.

CONCLUSION

Clinicians should be aware of the possibility that prolonged acute hepatitis might be associated with non-alcoholic steatohepatitis in adolescents.

Non-alcoholic steatohepatitis in children

Obesity has emerged as a significant new health problem in the pediatric population. Non-alcoholic steatohepatitis (NASH) is an entity in the spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from fat in the liver -- simple steatosis, NASH/ steatohepatitis -- fat with inflammation and/or fibrosis to advanced fibrosis and cirrhosis when fat may no longer be present. NASH is associated with obesity, diabetes, insulin resistance (IR), and hypertriglyceridemia. While majority of individuals with risk factors like obesity and IR have steatosis only a minority develop steatohepatitis, possible mechanisms have been discussed. Clinical experience with pediatric NASH is limited. Children generally present in the prepubertal age group, have a male predominance with a higher incidence in children of Hispanic origin. Body mass index (BMI) of 25-29.9 is considered to be overweight and that > or =30 obese. Acanthosis nigricans as a marker of IR should be looked for. As NASH is a diagnosis of exclusion, other causes of chronic liver disease must be excluded. Increased echogenicity in the liver is noted on ultrasound. Liver biopsy is considered the gold standard in establishing the diagnosis. Histopathological lesions thought to be necessary for diagnosis of NASH include steatosis (macrovesicular > microvesicular), mixed mild lobular inflammation and hepatocyte ballooning. A system of grading depending on degree of steatosis and/or inflammation and staging depending on the extent of fibrosis has also been proposed. Although there is no consensus for the treatment for NASH, effort needs to be made to prevent development of fibrosis, which results in cirrhosis and portal hypertension. Slow, consistent weight loss has been shown to be effective in childhood NAFLD, based on improvement of serum aminotransferases or liver sonogram. A low glycemic index diet has been shown to be more effective than a low fat diet in lowering BMI. Family based behavioral intervention may also enhance success with diet. Several pharmacological agents have been used including ursodeoxycholic acid, vitamin E, betaine, n-acetyl cysteine, and insulin sensitizing agents like metformin, rosiglitazone, and pioglitazone. Transplantation for overt NASH is rare, accounting for < 1% of liver transplantations in the USA. The disease can recur after liver transplantation. A strong association exists between the presence of steatosis in a donor liver and poor graft function. As a result, cadaveric donor livers with macrovesicular steatosis >40% are not used routinely. Prognosis in NASH is dependent not only on severity and number of risk factors but also on the degree of histological damage. Clinical trials are needed to identify an effective treatment that halts the progression of NAFLD to NASH in both pretransplantation and post-transplantation patients.

Nonalcoholic fatty liver disease in the pediatric population

Nonalcoholic fatty liver disease (NAFLD) covers the spectrum of features found in liver laden with macrovesicular fat and variable degrees of inflammation, cell injury, and fibrosis. By definition, NAFLD excludes those with significant ingestion of alcohol or alternative potential cause of steatohepatitis. NAFLD develops with rare exception in children who are obese. Given the rapid rise in prevalence of obesity in children globally, NAFLD is now recognized as the most common cause of liver disease in pediatrics. In obese individuals, Hispanic ethnicity and male gender appear to increase risk. Recent studies suggest that insulin resistance and oxidative stress are important in pathogenesis. Treatment trials are underway to determine if reduction of insulin resistance or oxidative stress will favorably affect outcome. This review summarizes what is known about pediatric nonalcoholic steatohepatitis in terms of prevalence, demographics, clinical presentation, histology,pathogenesis, and treatment. Important differences between pediatric and adult fatty liver disease are highlighted.

Fatty liver disease in children

NAFLD/NASH is now recognised as an increasing clinical problem in children and adolescents. Risk factors include obesity, insulin resistance, and hypertriglyceridaemia. Drug hepatoxicity and genetic or metabolic diseases that can cause hepatic steatosis must be excluded. Affected children are usually asymptomatic although a few may complain of malaise, fatigue, or vague recurrent abdominal pain. Liver biopsy is the gold standard for diagnosis, and is important in determining disease severity and prognosis. The natural history of childhood NASH may be progressive liver disease for a significant minority. Long term follow up studies in this population are still lacking. The mainstay of treatment is weight reduction. The use of pharmacological therapy, though promising, ideally needs further evaluation in well designed randomised controlled studies in children.

Vitamin E treatment in pediatric obesity-related liver disease: a randomized study

OBJECTIVE

A beneficial role of antioxidants in hepatopathic obese individuals has hitherto been inferred only from uncontrolled pilot studies. The authors compared the effect of vitamin E and weight loss on transaminase values and on ultrasonographic bright liver in a controlled group of children with obesity-related liver dysfunction.

METHODS

Twenty-eight children with obesity-related hypertransaminasemia and bright liver were randomly allocated to two single-blind groups: group 1 (n = 14) treated with a low-calorie diet associated with oral placebo for 5 months, and group 2 (n = 14) treated with a low-calorie diet associated with oral vitamin E (400 mg/d x 2 months, 100 mg/d x 3 months). Transaminase values and ultrasonographic liver brightness along with weight loss and vitamin E levels were monitored.

RESULTS

Variations in transaminase levels and percentage of patients with normalized transaminase values were comparable in the two groups. The disappearance of bright liver was observed only in patients who lost weight and was twice as common in patients from group 1. Two subgroups of patients with complete normalization of transaminase values emerged as a consequence of controlled adherence to diet alone (n = 6; significant decrease of percent overweight: P = 0.0019 ) and to vitamin E alone (n = 7; unmodified percent overweight and significant increase of vitamin E/cholesterol ratio: P < 0.0001). Changes in treatment-induced alanine aminotransferase levels in these two subgroups were comparable at month 2, whereas values at month 5 were significantly lower in the subgroup adherent to diet alone (P = 0.04). In the subgroup adherent to vitamin E alone, after 2 months washout, transaminase remained stable in 5 patients and increased in 2; bright liver persisted in all.

CONCLUSIONS

Oral vitamin E warrants consideration in obesity-related liver dysfunction for children unable to adhere to low-calorie diets.

Pediatric-onset primary biliary cirrhosis

Unlike other autoimmune liver diseases, primary biliary cirrhosis (PBC) has not been reported in childhood. We report 2 cases of PBC diagnosed at 16 and 15 years of age, respectively. The first girl was noted to have increased liver enzyme levels at 16 years of age. Antimitochondrial antibody (AMA) was strongly positive, and serum quantitative immunoglobulin M level was 8.26 g/L (normal, 0.6-3 g/L). A liver biopsy specimen showed stage II PBC. Despite treatment with ursodeoxycholic acid, she developed progressive cholestasis, intractable pruritus, and a significant sensory neuropathy and weight loss eventually requiring liver transplantation. Her mother had PBC/autoimmune overlap syndrome and underwent successful liver transplantation at 34 years of age. The second girl had persistently elevated liver enzyme levels following cholecystectomy at 15 years of age for symptomatic cholelithiasis. Endoscopic retrograde cholangiopancreatography showed no abnormalities. AMA was positive at 1:160, and serum quantitative immunoglobulin was 6.96 g/L. A liver biopsy specimen showed stage II PBC, and her liver enzyme levels almost normalized after starting treatment with ursodeoxycholic acid. In conclusion, we present 2 liver biopsy-confirmed cases of pediatric-onset AMA-positive PBC. With increased awareness of early-onset PBC, further pediatric cases may be discovered.

Obesity, insulin resistance, and other clinicopathological correlates of pediatric nonalcoholic fatty liver disease

OBJECTIVE

To describe the clinical characteristics of nonalcoholic fatty liver disease (NAFLD) in children, including insulin resistance, and to test for correlation with liver pathology.

STUDY DESIGN

A retrospective review of children with biopsy-proven NAFLD at Children's Hospital San Diego from 1999 to 2002. Liver biopsy specimens were independently reviewed by two pathologists.

RESULTS

Children with NAFLD (n=43) were mostly male (70%), Hispanic American (53%) and obese (88%). The criteria for insulin resistance were met by 95% of subjects. Steatosis was predicted by the combination of quantitative insulin sensitivity check index, age, and ethnicity (P<.0001). Portal inflammation was predicted by the combination of ALT and fasting insulin (P=.0009). Perisinusoidal fibrosis was predicted by the combination of AST, fasting insulin, and BMI Z score (P<.0001). Portal fibrosis was predicted by the combination of right upper quadrant pain and homeostasis model assessment of insulin resistance (P=.0028).

CONCLUSIONS

We identified significant predictors of liver pathology in children with NAFLD. Children being evaluated for NAFLD should be screened for insulin resistance, which is nearly universal and correlates with liver histology.

Nonalcoholic steatohepatitis in children

Nonalcoholic steatohepatitis (NASH) is one entity in a spectrum of chronic liver disease related to obesity, hyperinsulinemia, insulin resistance, and liver cell injury from free fatty acid toxicity or other oxidant stress. The more inclusive term "nonalcoholic fatty liver disease" (NAFLD) is increasingly being used to encompass the entire spectrum, which includes simple hepatic steatosis without inflammation (which may not lead to progressive liver injury), NASH itself, and the resulting cirrhosis (which may be devoid of steatosis). Children get NAFLD, and the incidence of this pediatric liver disease is rising as childhood obesity becomes increasingly prevalent. Although much remains to be learned about pediatric NAFLD, it is already evident that children with NASH risk progressive liver damage, including cirrhosis. Liver biopsy is required for definitive diagnosis, and other causes of fatty liver in childhood must be excluded. Gradual weight loss through increased regular exercise and a low-fat, low-refined carbohydrate diet appears to be effective. Drug treatments are being developed. Pediatric NASH is a serious complication of childhood obesity.

Nonalcoholic fatty liver disease (NAFLD) in children

Nonalcoholic fatty liver disease (NAFLD) is common in obese children and is a growing problem, given the increase in prevalence of obesity. NAFLD is also associated with diabetes, insulin resistance, hypercholesterolemia, and hypertriglyceridemia. Although mostly benign, some children with NAFLD develop fibrosis and cirrhosis, which necessitates close monitoring. Chronically elevated plasma liver enzyme levels is the most frequent finding. Ultrasound (US) examination allows confirmation of the diagnosis and it is useful for the follow-up. Gradual and sustained weight reduction is a management option that is worth trying initially. Other modalities of management, although interesting, await evidence as well as information on long-term benefits and effects. Sustained increase of transaminases despite weight reduction is a cause for concern and may require a liver biopsy both to assess severity of liver damage and for prognostic purposes.

Steatohepatitis in children

Steatohepatitis in children occurs in the childhood version of non-alcoholic fatty liver disease (NAFLD), as a result of hepatotoxicity and with certain genetic/metabolic diseases. Until recently, NAFLD was considered to be rare in children. It is now recognized as an important childhood liver disease, especially because childhood obesity is much more common. Children with NAFLD may present as young as 4 years old; males tend to predominate; fibrosis is often found on liver biopsy and cirrhosis has been reported. Treatment for childhood NAFLD currently consists of weight reduction plus regular aerobic exercise; vitamin E may be an effective adjunctive therapy. Drug hepatotoxicity and genetic/metabolic diseases that can cause fatty liver, such as Wilson's disease and cystic fibrosis, must be excluded since treatment is radically different. Other causes of chronic hepatitis, such as chronic viral hepatitis, must also be excluded. Multisystemic inherited diseases with hyperinsulinaemia plus insulin resistance may have NAFLD as hepatic involvement and should be identified.

Obese children with steatohepatitis can develop cirrhosis in childhood

Nonalcoholic steatohepatitis, in which fatty change and inflammation of the liver occur in the absence of excess alcohol intake, is increasingly recognized in obese children. Although fibrosis is common in pediatric nonalcoholic steatohepatitis, cirrhosis has been reported rarely. The two boys reported here developed cirrhosis from nonalcoholic steatohepatitis at ages 10 and 14 yr. One child progressed to cirrhosis with symptomatic portal hypertension within a 2-yr period.

Perspectives on childhood obesity

The high prevalence of overweight and obesity in children in the United States over the past 30 years makes it a topic of great interest. This article reviews the current understanding of childhood obesity, including its causes, effects, persistence into adulthood, and treatment. Societal and familial influences are addressed, as well as genetic factors.

Childhood obesity

The pediatrician's approach to overweight was best summarized by Bruch 25 years ago: The pediatrician plays an important role in the prevention of obesity. From birth on, feeding a child always involves a dual task--namely, offering food in appropriate amounts and gearing it to the child's expression of his needs. Only in this way can he develop discriminating awareness and become active in establishing self-regulation.... If a child is fed when he is hungry, played with when he needs attention, and encouraged to be active when he is restless, he is not likely to grow up inhibited and passive or overstuffed and helpless, unable to control his eating because every discomfort is misinterpreted as a need to eat.

Pediatric obesity

Pediatric obesity can be defined as BMI > 95th percentile for age and sex from large surveys that were carried out in the past. Using these cut points, over 10% of all children and adolescents are obese, and another 10% are overweight (BMI > 85th percentile). Obesity in childhood is associated with many immediate consequences, including orthopedic, neurologic, pulmonary, gastroenterologic, endocrinologic, metabolic, and cardiovascular disorders. Psychosocial and economic problems also are seen in obese adolescents. Long-term consequences of pediatric obesity include risks for cardiovascular disease and death that are independent of adult body weight. The differential diagnosis of pediatric obesity includes many multi-system genetic syndromes and a limited number of endocrine disorders that include abnormalities in the leptin signaling pathway, but most children with excess body weight do not have an established diagnosis. Treatment is best carried out at specialized centers, and usually involves a program of behavioral modification, caloric restriction, increased activity, and decreased sedentary behaviors. Medication for pediatric obesity cannot be recommended at present outside the context of clinical trials. Gastric bypass surgery is effective, but should be considered a last resort for the child with life-threatening complications of obesity.

Nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a liver disease that, until recently, has been underrecognized as a common cause of elevated liver enzymes. This distinct clinical entity is characterized by liver biopsy findings similar to those seen in alcoholic hepatitis but in the absence of alcohol consumption sufficient to cause such changes. Patients with NASH are often middle-aged and obese, with coexisting diabetes or hyperlipidemia, but NASH also occurs in younger lean, otherwise healthy individuals and even in children. Although NASH is generally a benign disorder, it may be progressive, leading to cirrhosis and complications of portal hypertension. Liver biopsy remains the gold standard for diagnosis. Therapy for NASH remains poorly defined, although weight reduction and ursodeoxycholic acid may have a beneficial effect.

Prevalence of abnormal serum aminotransferase values in overweight and obese adolescents

OBJECTIVES

(1) To determine the prevalence of abnormal liver enzymes in overweight and obese adolescents and (2) to determine the relationship of alcohol ingestion and serum antioxidants to the presence of abnormal liver enzymes in overweight and obese adolescents.

METHODS

Serum alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase levels were measured in 2450 children between the ages of 12 and 18 years, enrolled in the National Health and Examination Survey, cycle III (NHANES III). Obesity was defined as a body mass index >95th percentile for age and sex. Overweight was defined as a body mass index >85th percentile for age and sex. Nutritional intake was assessed by 24-hour dietary recall and food frequency questionnaires. Serum antioxidants were measured by high-pressure liquid chromatography.

RESULTS

Sixty percent of adolescents with elevated ALT levels were either overweight or obese. Overall, 6% of overweight adolescents had elevated ALT levels (odds ratio: 3.4 [95% CI: 3.5-12.8]). Ten percent of obese adolescents had elevated ALT levels (odds ratio: 6.7 [95% CI: 3.5-12.8]). In addition, approximately 1% of obese adolescents demonstrated ALT levels over twice normal. Approximately 50% of of obsese adolescents who reported modest alcohol ingestion (4 times per month or more) had elevated ALT levels (odds ratio: 10.8, 95% CI: 1.5-77). Other factors associated with elevated ALT levels in overweight and obese adolescents include increased age, elevated glycolated hemoglobin, elevated triglycerides, and decreased levels of serum antioxidants-vitamin E, beta-carotene, and vitamin C.

CONCLUSION

Overweight and obesity are the most common findings in adolescents with elevated ALT levels. Even modest alcohol consumption may significantly increase the likelihood of obese adolescents developing obesity-related liver disease.

Vitamin E treatment of nonalcoholic steatohepatitis in children: a pilot study

AIM

To determine whether supplemental oral vitamin E is effective in lowering serum aminotransferase and alkaline phosphatase levels in children with nonalcoholic steatohepatitis (NASH) associated with obesity.

STUDY DESIGN

Open-label pilot study enrolling all children <16 years old with chronically elevated serum aminotransferase (alanine aminotransferase and aspartate aminotransferase) levels for greater than 3 months, who demonstrated a diffusely echogenic liver on ultrasonography, had no demonstrable reason for abnormal serum chemistry values other than obesity, and therefore were diagnosed to have NASH. Patients were prescribed oral vitamin E between 400 and 1200 IU per day. Serum chemistry values were monitored monthly during treatment.

RESULTS

Eleven subjects with a mean age of 12.4 years were enrolled; treated patients were followed up for 4 to 10 months. The body mass index did not change significantly before and after treatment (32.8 +/- 3.8 kg/m(2) vs 32.5 +/- 4.4 kg/m(2), respectively). Serum alanine aminotransferase decreased from 175 +/- 106 IU/L to 40 +/- 26 IU/L (P <.001, paired Student t test), serum aspartate aminotransferase decreased from 104 +/- 61 IU/L to 33 +/- 11 IU/L (P <.002), and alkaline phosphatase decreased from 279 +/- 42 IU/L to 202 +/- 66 IU/L (P <.003) during treatment. Serum aminotransferase levels remained normal during treatment but returned to abnormal in those electing to stop treatment. Serum alpha-tocopherol levels were within the normal range before the commencement of therapy and increased significantly with supplementation. The liver remained diffusely echogenic during therapy, at the time serum aminotransferase levels were reduced.

CONCLUSIONS

Daily oral vitamin E administration normalized serum aminotransferase and alkaline phosphatase levels in children with NASH. Obese children with NASH should be encouraged to lose weight as part of a comprehensive weight reduction program and to consider taking supplemental alpha-tocopherol.