Gender-specific prevalences of fatty liver in obese children and adolescents: roles of body fat distribution, sex steroids, and insulin resistance

Interobserver reproducibility of the controlled attenuation parameter (CAP) for quantifying liver steatosis

PURPOSE

This study was conducted to prospectively investigate the interobserver reproducibility of controlled attenuation parameter (CAP) measurements and the relationship among the CAP and body mass index (BMI), gender and age.

METHODS

Consecutive subjects were studied using the M+ probe of the FibroScan device (Echosens, Paris, France). Measurements were performed by two raters (rater1 and rater2). Interobserver agreement was assessed by using the concordance correlation coefficient (CCC). The Pearson r coefficient was used to test correlation between two study variables, and linear regression was used for the multivariate model.

RESULTS

Three hundred fifty-one subjects (227 males and 124 females) were prospectively studied. The CCC was 0.82 (95 % CI 0.78-0.85) overall, 0.80 (95 % CI 0.75-0.85) for BMI <25 kg/m(2), 0.76 (95 % CI 0.69-0.84) for BMI 25-29 kg/m(2) and 0.65 (95 % CI 0.41-0.88) for BMI ≥30 kg/m(2). The CCC was 0.44 (95 % CI 0.31-0.56) for CAP values ≤240 dB/m and 0.72 (95 % CI 0.65-0.79) for CAP values >240 dB/m. In univariate analysis, age and BMI by gender were correlated with the CAP. Multiple regression analysis confirmed the relationship of the CAP with age and BMI, but not with gender.

CONCLUSIONS

The results of this study show that the interreader agreement in CAP measurement is good. In healthy volunteers, the CAP is strongly correlated with age and BMI.

Predicting hepatic steatosis in a racially and ethnically diverse cohort of adolescent girls

OBJECTIVE

To develop a risk assessment model for early detection of hepatic steatosis using common anthropometric and metabolic markers.

STUDY DESIGN

This was a cross-sectional study of 134 adolescent and young adult females, age 11-22 years (mean 13.3±2 years) from a middle school and clinics in Madison, Wisconsin. The ethnic distribution was 27% Hispanic and 73% non-Hispanic; the racial distribution was 64% Caucasian, 31% African-American, and 5% Asian, Fasting glucose, fasting insulin, alanine aminotransferase (ALT), body mass index (BMI), waist circumference (WC), and other metabolic markers were assessed. Hepatic fat was quantified using magnetic resonance imaging proton density fat fraction (MR-PDFF). Hepatic steatosis was defined as MR-PDFF>5.5%. Outcome measures were sensitivity, specificity, and positive predictive value (PPV) of BMI, WC, ALT, fasting insulin, and ethnicity as predictors of hepatic steatosis, individually and combined, in a risk assessment model. Classification and regression tree methodology was used to construct a decision tree for predicting hepatic steatosis.

RESULTS

MR-PDFF revealed hepatic steatosis in 16% of subjects (27% overweight, 3% nonoverweight). Hispanic ethnicity conferred an OR of 4.26 (95% CI, 1.65-11.04; P=.003) for hepatic steatosis. BMI and ALT did not independently predict hepatic steatosis. A BMI>85% combined with ALT>65 U/L had 9% sensitivity, 100% specificity, and 100% PPV. Lowering the ALT value to 24 U/L increased the sensitivity to 68%, but reduced the PPV to 47%. A risk assessment model incorporating fasting insulin, total cholesterol, WC, and ethnicity increased sensitivity to 64%, specificity to 99% and PPV to 93%.

CONCLUSION

A risk assessment model can increase specificity, sensitivity, and PPV for identifying the risk of hepatic steatosis and guide the efficient use of biopsy or imaging for early detection and intervention.

The effect of antenatal factors and postnatal growth on serum adiponectin levels in children

Low levels of serum adiponectin (i.e. hypoadiponectinaemia) are a marker of cardiometabolic risk in overweight children. It is not clear whether early-life factors may play a role in the development of hypoadiponectinaemia. We investigated whether antenatal factors and postnatal growth are associated with childhood adiponectin levels. This was an observational study in a birth cohort (Vulnerable Windows Cohort Study). Anthropometry was measured at birth, at 6 weeks, every 3 months up to 2 years and then every 6 months. Fasting glucose, insulin, lipids and adiponectin were measured at a mean age 11.5 years. Data on 323 children were analysed with age- and sex-adjusted multivariate analyses. The sizes of mother, placenta, fetus and newborn were not significantly associated with adiponectin levels. Current weight, body mass index (BMI), fat mass, waist circumference, glucose, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)], triglycerides and systolic blood pressure were inversely related to adiponectin (P < 0.05). Faster growth in BMI during late infancy and childhood was associated with lower adiponectin levels (P < 0.05). After adjusting for current waist circumference, faster growth in BMI during early infancy was positively associated with adiponectin (P < 0.01). Faster growth in BMI during childhood was inversely associated (P < 0.001). These associations were similar after adjusting for HOMA-IR. We concluded that antenatal factors are not determinants of childhood adiponectin levels. Faster growth in BMI during infancy is associated with higher levels, whereas faster rates during childhood are associated with hypoadiponectinaemia. Hypoadiponectinaemia is a marker of a more adverse cardiometabolic profile in Afro-Caribbean children.

Prevalence, risk factors, and predictors of nonalcoholic fatty liver disease among schoolchildren: a hospital-based study in Alexandria, Egypt

BACKGROUND AND STUDY AIMS

Nonalcoholic fatty liver disease (NAFLD) is an emerging problem in children and adolescents worldwide. This study was done to investigate the prevalence of NAFLD in children and adolescents as well as to determine the associated risk factors of fatty liver and to explore the ability of some obesity indices to predict and consequently be used as a screening method of fatty liver disease at certain cutoff points in schoolchildren.

PATIENTS AND METHODS

A cross-sectional, nested case-control study was carried out. Cases and controls were randomly selected from outpatient schoolchildren aged 6-18years attending the radiology clinic at Sporting Health Insurance Paediatric Hospital in Alexandria. They were subjected to ultrasonic examination as well as complete anthropometric and laboratory measurements including fasting plasma glucose (FPG) level, fasting insulin, alanine aminotransferase (ALT) level, and lipid profile.

RESULTS

Fatty liver was prevalent in schoolchildren (15.8%) and increased significantly with age (p=0.004). Positive family history of diabetes mellitus (DM), hypertension (HTN), obesity, and liver disease were all statistically significant risk factors for fatty liver. Waist circumference (WC), body mass index (BMI) and its Z-score were significantly sensitive predictors. BMI was considered the best predictor of paediatric NAFLD at a cutoff=22.9. NAFLD was significantly associated with high triglycerides (TGs), low high-density lipoprotein cholesterol (HDL), homoeostatic model assessment (HOMA) percentile, and the number of metabolic syndrome (MS) components.

CONCLUSION

Paediatric NAFLD is a substantial problem in schoolchildren and has a close relationship with obesity, dyslipidaemia, insulin resistance (IR), and consequently MS. BMI and WC can be used as useful predictors and screening tools for NAFLD in schoolchildren.

Gender and racial differences in nonalcoholic fatty liver disease

Due to the worldwide epidemic of obesity, nonalcoholic fatty liver disease (NAFLD) has become the most common cause of elevated liver enzymes. NAFLD represents a spectrum of liver injury ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) which may progress to advanced fibrosis and cirrhosis. Individuals with NAFLD, especially those with metabolic syndrome, have higher overall mortality, cardiovascular mortality, and liver-related mortality compared with the general population. According to the population-based studies, NAFLD and NASH are more prevalent in males and in Hispanics. Both the gender and racial ethnic differences in NAFLD and NASH are likely attributed to interaction between environmental, behavioral, and genetic factors. Using genome-wide association studies, several genetic variants have been identified to be associated with NAFLD/NASH. However, these variants account for only a small amount of variation in hepatic steatosis among ethnic groups and may serve as modifiers of the natural history of NAFLD. Alternatively, these variants may not be the causative variants but simply markers representing a larger body of genetic variations. In this article, we provide a concise review of the gender and racial differences in the prevalence of NAFLD and NASH in adults. We also discuss the possible mechanisms for these disparities.

Ectopic fat in youth: the contribution of hepatic and pancreatic fat to metabolic disturbances

OBJECTIVE

To study the relationships between parameters of glucose and insulin metabolism and visceral and abdominal ectopic fat in youth.

METHODS

A cross sectional study of 50 children (24 females), 8-18 years old. Anthropometrics, body composition, blood-work and visceral and ectopic fat by magnetic resonance imaging were assessed. Insulin secretion, insulin sensitivity and beta cell function were calculated from an oral glucose tolerance test.

RESULTS

BMI z-scores ranged between -1.3 and 4.5. The hepatic fat fraction (HFF) ranged between 0 and 36% and pancreatic fat fraction (PFF) between 0 and 14%. Visceral fat, HFF and PFF were associated with clinical and biochemical metabolic abnormalities, and correlated with markers of insulin sensitivity (r = -0.60, P < 0.01; r = -0.64, P < 0.01; r = -0.48, P < 0.01, respectively) insulin secretion (r = 0.55, P < 0.01; r = 0.57, P < 0.01; r = 0.41, P < 0.01, respectively), and beta cell function (r = -0.49, P < 0.01; r = -0.59, P < 0.01; r = -0.39, P < 0.01, respectively).

CONCLUSIONS

Accumulations of pancreatic and hepatic fat have complementary clinical consequences in youth. While visceral and hepatic fat demonstrated a dominant effect, even relatively small degrees of pancreatic fat deposition may contribute to metabolic alterations.

Hepatic glucose intolerance precedes hepatic steatosis in the male aromatase knockout (ArKO) mouse

Estrogens are known to play a role in modulating metabolic processes within the body. The Aromatase knockout (ArKO) mice have been shown to harbor factors of Metabolic syndrome with central adiposity, hyperinsulinemia and male-specific hepatic steatosis. To determine the effects of estrogen ablation and subsequent replacement in males on whole body glucose metabolism, three- and six-month-old male ArKO mice were subjected to whole body glucose, insulin and pyruvate tolerance tests and analyzed for ensuing metabolic changes in liver, adipose tissue, and skeletal muscle. Estrogen-deficient male ArKO mice showed increased gonadal adiposity which was significantly reduced upon 17β-estradiol (E2) treatment. Concurrently, elevated ArKO serum leptin levels were significantly reduced upon E2 treatment and lowered serum adiponectin levels were restored to wild type levels. Three-month-old male ArKO mice were hyperglycemic, and both glucose and pyruvate intolerant. These phenotypes continued through to 6 months of age, highlighting a loss of glycemic control. ArKO livers displayed changes in gluconeogenic enzyme expression, and in insulin signaling pathways upon E2 treatment. Liver triglycerides were increased in the ArKO males only after 6 months of age, which could be reversed by E2 treatment. No differences were observed in insulin-stimulated ex vivo muscle glucose uptake nor changes in ArKO adipose tissue and muscle insulin signaling pathways. Therefore, we conclude that male ArKO mice develop hepatic glucose intolerance by the age of 3 months which precedes the sex-specific development of hepatic steatosis. This can be reversed upon the administration of exogenous E2.

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.

Glucose homeostasis and insulin resistance: prevalence, gender differences and predictors in adolescents

BACKGROUND

Adolescence, due to transient pubertal insulin resistance (IR), is associated with a higher risk for disturbances of glucose metabolism. The aim of our study was 1) to investigate the prevalence of disturbances of glucose metabolism, 2) to define gender specific homeostasis model assessment of insulin resistance (HOMA-IR) thresholds associated with increased cardiometabolic risks and 3) to provide predictors of HOMA-IR.

METHODS

The studied cohort consisted of Czech adolescents aged 13.0-17.9 years: 1,518 individuals of general population and three studied groups according weight category (615 normal weight, 230 overweight and 683 obese). The prevalence of IR, impaired fasting glucose (IFG) and type 2 diabetes was assessed. Risky HOMA-IR thresholds based on components of metabolic syndrome were investigated. HOMA-IR prediction was calculated taking into account age, blood pressure, multiple anthropometric, biochemical and hormonal parameters.

RESULTS

In general population cohort, the prevalence of IFG and type 2 diabetes was 7.0% and <0.5%, respectively. Boys regardless of weight presented significantly higher levels of blood glucose and higher prevalence of IFG than girls. Obese boys were found more insulin resistant than obese girls. HOMA-IR thresholds of 3.6 for girls and 4.4 for boys were associated with increased cardiometabolic risks. For both genders, the model of HOMA-IR prediction was composed of age, BMI, ratio of free triiodthyronine to free thyroxine, gamma-glutamyltransferase activity and levels of triglycerides and sex hormone-binding globulin.

CONCLUSIONS

The type 2 diabetes in adolescents, including those who were obese, was rarely diagnosed. Obese adolescent boys were at greater risk for IR and for IFG than obese girls. In adolescence, thresholds of HOMA-IR in contrast to predictors were found gender specific.

Nonalcoholic fatty liver disease in prepubertal children born small for gestational age: influence of rapid weight catch-up growth

BACKGROUND/AIMS

We studied the association of low birth weight with ultrasound-assessed nonalcoholic fatty liver disease (NAFLD) to test the hypothesis that fetal growth retardation followed by a rapid weight catch-up growth might be an additional factor responsible for liver steatosis via insulin resistance (IR) and/or intra-abdominal fat.

METHODS

We enrolled 23 children born small for gestational age (SGA) with a rapid catch-up growth within the first 6-12 months, and 24 appropriate for gestational age (AGA) children as controls. All children underwent anthropometric, body composition measurements and evaluation of liver function tests, lipid profile, plasma glucose and insulin levels. Abdominal ultrasonography was performed in order to asses liver steatosis and thickness of subcutaneous and visceral adipose tissue.

RESULTS

NAFLD were observed in 8 out of the 23 SGA children (34.8%). IR and visceral fat were significantly increased in children with hepatic steatosis compared to those without. IR index was significantly related to liver steatosis, independently of body mass index standard deviation score and visceral fat.

CONCLUSIONS

NAFLD should be recognized as an emerging problem in SGA prepubertal children who presented a rapid weight gain in postnatal life, and IR plays the key role. An appropriate diet during pregnancy and in the first year of life might prevent metabolic syndrome and NAFLD in these subjects.

Sex differences in the hepatic cholesterol sensing mechanisms in mice

Cholesterol is linked to many multifactorial disorders, including different forms of liver disease where development and severity depend on the sex. We performed a detailed analysis of cholesterol and bile acid synthesis pathways at the level of genes and metabolites combined with the expression studies of hepatic cholesterol uptake and transport in female and male mice fed with a high-fat diet with or without cholesterol. Lack of dietary cholesterol led to a stronger response of the sterol sensing mechanism in females, resulting in higher expression of cholesterogenic genes compared to males. With cholesterol in the diet, the genes were down-regulated in both sexes; however, males maintained a more efficient hepatic metabolic flux through the pathway. Females had higher content of hepatic cholesterol but this was likely not due to diminished excretion but rather due to increased synthesis and absorption. Dietary cholesterol and sex were not important for gallbladder bile acids composition. Neither sex up-regulated Cyp7a1 upon cholesterol loading and there was no compensatory up-regulation of Abcg5 or Abcg8 transporters. On the other hand, females had higher expression of the Ldlr and Cd36 genes. These findings explain sexual dimorphism of cholesterol metabolism in response to dietary cholesterol in a high-fat diet in mice, which contributes to understanding the sex-basis of cholesterol-associated liver diseases.

Prevalence and predictors of alanine aminotransferase elevation among normal weight, overweight and obese youth in Mexico

OBJECTIVE

This study aimed to determine the prevalence of and risk factors associated with elevated alanine aminotransferase (ALT) levels among a sample of normal weight, overweight and obese youth from two urban populations in Central Mexico.

METHODS

Baseline data from 1262 youth aged 8-19 years who participated in the Mexican Health Worker Cohort Study from March 2004 to April 2006 were reviewed, including 680 girls and 582 boys, with a total of 83 participants with elevated ALT level (>40 U/L). Information was obtained from self-administered questionnaires, anthropometric results and clinical measurements. Associations of interest were examined using multivariate logistic regression models.

RESULTS

A total of 3.8% of girls and 9.8% of boys had elevated ALT levels. Elevated ALT was observed in 28.9% of the obese and 14.2% of the overweight participants. Metabolic syndrome (MS) occurred in 6.1% of the study population and those with MS had a high percentage of elevated ALT (14.5% of girls and 40.0% of boys, respectively). Abdominal obesity and insulin resistance were also associated with a greater risk of elevated ALT.

CONCLUSIONS

Obesity and certain metabolic risk factors are important predictors for elevated ALT. Screening for ALT levels in obese youth could help to identify those at risk and reduce the possibility of future liver diseases.

Herbal medicines for fatty liver diseases

BACKGROUND

Fatty liver disease is potentially a reversible condition that may lead to end-stage liver disease. Since herbal medicines such as Crataegus pinnatifida and Salvia miltiorrhiza have increasingly been used in the management of fatty liver disease, a systematic review on herbal medicine for fatty liver disease is needed.

OBJECTIVES

To assess the beneficial and harmful effects of herbal medicines for people with alcoholic or non-alcoholic fatty liver disease.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2012), MEDLINE, EMBASE, and Science Citation Index Expanded to 1 March 2012. We also searched the Chinese BioMedical Database, Traditional Chinese Medical Literature Analysis and Retrieval System, China National Knowledge Infrastructure, Chinese VIP Information, Chinese Academic Conference Papers Database and Chinese Dissertation Database, and the Allied and Complementary Medicine Database to 2 March 2012.

SELECTION CRITERIA

We included randomised clinical trials comparing herbal medicines with placebo, no treatment, a pharmacological intervention, or a non-pharmacological intervention such as diet or lifestyle, or Western interventions in participants with fatty liver disease.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. We used the 'risk of bias' tool to assess the risk of bias of the included trials. We assessed the following domains: random sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting, and other sources of bias. We presented the effects estimates as risk ratios (RR) with 95% confidence intervals (CI) or as mean differences (MD) with 95% CI, depending on the variables of the outcome measures.

MAIN RESULTS

We included 77 randomised clinical trials, which included 6753 participants with fatty liver disease. The risks of bias (overestimation of benefits and underestimation of harms) was high in all trials. The mean sample size was 88 participants (ranging from 40 to 200 participants) per trial. Seventy-five different herbal medicine products were tested. Herbal medicines tested in the randomised trials included single-herb products (Gynostemma pentaphyllum, Panax notoginseng, and Prunus armeniaca), proprietary herbal medicines commercially available, and combination formulas prescribed by practitioners. The most commonly used herbs were Crataegus pinnatifida,Salvia miltiorrhiza,Alisma orientalis,Bupleurum Chinense,Cassia obtusifolia, Astragalus membranaceous, and Rheum palmatum. None of the trials reported death, hepatic-related morbidity, quality of life, or costs. A large number of trials reported positive effects on putative surrogate outcomes such as serum aspartate aminotransferase, alanine aminotransferase, glutamyltransferase, alkaline phosphatases, ultrasound, and computed tomography scan. Twenty-seven trials reported adverse effects and found no significant difference between herbal medicines versus control. However, the risk of bias of the included trials was high.The outcomes were ultrasound findings in 22 trials, liver computed tomography findings in eight trials, aspartate aminotransferase levels in 64 trials, alanine aminotransferase activity in 77 trials, and glutamyltransferase activities in 44 trials. Six herbal medicines showed statistically significant beneficial effects on ultrasound, four on liver computed tomography, 42 on aspartate aminotransferase activity, 49 on alanine aminotransferase activity, three on alkaline phosphatases activity, and 32 on glutamyltransferase activity compared with control interventions.

AUTHORS' CONCLUSIONS

Some herbal medicines seemed to have positive effects on aspartate aminotransferase, alanine aminotransferase, ultrasound, and computed tomography. We found no significant difference on adverse effects between herbal medicine and control groups. The findings are not conclusive due to the high risk of bias of the included trials and the limited number of trials testing individual herbal medicines. Accordingly, there is also high risk of random errors.

[Non-alcoholic fatty liver disease in obese children and adolescents]

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in children and adolescents in industrialized countries. Recent studies have demonstrated a prevalence rate of NAFLD in overweight and obese children and adolescents in Germany of up to 30%. The spectrum of NAFLD ranges from pure fatty infiltration (simple steatosis) to inflammation (steatohepatitis, synonymous NASH) to fibrosis and cirrhosis. Age, gender, ethnicity, insulin resistance, and sex steroids are implicated in the pathogenesis of NAFLD in childhood and adolescence. Moreover, NAFLD in the pediatric age group is associated with marked cardiovascular comorbidities. This review focuses on current data regarding epidemiology, pathophysiology, comorbidities, and treatment of NAFLD in children and adolescents.

Serum retinol-binding protein 4 is independently associated with pediatric NAFLD and fasting triglyceride level

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is identified as a major liver disease in children. The present study aimed to identify the prevalence and predictors of pediatric NAFLD and the correlation between serum retinol-binding protein 4 (RBP4) levels and metabolic characteristics in children.

METHODS

A total of 748 schoolchildren, ages 6 to 12 years, were enrolled in 2009. The body weight and height were measured in the morning before intake. Laboratory tests included overnight fasting serum lipids, insulin, liver enzymes, and RBP4 levels. Hepatic steatosis was determined by ultrasound in 219 volunteers.

RESULTS

The rates of NAFLD were 3% in the normal-weight, 25% in the overweight, and 76% in the obese children. Twenty (22%) of obese children had abnormal alanine aminotransferase (ALT) levels. In children with NAFLD, younger age and higher body mass index (BMI), insulin/homeostasis model of assessment, and male sex rate were associated with abnormal liver function. Stepwise increments in BMI, insulin, homeostasis model of assessment, and ALT were found in children with normal livers to simple steatosis, and to steatosis with abnormal ALT. Multiple logistic regression analysis confirmed that serum RBP4 levels (P = 0.048), ALT (P = 0.048), and BMI (P < 0.001) were independently predictors of pediatric NAFLD. Moreover, multiple linear regression analysis revealed that only serum triglycerides levels were positively related to RBP4 levels (P < 0.001).

CONCLUSIONS

Higher RBP4 and ALT levels as well as BMI are independently associated with pediatric NAFLD in Taiwan. In addition, an increment in RBP4 levels was positively correlated to hypertriglyceridemia in children.

Female mice are more susceptible to nonalcoholic fatty liver disease: sex-specific regulation of the hepatic AMP-activated protein kinase-plasminogen activator inhibitor 1 cascade, but not the hepatic endotoxin response

As significant differences between sexes were found in the susceptibility to alcoholic liver disease in human and animal models, it was the aim of the present study to investigate whether female mice also are more susceptible to the development of non-alcoholic fatty liver disease (NAFLD). Male and female C57BL/6J mice were fed either water or 30% fructose solution ad libitum for 16 wks. Liver damage was evaluated by histological scoring. Portal endotoxin levels and markers of Kupffer cell activation and insulin resistance, plasminogen activator inhibitor 1 (PAI-1) and phosphorylated adenosine monophosphate-activated protein kinase (pAMPK ) were measured in the liver. Adiponectin mRNA expression was determined in adipose tissue. Hepatic steatosis was almost similar between male and female mice; however, inflammation was markedly more pronounced in livers of female mice. Portal endotoxin levels, hepatic levels of myeloid differentiation primary response gene (88) (MyD88) protein and of 4-hydroxynonenal protein adducts were elevated in animals with NAFLD regardless of sex. Expression of insulin receptor substrate 1 and 2 was decreased to a similar extent in livers of male and female mice with NAFLD. The less pronounced susceptibility to liver damage in male mice was associated with a superinduction of hepatic pAMPK in these mice whereas, in livers of female mice with NAFLD, PAI-1 was markedly induced. Expression of adiponectin in visceral fat was significantly lower in female mice with NAFLD but unchanged in male mice compared with respective controls. In conclusion, our data suggest that the sex-specific differences in the susceptibility to NAFLD are associated with differences in the regulation of the adiponectin-AMPK-PAI-1 signaling cascade.

Principal component analysis reveals gender-specific predictors of cardiometabolic risk in 6th graders

Background

The purpose of this study was to determine the sex-specific pattern of pediatric cardiometabolic risk with principal component analysis, using several biological, behavioral and parental variables in a large cohort (n = 2866) of 6th grade students.

Methods

Cardiometabolic risk components included waist circumference, fasting glucose, blood pressure, plasma triglycerides levels and HDL-cholesterol. Principal components analysis was used to determine the pattern of risk clustering and to derive a continuous aggregate score (MetScore). Stratified risk components and MetScore were analyzed for association with age, body mass index (BMI), cardiorespiratory fitness (CRF), physical activity (PA), and parental factors.

Results

In both boys and girls, BMI and CRF were associated with multiple risk components, and overall MetScore. Maternal smoking was associated with multiple risk components in girls and boys, as well as MetScore in boys, even after controlling for children’s BMI. Paternal family history of early cardiovascular disease (CVD) and parental age were associated with increased blood pressure and MetScore for girls. Children’s PA levels, maternal history of early CVD, and paternal BMI were also indicative for various risk components, but not MetScore.

Conclusions

Several biological and behavioral factors were independently associated with children’s cardiometabolic disease risk, and thus represent a unique gender-specific risk profile. These data serve to bolster the independent contribution of CRF, PA, and family-oriented healthy lifestyles for improving children’s health.

Anthropometric measures of visceral and subcutaneous fat are important in the determination of metabolic dysregulation in boys and girls at risk for nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasing at alarming rates in obese children. The study aim was to describe body composition/somatotype and its interrelationships to biomarkers of liver disease, insulin resistance, and lipid and cytokine expression in youth with NAFLD.

METHODS

Somatotype and body composition of children (7-18 years) diagnosed with NAFLD (n= 18) were compared with obese (n = 11) and lean children (n = 17). Anthropometric variables assessed included weight, height, body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHTR), and multiple skinfold thicknesses. Fat mass (FM) and somatotype analysis were measured using validated methodologies. Fasting liver biochemistries (aspartate aminotransferase [AST], alanine aminotransferase [ALT], γ-glutamyltransferase [GGT]), insulin, glucose, leptin, C-reactive protein (CRP), tumor necrosis factor-α, interleukin (IL) factors 6/10, apolipoproteins B-100/B-48 and C-III, triglycerides, and high-density lipoprotein (HDL)/low-density lipoprotein (LDL) cholesterol were measured. Insulin resistance was assessed by the homeostasis model of insulin resistance (HOMA-IR).

RESULTS

BMI z score, WC, FM, and somatotype did not differ between NAFLD and obese groups; however, lean children were lighter/leaner across all anthropometric measures (P < .001). Children with NAFLD had a higher sum-of-trunk to sum-of-extremity ratio (1.6 ± 0.4) than did obese (1.3 ± 0.2) and lean (1.1 ± 0.5) children (P < .001). Markers of central visceral (WC/WHTR) and subcutaneous fat (subscapular, abdominal, suprailiac skinfolds) were associated with elevated plasma concentrations of insulin, HOMA-IR, ALT, GGT, and AST and lower HDL cholesterol and IL-10 (P < .001).

CONCLUSION

Comprehensive assessment of body composition, including measurement of surrogate markers of subcutaneous and visceral fat, provides information regarding metabolic dysregulation and liver disease risk in obese children with NAFLD.

Importance of the liver ultrasound scores in pubertal obese children with nonalcoholic fatty liver disease

AIM

The purpose of our study was to determine the relationship between liver ultrasound scores and insulin sensitivity in a population of obese children with nonalcoholic fatty liver disease (NAFLD) and the relationships between other metabolic features and ultrasound scores.

METHODS

One hundred sixty-nine obese adolescents, 96 girls, and 73 boys (mean age: 12.7 ± 1.3 years, mean body mass index: 26.3 ± 4.6) were enrolled the study. The obese subjects were divided into 2 groups based on their pubertal status. Ultrasonography findings were scored in this study included hepatorenal echo contrast, liver brightness, deep attenuation, and vascular blurring. Scores ranged from 0 to 6 points, and NAFLD was defined if ultrasound score was ≥ 1. Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR) from fasting samples.

RESULTS

Prevalence of NAFLD in pubertal children (61.9%) had significantly higher than pre-pubertal children (40.8%) (P=.008). Transaminases ratio was significantly correlated in both prepubertal (r=0.231; P=.03) and pubertal (r=0.628, P=0.017) groups. HOMA-IR values were elevated in both groups; however, liver ultrasound score was positively correlated with HOMA-IR (r=0.735, P=.014) in pubertal children.

CONCLUSION

NAFLD prevalence among obese children is quite high, especially pubertal adolescents than prepubertal children. We demonstrated an association between insulin resistance and NAFLD ultrasound scoring in pubertal obese children. We suggested that ultrasound examination of the liver be included in the routine check-up of the pubertal obese children with insulin resistance to allow the detection of NAFLD at an early stage.

Keratin 18, Apoptosis, and Liver Disease in Children

Keratins, a major component of epithelial cell intermediate filaments, provide structural support to the cell and are important for the maintenance of structural integrity. Beyond its role of structural integrity in hepatocytes, keratin 18 (K18) is a known marker of apoptosis and has been proposed as an indicator of progression in chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common cause of chronic liver disease in children and adolescents in the United States and throughout the world and comprises a wide spectrum of disease ranging from simple steatosis (fatty liver) to nonalcoholic steatohepatitis (NASH) and cirrhosis. While simple steatosis is typically benign in nature, NASH is a more serious condition that may progress to end-stage liver disease and liver failure. Currently, liver biopsy is considered the most reliable method of assessing the histological severity of disease and differentiating between simple steatosis and NASH. Because biopsy is invasive in nature, expensive, and subject to sampling error and/or variability in interpretation, it is not suitable as a screening test. Therefore, it is necessary to examine known mechanisms associated with the progression of liver disease, such as hepatocellular apoptosis, and identify potential biomarkers that could be used as a diagnostic tool in NASH. This review will focus on the role of apoptosis in pediatric liver disease and how K18, an early marker of apoptosis, can be utilized as a noninvasive biomarker to diagnose NASH.

Differential effect of gender on hepatic fat

BACKGROUND

There are discrepant data on whether men or women have a higher risk for hepatic steatosis.

OBJECTIVE

To examine the influence of gender on hepatic adiposity in teenagers and young adults.

MATERIALS AND METHODS

We measured subcutaneous abdominal fat (SAF), intra-abdominal fat (IAF) and hepatic tissue density (a surrogate measure of hepatic fat) using CT in 505 healthy teenagers and young adults (254 males, 251 females; ages 15-22.9 years).

RESULTS

Overall, compared to men, women had higher values of SAF (P < 0.0001) but similar measures of IAF and liver tissue density (P = 0.09 and 0.92, respectively). However, when compared to overweight/obese men, overweight/obese women had strikingly similar IAF values (P = 0.85) but lower hepatic fat (P = 0.009). Multiple regression analyses indicated that, after adjusting for age and SAF, IAF independently predicted hepatic density in males (P < 0.0001) but not in females (P = 0.36). Hepatic fat increased with body mass in males from lean to overweight and obese (P < 0.0001) but not in females (P > 0.05).

CONCLUSION

When compared to overweight and obese young women, overweight and obese young men are at greater risk for hepatic steatosis, independent of IAF.

Obesity, insulin resistance and diabetes: sex differences and role of oestrogen receptors

Obesity increases the risk of coronary artery disease through insulin resistance, diabetes, arterial hypertension and dyslipidemia. The prevalence of obesity has increased worldwide and is particularly high among middle-aged women and men. After menopause, women are at an increased risk to develop visceral obesity due to the loss of endogenous ovarian hormone production. Effects of oestrogens are classically mediated by the two nuclear oestrogen receptors (ERs) α and β. In addition, more recent research has shown that the intracellular transmembrane G-protein-coupled oestrogen receptor (GPER) originally designated as GPR30 also mediates some of the actions attributed to oestrogens. Oestrogen and its receptors are important regulators of body weight and insulin sensitivity not only in women but also in men as demonstrated by ER mutations in rodents and humans. This article reviews the role of sex hormones and ERs in the context of obesity, insulin sensitivity and diabetes as well as the related clinical issues in women and men.

Treatment of atherogenic liver based on the pathogenesis of nonalcoholic fatty liver disease: a novel approach to reduce cardiovascular risk?

Nonalcoholic fatty liver disease (NAFLD), which spans a spectrum of conditions ranging from simple steatosis to progressive nonalcoholic steatohepatitis (NASH), is the most common chronic liver disease and a relevant public health issue. The prevalence of NAFLD depends on adiposity, age, gender and ethnicity. The natural history of liver disease in those with NAFLD critically depends on liver histological changes. However, cardiovascular mortality is increased in NAFLD, particularly in middle-aged adults. Against such a background, this review consists of three sections. First, data on NAFLD as a novel mechanism of increased cardiovascular risk via hyperinsulinism, pro-thrombotic potential, and subclinical inflammation are summarized. Next, the role of atherogenic liver in the development of manifestations of oxidative stress and atherosclerosis is emphasized. Finally, whether and how treating NAFLD will mechanistically result in reduced cardiovascular risk through ameliorated metabolic syndrome is discussed.

Factors associated with hepatic steatosis in obese children and adolescents

OBJECTIVES

Obesity is associated with high prevalence of hepatic steatosis. We speculate that determinant factors of susceptibility to hepatic steatosis in obesity could differ between children and adolescents.

PATIENTS AND METHODS

Blood biochemical parameters, systemic oxidative stress markers, proinflammatory cytokines, and adipokine levels were determined in 157 obese children and adolescents. The subjects were divided into 2 groups: children and adolescents, identified as such in accordance with Tanner stage and the measured level of dehydroepiandrosterone sulphate. Steatosis was evaluated by ultrasonography in 127 subjects.

RESULTS

Steatosis prevalence was 44.8%. In the "children" group, those with hepatic steatosis presented higher levels of erythrocyte oxidised glutathione (GSSG) and resistin, lower levels of high-density lipoprotein (HDL) cholesterol, and lower enzymatic activities of erythrocyte glutathione reductase (GRd) and glutathione oxidase (GPx). In the "adolescents" group, those with hepatic steatosis presented higher values for body mass index z score (BMIz), insulin, peptide C, homeostatic model assessment index (HOMA-IR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides, GSSG, and leptin. These subjects also presented lower values for soluble leptin receptor, GRd, and GPx. In the "children" group, the only independent factor of steatosis was a decrease in GRd activity (odds ratio [OR] 0.165, 95% CI 0.03-0.84, P = 0.030). Moreover, in the "adolescent" group, the independent factors were higher for GSSG (OR 6.8, 95% CI 1.6-28.7, P = 0.010) and HOMA-IR (OR 1.9, 95% CI 1.17-3.1, P = 0.009).

CONCLUSIONS

Factors associated with hepatic steatosis differ between obese children and adolescents. Oxidative stress is seen to be the main process in children, whereas in adolescents oxidative stress and insulin resistance are significant factors for steatosis.

Gamma-glutamyl transferase is strongly associated with degree of overweight and sex

Gamma-glutamyl transferase (GGT) is a marker for cardiovascular risk and an independent predictor of long-term outcome in adults. Epidemiological data from pediatric cohorts are rare. We studied the association of GGT to body mass index as a standard deviation score, sex, and age in 68,415 children (age 11.7 ± 4.4 years; 48% boys; body mass index 27.2 ± 7.4 kg/m2; GGT measured in n = 23,955). GGT >50 U/L is strongly associated with extreme obesity (odds ratio 27.13, 95% confidence interval 15.07-48.85) and male sex (odds ratio 2.60, 95% confidence interval 2.03-3.31). GGT seems to be of clinical relevance and may be marketable as a surrogate in risk profiling for children with obesity.

Gender-specific differences in adipose distribution and adipocytokines influence adolescent nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a predominantly adult-diagnosed disorder. Knowledge regarding the epidemiology, phenotype, and metabolic risk factors, during adolescence is limited. We sought to determine the prevalence, phenotype, and predictors of NAFLD in 1170 community-based adolescents in the Western Australian Pregnancy Cohort (Raine) Study (the Raine Cohort) who underwent a cross-sectional assessment that included questionnaires, anthropometry, cardiovascular examinations, blood tests, and abdominal ultrasound examinations. Among the 1170 adolescents assessed, the prevalence of NAFLD was 12.8%. Females compared with males had a significantly higher prevalence of NAFLD (16.3% versus 10.1%, P = 0.004) and central obesity (33.2% versus 9.9%, P < 0.05). The severity of hepatic steatosis was associated with the body mass index, waist circumference, subcutaneous adipose tissue thickness (SAT), serum leptin level, homeostasis model assessment for insulin resistance score (P < 0.001 for all), and serum alanine aminotransferase level (P < 0.005) in both genders, but it was associated with increasing visceral adipose tissue thickness (VAT; P < 0.001) and decreasing serum adiponectin levels (P < 0.05) in males alone. Males and females with NAFLD had similar amounts of SAT (P > 0.05); however, in comparison with females with NAFLD, males with NAFLD had greater VAT, a more severe metabolic phenotype with higher glucose levels and systolic blood pressure and lower adiponectin and high-density lipoprotein cholesterol levels (P < 0.001 for all), and greater measures of liver injury (alanine aminotransferase and aspartate aminotransferase, P < 0.001 for all). Similarly, metabolic syndrome was more common in males than females with NAFLD (24% versus 8%, P = 0.01). Suprailiac skinfold thickness predicted NAFLD independently of the body mass index, insulin resistance, and VAT.

CONCLUSION

Gender differences in adolescent NAFLD are related to differences in adipose distribution and adipocytokines. The male phenotype of NAFLD is associated with more adverse metabolic features and greater visceral adiposity than the female phenotype despite the lower prevalence of NAFLD.

CRTC3 links catecholamine signalling to energy balance

The adipose-derived hormone leptin maintains energy balance in part through central nervous system-mediated increases in sympathetic outflow that enhance fat burning. Triggering of β-adrenergic receptors in adipocytes stimulates energy expenditure by cyclic AMP (cAMP)-dependent increases in lipolysis and fatty-acid oxidation. Although the mechanism is unclear, catecholamine signalling is thought to be disrupted in obesity, leading to the development of insulin resistance. Here we show that the cAMP response element binding (CREB) coactivator Crtc3 promotes obesity by attenuating β-adrenergic receptor signalling in adipose tissue. Crtc3 was activated in response to catecholamine signals, when it reduced adenyl cyclase activity by upregulating the expression of Rgs2, a GTPase-activating protein that also inhibits adenyl cyclase activity. As a common human CRTC3 variant with increased transcriptional activity is associated with adiposity in two distinct Mexican-American cohorts, these results suggest that adipocyte CRTC3 may play a role in the development of obesity in humans.

The prevalence of non-alcoholic fatty liver disease and metabolic syndrome in obese children

BACKGROUND AND AIM

In the context of present epidemic of childhood obesity, we aimed to find the prevalence of nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MS) in a cohort of obese children.

METHODOLOGY

Retrospective chart analysis of 700 obese children was done for their anthropometric and biochemical investigations.

RESULTS

Some 15.4% (9.8% girls, 22% boys) subjects had NAFLD (ALT > 40 IU/L) after excluding other identifiable causes of liver dysfunction. Age, weight, TG, fasting serum insulin and HOMA-IR levels were higher in children with NAFLD. Twenty-eight percent children had MS. Children with NAFLD had an odds ratio of 2.65 for having MS (boys 4.6, girls 1.7). The prevalence of MS increased with age 5-9 years (21%), 10-16 years (30%), 17-20 years (35%).

CONCLUSION

Given high prevalence of NAFLD and MS in obese children, childhood obesity should be seriously considered as a disease and not just a cosmetic issue.

Prevalence of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis among a largely middle-aged population utilizing ultrasound and liver biopsy: a prospective study

BACKGROUND & AIMS

Prevalence of nonalcoholic fatty liver disease (NAFLD) has not been well established. The purpose of this study was to prospectively define the prevalence of both NAFLD and nonalcoholic steatohepatitis (NASH).

METHODS

Outpatients 18 to 70 years old were recruited from Brooke Army Medical Center. All patients completed a baseline questionnaire and ultrasound. If fatty liver was identified, then laboratory data and a liver biopsy were obtained.

RESULTS

Four hundred patients were enrolled. Three hundred and twenty-eight patients completed the questionnaire and ultrasound. Mean age (range, 28-70 years) was 54.6 years (7.35); 62.5% Caucasian, 22% Hispanic, and 11.3% African American; 50.9% female; mean body mass index (BMI) (calculated as kg/m(2)) was 29.8 (5.64); and diabetes and hypertension prevalence 16.5% and 49.7%, respectively. Prevalence of NAFLD was 46%. NASH was confirmed in 40 patients (12.2% of total cohort, 29.9% of ultrasound positive patients). Hispanics had the highest prevalence of NAFLD (58.3%), then Caucasians (44.4%) and African Americans (35.1%). NAFLD patients were more likely to be male (58.9%), older (P = .004), hypertensive (P < .00005), and diabetic (P < .00005). They had a higher BMI (P < .0005), ate fast food more often (P = .049), and exercised less (P = 0.02) than their non-NAFLD counterparts. Hispanics had a higher prevalence of NASH compared with Caucasians (19.4% vs 9.8%; P = .03). Alanine aminotransferase, aspartate aminotransferase, BMI, insulin, Quantitative Insulin-Sensitivity Check Index, and cytokeratin-18 correlated with NASH. Among the 54 diabetic patients, NAFLD was found in 74% and NASH in 22.2%.

CONCLUSION

Prevalence of NAFLD and NASH is higher than estimated previously. Hispanics and patients with diabetes are at greatest risk for both NAFLD and NASH.

Relationship between aminotransferases levels and components of the metabolic syndrome among multiethnic adolescents

BACKGROUND

Data evaluating the frequency of elevated aminotransferases (as a surrogate for non-alcoholic fatty liver disease [NAFLD]) and metabolic syndrome (MS) components among overweight multiethnic children/adolescents originating predominantly from South/Central America and the Caribbean are limited.

METHODS

A sample (N = 284) of multiethnic (75% Latino, 25% Afro Caribbean/non-Hispanic black) overweight children/ adolescents' (mean age 12.24 +/- 3.48) overnight fasting insulin and glucose, systolic/diastolic blood pressure, HDL/LDL/total cholesterol, triglyceride, aspartate aminotransferase (AST) and alanine aminostransferase (ALT) were analyzed.

RESULTS

A total of 22% of the sample had elevated ALT (> or = 30 U/L; mean 25.94 U/L for Hispanics, 23.05 U/L for blacks) and 8% had elevated AST (> or = 35 U/L; mean 23.05 U/L for Hispanics, 24.68 U/L for blacks). AST and ALT were significantly correlated with triglycerides (r = 0.23, P < .01; r = 0.18, P < .05, respectively) for the overall sample.

CONCLUSIONS

Among overweight adolescents, MS components are associated with NALFD in subgroups of major ethnic groups suggesting that AST and ALT as surrogate markers for NAFLD should be included in addition to the standard cardio metabolic tests.

Role of obesity-associated dysfunctional adipose tissue in cancer: a molecular nutrition approach

Obesity is a complex disease caused by the interaction of a myriad of genetic, dietary, lifestyle and environmental factors, which favors a chronic positive energy balance, leading to increased body fat mass. There is emerging evidence of a strong association between obesity and an increased risk of cancer. However, the mechanisms linking both diseases are not fully understood. Here, we analyze the current knowledge about the potential contribution that expanding adipose tissue in obesity could make to the development of cancer via dysregulated secretion of pro-inflammatory cytokines, chemokines and adipokines such as TNF-α, IL-6, leptin, adiponectin, visfatin and PAI-1. Dietary factors play an important role in the risk of suffering obesity and cancer. The identification of bioactive dietary factors or substances that affect some of the components of energy balance to prevent/reduce weight gain as well as cancer is a promising avenue of research. This article reviews the beneficial effects of some bioactive food molecules (n-3 PUFA, CLA, resveratrol and lipoic acid) in energy metabolism and cancer, focusing on the molecular mechanisms involved, which may provide new therapeutic targets in obesity and cancer.

Impact of nonalcoholic fatty liver disease on insulin resistance in relation to HbA1c levels in nondiabetic subjects

OBJECTIVES

A cross-sectional analysis was conducted in healthy, nondiabetic Korean adults to assess the prevalence of nonalcoholic fatty liver disease (NAFLD), to compare the prevalence of NAFLD across different glycemic ranges as assessed by glycosylated hemoglobin (HbA1c), and to examine the impact of NAFLD on insulin resistance in relation to HbA1c levels.

METHODS

After rigorous exclusion criteria, the final number of subjects who participated in a comprehensive health status checkup program was 99,969. All subjects were classified into four categories with respect to HbA1c level (≤4.9, 5.0-5.4, 5.5-5.9, and 6.0-6.4%). We estimated the odds ratio (OR) for prevalence of NAFLD according to the categorized level of HbA1C and evaluated the association of NAFLD with the homeostatic model assessment of insulin resistance (HOMA-IR) in relation to the HbA1c level.

RESULTS

Twenty-eight percent (n=28,130, 40.2% of the men, 10.3% of the women) of the study subjects had NAFLD. Men had a 5.83-fold (95% confidence interval 5.63-6.05) increased risk for having NAFLD than did women. The risk for NAFLD increased with increasing level of HbA1c (OR 1.44, 2.62, and 7.18) when compared with the lowest quartile (HbA1C≤4.9%). HOMA-IR increased in the NAFLD subjects as the level of HbA1c increased. The magnitude of association of HOMA-IR with HbA1c level was greater in NAFLD subjects than in non-NAFLD subjects (P<0.001 for interaction). These associations were consistent even after adjustment for body mass index and other metabolic components.

CONCLUSIONS

NAFLD had an association with HbA1c level and insulin resistance in nondiabetic individuals, and these associations were independent of obesity and other metabolic components.

Pediatric nonalcoholic fatty liver disease: A clinical and laboratory challenge

The true prevalence of pediatric nonalcoholic fatty liver disease (NAFLD) is unknown. Challenges in determining the population prevalence of NAFLD include the type of test (and the reference intervals used to define normal and abnormal), the type of population (general population, hospital series), the demographic characteristics of the population sampled, and the nature of the study design. The natural history of pediatric NAFLD remains uncertain. The issue of when to perform a liver biopsy in children with suspected NAFLD remains controversial. Children with NAFLD but normal alanine aminotransferase are rarely investigated. However, evidence of alterations in glucose metabolism parameters should prompt a better understanding of the natural history of pediatric NAFLD not only in terms of the progression of liver disease but also regarding its potential relationship with other health outcomes such as type 2 diabetes mellitus and cardiovascular disease. This evidence could make liver biopsy mandatory in the majority of cases at risk of progressive and severe hepatic and extrahepatic disease. This conclusion, however, raises the question of the feasibility of liver biopsy assessment in an extremely large at risk population, and of the cost/effectiveness of this policy. There is a considerable, continuous interest in reliable, noninvasive alternatives that will allow the prognosis of pediatric NAFLD to be followed in large community or population-based studies.

Relationships of cardiorespiratory fitness with metabolic risk factors, inflammation, and liver transaminases in overweight youths

The aim of this study was to assess the relationships of fatness and fitness with metabolic risk factors, including liver transaminases and inflammation in obese youth, taking in account gender, age, and pubertal stage. 241 children were studied (135 girls), age 11.9 +/- 2.2 years (x +/- SD), Body Mass Index z score 5.4 +/- 2.7. For girls, VO(2max) was significantly associated with insulin (P = .001), Insulin resistance (HOMA-IR) (P = .005), and ALT (P = .012); a relationship was displayed between fibrinogen and age and % fat mass (FM) (P = .008); for boys, relationships were found between VO(2max) and diastolic blood pressure and triglycerides; independent associations were also found between age and insulin, HOMA-IR and HDL cholesterol; fibrinogen and sedimentation rate were related (P </= .004) with %FM. Their relationships are observed from young age and increase with the continuous increase of factors. This supports the need to treat overweight as soon as it is detected; improving CRF is one of the ways which could be used to prevent the complications of obesity.

Obese boys at increased risk for nonalcoholic liver disease: evaluation of 16,390 overweight or obese children and adolescents

OBJECTIVE

Comorbidities of childhood obesity challenge health-care systems in Europe. Further, there is a lack of population-specific prevalence data and diagnostic strategies available, especially for obesity-related disturbances of liver function. Therefore, the prevalence of elevated liver enzymes and their relationship to biological parameters were studied in a large pediatric obesity cohort.

METHODS

In 111 specialized pediatric obesity centers in Germany, Austria and Switzerland, 16,390 children and adolescents (age 12.4±2.6 years, 58% boys) were categorized as overweight (body mass index (BMI) >90th percentile) and obese (>97th percentile) and studied for related comorbidities, especially nonalcoholic fatty liver disease (NAFLD; as defined by aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) >50 U l(-1)). Data were collected using a standardized software program (APV) for longitudinal multicenter documentation. Pseudonymized data were transmitted for central statistical analysis.

RESULTS

In this pediatric cohort, 16% of the study population was overweight, 46% obese and 35% extremely obese (>99.5th percentile extreme obesity (Xob)). NAFLD was present in 11% of the study population, but predominantly in boys (boys vs girls; 14.4:7.4%; P<0.001), in Xob (obese vs Xob; 9.5:17.0%; P<0.001) and in older age (< 12 vs ≥12 years; 8:12%; P<0.001; adjusted for BMI). ALT >50 U l(-1) was significantly associated with fasting insulin and BMI-SDS. In multiple logistic regression models, Xob and male gender were strongly associated with NAFLD (odds ratio Xob vs normal weight=3.2; boys vs girls OR=2.3).

CONCLUSION

In a large cohort of overweight and obese European children and adolescents, markers of nonalcoholic liver disease, especially ALT, are frequent and predicted by Xob and male gender. The results underline the epidemiological dimension of this obesity-related morbidity even in childhood. Therefore, at least ALT is recommended as a screening parameter in basic care.

Abdominal fat and metabolic risk in obese children and adolescents

The aim of this study was to investigate fat distribution, mainly abdominal fat, and its relationship with metabolic risk variables in a group of 126 children and adolescents (60 males and 66 females) aged 5.0 to 14.9. According to IOTF criteria, 46 were classified as normal weight, 28 overweight and 52 obese. Weight, height, waist (WC) and hip circumferences were measured. The body mass index (BMI) was calculated. Total body fat, trunkal and abdominal fat were also assessed by dual energy x-ray absorptiometry (DXA). Glucose, insulin, HDL-Cholesterol, triglycerides (TG), ferritine, homocystein and C-reactive protein (CRP) were measured. Obesity status was related with insulin concentrations, CRP, TG and HDL. Obese patients had higher abdominal fat and higher CRP values than overweight and normal subjects. All markers of central body adiposity were related with insulin and lipid metabolism; however, they were not related with homocystein or ferritin. A simple anthropometric measurement, like waist circumference, seems to be a good predictor of the majority of the obesity related metabolic risk variables.

Hepatic complications of obesity

Obesity is associated with a spectrum of chronic liver disease. Because obesity increases the risk for advanced forms of liver disease (ie, cirrhosis and liver cancer), the obesity epidemic is emerging as a major factor underlying the burden of liver disease in the United States and many other countries. This article reviews mechanisms that mediate the pathogenesis of obesity-related liver disease, summarizes clinical evidence that demonstrates obesity-related liver disease can be life-threatening, and discusses whether or not treatments for obesity or related comorbidities impact liver disease outcomes.