Fasting insulin resistance affects the prevalence of metabolically healthy obesity in Brazilian adolescents

Predictive markers of metabolically healthy obesity in children and adolescents: can AST/ALT ratio serve as a simple and reliable diagnostic indicator?

This study aimed to estimate the prevalence of metabolically healthy obesity (MHO) according to two different consensus-based criteria and to investigate simple, measurable predictive markers for the diagnosis of MHO. Five hundred and ninety-three obese children and adolescents aged 6-18 years were included in the study. The frequency of MHO was calculated. ROC analysis was used to estimate the predictive value of AST/ALT ratio, waist/hip ratio, MPV, TSH, and Ft4 cut-off value for the diagnosis of MHO. The prevalence of MHO was 21.9% and 10.2% according to 2018 and 2023 consensus-based MHO criteria, respectively. AST/ALT ratio cut-off value for the diagnosis of MHO was calculated as ≥ 1 with 77% sensitivity and 52% specificity using Damanhoury et al.'s criteria (AUC = 0.61, p = 0.02), and 90% sensitivity and 51% specificity using Abiri et al.'s criteria (AUC = 0.70, p = 0.01). Additionally, using binomial regression analysis, only the AST/ALT ratio is independently and significantly associated with the diagnosis of MHO (p = 0.03 for 2018 criteria and p = 0.04 for 2023 criteria).

CONCLUSION

The ALT/AST ratio may be a useful indicator of MHO in children and adolescents.

WHAT IS KNOWN

• Metabolically healthy obesity refers to people who are obese but do not have any of the standard cardio-metabolic risk factors. • Metabolically healthy obesity is not entirely harmless; the metabolic characteristics of individuals with this phenotype are less favorable than those of healthy lean groups. Moreover, it is not a constant state, and there may be a transition to metabolically unhealthy phenotypes over time.

WHAT IS NEW

• The prevalence of MHO is 21.9% and 10.2% according to 2018 and 2023 consensus-based metabolically healthy obesity criteria, respectively. • The ALT/AST ratio may be a useful indicator of metabolically healthy obesity in children and adolescents.

Risk factors, cutoff points, and definition of metabolically healthy/unhealthy obesity in children and adolescents: A scoping review of the literature

Diagnosis of metabolically healthy obesity (MHO) and its definition do not have universal criteria in the pediatric age group. Hence, this scoping review aims to identify the components, the cutoff points, and the definition of MHO in children and adolescents. A comprehensive, systematic search was conducted in PubMed, Scopus, EMBASE, and Google Scholar databases. A consensus-based definition of MHO was developed through a Delphi process involving an international panel of 23 experts. This review included a total of 63 non-randomized studies, published between 2007 and 2022. According to our consensus (≥80% agreement), the proposed definition for MHO included the following components: high-density lipoprotein cholesterol >40 mg/dl (or >1.03 mmol/l), triglycerides ≤150 mg/dl (or ≤1.7 mmol/l), fasting plasma glucose <100 mg/dl (or <5.6 mmol/l), a measure of insulin, and systolic and diastolic blood pressure ≤90th percentile. Therefore, MHO was defined as the absence of the above metabolic risk factors; and those children and adolescents with one or more criteria were considered as metabolically unhealthy. A universal definition of MHO will allow comparisons between studies in the field of childhood obesity and can be useful in clinical practice.

Insulin Resistance as a Diagnostic Criterion for Metabolically Healthy Obesity in Children

OBJECTIVES

In recent years, a subgroup of individuals with obesity has been described as having a lower risk of metabolic and cardiovascular complications. These individuals have what is referred to as metabolically healthy obesity (MHO), which has a favorable metabolic profile and a lower probability of long-term complications. The definition of this subtype in children is not clear. The aim of the present study was to determine whether Homeostasis Model Assessment (HOMA) above a set threshold could be the marker of metabolically unhealthy obesity (MUO) in children, or a parameter that can be used in the overall assessment. It is intended to compare the International Diabetes Federation (IDF) criteria against HOMA in the diagnosis of MUO.

METHODS

This observational, retrospective, cohort study included children with obesity and analyzed their metabolic state by means of blood testing and dual-energy X-ray absorptiometry.

RESULTS

A total of 96 patients were included, 44.8% boys and 55.2% girls, ages 6-17 years. The patients with MHO according to the HOMA criterion were younger (P = 0.001), had a lower body mass index (BMI) z score (P = 0.006), waist-height index (P = 0.009), hip-height index (P = 0.010), blood glucose (P = 0.003), insulin (P < 0.001), and lower percentages of total fat (P = 0.002), trunk fat (P = 0.001), and android fat (P = 0.009) than those with MUO. The logistic regression analysis according to IDF criteria detected an area under the receiver operating characteristic (ROC) curve of 0.659 (95% CI 0.546-0.771; P = 0.009) versus the area under the ROC curve of 0.854 (95% CI 0.777-0.931; P < 0.001) for the HOMA definition. Therefore, the determination of the metabolic state according to HOMA has greater sensitivity and specificity than the IDF criteria. The multivariate analysis in children classified according to HOMA revealed that the percentage of total fat and gynoid fat distributions and triglyceride level could be markers of a healthy or unhealthy metabolic state in children with obesity (P < 0.001).

CONCLUSIONS

The use of HOMA as a single criterion was demonstrated to be an effective and simple detector of adiposity, which predicts the metabolically healthy obesity in children.

Relationship of age at menarche and serum leptin with the metabolically unhealthy phenotype in adolescents

Introduction

Objective: to analyze the relationship of age at menarche and leptin with the metabolically healthy (MH) and metabolically unhealthy (MUH) phenotypes in adolescent girls in different body mass index (BMI) categories. Method: an observational and cross-sectional study consisting of 139 female adolescents attended to at the Adolescent Reference Center in Macaé, Rio de Janeiro. Menarche was classified as early (EM) when the first menstruation occurred at or before 11 years of age; normal menarche (NM) was categorized at ages 12 to 14; menarche was considered late (LM) when it occurred at age 15 or older. The factors required to ascertain the subjects' phenotype, as well as their leptin levels, weight, and height, were measured and their BMIs were calculated. The girls were classified as MH or MUH based on the NCEP-ATP III criteria as adapted for children and adolescents. Results: 82 % (n = 114) of the girls were classified as MH and 18 % (n = 25) as MUH. Mean age at menarche was 11.79 ± 1.39 years. There was a higher prevalence of MUH amongst the girls who had EM (p = 0.04). A higher inadequacy of serum leptin concentrations was found in girls who had EM (p = 0.05) and in those classified as MUH (p = 0.01). The adolescents who were severely obese exhibited inadequate leptin levels (p < 0.01) and had gone through EM (p = 0.02). A total of 8.1 % (n = 7) of the normal-weight girls were classified as MUH, and 29.4 % (n = 5) of those who were severely obese were classified as MH (p < 0.01). Conclusion: early menarche and high serum leptin concentrations are related with the MUH phenotype in adolescent girls in different BMI categories.

Triglyceride/glucose index is a reliable alternative marker for insulin resistance in South American overweight and obese children and adolescents

Background The aim of the present study was to investigate the correlation between the triglyceride/glucose index (TyG index) and homeostasis model assessment of insulin resistance (HOMA-IR). Additionally, we compared the ability of the TyG index and triglycerides/high-density lipoprotein cholesterol (TG/HDL-c) index and the combination of these two indices (TyG index plus TG/HDL-c) to predict insulin resistance (IR) in South American overweight and obese children and adolescents. Methods A cross-sectional study was carried out in 345 overweight adolescents aged 10-18 years, from both the sexes. The TyG index was calculated as Ln (fasting triglycerides [mg/dL] × fasting glucose [mg/dL])/2, while the TG/HDL-c index was calculated by the division of TG (mg/dL) by HDL-c (mg/dL). HOMA-IR was calculated with the formula: fasting insulin (FI) (U/mL) × fasting glucose (mmol/L)/22.5. The cut-off point used to determine the presence of IR was HOMA-IR ≥ 3.16. Results The TyG index showed a positive correlation with HOMA-IR. The area under the receiver operating characteristic (ROC) curve of the TyG index was 0.74, indicating good sensitivity (75.7%) and specificity (67.4%). Furthermore, the TyG index cut-off point of >4.44 was established for IR prediction in this population. Conclusions The TyG index is a simple and cost-effective surrogate marker of IR in South American overweight children and adolescents. Moreover, due to its good accessibility, it can be used in large epidemiological studies.

Can Visceral Adiposity Index Serve as a Simple Tool for Identifying Individuals with Insulin Resistance in Daily Clinical Practice?

Background and objectives: The visceral adiposity index (VAI), estimating visceral adiposity dysfunction through a simple formula, could serve as a useful tool for identifying individuals at higher cardiometabolic risk. Its relationship with insulin resistance (IR), assessed using the homeostasis model assessment of IR (HOMA-IR), and metabolic syndrome (MetS) components remains unclear. The study aimed to investigate the association of VAI with both HOMA-IR and MetS. Materials and Methods: After undergoing anthropometric and biochemical studies, 783 individuals were divided into three groups according to a number of present MetS components. The VAI cut-offs signaling MetS and HOMA-IR were determined by maximizing the sum of the sensitivity and specificity. Correlation analysis was performed to explore the associations between VAI and other tested parameters. A logistic stepwise regression analysis was applied to identify statistically significant determinants of HOMA-IR. Given the variability of reference values, two thresholds of HOMA-IR were applied, namely 2.0 and 3.8. Results: VAI increased significantly between the groups with a rising number of MetS components. The VAI cut-off for MetS was 2.37, with a sensitivity of 0.86 and a specificity of 0.78. The same cut-off point identified subjects with HOMA-IR = 3.8, with a sensitivity of 0.79 and a specificity of 0.66. The VAI cut-off for HOMA-IR = 2.0 was 1.89, with a sensitivity of 0.74 and a specificity of 0.68. The strongest correlations of VAI were noted with HOMA-IR (r = 0.51) and insulin (r = 0.49), respectively, while the strongest correlation of HOMA-IR was with waist circumference (r = 0.54). Not one of the routine parameters was a significant predictor in the regression analysis. Conclusions: The obtained results show an existing association of VAI with HOMA-IR. The high sensitivity and specificity of the cut-offs may allow the application of VAI in common clinical practice.