Phenotypes of prediabetes and metabolic risk in Caucasian youths with overweight or obesity

Association of HDL-Cholesterol, hypertension and left ventricular hypertrophy in youths with overweight or obesity

BACKGROUND AND AIM

To evaluate the relationship between HDL-Cholesterol (HDL-C), hypertension, and left ventricular hypertrophy (LVH) in a large sample of Caucasian youths with overweight/obesity (OW/OB).

METHODS AND RESULTS

A cross-sectional multicenter study was performed in 1469 youths (age 6-16 years) with OW/OB observed in the period 2016-2020. An additional independent sample of 244 youths with an echocardiographic evaluation, observed in a single center was analyzed. The sample was divided in six quantiles (Q) of HDL-C: Q1: >56, Q2: ≤56 > 51, Q3: ≤51 > 45, Q4: ≤45 > 41, Q5: ≤41 > 39, Q6: <39 mg/dL. The nadir of the relationship was identified in youths in the first quantile. Among HDL-Cholesterol quantiles the distribution of hypertension was non-linear with a percentage of 25.0%, 40.1%, 33.6%, 31.3%, 35.2% and 39.7% in the six quantiles, respectively. The percentage of LVH was 21.8%, 43.6%, 48.8%, 35.5%, 38.5% and 52.0% in the six quantiles, respectively. The highest odds [95%Cl] of hypertension were 2.05 (1.33-3.16) (P < 0.01) in Q2, 1.67 (1.10-2.55) (P < 0.05) in Q3 and 1.59 (1.05-2.41) (P < 0.05) in Q6 vs Q1. The odds of LVH were 3.86 (1.15-10.24) (P < 0.05) in Q2, 4.16 (1.58-10.91) (P < 0.05) in Q3 and 3.60 (1.44-9.02) (P < 0.05) in Q6 vs Q1, independently by centers, age, sex, prepubertal stage, and body mass index.

CONCLUSION

Contrary to the common belief, the present study shows that high levels of HDL-C may be not considered a negative predictor of hypertension and LVH, two risk factors for future CV disease.

Sex Differences in Diet and Physical Activity Behaviors Among Racial/Ethnic Minority Adolescents with High Metabolic Risk

Certain dietary and physical activity (PA) behaviors may differentially predispose male and female adolescents to obesity and diabetes; however, sex differences in dietary and PA behaviors and in factors that impact these behaviors (e.g., self-efficacy, social support) in this population remain unknown. Using data from a community-based adolescent diabetes prevention intervention conducted in East Harlem in New York City, we examined sex differences in baseline characteristics including clinical measurements, lifestyle behaviors, and behavioral determinants. Among 147 overweight/obese adolescents aged 13-19 years, 61.9% were girls, 69.7% were of Hispanic ethnicity, 24.8% were non-Hispanic Black, and 60.5% were diagnosed with prediabetes. Boys had higher metabolic risk scores than girls (3.8 vs. 3.3, p = 0.002) despite girls reporting more perceived barriers to healthy eating and PA. Boys reported doing more moderate to vigorous PA but also had more sedentary behaviors than girls. Boys reported higher self-efficacy and more peer support for PA. Girls reported more depressive symptoms and were more likely to compare their body images to those in magazines/social media. Overall, among a sample of urban adolescents with high metabolic risk, we found significant sex differences in many dietary and PA behaviors and related factors, which could be used to inform tailored strategies for weight management to reduce cardiometabolic risk among youth from similar high-risk populations.

Prediabetes in children and adolescents: An updated review

Prediabetes, the precursor of type 2 diabetes mellitus, is an intermediate stage between normal glucose homeostasis and overt diabetes. This asymptomatic metabolic state is increasingly prevalent in pediatric population and is very difficult to detect without appropriate screening. Studies have shown that a certain proportion of children with prediabetes will develop diabetes in a few years. Even more alarming is the evidence that youth-onset diabetes has a more aggressive clinical course with progressive beta-cell decline and accelerated end-organ damage. Despite its importance, several aspects involving prediabetes in childhood are disputed or unknown. This review presents the latest insights into this challenging entity and outlines a simplified screening approach to aid clinical practice. In summary, childhood prediabetes is an important clinical condition indicating the need for proper screening and timely intervention.

Serum endocan as a predictive biomarker of cardiovascular risk in obese pediatric patients

BACKGROUND

Endocan is a soluble dermatan sulfate proteoglycan (50 kDa) secreted by endothelial cells and expressed by dermal, coronary, pulmonary and adipose tissue microvasculature. It plays an important role in the pathogenesis of vascular disorders, inflammatory state, endothelium dysfunction and neoangiogenesis. Aims of the study were to compare fasting serum endocan levels between children with obesity and healthy controls and to investigate the relationships between endocan, body mass index (BMI) and other indices of cardiometabolic risk.

METHODS

This single-center, observational, retrospective study included 19 pediatric patients with obesity aged 11.94 ± 0.52 years and 19 lean matched controls. Each patient underwent clinical and auxological examination and laboratory investigations including routine organs function tests and lipid profile. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Fasting endocan serum levels were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to healthy subjects, serum endocan levels were found to be significantly upraised in children with obesity. Endocan resulted significantly correlated with insulin levels (rho 0.47; p = 0.04); in addition, an association with HOMA-IR values with a trend toward the statistical significance (rho 0.43; p = 0.07) was found. No significant correlation with fasting blood glucose values and lipid serum levels was demonstrated. Although not statistically significant, a correlation between endocan and the presence and grading of liver steatosis on ultrasound (rho 0.51; p = 0.08 and rho 0.51; p = 0.08, respectively) was found.

CONCLUSIONS

These findings confirm the association between endothelial damage and insulin resistance in children with obesity. Endocan could be used as a biomarker of early endothelial dysfunction in children with obesity and could be a valid predictor of future cardiovascular risk in adulthood.

One-Hour Post-Load Plasma Glucose and Altered Glucometabolic Profile in Youths with Overweight or Obesity

In youths, two cut-offs (133 and 155 mg/dL) have been proposed to identify high glucose levels at the 1 h (G60) mark during an oral glucose tolerance test (OGTT). We evaluated which cut-off was more closely associated with isolated impaired glucose tolerance (IGT) and cardiometabolic risk (CMR) in 1199 youth with overweight/obesity (OW/OB) and normal fasting glucose and/or HbA1c. The disposition index (DI) was available in 724 youths. The sample was divided by two cut-offs of G60: <133 mg/dL (n = 853) and ≥133 mg/dL (n = 346), or G60 < 155 mg/dL (n = 1050) and ≥155 mg/dL (n = 149). Independent of the cut-off, youths with high levels of G60 showed higher levels of G120, insulin resistance (IR), triglycerides to HDL ratio (TG/HDL), alanine aminotransferase (ALT), and lower insulin sensitivity (IS) and DI than youths with lower levels of G60. The percentage of youths showing IGT, IR, low IS, high TG/HDL ratio, high ALT, and low DI was 50% higher in the G60 ≥ 133 mg/dL group than in the G60 ≥ 155 mg/dL one. In youths with OW/OB and IGT, a cut-off of G60 ≥ 133 mg/dL is more useful than G60 ≥ 155 mg/dL to identify those at high risk of IGT and altered CMR profile.

Is Metabolic Syndrome Useful for Identifying Youths with Obesity at Risk for NAFLD?

The definition of metabolic syndrome (MetS) in childhood is controversial. Recently, a modified version of the International Diabetes Federation (IDF) definition was proposed using reference data from an international population for high waist circumference (WC) and blood pressure (BP), while the fixed cutoffs for lipids and glucose were not changed. We analyzed MetS prevalence using this modified definition (MetS-IDF_m) and its association with non-alcoholic fatty liver disease (NAFLD) in 1057 youths (age 6-17 years) with overweight/obesity (OW/OB). A comparison with another modified definition of MetS according to the Adult Treatment Panel III (MetS-ATPIII_m) was performed. The prevalence of MetS-IDF_m was 27.8% and 28.9% by MetS-ATPIII_m. The Odds (95% Confidence Intervals) of NAFLD was 2.70 (1.30-5.60) (p = 0.008) for high WC, 1.68 (1.25-2.26)(p = 0.001) for MetS, 1.54 (1.12-2.11)(p = 0.007) for low HDL-Cholesterol, 1.49 (1.04-2.13)(p = 0.032) for high triglycerides and 1.37 (1.03-1.82)(p = 0.033) for high BP. No substantial difference was found in the prevalence of MetS-IDF_m and frequency of NAFLD compared to Mets-ATPIII_m definition. Our data demonstrate that one third of youths with OW/OB have MetS, whichever was the criterion. Neither definition was superior to some of their components in identifying youths with OW/OB at risk for NAFLD.

Identification of FGF13 as a Potential Biomarker and Target for Diagnosis of Impaired Glucose Tolerance

Early identification of pre-diabetes provides an opportunity for intervention and treatment to delay its progression to type 2 diabetes mellitus (T2DM). We aimed to identify the biomarkers of impaired glucose tolerance (IGT) through bioinformatics analysis. The GSE76896 dataset, including non-diabetic (ND), IGT, and T2DM clinical samples, was deeply analyzed to identify 309 Co-DEGs for IGT and T2DM. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that inflammatory responses and the PI3K-AKT signaling pathway are important patho-physiological features of IGT and T2DM. Protein-protein interaction (PPI) network analysis and cytoHubba technolgy identified seven hub genes: namely, CCL2, CXCL1, CXCL8, EDN1, FGF13, MMP1, and NGF. The expression and ROC curves of these hub genes were validated using the GSE38642 dataset. Through an immunofluorescence assay, we found that the expression of FGF13 in islets of mice in the HFD and T2DM groups was significantly lower than in the control group. Similarly, the level of FGF13 in the sera of IGT and T2DM patients was lower than that in the healthy group. Together, these results suggest that FGF13 can be treated as a novel biomarker of IGT, which may provide new targets for the diagnosis and treatment of pre-diabetes and T2DM.

Association between Fasting and Postprandial Levels of Liver Enzymes with Metabolic Syndrome and Suspected Prediabetes in Prepubertal Children

Elevated liver enzyme activity may be associated with metabolic syndrome (MetS); however, it is not included in the MetS definition for children. Postprandial changes in the levels of biochemistry tests are related to manifestations of metabolic abnormalities. We assessed the association between fasting and postprandial liver enzymes levels with MetS and elevated hemoglobin A1c (HbA1c) in children aged 9-11. The study included 51 girls and 48 boys, all presumably healthy. In all participants' anthropometric indices, fasting glucose, insulin, lipid profile and HbA1c were measured. Enzymes, including alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), were assayed in fasting and postprandial states. Individuals were divided into subgroups: with (MetS(+): n = 26); without MetS (MetS(-): n = 73); with HbA1c levels ≤ 5.3% (n = 39); and ≥5.7% (n = 11). Elevated fasting GGT levels were found in 23% of MetS(+) children and rarely in MetS(-) children; increased postprandial GGT was noted in 35% of MetS(+) individuals. Postprandial GGT changes tend to predict MetS (OR = 1.16; p = 0.092). Increased fasting ALT was found rarely in MetS(+) children, but did not occur in MetS(-) children. HbA1c ≥ 5.7% occurred rarely and neither fasting ALT nor GGT were related to elevated HbA1c. However, postprandial change of ALT was a good positive predictor of increased HbA1c (OR = 1.33; p = 0.021). Postprandial GGT performs better as an indicator of metabolic syndrome occurrence, and instead postprandial ALT may predict prediabetes in prepubertal children.

Which Is the Most Appropriate Cut-Off of HbA1c for Prediabetes Screening in Caucasian Youths with Overweight or Obesity?

This cross-sectional study aimed to assess the best cut-off of HbA1c for detection of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), beta-cell impairment and cardiometabolic risk (CMR) profile in overweight or obese (OW/OB) Caucasian youths. Two-hour oral glucose tolerance test was available in 1549 youths, one-hour glucose (G₆₀) in 1430 youths and disposition index (DI) in 972 youths. Insulin resistance (IR) was calculated as Homeostatic Model Assessment for IR and insulin sensitivity (IS) as 1/fasting insulin. High G₆₀ was defined by a value ≥ 133 mg/dL. The best cut-off of HbA1c for IFG or IGT was 5.5%. The frequency of individuals with HbA1c ≥ 5.5% was 32.5%, compared to 16.3% with HbA1c ≥ 5.7% (as proposed by the American Diabetes Association). HbA1c ≥ 5.5% showed higher sensitivity and lower specificity with respect to HbA1c ≥ 5.7% for all the abnormalities examined (IFG, IGT, high G₆₀, IR, low IS, DI and CMR factors). In conclusion, this lower cut-off might represent a more appropriate screening marker of glucose dysmetabolism in youths with OW/OB. Prospective studies are needed to validate this cut-off for predicting prediabetes/diabetes in youths with OW/OB.

Central sensitivity to thyroid hormones is reduced in youths with overweight or obesity and impaired glucose tolerance

BACKGROUND

Thyroid hormones (TH) play multiple effects on glucose metabolism. Some recent studies carried out in adult patients suggested an association between altered sensitivity to TH and type 2 diabetes, obesity, and metabolic syndrome. No studies are currently available on the presence of altered sensitivity to the action of TH in youths with prediabetes.

OBJECTIVE

To evaluate the relationship between sensitivity to TH and impaired glucose tolerance (IGT), impaired fasting glucose (IFG), or glycosylated hemoglobin (HbA1c) ≥ 5.7% in youths with overweight/obesity (OW/OB).

MATERIALS AND METHODS

This cross-sectional study included 805 Caucasian youths with OW or OB (aged 6-18 years) recruited at seven Italian centers for the care of OW/OB. Individuals with TH out of the normal range of TH in each center were excluded. The fT3/fT4 ratio was evaluated to assess peripheral sensitivity, while TSH index (TSHI), Thyrotroph T4 Resistance Index (TT4RI), Thyroid Feedback Quantile-based Index (TFQI) and Parametric TFQI were calculated to assess central sensitivity.

RESULTS

Youths with IGT (n =72) showed higher levels of TSH (3.08 ± 0.98 vs 2.68 ± 0.98 mIU/L, P =0.001), TSHI (3.06 ± 0.51 vs 2.85 ± 0.53, P =0.001), TT4RI (46.00 ± 17.87 vs 38.65 ± 16.27, P <0.0001), TFQI [1.00 (0.97-1.00) vs 1.00 (0.99-1.00)], P=0.034), PTFQI (0.67 ± 0.20 vs 0.60 ± 0.22, P =0.007) compared to youths without IGT (n =733), independently of centers and age. No differences were observed for fT3/fT4-ratio. The others phenotypes of prediabetes were not associated with altered sensitivity to TH. Odds ratio of IGT raised of 1-7-fold for each increase of 1 mIU/L in TSH (P =0.010), 1 unit in TSH Index (P =0.004), TT4RI (P =0.003) or PTFQI (P =0.018), independently of centers, age, and prepubertal stage.

CONCLUSION

IGT was associated with a reduced central sensitivity to TH in youths with OW/OB. Our finding suggests that IGT phenotype, known to be associated with an altered cardiometabolic risk profile, might also be associated with an impaired TH homeostasis in youths with OW/OB.

Childhood Obesity and Incorrect Body Posture: Impact on Physical Activity and the Therapeutic Role of Exercise

Obesity is associated with various dysfunctions of the organism, including musculoskeletal problems. In this narrative review, we aim to consider postural problems in children and adolescents with obesity, focusing on the relationship with its negative impact on physical activity, and to discuss the role of exercise as a therapeutic approach. The body reacts to excess weight by changing its normal balance, and the somatosensory system of children with obesity is forced to make major adjustments to compensate for postural problems. These adaptations become more difficult and tiring if activities that require continuous postural changes and multi-tasking are engaged in. Children with obesity have less body control and functional ability due to the excess fat mass, which reduces their ability to perform motor skills and take part in physical activity. Appropriate early interventions for the management of musculoskeletal problems are needed to ensure healthy growth and to prevent comorbidities in childhood and adulthood. Prevention programs must be based not only on the reduction of body weight but also on the definition of correct postural habits from an early age. It is equally important to provide correct information on the types and doses of physical activity that can help prevent these problems.

A new formula to improve the screening of impaired glucose tolerance in youths with overweight or obesity

AIM

To assess a new formula to improve the screening of isolated impaired glucose tolerance (IGT) in youth with overweight/obesity (OW/OB).

METHODS AND RESULTS

A cross-sectional study was performed in 1189 Caucasian youths with OW/OB aged 5-17 years, in whom impaired fasting glucose and high glycosylated hemoglobin were excluded. The sample was divided into training set (TS) (n = 883) and validation set (VS) (n = 306). Fasting (FG) and post-load plasma glucose, alanine aminotransferase (ALT), lipids and familial history for type 2 diabetes (FD) were available in all individuals. In the TS youths with IGT (n = 58, 7.0%) showed higher prevalence of female sex (FS), FD, and higher levels of FG, post-load glucose, ALT and lower levels of HDL-cholesterol vs individuals without IGT. The linear formula was obtained by logistic regression analysis in the TS: 0.05∗ALT + 0.07∗FG + 0.87∗FD + (0.06∗HDL∗ - 1) + 1∗FS. The best cut-off was 5.84. The performance of the formula vs IGT was: sensitivity: 0.74 and specificity: 0.71. Similar results were obtained in the VS.

CONCLUSIONS

Using metabolic and anamnestic data we obtained a simple formula with a good performance for screening isolated IGT. This formula may support pediatricians to identify youths with OW/OB in whom the OGTT may be useful for detecting IGT.

Circulating microRNA levels differ in the early stages of insulin resistance in prepubertal children with obesity

AIMS

The increasing prevalence of childhood obesity escalates the risk for related complications. Circulating microRNAs (miRNAs) have been suggested as good predictive markers of insulin resistance in those with obesity. The aim was to identify a circulating miRNA profile that reflects insulin resistance in prepubertal children with obesity.

MATERIAL AND METHODS

Plasma miRNAs were measured in prepubertal children (n = 63, 5-9 years) using TaqMan Advanced miRNA Human Serum/Plasma plates and then were validated by RT-qPCR. Subjects were divided into normal weight (n = 20, NW) and overweight or obese (n = 43, OW/OB) groups according to their BMI z-scores. The OW/OB group was further subdivided into insulin sensitive or metabolically healthy obese (n = 26, MHO) and insulin resistant or metabolically unhealthy obese (n = 17, MUO) according to HOMA-IR.

KEY FINDINGS

While no differences were observed in the fasting plasma glucose levels, serum insulin levels were significantly elevated in the OW/OB compared to the NW group. Of 188 screened miRNAs, eleven were differentially expressed between the NW and OW/OB groups. Validation confirmed increased circulating levels of miR-146a-5p and miR-18a-5p in the OW/OB group, which correlated with BMI z-score. Interestingly, miR-146a-5p was also correlated with HOMA-IR index. While only miR-18a-5p was upregulated in the OW/OB children, independently of their degree of insulin sensitivity, miR-146-5p, miR-423-3p and miR-152-3p were associated with insulin resistance.

SIGNIFICANCE

The present study provides evidence of molecular alterations that occur early in life in prepubertal obesity. These alterations may potentially be crucial for targeted prevention or prompt precision therapeutic development and subsequent interventions.

Medical treatment of weight loss in children and adolescents with obesity

Obesity remains one of the biggest health problems both in adults and children. Lifestyle modification, including diet and exercise, continues to be the mainstay of obesity prevention and treatment. Unfortunately, lifestyle modifications are often unsuccessful. Pharmacological treatment of obesity in pediatric patients can be applied in selected cases, and not before evidence of failure of the multidisciplinary lifestyle intervention. In this narrative review, we revised the most up-to-date evidence on medical treatment of weight loss in children and adolescents with obesity, including FDA- or EMA-approved and -experimented, not approved, drugs for pediatric population. Multidisciplinary treatment of childhood obesity, regulation of appetite control, energy balance and body weight were also discussed, in order to clarify the indications and mechanism action of drugs. Despite a substantial number of medications used for the treatment of obesity in adults, a limited number of drugs are approved by the drug regulatory agencies for pediatric population. Further research is needed to evaluate the efficacy and safety of novel pharmacological approaches for treatment of pediatric obesity in order to optimize weight management for children and adolescents and limit the development obesity-related comorbidities.