Obesity-related insulin resistance in adolescents: a systematic review and meta-analysis of observational studies

Lower adiponectin is associated with higher anthropometry and insulin resistance but not with low cardiorespiratory fitness in adolescents

PURPOSE

The aim of this study was to analyze the relationship between adiposity, cardiometabolic risk and cardiorespiratory fitness (CRF) according to different groups of adiponectin concentration.

METHODS

255 adolescents of both sexes, aged 11-17 years old, participated. Anthropometric and biochemical parameters such as body mass, height, abdominal circumference (AC), waist circumference (WC), fat mass, fat-free mass, total cholesterol (TC), high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), triglycerides (TG), glucose, insulin, adiponectin, blood pressure, peak oxygen consumption (VO2peak) were measured. Body mass index (BMI), z-score BMI (BMI-z), triponderal mass index (TMI), waist-to-height ratio (WHtR), homeostasis model to assessment insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI) were calculated. Adiponectin was categorized: low adiponectin concentration (LAC  ≤ 5.18 µg/mL-1), intermediate (IAC = 5.18 and 7.63 µg/mL-1) and high (HAC ≥ 7.63 µg/ml-1).

RESULTS

LAC showed higher BMI, BMI-z and TMI than the other groups (p < 0.05) and higher AC, WC and WHtR that the HAC (p < 0.05). IAC showed lower values of TC, LDL-c and TG, and the LAC presented the highest values of insulin, HOMA-IR and QUICKI (p < 0.05) to the IAC and HAC. HAC presented the lower VO2peak than the other groups (p < 0.01). BMI, TMI, glucose, insulin, HOMA-IR showed inverse, and QUICKI a direct and weak correlation with adiponectin (p < 0.05). No significant association was found between adiponectin and VO2peak (p > 0.05).

CONCLUSION

The LAC group had higher means in the anthropometric variables and the worst results related to insulin resistance and sensitivity. Thus, adiponectin may play an important role in obesity and reduced concentration may be a factor in the development of obesity-associated morbidities.

Mapping the landscape of research on insulin resistance: a visualization analysis of randomized clinical trials

BACKGROUND

Insulin resistance, a condition in which cells do not respond adequately to insulin, plays a crucial role in diabetes and related metabolic disorders. Randomized clinical trials (RCTs) explore interventions to manage insulin resistance, contributing to evidence-based medical progress. The current study aimed to analyze the global research landscape and trends in RCTs targeting insulin resistance.

METHODS

This study used bibliometric analysis and data visualization to examine RCT publications on insulin resistance from 2003 to 2022. The Scopus database was used due to its comprehensive coverage. The search strategy involved combining terms related to insulin resistance with RCT-related terms. The search query was validated, and core bibliometric indicators were used to analyze publication growth, origin, productivity, quality, and citations.

RESULTS

Between 2003 and 2022, 1077 RCT-focused publications on insulin resistance were identified from a pool of 24,932 related articles. The growth followed two phases, with a significant increase after 2008. The USA (n = 308; 28.60%), Iran (n = 165; 15.32%), China (n = 110; 10.21%), and the UK (n = 92; 8.54%) were the main contributors. The active institutions included Tehran University of Medical Sciences (n = 38; 3.53%) and Harvard Medical School (n = 31; 2.88%). Prominent funding agencies include the National Institutes of Health (n = 88; 8.17%) and the National Institute of Diabetes and Digestive and Kidney Diseases (n = 86; 7.99%). The top journals included the American Journal of Clinical Nutrition (n = 44; 4.09%) and Diabetes Care (n = 35; 3.25%). Co-occurrence analysis revealed three clusters addressing "utilizing lipid panels as indicators of insulin resistance," "analyzing the impact of diet composition and physical activity on insulin sensitivity among obese individuals," and "exploring insulin resistance in cases of polycystic ovary syndrome."

CONCLUSIONS

This comprehensive bibliometric analysis highlights the global research landscape and trends in RCTs targeting insulin resistance. Research on lipid panels, diet impact, and insulin resistance in patients with polycystic ovary syndrome will continue to be a hotspot. The findings offer valuable information on research priorities, international collaborations, and impactful publications. This study provides a foundation for future directorial investigations in this critical area of metabolic health.

Trends in HOMA-IR values among South Korean adolescents from 2007-2010 to 2019-2020: a sex-, age-, and weight status-specific analysis

BACKGROUND/OBJECTIVES

An increase in obesity prevalence may lead to an increase in the HOMA-IR value. This study aimed to investigate changes in age- and sex-specific homeostasis model assessment of insulin resistance (HOMA-IR) values among South Korean adolescents, using data from the Korean National Health and Nutrition Examination Survey (KNHANES) IV, V, and VIII conducted between 2007-2010 and 2019-2020.

SUBJECTS/METHODS

Overall, 4621 adolescents aged 10-18 years were evaluated, including 3473 from the 2007-2010 dataset and 1148 from the 2019-2020 dataset. The mean HOMA-IR values and percentile curves were evaluated by age, sex, and weight status.

RESULTS

The mean HOMA-IR values peaked at puberty in both sexes and further increased during puberty in the 2019-2020 dataset (boys 5.21, 95% confidence interval [CI] 4.16-6.26; girls 5.21, 95% CI 3.09-7.33) compared with the 2007-2010 dataset (boys 3.25, 95% CI 3.04-3.47; girls 3.58, 95% CI 3.31-3.85). Both groups (with normal-weight and overweight/obesity) exhibited a peak HOMA-IR value during puberty in both sexes and both datasets, although the group with overweight/obesity had a higher and wider peak age range. While the mean HOMA-IR values did not change in adolescents with normal-weight, they increased during puberty and post-puberty in boys with overweight/obesity.

CONCLUSIONS

HOMA-IR values should be interpreted considering sex, weight status, and pubertal stages. In particular, during the pubertal period, insulin resistance (IR) can coexist not only due to weight-related factors but also as a result of the distinct hormonal changes characteristic of puberty. Over the 10-year period, the mean HOMA-IR values increased in the group with overweight/obesity during puberty and post-puberty, highlighting the need for active intervention to prevent metabolic complications in adolescents with overweight/obesity.

The association of serum C-peptide with the risk of cardiovascular events: a meta-analysis and systematic review

BACKGROUND

C-peptide is considered a peptide with active function in the body, which can affect people's health. However, the results of previous studies on the possible association of C-peptide with the risk of cardiometabolic disorders have not been fully understood. This systematic review and meta-analysis aimed to investigate the association between serum C-peptide level and the risk of cardiovascular disease (CVD) events.

METHODS

The various important databases, including PubMed, Scopus, and Web of Science, were searched comprehensively to November 2022 to identify the relevant studies. The HR(95% CI) or OR(95% CI) for observational studies were extracted and converted into log HR or log OR and their standard deviation(SD) was computed. A random-effects model with an inverse variance weighting method was conducted, to calculate the pooled effect size.

RESULTS

Sixteen observational studies, including one case-control study, eight cohort studies, and seven cross-sectional studies were included in the current meta-analysis. The sample size ranged from 90 to 7030, with an age range from 12 to 85 years. During the follow-up time (ranging from 5 to 17 years), 4852 CVD events occurred. Based on cohort and case-control studies, the pooled results showed no significant association between serum C-peptide with CVD events risk (RR = 1.02;95%CI:0.91-1.15, I2 = 34.7%; P-heterogeneity = 0.140). For cross-sectional studies, the pooled results indicated a positive association between serum C-peptide and the odds of CVD outcomes (OR = 1.35;95%CI:1.04-1.76, I2 = 83.6%; P-heterogeneity < 0.001).

CONCLUSIONS

The pooled results of the current study suggested that C-peptide level was not related to the risk of CVD events in cohort studies, however, the meta-analysis of cross-sectional studies showed a significant association between C-peptide and an increased risk of CVD events.

Childhood obesity and hypertension in pregnancy: a two-sample Mendelian randomization analysis

BACKGROUND

The causal relationship between childhood obesity and hypertension in pregnancy remains unclear. To examine the causal association between childhood obesity and hypertension in pregnancy, two-sample Mendelian randomization analysis was applied.

METHODS

Single-nucleotide polymorphisms (SNPs) associated with childhood obesity were obtained from a published genome-wide association study (GWAS) of 13 848 European individuals. Summary-level data for hypertension in pregnancy were obtained from the FinnGen consortium (11534 cases and 162212 controls). Inverse-variance weighted analysis, weighted-median analysis, and Mendelian randomization-Egger regression were conducted in this Mendelian randomization analysis. Sensitivity analyses were conducted to confirm the accuracy and robustness of our results.

RESULTS

Genetically determined childhood obesity significantly affects hypertension in pregnancy by IVW [odds ratio (OR) = 1.161, 95% confidence interval (CI) 1.086-1.039; P = 9.92 × 10 -6 ] and weighted median (OR = 1.123, 95% CI 1.038-1.214; P  = 0.004). These results were validated by multiple sensitivity analyses.

CONCLUSION

A causal effect between genetically predicted childhood obesity and the risk of hypertension in pregnancy was identified. The prevention of hypertension in pregnancy should be promoted in populations with childhood obesity.

Concentration of Selected Adipokines and Factors Regulating Carbohydrate Metabolism in Patients with Head and Neck Cancer in Respect to Their Body Mass Index

Head and neck cancers (HNCs) are a group of tumors not common in European populations. So far, not much is known about the role of obesity, adipokines, glucose metabolism, and inflammation in the pathogenesis of HNC. The aim of the study was to determine the concentrations of ghrelin, omentin-1, adipsin, adiponectin, leptin, resistin, visfatin, glucagon, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), plasminogen activator inhibitor-1 (PAI-1), and gastric inhibitory peptide (GIP) in the blood serum of HNC patients depending on their body mass index (BMI). The study included 46 patients divided into two groups according to their BMI values: the normal BMI group (nBMI) included 23 patients with BMI < 25 kg/m² and the increased BMI group (iBMI) included patients with BMI ≥ 25 kg/m². A control group (CG) included 23 healthy people (BMI < 25 kg/m²). Statistically significant differences in the levels of adipsin, ghrelin, glucagon, PAI-1, and visfatin were shown between nBMI and CG. In the case of nBMI and iBMI, statistically significant differences were observed in the concentrations of adiponectin, C-peptide, ghrelin, GLP-1, insulin, leptin, omentin-1, PAI-1, resistin, and visfatin. The obtained results indicate a disruption of endocrine function of adipose tissue and impaired glucose metabolism in HNC. Obesity, which is not a typical risk factor for HNC, may aggravate the negative metabolic changes associated with this type of neoplasm. Ghrelin, visfatin, PAI-1, adipsin, and glucagon might be related to head and neck carcinogenesis. They seem to be promising directions for further research.

Intravenous insulin injection supplemented with subsequent milk consumption is a safer formulation for cardiac viability 18F-FDG imaging

BACKGROUND

The safety and efficacy of intravenous insulin injection coupled with subsequent milk consumption was evaluated for high-quality cardiac viability F-18-fluorodeoxyglucose (18F-FDG) images.

METHODS AND RESULTS

A total of 328 patients with known/suspected coronary artery disease received intravenous insulin injection with or without subsequent milk consumption for cardiac 18F-FDG imaging. When blood glucose levels had decreased by ≥ 20%, 18F-FDG was injected. Patients were scored for hypoglycemic symptoms using a 10-point scale (discomfort: 0, none; 1 to 3, mild; 4 to 6, moderate; 7 to 9, severe). An insulin-related hypoglycemic event was defined as an increased symptomatic score following insulin injection. The number of hypoglycemic events was significantly lower in the milk consumption group than in the group that did not (24/164 vs. 51/164, P < .01). Maximal and averaged standardized uptake value of the left ventricular myocardium (MyoSUVmax and MyoSUVmean) were also measured. The milk and control groups had similar mean hypoglycemic symptom scores (4.2 ± 4.0 vs. 3.3 ± 3.1, respectively), MyoSUVmax, and MyoSUVmean (11.1 ± 4.8, 7.3 ± 3.2 vs. 11.4 ± 4.5, 7.4 ± 3.2, respectively).

CONCLUSION

Intravenous insulin injection supplemented with subsequent milk consumption is a safer formulation for cardiac viability 18F-FDG imaging without impairing image quality.

β-cell function and body mass index are predictors of exercise response in elderly patients with pre-diabetes

Aims/Introduction

To explore the predicting factors of exercise response (whether the participants converted to diabetes) in elderly patients with prediabetes.

Materials and Methods

This is a retrospective subgroup analysis of the registered clinical trial with previous publication of the same cohort. A total of 248 participants with prediabetes were randomized to the aerobic training (n = 83) group, resistance training (n = 82) group and control group (n = 83). The patients who finished the 2‐year exercise intervention were included in this analysis to explore the factors impacting exercise response.

Results

A total of 113 patients with prediabetes completed 2 years of exercise, with 56 participants in the aerobic exercise group and 57 in the resistance exercise group. Patients who reversed to normal glucose tolerance, remained in prediabetes and developed diabetes were 18 (15.90%), 70 (62.00%) and 25 (22.10%), respectively. Logistic regression showed that baseline, homeostatic model 2 assessment of β‐cell function (β = −0.143, P = 0.039), hemoglobin A1c (β = 3.301, P = 0.007) and body mass index (β = 0.402, P = 0.012) were related to exercise response, whereas the waist‐to‐hip ratio (β = −3.277, P = 0.693) and types of exercise (β = 1.192, P = 0.093) were not significantly related to exercise response.

Conclusions

Baseline homeostatic model 2 assessment of β‐cell function, hemoglobin A1c and body mass index were the predictors for the response to exercise in elderly patients with prediabetes.

New Insights in Cytokines in Childhood Obesity: Changes in TWEAK and CD163 After a 2-Year Intervention Program in Prepubertal Children With Obesity

OBJECTIVE

Obesity is characterized by a low-grade inflammatory state in adipose tissue. Tumor Necrosis Factor Weak Inducer of Apoptosis (TWEAK) and Cluster of Differentiation 163 (CD163) are cytokines potentially involved in the pathogenesis of obesity. Little is known about them in children. The aim of this study was to observe serum levels of TWEAK and CD163 in prepubertal children with obesity compared to lean, and to evaluate its changes after a 2-year intervention program in children with obesity.

METHODS

Case-control study with a prospective follow-up of cases for 2 years in a referral pediatric endocrine outpatient centre. Seventy-three prepubertal children with obesity, and forty-seven age- and gender-matched lean controls were studied. Sixty-two cases finished the program. Anthropometric parameters, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), lipid profile, and concentrations of TWEAK and CD163 were determined. Children with obesity were re-evaluated after a 2-year intervention program consisting of diet and exercise. Weight loss was considered if z-score Body Mass Index (BMI) decreased at least 0.5 Standard Deviations (SD).

RESULTS

We observed higher CD163 levels in children with obesity compared to controls. No significant differences were observed in TWEAK and CD163/TWEAK ratio at baseline. After the 2-year intervention program, TWEAK levels were higher and CD163/TWEAK ratio was lower in children with weight loss than those without weight loss. CD163 decreased in both groups.

CONCLUSION

TWEAK and CD163 seem to have a role in the pathogenesis of obesity in prepubertal children.

Eating behaviors and alexithymic features of obese and overweight adolescents

BACKGROUND

In this study, eating behaviors and alexithymia levels in obese adolescents were investigated. Relationships between alexithymia, eating behavior and insulin resistance were studied.

METHODS

The patient group consisted of 87 obese adolescents or overweight adolescents (O + OW). The comparison group consisted of 101 normal weight adolescents (N). Alexithymia Questionnaire for Children, Dutch Eating Behavior Questionnaire, and Revised Child Anxiety and Depression Scale-Child Version, are used for assessing adolescents. The homeostasis model assessment-estimated insulin resistance was calculated to determine insulin resistance.

RESULTS

Alexithymia Questionnaire for Children scores were significantly higher in O + OW than N (P = 0.009). Both emotional and restrained eating scores are higher in O + OW (P < 0.001 for both). On the other hand, external eating scores were not significantly different. In O + OW, external eating was positively associated with homeostasis model assessment-estimated insulin resistance (r: 035, P = 0.006), but is not associated with fasting blood glucose and the hemoglobin A1c (HbA1c) (r: -0.05, P = 0.62; r: -0.05, P = 0.73). Regression analysis showed that restrained and emotional eating were predictors of O + OW (B: 0.1, P < 0.001; B: 0.06, P = 0.001). Emotional eating was positively correlated with the Alexithymia Questionnaire for Children and Revised Child Anxiety and Depression Scale-Child Version in O + OW (r: 0.29, P = 0.008; r: 0.48, P < 0.001).

CONCLUSIONS

Obese and overweight adolescents were more alexithymic than normal weight adolescents. Alexithymia scores were also positively associated with emotional eating. On the other hand, alexithymia was not a predictor of obesity/overweight. Restrained and emotional eating were predictors of obesity/overweight. Emotional and restrained eating were more common in obese and overweight adolescents than normal-weight adolescents. External eating is not significantly associated with obesity but is related to insulin resistance.

Effect of 8 weeks' supplementation grape seed extract on insulin resistance in iranian adolescents with metabolic syndrome: A randomized controlled trial

BACKGROUND AND AIMS

Insulin resistance in adolescents is a major health concern. The aim of this study was to evaluate the effect of grape seed extract on insulin resistance in adolescents with metabolic syndrome (MetS).

METHODS

Participants were divided into grape seed extract (GSE) and placebo groups (n = 24 each) and received 100 mg/day of GSE or placebo and were placed on a weight loss diet for 8 weeks. Anthropometric and biochemical indices, blood pressure, dietary intake, and physical activity were measured before and after the intervention.

RESULTS

Forty-two participants completed the trial. After the intervention, the age, sex, baseline values, energy intake and physical activity as a covariate adjusted using ANCOVA for determine differences between groups. The MD (mean difference ±SEM) of HOMA-IR between the GSE group (-1.46 ± 0.45) and the placebo group (-0.48 ± 0.47), (p = 0.020), and the MD of insulin between the GSE group (-7.05 ± 2.11) and the placebo group (-1.71 ± 2.12), (p = 0.024), were significant. Although changes were observed in other variables, they were not statistically significant.

CONCLUSIONS

GSE improves insulin concentration and insulin resistance in adolescents with MetS and provides a basis for possible application of the GSE in the clinical management of MetS in adolescents. This study registered under Randomized Clinical Trials.gov Identifier no. IRCT2013112611288N7.

The Fat-to-Lean Mass Ratio Is Associated with Hyperinsulinemia in Healthy Mexican Adolescents

Objective: To evaluate whether the Fat-to-Lean Mass (FyM) ratio is associated to hyperinsulinemia in healthy adolescents.Methods: Apparently healthy adolescents aged 10 to 15 years that according to sex, age, and percentiles of body fat percent, were included and allocated into the groups with elevated (body fat percent ≥85 percentile) and normal total body fat (body fat percent <85 percentile). The FyM ratio was calculated as total lean mass (kg)/total body fat (kg) and hyperinsulinemia was defined by fasting insulin levels ≥20 µUI/mL.Results: A total of 1,299 adolescents, 665 (51.9%) girls and 634 (48.1%) boys, were enrolled and allocated into the groups with high (n = 439) and normal (n = 860) body fat. The FyM index remained significantly associated with hyperinsulinemia (OR 5.58; _95%CI: 1.54-28.10) after logistic regression analysis adjusted by sex, age, body-weight, body mass index, and waist circumference.Conclusion: The FyM index is highly associated to the presence of hyperinsulinemia in adolescents, emerging as a useful tool from anthropometric measurements for identify insulin abnormalities.

Maternal overnutrition impairs offspring's insulin sensitivity: A systematic review and meta-analysis

This systematic review and meta‐analysis aimed to investigate the association between maternal overnutrition and offspring's insulin sensitivity—following the Preferred Reporting Items for Systematic Reviews and Meta‐analyses statement. Studies published in English before April 22, 2019, were identified through searches of four medical databases. After selection, 15 studies aiming to explore the association between prepregnancy body mass index (ppBMI) or gestational weight gain (GWG) of non‐diabetic mothers and their offspring's insulin sensitivity (fasting insulin or glucose level and Homeostatic Measurement Assessment for Insulin Resistance [HOMA‐IR]) were included in the meta‐analysis. Associations of ppBMI and GWG with offspring's insulin sensitivity were analysed by pooling regression coefficients or standardized differences in means with 95% confidence intervals (CIs). Maternal ppBMI showed significant positive correlations with the level of both fasting insulin and HOMA‐IR in offspring (standardized regression coefficient for fasting insulin: 0.107, CI [0.053, 0.160], p < 0.001 and that for HOMA‐IR: 0.063, CI [0.006, 0.121], p = 0.031). However, the result of the analysis on coefficients adjusted for offspring's actual anthropometry (BMI and adiposity) was not significant. Independent from ppBMI, GWG tended to show a positive correlation with insulin level, but not after adjustment for offspring's anthropometry. Offspring of mothers with excessive GWG showed significantly higher HOMA‐IR than those of mothers with optimal GWG (p = 0.004). Our results demonstrate that both higher ppBMI and GWG increase the risk of offspring's insulin resistance, but the effect of ppBMI on insulin sensitivity in offspring may develop as consequence of their adiposity.

Discovery of a role of the novel hepatokine, hepassocin, in obesity

Obesity is a public health problem that has raised concerns worldwide and is often associated with hepatic steatosis. Hepassocin is a novel hepatokine that causes hepatic steatosis and induces insulin resistance (IR). However, the role of hepassocin in obesity remains obscure. Thus, the aim of this study was to investigate the relationship between hepassocin levels and obesity. In total, 371 subjects who had a normal weight (NW), were overweight, or were obese were enrolled. We found that hepassocin levels in subjects who were overweight (6,705 ± 1,707 pg/ml) or obese (7,335 ± 2,077 pg/ml) were significantly higher than those of subjects with a NW (5,767 ± 1,500 pg/ml) (p < .001, test for trend). A multiple linear regression analysis showed that the body-mass index, waist circumference, nonalcoholic fatty liver disease, and homeostatic model assessment of IR were independently associated with hepassocin after adjusting for age, sex, high-sensitivity C-reactive protein, systolic blood pressure, high-density lipoprotein-cholesterol, log triglycerides, alanine transaminase, and the estimated glomerular filtration rate. This study provides evidence that subjects who were overweight or obese had significantly higher hepassocin levels than those with a NW. Hepassocin may be a useful biomarker in managing obesity and its related metabolic dysregulation.

Obesity and insulin sensitivity effects on cardiovascular risk factors: Comparisons of obese dysglycemic youth and adults

BACKGROUND

Obesity and pubertal insulin resistance worsen cardiovascular (CV) risk factors in youth. It is unclear how the relationships of obesity and insulin resistance with CV risk compare to adults.

SUBJECTS AND METHODS

We evaluated 66 pubertal youth (mean ± SD: age 14.2 ± 2.0 years, body mass index [BMI] 36.6 ± 6.0 kg/m² , hemoglobin A1c [HbA1c] 38.5 ± 6.1 mmol/mol) and 355 adults with comparable BMI (age 52.7 ± 9.4 years, BMI 35.1 ± 5.1 kg/m² , HbA1c 39.8 ± 4.2 mmol/mol) participating in a multicenter study. Insulin sensitivity was quantified using hyperglycemic clamps. Assessment of CV risk factors was standardized across sites. Regression analyses compared the impact of insulin sensitivity and CV risk factors between youth and adults.

RESULTS

Obese pubertal youth were more insulin resistant than comparably obese adults (P < .001), but with similar slopes for the inverse relationship between insulin sensitivity and obesity. The impact of obesity on CV risk factors was explained by insulin sensitivity (P = NS after adjustment for sensitivity). The two age groups did not differ in relationships between insulin sensitivity and diastolic blood pressure, total cholesterol, and low-density lipoprotein (LDL) cholesterol, after adjusting for obesity. However, while systolic blood pressure (SBP) and high-density lipoprotein (HDL) cholesterol exhibited the expected direct and inverse relationships, respectively with insulin sensitivity in adults, these slopes were flat in youth across the range of insulin sensitivity (P ≤ .05 for group differences).

CONCLUSIONS

Effects of obesity on CV risk factors were attributable to insulin sensitivity in both groups. The relationships between insulin sensitivity and CV risk factors were similar in obese youth and adult groups except for SBP and HDL cholesterol.

CLINICAL TRIAL REGISTRATION

The RISE consortium studies are registered through Clinicaltrials.gov as NCT01779362 (Adult Medication Study); NCT01763346 (Adult Surgery Study); and NCT01779375 (Pediatric Medication Study). Clinical trial registration numbers: NCT01779362, NCT01779375 and NCT01763346 at clinicaltrials.gov.

Cutoff values for HOMA-IR associated with metabolic syndrome in the Study of Cardiovascular Risk in Adolescents (ERICA Study)

OBJECTIVE

The aim of this study was to determine the distribution of homeostatic model assessment of insulin resistance (HOMA-IR) values and define its cutoff associated with metabolic syndrome (MetS) in the participants of the Study of Cardiovascular Risk in Adolescents (Estudo de Risco Cardiovascular em Adolescentes).

METHODS

MetS was defined according to the International Diabetes Federation criteria. HOMA-IR values were calculated and tabulated by corresponding percentiles for age and sex. Receiver operating characteristic curves were constructed to identify the optimal cutoff values of HOMA-IR associated with MetS in the total population and by sex.

RESULTS

We evaluated 37 815 adolescents ages 12 to 17 y. The highest HOMA-IR medians were found among girls and boys ages 12 and 14 y, respectively. Thereafter, values tended to decrease with age. The optimal cutoff values of the HOMA-IR associated with MetS in the total population, in female adolescents, and in male adolescents were 2.80, 2.32, and 2.87, respectively. Insulin resistance was prevalent in 19.1% (95% confidence interval, 17.7-20.7) of the total population, and the prevalence was higher among girls and overweight Brazilian adolescents.

CONCLUSIONS

These findings may serve as new reference points for detecting insulin resistance in Brazilian adolescents.

Relationship between body fat percentage and insulin resistance in adults with Bmi values below 25 Kg/M2 in a private clinic

AIM

To evaluate the association between elevated body fat percent (BF%) and the prevalence of insulin resistance (IR) in the adult population with body mass index (BMI) in the normal values.

METHODS

We carry out an analytical cross-sectional study. The participants attended outpatient from 2012 to 2016 in a private clinic in Lima-Peru between 18 and 60 years with a BMI between 19 and 24.9/Kg/m2. We defined elevated BF% if the values were greater than 25% in men and 30% in women and IR with a cut-off point of HOMA-IR based in the 75th percentile. We performed a generalized linear model from family Poisson (crude and adjusted) with robust standard errors to evaluate the association between BF% and the IR. We reported as association measure the prevalence ratio (PR) with their respective 95% confidence intervals (CI).

RESULTS

We included 284 participants, the average age was 33.77 ± 10.86 (SD) years and the percentage of women was 88.1%. The prevalence of elevated BF% was 71.13% and the prevalence of IR was 25%. We found an association between the elevated BF% and IR, PR = 3.17; 95% CI: 1.46-6.91.

CONCLUSIONS

Body fat percentage seems to be a good indicator of IR in patients with normal BMI and without endocrine comorbidities. Longitudinal prospective studies are recommended to corroborate our findings.

Glucose-Responsive Composite Microneedle Patch for Hypoglycemia-Triggered Delivery of Native Glucagon

Insulin-dependent patients with diabetes mellitus require multiple daily injections of exogenous insulin to combat hyperglycemia. However, administration of excess insulin can lead to hypoglycemia, a life-threatening condition characterized by abnormally low blood glucose levels (BGLs). To prevent hypoglycemia associated with intensive insulin therapy, a "smart" composite microneedle (cMN) patch is developed, which releases native glucagon at low glucose levels. The cMN patch is composed of a photo-crosslinked methacrylated hyaluronic acid (MeHA) microneedle array with embedded multifunctional microgels. The microgels incorporate zwitterionic moieties that stabilize loaded glucagon and phenylboronic acid moieties that provide glucose-dependent volume change to facilitate glucagon release. Hypoglycemia-triggered release of structurally unchanged glucagon from the cMN patch is demonstrated in vitro and in a rat model of type 1 diabetes (T1D). Transdermal application of the patch prevented insulin-induced hypoglycemia in the diabetic rats. This work is the first demonstration of a glucose-responsive glucagon-delivery MN patch for the prevention of hypoglycemia, which has a tremendous potential to reduce the dangers of intensive insulin therapy and improve the quality of life of patients with diabetes and their caregivers.

Effects of CPAP on the transcriptional signatures in patients with obstructive sleep apnea via coexpression network analysis

A growing number of studies provide epidemiological evidence linking obstructive sleep apnea (OSA) with a number of chronic disorders. Transcriptional analyses have been conducted to analyze the gene expression data. However, the weighted gene coexpression network analysis (WGCNA) method has not been applied to determine the transcriptional consequence of continuous positive airway pressure (CPAP) therapy in patients with severe OSA. The aim of this study was to identify key pathways and genes in patients with OSA that are influenced by CPAP treatment and uncover/unveil potential molecular mechanisms using WGCNA. We analyzed the microarray data of OSA (GSE 49800) listed in the Gene Expression Omnibus database. Coexpression modules were constructed using WGCNA. In addition, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were also conducted. After the initial data processing, 5101 expressed gene profiles were identified. Next, a weighted gene coexpression network was established and 16 modules of coexpressed genes were identified. The interaction analysis demonstrated a relative independence of gene expression in these modules. The black module, tan module, midnightblue module, pink module, and greenyellow module were significantly associated with the alterations in circulating leukocyte gene expression at baseline and after exposure to CPAP. The five hub genes were considered to be candidate OSA-related genes after CPAP treatment. Functional enrichment analysis revealed that steroid biosynthesis, amino sugar and nucleotide sugar metabolism, protein processing in the endoplasmic reticulum, and the insulin signaling pathway play critical roles in the development of OSA in circulating leukocyte gene expression at baseline and after exposure to CPAP. Using this new systems biology approach, we identified several genes and pathways that appear to be critical to OSA after CPAP treatment, and these findings provide a better understanding of OSA pathogenesis.

Glucose regulation by modified boronic acid-sulfobetaine zwitterionic nanogels - a non-hormonal strategy for the potential treatment of hyperglycemia

We have introduced a non-hormonal hyperglycemia treatment strategy by using an injectable glucose-responsive boronic acid- zwitterionic nanogel. The synthesized system, similar to an artificial liver, is capable of storing/releasing glucose at high/low blood glucose concentrations. In vivo performance revealed that the injection of the nanogels can effectively regulate blood glucose in type 1 diabetic rats for at least 6 hours.

Physical activity in adolescents and children and relationship to metabolic health

PURPOSE OF REVIEW

To summarize the recent developments relating to the role of physical activity in improving insulin resistance and metabolic syndrome in children and adolescents.

RECENT FINDINGS

The current literature strengthens previous findings on the relationship between physical activity and metabolic health in children; suggests a protective role for physical activity in the setting of obesity; examines population-specific findings; addresses specific effects of different modalities of physical activity in improving health; reveals potential mediators in the relationship between physical activity and metabolic health; and suggests new markers of metabolic health that could potentially be used as outcomes in future physical activity studies.

SUMMARY

Recent research generally confirms the role of physical activity in decreasing insulin resistance and metabolic syndrome in children and adolescents. However, the current literature is limited by unstandardized research methods and definitions, and also aggregation of different age groups, genders, and weight status. Future research should address these issues to offer targeted physical activity interventions.

Triglycerides and glucose index as an insulin resistance marker in a sample of healthy adults

AIM

To assess the association between elevated triglycerides/glucose index (TGI) and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in a sample of healthy adults.

METHODS

We conducted an analytical cross-sectional study in euthyroid non-diabetic adults, who attended the outpatient service of a private clinic in Lima-Peru during the 2012-2016 period. Participants were categorized in two groups according to the presence or absence of elevated TGI, IR or hyperinsulinemia after OGTT. A TGI value ≥ 8.65 was considered as elevated. We defined IR as a Homeostasis Model Assessment (HOMA-IR) value ≥ 2.28 and hyperinsulinemia after OGTT as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson regression models to assess the association between elevated TGI and IR or hyperinsulinemia after OGTT. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed 118 individuals, the average age was 37.5 ± 11.3 years, 21 (17.8%) were males and the median BMI was 22.7 ± 1.6 kg/m². The prevalence of elevated TGI was 25.4% (n=30) while the prevalence of IR and hyperinsulinemia after OGTT was 24.6% (n=29) and 17.0% (n=20) respectively. In the adjusted model, elevated TGI was associated with both IR (aPR=6.36; 95%CI: 3.41-11.86) and hyperinsulinemia after OGTT (aPR=4.19; 95%CI: 1.81-9.70).

CONCLUSIONS

We found that elevated TGI was associated with both IR markers in a sample of euthyroid adults without T2DM and with a normal BMI. The simplicity of the TGI calculation makes it the first-choice alternative when the hyperinsulinemic-euglycemic clamp or HOMA-IR are not available.

High waist-to-hip ratio levels are associated with insulin resistance markers in normal-weight women

AIM

To assess the association between high waist-to-hip ratio (WHR) levels and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in a sample of normal-weight women.

METHODS

We conducted an analytical cross-sectional study in euthyroid non-diabetic women, who attended the outpatient service of a private clinic in Lima-Peru from 2012 to 2016. Participants were divided in two groups according to the presence or absence of high WHR levels, IR or hyperinsulinemia after OGTT. We considered WHR values > 0.85 as high levels. IR was defined as a Homeostasis Model Assessment (HOMA-IR) value > 2.39 and hyperinsulinemia after OGTT as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson generalized linear models to evaluate the association between high WHR levels and IR or hyperinsulinemia after OGTT and reported the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed the data of 248 euthyroid, non-diabetic and normal-weight women. The prevalence of high WHR levels was 68.9% (n = 171) while the prevalence of IR and hyperinsulinemia after OGTT was 25% (n = 62) and 15.3% (n = 38), respectively. WHR values were positively correlated with HOMA-IR (r = 0.307; p < 0.001) and serum insulin after OGTT (r = 0.260; p < 0.001). In the adjusted model, high WHR levels were associated with both IR (aPR = 2.63; 95%CI: 1.39-5.01) and hyperinsulinemia after OGTT (aPR = 2.35; 95%CI: 1.03-5.38).

CONCLUSION

High WHR levels were associated with both IR markers used in our study, appearing to be a useful anthropometric indicator to assess IR in euthyroid normal-weight women without type 2 diabetes mellitus.

Insulin resistance: Review of the underlying molecular mechanisms

Most human cells utilize glucose as the primary substrate, cellular uptake requiring insulin. Insulin signaling is therefore critical for these tissues. However, decrease in insulin sensitivity due to the disruption of various molecular pathways causes insulin resistance (IR). IR underpins many metabolic disorders such as type 2 diabetes and metabolic syndrome, impairments in insulin signaling disrupting entry of glucose into the adipocytes, and skeletal muscle cells. Although the exact underlying cause of IR has not been fully elucidated, a number of major mechanisms, including oxidative stress, inflammation, insulin receptor mutations, endoplasmic reticulum stress, and mitochondrial dysfunction have been suggested. In this review, we consider the role these cellular mechanisms play in the development of IR.

Insulin resistance and metabolic syndrome criteria in lean, normoglycemic college-age subjects

AIMS

The goal of this study was to determine insulin sensitivity in a fasted state and during an oral glucose tolerance test (OGTT), in normoglycemic (NGT), lean (L) (n = 35) and, for comparison, overweight/obese (OW/O) (n = 9) college-aged subjects.

MATERIALS AND METHODS

Insulin sensitivity for 44 NGT, normotensive subjects, age 18-26 yrs., was determined by homeostasis model assessment (HOMA-IR) and from Matsuda index (ISI Matsuda).

RESULTS

Subjects were normoglycemic fasted (4.59 + 0.35 mmol/L) and at two hours post OGTT (4.52  + 1.35 mmol/L). Besides anthropometric measures, there were significant differences between OW/O and L for fasting insulin (P < 0.001) and both measures of insulin sensitivity (P < 0.05). All subjects exhibited a 9-fold range in HOMA-IR (0.88 + 0.51, range 0.3-2.7) and an 8-fold range in ISI Matsuda (11.9 + 4.7, range 3.0-24.2). The latter was inversely correlated with systolic blood pressure (r = 0.35, P = 0.04) even though subjects were normotensive. In lean subjects, 2.3% were IR by HOMA-IR > 2.1, 5.7% by ISI Matsuda < 5.9, and 22.9% had >one criteria for metabolic syndrome (MetS); 28.6% had some negative metabolic biomarker.

CONCLUSIONS

Insulin resistance is present in lean, NGT college-age subjects even without MetS criteria and is discernable with an easily applicable OGTT-derived index.

Intrauterine hyperglycemia exposure results in intergenerational inheritance via DNA methylation reprogramming on F1 PGCs

BACKGROUND

The existing reports about intergenerational or transgenerational effects of intrauterine hyperglycemia have included both intrauterine and postnatal metabolic exposure factors, while the impact of intrauterine hyperglycemia per se has not been assessed alone. A number of studies suggest DNA methylation reprogramming of gametes plays a crucial role in the metabolic inheritance, but it is unclear when and how DNA methylation patterns are altered when exposed to intrauterine hyperglycemia. In this study, we selected nondiabetic F1- and F2-gestational diabetes mellitus (GDM) male mice as founders to examine metabolic changes in the next generation and performed methylome sequencing of day 13.5 primordial germ cells (PGCs) from F1-GDM to explore the underlying epigenetic mechanism.

RESULTS

We found that intrauterine hyperglycemia exposure resulted in obesity, insulin resistance, and/or glucose intolerance in F2 male mice, but no metabolic changes in F3 male mice at 8 weeks. Using reduced representation bisulfite sequencing, we found DNA methylome of day 13.5 PGCs from F1-GDM fetuses revealed differently methylated genes enriched in obesity and diabetes. Methylation validation of the insulin resistance and fat accumulation gene Fyn showed a consistent hypomethylation status in F1 PGCs, F1 fetal testes, sperm from F1/C-GDM mice, and somatic cells from F2-GDM male mice. In contrast, no methylation alteration was observed in F2-GDM male germ cells and F3-GDM somatic cells.

CONCLUSION

We provide evidence that intrauterine hyperglycemia exposure per se contributes to intergenerational metabolic changes in the F2 but not F3 generation. And the aberrant DNA methylation reprogramming occurs as early as day 13.5 in PGCs of the F1 generation. Our findings suggest that intrauterine exposure alone is sufficient to cause the epigenetic inheritance in F2 offspring, and the epigenetic memory carried by DNA methylation pattern could be erased by the second wave of methylation reprogramming in F2 PGCs during fetal development.

Metabolic Profiles in Obese Children and Adolescents with Insulin Resistance

BACKGROUND:

In the past several decades, the increasing frequency of overweight and obese children and adolescents in the world has become a public health problem. It has contributed significantly to the already high tide of diabetes, cardiovascular and cerebrovascular diseases.

AIM:

To investigate the frequency of insulin resistance and to evaluate the metabolic profile of insulin resistant and non-insulin resistant obese children and adolescents.

SUBJECTS AND METHODS:

The study included 96 (45 boys, 51 girls) obese children and adolescents aged 4-17 years old (10.50 ± 2.87 years). Only participants with Body Mass Index ≥ 95 percentile were included. We analysed sera for fasting insulin levels (FI), fasting serum triglycerides (TG), total serum cholesterol (TC), fasting plasma glucose (FPG) and plasma glucose 2 hours after the performance of the oral glucose tolerance test (2-h G). Homeostatic model assessment for insulin resistance (HOMA-IR) index was calculated as fasting insulin concentration (microunits per millilitre) x fasting glucose concentration (millimolar)/22.5. The value of HOMA-IR above 3.16 was used as a cut-off value for both genders.

RESULTS:

Insulin resistance was determined in 58.33% of study participants. Insulin resistant participants had significantly higher level of 2-h G (p = 0.02), FI level (p = 0.000) as well as TG levels (p = 0.01), compared to non-insulin resistant group. Strikingly, 70.73% of the pubertal adolescents were insulin resistant in comparison to 49.09% of the preadolescents (p = 0.03). Significantly higher percentage of insulin-resistant participants were girls (p = 0.009). Moreover, a higher percentage of the girls (70.59%) than boys (44.44%) had HOMA-IR above 3.16 and had elevated FI levels (70.59% vs 48.89%). The difference in the frequency of insulin resistance among obese versus severely obese children and adolescents was not significant (p = 0.73, p > 0.05). Our study results also showed positive, but weak, correlation of HOMA-IR with age, FPG, TG and BMI of the participants (p < 0.05).

CONCLUSION:

Higher percentage of insulin-resistant participants was of female gender and was adolescents. In general, insulin resistant obese children and adolescents tend to have a worse metabolic profile in comparison to individuals without insulin resistance. It is of note that the highest insulin resistance was also linked with the highest concentrations of triglycerides.

High serum ferritin levels are associated with insulin resistance but not with impaired glucose tolerance in a healthy people population

AIM

To assess the association between elevated serum ferritin levels and the presence of insulin resistance (IR) or impaired glucose tolerance (IGT) in a population of individuals with no endocrine or metabolic disorders background.

METHODS

Analytical cross-sectional study, carried out in adults of both sexes with no medical history of type 2 diabetes mellitus (T2DM) or other metabolic or endocrine disorder, who attended the outpatient service of a private clinic in Lima-Peru during 2012-2014 period. Impaired serum ferritin levels were defined as serum ferritin values >300μg/L in men and >200μg/L in women. IR was defined as a Homeostasis Model Assessment (HOMA-IR) value ≥3.8 and IGT was defined as an oral glucose tolerance test (OGTT) value between 126mg/dL and 199mg/dL. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95% CI).

RESULTS

We analyzed 213 participants, the average age was 35.8±11.1years and 35.7% were males. The prevalence of impaired serum ferritin levels, IR and IGT in the population was 12.7%, 33.3% and 9.9% respectively. In the adjusted Poisson regression models, the prevalence of IR was higher among the group with impaired serum ferritin levels (PR=1.74; 95%CI:1.18-2.56); however, we found no association between impaired serum ferritin levels and IGT (PR=1.42; 95%CI:0.47-4.30).

CONCLUSIONS

Impaired levels of serum ferritin are associated with IR, nevertheless, not with IGT in a metabolically healthy population. Serum ferritin could be considered as an early marker of IR prior to the onset of glycaemia disorders.