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

Potential Mediating Role of Iron Biomarkers in the Association of Sex With Glucose, Insulin, and Type 2 Diabetes

Context

Sex-specific prevalence and incidence of type 2 diabetes (T2D) have been reported, but the underlying mechanisms are uncertain.

Objective

In this study, we aimed to investigate whether iron biomarkers mediate the association between biological sex and glucose metabolism and the incidence of T2D.

Methods

We used data from the general population enrolled in the prospective Prevention of REnal and Vascular ENd-stage Disease study in Groningen, The Netherlands. We measured ferritin, transferrin saturation (TSAT), hepcidin, soluble transferrin receptor (sTfR), fasting plasma glucose (FPG), fasting plasma insulin (FPI) levels, and incidence of T2D. We used multivariable regression and mediation analyses to investigate our hypothesis. All iron biomarkers, FPG, and FPI were log-transformed.

Results

The mean (SD) age of the 5312 (51.3% female) individuals was 52.2 (11.6) years. Compared with males, females had lower FPG (β = -.01; 95% CI -0.02, -0.01) and FPI (β = -.03; 95% CI -0.05, -0.02) levels. Ferritin, hepcidin, and sTfR showed potential mediating effects on the association between sex and FPG, 21%, 5%, and 7.1%, respectively. Furthermore, these variables mediated 48.6%, 5.7%, and 3.1% of the association between sex and FPI, respectively. Alternatively, TSAT had a suppressive mediating role in the association of sex with FPG and FPI. The incidence of T2D was lower in females than in males (hazard ratio 0.58; 95% CI 0.44, 0.77), with 19.2% of this difference being mediated by ferritin.

Conclusion

Iron biomarkers may partially mediate the association between sex and glucose homeostasis. Future studies addressing the causality of our findings are needed.

Effectiveness of the ALT/AST ratio for predicting insulin resistance in a Korean population: A large-scale, cross-sectional cohort study

Insulin resistance is a common pathophysiology in patients with type 2 diabetes mellitus, cardiovascular disease, and non-alcoholic fatty liver disease. Thus, screening for the risk of insulin resistance is important to prevent disease progression. We evaluated the alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio to predict insulin resistance in the general population, regardless of comorbidities. Datasets from the 2015, 2019, and 2020 Korea National Health and Nutrition Examination Surveys were used, and the following four indices were implemented to indicate insulin resistance: fasting serum glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), and β-cell function. We analyzed the degree of association between the liver enzyme profile and insulin resistance indices using Pearson's correlation coefficient and determined the associations using linear or logistic regression analysis. Accordingly, ALT levels in both sexes were positively and consistently correlated with the four aforementioned insulin resistance indices in stratification analyses based on diabetes, dyslipidemia, alcohol consumption, and obesity status. In multivariate linear regression, when comparing with ALT levels, the ALT/AST ratio exhibited superior predictive performance for fasting serum glucose and HOMA-β in Korean men and improved outcomes for all insulin resistance indices in Korean women. In this analysis that included a large community-based population, the ALT/AST ratio was a more useful predictive marker than the HOMA-IR. Regarding the predicted presence or absence of insulin resistance, the ALT/AST ratio could better predict HOMA-IR than the ALT level alone in Koreans. A simple, precise marker that represents the ALT/AST ratio could be a practical method to screen for insulin resistance in the general population, regardless of diabetes mellitus, alcohol intake, and sex.

Sex-specific, non-linear and congener-specific association between mixed exposure to polychlorinated biphenyls (PCBs) and diabetes in U.S. adults

BACKGROUND

Whether and to what extent the impact of exposure to various polychlorinated biphenyls (PCBs) congeners on diabetes, as well as the important contributors, have remained unclear.

OBJECTIVE

We aimed to investigate the association patterns between PCBs mixture and diabetes, identify the critical congeners, and explore the potential modifiers.

METHODS

The present study included 5900 U.S. adults from the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016. Weighted logistic regression, restricted cubic spline regression, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were applied to estimate the linear and non-linear associations of single and mixed PCB exposure with diabetes. Subgroup analyses were also conducted to explore potential sex differences.

RESULTS

In the weighted logistic regression model, total PCBs were positively associated with diabetes (OR = 1.33, P < 0.025), and significant non-linear associations were observed using RCS analyses. The non-linear positive association between PCBs mixed exposure and diabetes was likewise found in the WQS and BKMR results. PCB180, PCB194, PCB196, and PCB167 were with the highest weights in the WQS, and PCB209 and PCB66 were with the highest posterior inclusion probabilities in the BKMR. Additionally, exposure to total PCBs and most of individual PCB congeners were significantly associated with elevated risk of in females (OR = 1.74; P for trend < 0.001), while fewer significant associations were observed in males.

CONCLUSION

The present study highlighted the importance of the long-term surveillance of PCBs and the need to enhance protective measures against them. Notably, these associations were non-linear, congener-specific, and significantly stronger in females than males, especially at relatively high levels of PCBs exposure. Further prospective and mechanistic studies were warranted to ascertain the causal effects between PCBs mixture and diabetes.

Tea seed saponin‑reduced extract ameliorates palmitic acid‑induced insulin resistance in HepG2 cells

Tea (Camellia sinensis) seed cake is a potential resource that contains a wealth of bioactive compounds. However, the high toxicity of tea saponins in tea seed cake restricts its applications. The present study aimed to i) develop a method of extracting bioactive compounds and reducing tea saponins during the process of tea seed cake extraction and ii) investigate the anti‑insulin resistance effect of tea seed saponin‑reduced extract (TSSRE) in a palmitic acid (PA)‑induced insulin resistance HepG2‑cell model. The concentration of tea saponins in TSSRE was ~10‑fold lower than that in tea seed crude extract (TSCE) after the saponin‑reduction process. In addition, TSSRE cytotoxicity was significantly lower than that of TSCE in HepG2 cells. TSSRE treatment improved glucose consumption as well as glucose transporter (GLUT) 2 and GLUT4 expression levels in PA‑stimulated HepG2 cells. Moreover, TSSRE enhanced the phosphorylation of the insulin receptor substrate 1/protein kinase B/forkhead box protein O1/glycogen synthase kinase 3β and inhibited the elevated expression of phosphoenolpyruvate carboxykinase in PA‑exposed HepG2 cells. The effect of TSSRE on the mediation of the insulin signaling pathway was attributed to the inhibition of PA‑induced mitogen‑activated protein kinase activation. The findings of the present study indicated that TSSRE ameliorates hepatic insulin resistance by ameliorating insulin signaling and inhibiting inflammation-related pathways.

Predicting Insulin Resistance in a Pediatric Population With Obesity

OBJECTIVES

Insulin resistance (IR) affects children and adolescents with obesity and early diagnosis is crucial to prevent long-term consequences. Our aim was to identify predictors of IR and develop a multivariate model to accurately predict IR.

METHODS

We conducted a cross-sectional analysis of demographical, clinical, and biochemical data from a cohort of patients attending a specialized Paediatric Nutrition Unit in Portugal over a 20-year period. We developed multivariate regression models to predict IR. The participants were randomly divided into 2 groups: a model group for developing the predictive models and a validation group for cross-validation of the study.

RESULTS

Our study included 1423 participants, aged 3-17 years old, randomly divided in the model (n = 879) and validation groups (n = 544). The predictive models, including uniquely demographic and clinical variables, demonstrated good discriminative ability [area under the curve (AUC): 0.834-0.868; sensitivity: 77.0%-83.7%; specificity: 77.0%-78.7%] and high negative predictive values (88.9%-91.6%). While the diagnostic ability of adding fasting glucose or triglycerides/high density lipoprotein cholesterol index to the models based on clinical parameters did not show significant improvement, fasting insulin appeared to enhance the discriminative power of the model (AUC: 0.996). During the validation, the model considering demographic and clinical variables along with insulin showed excellent IR discrimination (AUC: 0.978) and maintained high negative predictive values (90%-96.3%) for all models.

CONCLUSION

Models based on demographic and clinical variables can be advantageously used to identify children and adolescents at moderate/high risk of IR, who would benefit from fasting insulin evaluation.

Sex-based impact of pancreatic islet stressors in GluCreERT2/Rosa26-eYFP mice

The present study examines differences in metabolic and pancreatic islet adaptative responses following streptozotocin (STZ) and hydrocortisone (HC) administration in male and female transgenic GluCreERT2/Rosa26-eYFP mice. Mice received five daily doses of STZ (50 mg/kg, i.p.) or 10 daily doses of HC (70 mg/kg, i.p.), with parameters assessed on day 11. STZ-induced hyperglycaemia was evident in both sexes, alongside impaired glucose tolerance and reduced insulin concentrations. HC also had similar metabolic effects in male and female mice resulting in classical increases of circulating insulin indicative of insulin resistance. Control male mice had larger pancreatic islets than females and displayed a greater reduction of islet and beta-cell area in response to STZ insult. In addition, female STZ mice had lower levels of beta-cell apoptosis than male counterparts. Following HC administration, female mouse islets contained a greater proportion of alpha cells when compared to males. All HC mice presented with relatively comparable increases in beta- and alpha-cell turnover rates, with female mice being slightly more susceptible to HC-induced beta-cell apoptosis. Interestingly, healthy control female mice had inherently increased alpha-to-beta-cell transdifferentiation rates, which was decreased by HC treatment. The number of glucagon-positive alpha cells altering their lineage to insulin-positive beta cells was increased in male, but not female, STZ mice. Taken together, although there was no obvious sex-specific alteration of metabolic profile in STZ or HC mice, subtle differences in pancreatic islet morphology emphasises the impact of sex hormones on islets and importance of taking care when interpreting observations between males and females.

Gender Differences in Insulin Resistance: New Knowledge and Perspectives

Insulin resistance is the main mechanism in a whole series of pathological conditions, which are not only of metabolic interest but also of a systemic type. This phenomenon means that the body's cells become less sensitive to the hormone insulin, leading to higher levels of insulin in the blood. Insulin resistance is a phenomenon that can be found in both men and women and in particular, in the latter, it is found mainly after menopause. Premenopause, hormonal fluctuations during the menstrual cycle, and the presence of estrogen can affect insulin sensitivity. Androgens, such as testosterone, are typically higher in men and can contribute to insulin resistance. In both sexes, different human body types affect the distribution and location of body fat, also influencing the development of diabetes and cardiovascular disease. Insulin resistance is also associated with some neurological and neurogenerative disorders, polycystic ovary syndrome, atherosclerosis, and some of the main neoplastic pathologies. A healthy lifestyle, including regular physical activity, a balanced diet, and self-maintenance, can help to prevent the onset of insulin resistance, regardless of gender, although the different habits between men and women greatly affect the implementation of preventative guidelines that help in fighting the manifestations of this metabolic disorder. This review may help to shed light on gender differences in metabolic diseases by placing a necessary focus on personalized medical management and by inspiring differentiated therapeutic approaches.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

Association of Atherogenic Index of Plasma with Cardiometabolic Risk Factors and Markers in Lean 14-to-20-Year-Old Individuals: A Cross-Sectional Study

Cardiometabolic risk factors at a young age pose a significant risk for developing atherosclerotic cardiovascular disease in adulthood. Atherogenic dyslipidemia is highly associated with obesity and metabolic syndrome already in young age. It remains unclear whether cardiometabolic risk factors associate with the atherogenic index of plasma (AIP = log (TAG/HDL-C) in lean subjects with low atherogenic risk. As both the AIP and markers of cardiometabolic risk are continuous variables, we expected their association to be linear before the manifestation of obesity and atherogenic dyslipidemia. We analyzed the prevalence of increased atherogenic risk (AIP ≥ 0.11) in 2012 lean 14-to-20-year-old subjects (55% females) and the trends of cardiometabolic risk factors across the quartiles (Q) of AIP in a subgroup of 1947 (56% females) subjects with low atherogenic risk (AIP < 0.11). The prevalence of AIP ≥ 0.11 reached 3.6% in females and 8.5% in males. HDL-C, non-HDL-C, triglycerides, and the continuous metabolic syndrome score showed a stepwise worsening across the AIP quartiles in both sexes. Measures of obesity and insulin resistance were worse in Q4 vs. Q1 groups, and leukocyte counts were higher in Q4 and Q3 vs. Q1. Females in Q4 presented with a higher C-reactive protein and lower adiponectin, estradiol, and testosterone levels. The multivariate regression model selected non-HDL-C, QUICKI, and erythrocyte counts as significant predictors of AIP in males; and non-HDL-C and C-reactive protein in females. A question arises whether the lean individuals on the upper edge of low atherogenic risk are prone to earlier manifestation of metabolic syndrome and shift to the higher AIP risk group.

Impact of puberty, sex determinants and chronic inflammation on cardiovascular risk in young people

Worrying trends of increased cardiovascular disease (CVD) risk in children, adolescents and young people in the Modern Era have channelled research and public health strategies to tackle this growing epidemic. However, there are still controversies related to the dynamic of the impact of sex, age and puberty on this risk and on cardiovascular health outcomes later in life. In this comprehensive review of current literature, we examine the relationship between puberty, sex determinants and various traditional CVD-risk factors, as well as subclinical atherosclerosis in young people in general population. In addition, we evaluate the role of chronic inflammation, sex hormone therapy and health-risk behaviours on augmenting traditional CVD-risk factors and health outcomes, ultimately aiming to determine whether tailored management strategies for this age group are justified.

Uric acid and gamma-glutamyl-transferase in children and adolescents with obesity: Association to anthropometric measures and cardiometabolic risk markers depending on pubertal stage, sex, degree of weight loss and type of patient care: Evaluation of the adiposity patient follow-up registry

OBJECTIVES

Associations between body mass index (BMI)- standard deviation score (SDS)/waist-to-height ratio (WHtR) were studied with (i) serum uric acid (sUA)/gamma-glutamyl-transferase (GGT) and (ii) cardiometabolic risk markers in children with obesity, considering sex, pubertal development, and degree of weight loss/type of patient care.

METHODS

102 936 children from the Adiposity-Follow-up registry (APV; 47% boys) were included. Associations were analysed between sUA/GGT and anthropometrics, transaminases, lipids, fasting insulin (FI), homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides to HDL-cholesterol (TG/HDL)-ratio. Follow-up analyses (3-24 months after baseline) considered a BMI-SDS reduction ≥0.2 (n = 11 096) or ≥0.5 (n = 3728). Partialized correlation analyses for sex and BMI-SDS were performed, taking pubertal development into consideration.

RESULTS

At baseline, BMI-SDS showed the strongest correlations to sUA (r = 0.35; n = 26 529), HOMA-IR/FI (r = 0.30; n = 5513 /n = 5880), TG/HDL-ratio (r = 0.23; n = 24 501), and WHtR to sUA (r = 0.32; n = 10 805), GGT (r = 0.34; n = 11 862) and Alanine-aminotransferase (ALAT) (r = 0.33; n = 11 821), with stronger correlations in boys (WHtR and GGT: r = 0.36, n = 5793) and prepubertal children (r = 0.36; n = 2216). GGT and sUA (after partializing effects of age, sex, BMI-SDS) showed a correlation to TG/HDL-ratio (r = 0.27; n = 24 501). Following a BMI-SDS reduction ≥0.2 or ≥0.5, GGT was most strongly related to Aspartate-aminotransferase (ASAT)/ ALAT, most evident in prepuberty and with increasing weight loss, and also to TG/HDL-ratio (r = 0.22; n = 1528). Prepubertal children showed strongest correlations between BMI-SDS/WHtR and GGT. ΔBMI-SDS was strongly correlated to ΔsUA (r = 0.30; n = 4160) and ΔGGT (r = 0.28; n = 3562), and ΔWHtR to ΔGGT (r = 0.28; n = 3562) (all p < 0.0001).

CONCLUSION

Abdominal obesity may trigger hyperuricemia and hepatic involvement already in prepuberty. This may be stronger in infancy than anticipated to date. Even moderate weight loss has favourable effects on cardiometabolic risk profile and glucose homeostasis.

Insulin Resistance and Cardiometabolic Risk Profile Among Nondiabetic American Young Adults: Insights From NHANES

BACKGROUND

The burden of insulin resistance (IR) among young American adults has not been previously assessed. We evaluated (1) the prevalence and trends of IR and cardiometabolic risk factors and (2) the association between measures of adiposity and IR among adults 18 to 44 years of age without diabetes and preexisting cardiovascular disease.

METHODS

Cross-sectional survey data from six consecutive National Health and Nutrition Examination Survey (2007-2008 to 2017-2018) cycles were analyzed. IR was defined by the homeostatic model assessment for IR (HOMA-IR) of ≥2.5. The temporal trends of IR, cardiometabolic risk factors, and the relationship between IR and measures of adiposity were assessed using multivariable-adjusted regression models.

RESULTS

Among 6247 young adults 18 to 44 years of age, the prevalence of IR was 44.8% (95% CI: 42.0%-47.6%) in 2007-2010 and 40.3% (95% CI: 36.4%-44.2%) in 2015-2018 (P for trend = 0.07). There was a modest association of HOMA-IR with higher body mass index (BMI), waist circumference, total lean fat mass, and total and localized fat mass (all Ps < 0.001). Participants with IR had a higher prevalence of hypertension [31.3% (95% CI: 29.2%-33.5%) vs 14.7% (95% CI: 13.2%-16.2%)], hypercholesterolemia [16.0% (95% CI: 12.4%-19.5%) vs 7.0% (95% CI: 5.8%-8.5%)], obesity [56.6% (95% CI: 53.9%-59.3%) vs 14.7% (95% CI: 13.0%-16.5%)], and poor physical activity levels [18.3% (95% CI: 16.4%-20.2%) vs 11.7% (95%CI: 10.3-13.1%)] compared to participants without IR (all Ps < 0.05).

CONCLUSIONS

Four-in-10 young American adults have IR, which occurs in a cluster with cardiometabolic risk factors. Nearly half of young adults with IR are nonobese. Screening efforts for IR irrespective of BMI may be required.

A population-based study of TyG index distribution and its relationship to cardiometabolic risk factors in children and adolescents

The purpose of this study was to present age- and sex-specific distributions of the triglyceride-glucose (TyG) index and to evaluate their relationship with cardiometabolic risk factors in children and adolescents. A total of 7404 participants aged 10-18 years from the Korean National Health and Nutrition Survey were included as the reference population. The TyG index was calculated as ln(fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2). The percentile of the TyG index exhibited a steady linear relationship with age for both sexes. TyG index significantly correlated with waist circumference (WC) standard deviation score (SDS; r = 0.110, p < 0.001), systolic blood pressure (SBP; r = 0.104, p < 0.001), diastolic blood pressure (DBP; r = 0.083, p < 0.001), glucose (r = 0.220, p < 0.001), high-density lipoprotein cholesterol (HDL-C; r = - 0.325, p < 0.001), and triglycerides (TG; r = 0.926, p < 0.001). Multiple linear regression analysis revealed that the TyG index was significantly associated with WC SDS (β = 0.116, p < 0.001), SBP (β = 2.009, p < 0.001), DBP (β = 1.464, p < 0.001), glucose (β = 3.376, p < 0.001), HDL-C (β =  - 6.431, p < 0.001), and TG (β = 85.518, p < 0.001). Our results suggest that the TyG index has a steady linear distribution for sex and age in children and adolescents and constitutes an indicator for predicting metabolic disorders that could lead to cardiovascular disease later in life.

Hepatic sexual dimorphism - implications for non-alcoholic fatty liver disease

The liver is often thought of as a single functional unit, but both its structural and functional architecture make it highly multivalent and adaptable. In any given physiological situation, the liver can maintain metabolic homeostasis, conduct appropriate inflammatory responses, carry out endobiotic and xenobiotic transformation and synthesis reactions, as well as store and release multiple bioactive molecules. Moreover, the liver is a very resilient organ. This resilience means that chronic liver diseases can go unnoticed for decades, yet culminate in life-threatening clinical complications once the adaptive capacity of the liver is overwhelmed. Non-alcoholic fatty liver disease (NAFLD) predisposes individuals to cirrhosis and increases liver-related and cardiovascular disease-related mortality. This Review discusses the accumulating evidence of sexual dimorphism in NAFLD, which is currently rarely considered in preclinical and clinical studies. Increased awareness of the mechanistic causes of hepatic sexual dimorphism could lead to improved understanding of the biological processes that are dysregulated in NAFLD, to the identification of relevant therapeutic targets and to improved risk stratification of patients with NAFLD undergoing therapeutic intervention.

The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys: a pilot study

Background

Current evidence of metabolic health benefits of high-intensity interval training (HIIT) are limited to longer training periods or conducted in overweight youth. This study assessed 1) fasting and postprandial insulin and glucose before and after 2 weeks of HIIT in healthy adolescent boys, and 2) the relationship between pre intervention health outcomes and the effects of the HIIT intervention.

Methods

Seven healthy boys (age:14.3 ± 0.3 y, BMI: 21.6 ± 2.6, 3 participants classified as overweight) completed 6 sessions of HIIT over 2 weeks. Insulin resistance (IR) and blood glucose and insulin responses to a Mixed Meal Tolerance Test (MMTT) were assessed before (PRE), 20 h and 70 h after (POST) the final HIIT session.

Results

Two weeks of HIIT had no effect on fasting plasma glucose, insulin or IR at 20 h and 70 h POST HIIT, nor insulin and glucose response to MMTT (all P > 0.05). There was a strong negative correlation between PRE training IR and change in IR after HIIT (r = − 0.96, P < 0.05).

Conclusion

Two weeks of HIIT did not elicit improvements to fasting or postprandial glucose or insulin health outcomes in a group of adolescent boys. However the negative correlation between PRE IR and improvements after HIIT suggest that interventions of this type may be effective in adolescents with raised baseline IR.

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.

Sex-Specific Association of Circulating Ferritin Level and Risk of Type 2 Diabetes: A Dose-Response Meta-Analysis of Prospective Studies

CONTEXT

Although the role of iron in the development of type 2 diabetes (T2D) has long been a concern, prospective studies directly linking body iron stores to T2D risk in a sex-dependent context have been inconsistent.

OBJECTIVE

A systematic meta-analysis was conducted to explore the sex-specific association of circulating ferritin with T2D risk.

DATA SOURCES

We searched PubMed, Web of Science, and EMBASE databases to identify available prospective studies through 1 August 2018.

RESULTS

Fifteen prospective studies comprising 77,352 participants and 18,404 patients with T2D, aged 20 to 80 years, and with ∼3 to 17 years of follow-up were identified. For each 100-μg/L increment in ferritin levels of overall participants, T2D risk increased by 22% (RR, 1.22; 95% CI, 1.14 to 1.31). Of note, major heterogeneities by sex were identified, with increased ferritin level having an apparently greater effect on T2D risk in women (RR, 1.53; 95% CI, 1.29 to 1.82) than in men (RR, 1.21; 95% CI, 1.15 to 1.27) after exclusion of a study with high heterogeneity (41,512 men and 6974 women for sex-specific analyses; P = 0.020 for sex difference). Further nonlinear analysis between circulating ferritin and T2D risk also showed sex-dimorphic association in that the T2D risk of women was twice as strong in magnitude as that of men at the same ferritin level.

CONCLUSIONS

Greater circulating ferritin levels were independently associated with increased T2D risk, which appeared stronger among women than men. Our findings provide prospective evidence for further testing of the utility of ferritin levels in predicting T2D risk in a sex-specific manner.

Interleukin-1 Alpha Polymorphisms Are Associated With Body Mass Index in Male But Not in Female Adolescents

BACKGROUND

The Interleukin (IL)-1 family of cytokines plays a key role in the inflammatory response. Genes coding for IL-1α, IL-1β, and IL-1Ra are located together as a block gene known as the IL-1 cluster. This genomic region shows wide nucleotide variability, and some polymorphisms have been widely studied and associated with features related to the metabolic syndrome.

METHODS

Eight polymorphisms within three genes of the IL-1 cluster, including IL1A (rs3783553, rs17561, and rs1800587), IL1B (rs1143634, rs1143627, and rs16944) and IL1RN (rs419598 and rs2234663) were genotyped in 460 Mexican adolescents. Genotype and haplotype frequencies are reported, as well as the linkage disequilibrium analysis. Genetic associations with some anthropometric and metabolic traits were evaluated.

RESULTS

Allele frequencies were similar to those found in other populations, and genotype proportions were according to the Hardy-Weinberg equilibrium. Seven haplotypes were observed at frequencies ≥5%. Of the entire cluster, only the rs17561-rs1800587 and rs1143627-rs16944 pairs showed highest and significant linkage disequilibrium values. An haplotype of IL1A, rs17561T-rs1800587T, was significantly associated with increase in body mass index in males (p <0.008), whereas IL1B and IL1RN variants showed associations with insulin, and hs-CRP (p <0.05).

CONCLUSIONS

Some MetS parameters seem to be influenced by variations in the IL-1 gene cluster in Mexican adolescents. These variations may confer risk for metabolic alterations from early ages, and and these risks may be different when variables such as sex are considered. Strategies leading to generate protective behaviors could be designed to take into account specific variations in the IL-1 gene cluster and biological conditions such as sex.

Sex differences in diabetes and kidney disease: mechanisms and consequences

Type 1 and type 2 diabetes, along with their accompanying hyperglycemia, are associated with a multitude of comorbidities including the development of diabetic kidney disease. Although the hallmarks of these metabolic disorders have been well characterized in population and animal studies, it is becoming increasingly apparent that diabetes manifests itself differently in men and women. This review summarizes the recent diabetic literature with a focus on known sex differences in clinical and preclinical studies. It explores the physiological differences of glucose handling and the development of diabetes between men and women. This review also uncovers potential mechanisms for these differences, honing in on the vital role that sex hormone signaling plays in the progression of diabetes and renal complications.

Insulin Resistance in Children

Insulin resistance (IR) is a pathological condition strongly associated with obesity. However, corticosteroids or growth hormone therapy and genetic diseases may affect insulin sensitivity lifelong. In obese children and adolescents of any age there is an evident association between IR and an increased prevalence of type 2 diabetes (T2D) and other elements contributing to the metabolic syndrome, leading to a higher cardiovascular risk. Therefore, early diagnosis and interventions in the attempt to prevent T2D when glycemia values are still normal is fundamental. The gold standard technique used to evaluate IR is the hyperinsulinemic euglycemic clamp, however it is costly and difficult to perform in clinical and research sets. Therefore, several surrogate markers have been proposed. Although the treatment of insulin resistance in children is firstly targeted to lifestyle interventions, in selected cases the integration of a pharmacological intervention might be taken into consideration. The aim of this review is to present the current knowledge on IR in children, starting with an outline of the recent evidences about the congenital forms of deficiency in insulin functioning and therefore focusing on the physiopathology of IR, its appropriate measurement, consequences, treatment options and prevention strategies.

Normative range of blood biochemical parameters in urban Indian school-going adolescents

Adolescence is the most critical phase of human growth that radically alters physiology of the body and wherein any inconsistency can lead to serious health consequences in adulthood. The timing and pace at which various developmental events occur during adolescence is highly diverse and thus results in a drastic change in blood biochemistry. Monitoring the physiological levels of various biochemical measures in ample number of individuals during adolescence can call up for an early intervention in managing metabolic diseases in adulthood. Today, only a couple of studies in different populations have investigated blood biochemistry in a small number of adolescents however, there is no comprehensive biochemical data available worldwide. In view, we performed a cross-sectional study in a sizeable group of 7,618 Indian adolescents (3,333 boys and 4,285 girls) aged between 11–17 years to inspect the distribution of values of common biochemical parameters that generally prevails during adolescence and we observed that various parameters considerably follow the reported values from different populations being 3.56–6.49mmol/L (fasting glucose), 10.60–199.48pmol/L (insulin), 0.21–3.22nmol/L (C–peptide), 3.85–6.25% (HbA₁c), 2.49–5.54mmol/L (total cholesterol), 1.16–3.69mmol/L (LDL), 0.78–1.85mmol/L (HDL), 0.33–2.24mmol/L (triglycerides), 3.56–11.45mmol/L (urea), 130.01–440.15μmol/L (uric acid) and 22.99–74.28μmol/L (creatinine). Barring LDL and triglycerides, all parameters differed significantly between boys and girls (p< 0.001). Highest difference was seen for uric acid (p = 1.3 x10^-187) followed by C–peptide (p = 6.6 x10^-89). Across all ages during adolescence, glycemic and nitrogen metabolites parameters varied markedly with gender. Amongst lipid parameters, only HDL levels were found to be significantly associated with gender following puberty (p< 0.001). All parameters except urea, differed considerably in obese and lean adolescents (p< 0.0001). The present study asserts that age, sex and BMI are the essential contributors to variability in blood biochemistry during adolescence. Our composite data on common blood biochemical measures will benefit future endeavors to define reference intervals in adolescents especially when the global availability is scarce.

Endoplasmic reticulum stress and development of insulin resistance in adipose, skeletal, liver, and foetoplacental tissue in diabesity

Diabesity is an abnormal metabolic condition shown by patients with obesity that develop type 2 diabetes mellitus. Patients with diabesity present with insulin resistance, reduced vascular response to insulin, and vascular endothelial dysfunction. Along with the several well-described mechanisms of insulin resistance, a state of endoplasmic reticulum (ER) stress, where the primary human targets are the adipose tissue, liver, skeletal muscle, and the foetoplacental vasculature, is apparent. ER stress characterises by the activation of the unfolded protein response via three canonical ER stress sensors, i.e., the protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6. Slightly different cell signalling mechanisms preferentially enable in diabesity in the ER stress-associated insulin resistance for adipose tissue (IRE1α/X-box binding protein 1 mRNA splicing/c-jun N-terminal kinase 1 activation), skeletal muscle (tribbles-like protein 3 (TRB3)/proinflammatory cytokines activation), and liver (PERK/activating transcription factor 4/TRB3 activation). There is no information in human subjects with diabesity in the foetoplacental vasculature. However, the available literature shows that pregnant women with pre-pregnancy obesity or overweight that develop gestational diabetes mellitus (GDM) and their newborn show insulin resistance. ER stress is recently reported to be triggered in endothelial cells from the human umbilical vein from mothers with pre-pregnancy obesity. However, whether a different metabolic alteration to obesity in pregnancy or GDM is present in women with pre-pregnancy obesity that develop GDM, is unknown. In this review, we summarised the findings on diabesity-associated mechanisms of insulin resistance with emphasis in the primary targets adipose, skeletal muscle, liver, and foetoplacental tissues. We also give evidence on the possibility of a new GDM-associated metabolic condition triggered in pregnancy by maternal obesity, i.e. gestational diabesity, leading to ER stress-associated insulin resistance in the human foetoplacental vasculature.

The FTO rs9939609 "A" allele is associated with impaired fasting glucose and insulin resistance in Emirati population

BACKGROUND

Fat mass and obesity-associated protein gene variants have shown diverse influence on body weight and metabolism across different populations. Overweight, obesity and metabolic syndrome are multifactorial major health problems in the UAE and worldwide. Insulin resistance represents the link between overweight and development of metabolic syndrome and type 2 diabetes mellitus. We investigated two (FTO) variants in Emirati population, in relation to insulin resistance and different parameters of metabolic syndrome.

METHODS

We recruited 259 Emiratis through the UAE National Diabetes and Lifestyle Project. Ethical approval was obtained. Besides basic data collection, venous blood samples were collected. Fasting blood glucose, Lipid profile, and insulin levels were measured. Genotyping for (FTO) rs9939609 (A>T) and rs9930506 (G>A) were performed using real time-PCR. Insulin resistance were identified using HOMA2-IR calculation; with a cut-off point of 1.4 for female and 1.18 for male subjects.

RESULTS

The study included 259 Emiratis (age range 30-53 years, mean 41.76 years, 54.4% females), 24.5% are diabetic and 30.8% are hypertensive, with body mass index of 28.4 ± 5.9 and 28.7 ± 5.7 kg/m² in female and male subjects, respectively. Homozygous A of rs9939609 showed significantly higher fasting glucose compared to other genotypes (p = 0.04) with a trend of higher insulin level and HOMA-2IR. The A/A diabetic patients (n = 13) showed significantly higher insulin levels compared to other genotypes. G allele of rs9930506 showed a trend of higher fasting glucose and HOMA-2IR, but lower insulin level and HbA1c. No association of genotypes was detected with other components of metabolic syndrome.

CONCLUSION

There is an association of FTO rs9939609 A/A genotype and impaired fasting glucose and insulin resistance. Homozygous A genotype diabetic patients may be more vulnerable to blood glucose fluctuation. Focused genotyping can help the health care providers to identify high risk groups of both normal population and diabetic patients to intervene accordingly.

Impact of dietary intake, lifestyle and biochemical factors on metabolic health in obese adolescents

BACKGROUND AND AIMS

Obesity devoid of metabolic abnormalities is known as metabolically healthy obesity (MHO). The aim of the study was to examine determinants of MHO during adolescence.

METHODS AND RESULTS

From among 710 obese adolescents, 43 girls and 57 boys were classified as metabolically unhealthy (abdominal obesity and ≥2 risk components of metabolic syndrome). MHO (absence of any cardiometabolic risk factor) was found in 211 girls and 131 boys (regardless of waist circumference) and in 33 girls and 27 boys (without abdominal obesity). Laboratory and anthropometric parameters, dietary records and various lifestyle factors were compared between MHO vs. those unhealthy. The prevalence of MHO regardless of waist circumference was higher in girls than in boys (53.1 vs. 41.9%) but comparable when abdominal obesity was excluded (8.3 vs. 8.6%). Anthropometric variables, levels of gamma-glutamyl transferase, total and low-density lipoprotein cholesterol in both genders, hs-C-reactive protein in girls and alanine aminotransferase in boys differentiated the two metabolic phenotypes. Uric acid was related to metabolic health only in the analysis of MHO without abdominal obesity. Total hours of sleep, bedtime, time of the last daily meal, regular meal consumption and protein intake in boys and screen time, the score of disinhibition and diet composition in girls were found to impact cardiometabolic health.

CONCLUSIONS

In obese adolescents, metabolic health was related to anthropometric and biochemical parameters and only weak associations were found with most of the lifestyle factors studied. Uric acid concentration associated with metabolic health when abdominal obesity was excluded.

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

Insulin resistance is common among obese adolescents; however, the extent of this problem is not clear. We conducted a systematic review of PubMed-Medline, CINAHL, The Web of Science, EMBASE and Scopus for observational studies evaluating components defining insulin resistance (insulin, C-peptide and homeostatic model assessment-insulin resistance [HOMA-IR]) in obese adolescents (12-18 years) versus non-obese adolescents. Our systematic review and meta-analysis followed the PRISMA guidelines. Data were combined using a random-effects model and summary statistics were calculated using the mean differences (MDs). 31 studies were included (n = 8655). In 26 studies, fasting insulin levels were higher in obese adolescents when compared to non-obese adolescents (MD = 64.11 pmol/L, 95%CI 49.48-78.75, p < 0.00001). In three studies, fasting C-peptide levels were higher in obese adolescents when compared to non-obese adolescents (MD = 0.29 nmol/L, 95%CI 0.22-0.36, p < 0.00001). In 24 studies, HOMA-IR values were higher in obese adolescents when compared to non-obese adolescents (MD = 2.22, 95%CI 1.78-2.67, p < 0.00001). Heterogeneity of effects among studies was moderate to high. Subgroup analyses showed similar results to the main analyses. Circulating insulin and C-peptide levels and HOMA-IR values were significantly higher in obese adolescents compared to those non-obese.

Insulin sensitivity and its relation to hormones in adolescent boys and girls

BACKGROUND AND AIMS

A subset of obese individuals lacks cardiometabolic impairment. We aimed to analyze hormonal profiles of insulin-sensitive obese (ISO) and insulin-resistant obese (IRO) adolescents and determine hormonal predictors of homeostasis model of insulin resistance (HOMA-IR).

MATERIALS AND METHODS

A threshold of 3.16 of HOMA-IR was used to classify ISO (<3.16) IRO (≥3.16). In 702 individuals aged 13-18years (55.8% girls) anthropometric and laboratory [blood glucose, insulin, thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), sex hormone-binding globulin (SHBG), steroid hormones, luteinizing hormone, follicle stimulating hormone, prolactin, ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like-peptide 1glucagon, leptin, resistin, visfatin, leptin, adiponectin and adipsin] assessments were performed. Orthogonal projections to latent structures and Mann-Whitney tests with Bonferroni correction were applied for statistical analysis.

RESULTS

52.6% girls and 42.9% boys were insulin sensitive. In the predictive model of HOMA-IR thyroid function tests, adiponectin, ghrelin and leptin concentrations played an important role in both genders. Prolactin, testosterone and glucagon contributed to the model only in boys, while progesterone and dehydroepiandrosterone sulfate levels only in girls. After Bonferroni correction levels of leptin, adiponectin, leptin/adiponectin ratio, SHBG and fT4/TSH ratio in both genders, testosterone and glucagon levels in boys and levels of TSH and fT3 in girls were related to insulin sensitivity.

CONCLUSION

Metabolic health defined by HOMA-IR is partly predicted by various hormones. Some of them are gender specific. Free T4/TSH and leptin/adiponectin ratios are related to insulin sensitivity in both genders.

Altered Regional Gray Matter Volume in Obese Men: A Structural MRI Study

Obesity is associated with a number of health problems, especial insulin resistance and Type 2 diabetes. Our previous study showed that obese males had decreased neural activity in the orbital frontal cortex (OFC) and increased activity in the left putamen (Zhang et al., 2015b), which could indicate altered eating behaviors in obesity related to a hyper-functioning striatum and hypo-functioning inhibitory control. Accordingly, our goal of the current study was to determine whether there are alterations in the brain structures within these two neural systems in obese individuals. Twenty obese men (age: 20–28 years) and 20 age-matched lean male subjects were involved in the current study. Plasma glucose and insulin were tested during hunger state, and homeostasis model assessment of insulin resistance (HOMA-IR) was based on the blood samples. In the study, we used structural MRI and a voxel-based morphometry (VBM) method to investigate regional structures in obese subjects and find out whether there are correlations between the insulin and the brain structures. We found that obese men only showed a significantly increased gray matter volume (GMV) in the left putamen and that the GMV of the left putamen was positively correlated with body mass index, plasma insulin and HOMA-IR. The putamen is a core region participating in insulin signal regulation, and our results showed an abnormal GMV of the putamen is a core alternation in aberrant insulin. Furthermore, the GMV of the OFC was negatively correlated with hunger rating, despite there being no significant difference between the two groups in the OFC. In conclusion, the altered structure and function of the putamen could play important roles in obesity and aberrant insulin.

Gender difference in type 2 diabetes and the role of body iron stores

Background Studies of gender difference in type 2 diabetes have been inconclusive. We investigated gender difference in type 2 diabetes and the contribution of body iron, as assessed by serum ferritin to this difference. Methods We performed cross-sectional ( n = 1707) and prospective ( n = 1506) analyses in males and females aged 53-73 years in 1998-2001. Type 2 diabetes diagnosis was determined by questionnaire, blood glucose measurements and record linkage to type 2 diabetes registers. Gender difference in type 2 diabetes and serum ferritin contribution to the difference was examined in multivariable logistic and Cox regression models. Gender difference in fasting plasma glucose and insulin and homeostasis model assessment of insulin resistance was examined in linear regression analysis. Results In the cross-sectional analysis, a total of 201 type 2 diabetes cases were observed (males = 111 [55.2%] vs. female = 90 [44.8%], P = 0.032), and in adjusted models, males had higher odds of type 2 diabetes (OR = 1.61, 95% CI 1.10 to 2.34); higher fasting plasma glucose (β = 0.28, 95% CI 0.15 to 0.41), fasting plasma insulin (β = 0.73, 95% CI 0.26 to 1.19) and homeostasis model assessment of insulin resistance (β = 0.11, 95% CI 0.04 to 0.17). In the prospective analysis, males had increased risk of type 2 diabetes (HR = 1.46, 95% CI 1.03 to 2.07). With serum ferritin introduction (100  µg/L, log-transformed) into the models, the type 2 diabetes prevalence (OR = 1.35, 95% CI 0.91 to 1.99) and incidence (HR = 1.38, 95% CI 0.96 to 1.97) were appreciably attenuated. Conclusions These data suggest a gender difference in type 2 diabetes, with a higher prevalence and increased type 2 diabetes risk in males. Body iron explains about two-fifths and one-fifth of the gender difference in type 2 diabetes prevalence and incidence, respectively.

Cardiometabolic Health in Obese Adolescents Is Related to Length of Obesity Exposure: A Pilot Study

CONTEXT

Metabolically healthy obesity (MHO) is found in a subset of obese individuals.

OBJECTIVE

This study sought to examine possible determinants of MHO related to the length of exposure to obesity, lifestyle factors, and dietary intake in adolescent boys.

DESIGN

This was a cross-sectional Childhood Obesity Prevalence And Treatment study. Participants and Main Measures: Of 313 boys age 13.0-17.9 years with a body mass index (BMI) ≥ 97th percentile for age, two study cohorts were established based on two definitions of metabolically unhealthy obesity (MUO). Cohort 1 included 18 boys with at least three risk factors (hypertension, dyslipidemia, dysglycemia) who were matched for age, weight, height, and BMI with 18 boys with MHO. Cohort 2 included 35 boys with at least two risk factors who were compared with 31 boys with MHO. MHO was defined by the absence of cardiometabolic risk factors (excluding waist). Data on lifestyle factors and BMI growth trajectories were compared (MHO vs MUO).

RESULTS

Boys with MUO (Cohort 1) presented with an earlier onset (4.3 vs 9.1 y; P = .005) and a longer duration of obesity (11.2 vs 6.4 y; P = .003) compared with those with MHO in both group comparisons using different MUO definitions. We found an overall trend toward higher BMI z scores (significant from 3-7 y; P < .001) in metabolically unhealthy compared with their healthy counterparts (Cohort 1). Boys with MHO had higher carbohydrate intake (P < .001). No additional determinants of MHO were observed.

CONCLUSIONS

Increased cardiometabolic risk in boys is related to an earlier onset and a longer duration of obesity.

Metabolic Syndrome: Does it Differ Between Women and Men?

Cardiovascular disease represents a massive healthcare burden worldwide. Gender differences in the pathophysiology, presentation and prognosis of cardiovascular disease have been described in the literature. Metabolic syndrome, characterized by a cluster of metabolic abnormalities is associated with increased risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. With the global obesity epidemic, the prevalence of metabolic syndrome is rising rapidly in the developed as well as developing world. However, there is considerable variation in the prevalence based on geography, age, sex and, definition used for diagnosis. Data on gender related differences in metabolic syndrome is relatively scarce. Here, we aim to review the gender differences in epidemiology and pathophysiology of metabolic syndrome as well as its individual components. Knowledge of gender differences in metabolic syndrome can help design gender specific preventative and therapeutic strategies that will have a positive impact on overall population health.

Altered baseline brain activity differentiates regional mechanisms subserving biological and psychological alterations in obese men

Obesity as a chronic disease is a major factor for insulin resistance and Type 2 diabetes, which has become a global health problem. In the present study, we used resting state functional MRI to investigate the amplitude of low frequency fluctuations of spontaneous signal during both hunger and satiety states in 20 lean and 20 obese males. We found that, before food intake, obese men had significantly greater baseline activity in the precuneus and lesser activity in dorsal anterior cingulate cortex (dACC) relative to lean subjects. Furthermore, after food intake, obese males had significantly lesser activity in dACC than lean males. We further found a significant positive correlation between precuneus activation and hunger ratings before food intake, while dACC activity was negatively correlated with plasma insulin levels before and after food intake. These results indicated that both precuneus and dACC may play an important role in eating behavior. While precuneus rather seemed to mediate subjective satiety, dACC levels rather reflected indirect measures of glucose utilization.

Population-Based Studies on the Epidemiology of Insulin Resistance in Children

BACKGROUND

In view of the alarming incidence of obesity in children, insight into the epidemiology of the prediabetic state insulin resistance (IR) seems important. Therefore, the aim of this systematic review was to give an overview of all population-based studies reporting on the prevalence and incidence rates of IR in childhood.

METHODS

PubMed, Embase, and Cochrane library were searched in order to find all available population-based studies describing the epidemiology of IR in pediatric populations. Prevalence rates together with methods and cut-off values used to determine IR were extracted and summarized with weight and sex specific prevalence rates of IR if available.

RESULTS

Eighteen population-based studies were identified, describing prevalence rates varying between 3.1 and 44%, partly explained by different definitions for IR. Overweight and obese children had higher prevalence rates than normal weight children. In seven out of thirteen studies reporting sex specific results, girls seemed to be more affected than boys.

CONCLUSION

Prevalence rates of IR reported in children vary widely which is partly due to the variety of definitions used. Overweight and obese children had higher prevalence and girls were more insulin resistant than boys. Consensus on the definition for IR in children is needed to allow for comparisons between different studies.