Plasma adiponectin does not correlate with insulin resistance and cardiometabolic variables in nondiabetic Asian Indian teenagers

Adiponectin, HOMA-Adiponectin, HOMA-IR in Children and Adolescents: Ouro Preto Study

OBJECTIVES

To examine the association and predictive capacity of adiponectin levels, HOMA-AD and HOMA-IR indexes with metabolic risk markers in children and adolescents.

METHODS

A cross-sectional study was conducted with 691 children and adolescents (7-14 y), of both sexes. Demographic (sex, age), anthropometric (weight, height, body mass index, waist circumference, body fat), biochemical [total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, fasting glycemia, insulin and adiponectin] and clinical parameters (arterial blood pressure) were analyzed.

RESULTS

In multiple linear regression models, metabolic risk were analyzed in relation to adiponectin levels, HOMA-AD and HOMA-IR. ROC curve analysis was used to define the cut-off for metabolic syndrome for each method studied. Adiponectin level was inversely correlated with weight (r = -0.12; p = 0.01), waist circumference (WC) (r = -0.12; p = 0.01), and triglycerides (r = -0.11; p = 0.02); it was directly correlated with HDL (r = 0.10; p = 0.03) only in the adolescents. In the final linear regression model, after adjustment, only triglycerides (p = 0.03) and HDL (p = 0.04) remained significant. However, HOMA-AD and HOMA-IR were associated with metabolic risk and were the most suitable methods for metabolic syndrome screening in both age groups. For children, independent variables explained 16.0% and 14.5% of HOMA-AD and HOMA-IR, respectively. For adolescents, R² was higher in HOMA-AD and HOMA-IR models (R²_adjusted = 31.9% and R²_adjusted = 29.6%, respectively).

CONCLUSIONS

HOMA-AD and HOMA-IR are better explained by metabolic markers than adiponectin levels.

Adiponectin, in contrast to leptin, is not associated with body mass index, waist circumference and HOMA-IR in subjects of a west-African population

Factors associated with plasma levels of adiponectin and leptin were studied in adult subjects without diabetes from Cotonou in Benin (West-Africa). Seventy (70) men and 45 women were included in the study. Anthropometric variables were measured and a venous blood sample was drawn from each subject, after an overnight fasting period, for measurement of plasma glucose, insulin, leptin, and adiponectin levels. HOMA-IR was determined to assess insulin resistance. Adiponectin and leptin levels were higher in women than in men (with adiponectin 18.48 ± 12.77 vs.7.8 ± 10.39 μg/mL, P < 0.0001, and leptin 30.77 ± 19.16 vs. 8.66 ± 8.24 ng/mL, P < 0.0001). Fasting insulin level and HOMA-IR were also higher in the females. Hyperleptinemia was observed in 66,96% of subjects and hypoadiponectinemia was present in 44.35% of subjects. In both men and women, leptin correlated with age (r = 0.2; P = 0.02), BMI (r = 0.572; P < 0.0001), waist circumference (r = 0.534; P < 0.0001), fasting insulin (r = 0.461; P < 0.001), and HOMA-IR (r = 0.430; P < 0.0001). No significant correlation was observed for adiponectin levels with these variables. Only in women, adiponectin was inversely correlated with fasting glucose (r = -0.423; P < 0.004). These data confirm previous descriptions of leptin but suggest that variations in factors determining serum adiponectin levels observed between ethnicities could also been seen between populations from the same ethnicity.

Adiponectin: A potential therapeutic target for metabolic syndrome

Adiponectin is an important adipocytokine secreted chiefly by fat containing adipocytes, and plays a crucial role in glucose and lipid metabolism, inflammation and oxidative stress. Alterations in adiponectin levels have been shown to directly affect lipid and glucose metabolism that further increase the synthesis of lipids, free fatty acids and inflammatory cytokines. Changes in adiponectin levels also contribute to insulin resistance, obesity, cardiovascular diseases and type 2 diabetes. In the present review, we provide a comprehensive evaluation of the role of adiponectin and its molecular mechanisms in metabolic syndrome. Clinical improvement in adiponectin levels have been shown to positively modulate lipid and glucose metabolism, thus further substantiating its role in regulation of lipid and glucose metabolism. Currently adiponectin is being investigated as a potential therapeutic target for metabolic syndrome, although more research is required to understand the underlying mechanisms controlling adiponectin levels, including dietary and lifestyle interventions, that may target adiponectin as a therapeutic intervention in metabolic syndrome.

Chronic sub-clinical inflammation in the abdominal adipose tissue - Evaluation of inflammatory cytokines and their link with insulin resistance in metabolically obese South Indians: A cross-sectional observational study

OBJECTIVE

To measure the levels of proinflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-6(IL-6), and high-sensitive C-reactive protein (hs-CRP) and the anti-inflammatory cytokine adiponectin (AN) in obese South Indian subjects and to ascertain whether or not a causal role could be ascribed to these cytokines in the development of insulin resistance (IR).

MATERIALS AND METHODS

Forty obese and forty nonobese volunteers of both genders were recruited. Parameters such as body mass index (BMI), waist circumference (WC), and blood pressure were evaluated. Fasting blood sugar (FBS), fasting insulin level, hemoglobin A1c (HbA1C), lipid profile, TNF-α, IL-6, hs-CRP, and AN levels were measured. IR was evaluated by homeostatic model assessment-IR method. Abdominal adiposity was measured by ultrasonography. The results were statistically evaluated by appropriate tests.

RESULTS

BMI, WC, and visceral fat were high in the obese group. Females had higher subcutaneous fat in both groups. HbA1C was marginally high in the obese group (P = 0.014). IR was high in all the groups, obese males showing higher values (not significant[NS]). Total cholesterol and low-density lipoprotein were high in the obese group (P = 0.028, P = 0.003). TNF-α was high in obese males (NS), IL-6 was high in both groups, higher in nonobese females (NS), hs-CRP was high in both groups, higher in females of both groups (NS). AN was high in females of both groups (P = 0.002).

CONCLUSIONS

In this study on South Indian subjects, proinflammatory cytokines such as IL-6 and hs-CRP, despite being high, did not show any causal correlation either with abdominal obesity or with IR. TNF-α being normal showed some correlation which was inconsistent. Even the anti-inflammatory adipokine, AN did not show any correlation with IR. Cytokines had an inconsistent correlation with the components of metabolic syndrome hence were not useful.

Adiponectin, leptin, interleukin-6 and HbA1c in the prediction of incident type 2 diabetes: A nested case-control study in Asian Indian men with impaired glucose tolerance

AIMS

The aims of this study were: (1) to assess the association of adiponectin, leptin and interleukin-6 (IL-6) with incidence of type 2 diabetes (T2DM) in Asian Indian men with impaired glucose tolerance (IGT) and (2) to evaluate the additional contribution of these with the well-established glycaemic marker HbA1c.

METHODS

This is an ancillary analyses of a nested case-control study derived from a prospective, prevention trial in India. All the participants had IGT at baseline. For this subanalysis a total of 147 (T2DM: 71; nondiabetic: 76) participants were selected based on the final glycemic outcomes. Association of these selected adipokines with T2DM were assessed using logistic regression analyses. Clinical usefulness of adding adipokine markers with HbA1c on prediction of T2DM was assessed using the area under the curve (AUC) of the receiver operating characteristics.

RESULTS

Baseline levels of adiponectin were lower and the levels of IL-6 were higher in T2DM cases when compared with non-diabetic cases (P<0.05). Levels of leptin were similar in both groups. In fully adjusted models, adiponectin (odds ratio (OR): 0.55 [95%CI: 0.33-0.91]; P=0.019) and IL-6 (OR: 2.27 [95%CI: 1.40-3.691]; P=0.001) were associated with diabetes. Addition of adiponectin to HbA1c improved the AUC (ΔAUC: 0.0619; P=0.0251), whereas addition of IL-6 did not improve the predictive power of HbA1c alone.

CONCLUSIONS

Adiponectin and IL-6 are independently associated with incident diabetes. However, they are unlikely to serve as simple tools to predict future risk of diabetes but may have a role in understanding the pathogenesis.

Association of chemerin levels with anthropometric indexes and C-reactive protein in obese and non-obese adolescents

BACKGROUND

Obesity is a low-grade chronic inflammation. This epidemic is growing in different age groups including adolescents. It is accompanied with a decrease in the age for incidence of obesity-related disorders. Chemerin, as a chemokine and stimulator of anti-inflammatory adiponectin, links immune system, adipose tissue and inflammation. It may be useful in predicting obesity in the hit phase of life. This study aims to assess serum chemerin and adiponectin in relation to the inflammation and obesity indices.

METHODS

This case-control study was conducted on 82 adolescent girls, aged12-18 years. They were categorized based on the percentiles of the body mass index (BMI).Serum chemerin, adiponectin, high-sensitive C-reactive protein (Hs-CRP), body fat mass and its percent, waist circumference (WC) ,hip circumference (HC) were measured; BMI and waist-to-hip ratio (WHR)were calculated. Data were analyzed by independent Student's t-test and Pearson correlation; path analysis was conducted, as well.

RESULTS

We found a negative significant association between chemerin and adiponectin levels in both obese and non-obese groups(r =-0.387, P = 0.014 vs. r = 0.362, respectively, P = 0.018). Serum chemerin was higher in obese than in non-obese adolescents (441.83 ± 47.79 vs. 409.30 ± 66.12 µg /l, respectively, P = 0.012), whereas mean adiponectin level was lower in obese participants than in the other group (4.79 ± 0.94 versus 5.2 ± 0.53µg/ml, respectively, P = 0.016). Chemerin concentrations had significant positive correlation with Hs-CRP levels, BMI, WC, HC, WHR, body fat mass and its percent (P < 0.05).

CONCLUSION

Chemerin concentrations were associated with and adiponectin levels in obese girl adolescents, negatively. Hs-CRP, BMI, WC, HC, WHR, body fat mass and its' percent were in positive relation with chemerin levels, and inverse association with serum adiponectin concentrations. Our findings suggest that chemerin can be considered as an early marker of the inflammatory process in obesity.

Adiponectin is not associated with blood pressure in normotensives and untreated hypertensives with normal kidney function

The role of adiponectin in hypertension is still a matter of debate. Obtained conflicting results could be mostly explained with diversity of subjects included in different studies. Our aim was to analyze association of adiponectin with blood pressure (BP) in a group of normotensive and untreated hypertensive subjects. Participants (N=257) were selected from a random sample of 2487 subjects enrolled in an observational cross-sectional study. Subjects with diabetes and chronic kidney diseases were excluded. BP was measured using Omron M6 device following ESH/ESC guidelines. Adiponectin concentration was determined by ELISA. There were no differences in adiponectin values (mg/L) between hypertensives and normotensives (median 9.75; iqr: 7.44-17.88 vs 11.35; iqr: 7.43-12.63; P=0.17). On univariate linear regression adiponectin was not associated with systolic or diastolic BP (P>0.05). Furthermore, multivariate analysis did not show significant contribution of log-transformed adiponectin either to systolic (β=-0.040; P=0.43) or diastolic BP (β=0.066; P=0.33). In our group of normotensives and untreated hypertensives with normal kidney function adiponectin was not associated with BP even after adjustment for other risk factors. Our results and conclusions should not be extrapolated to subjects with other characteristics.

Adiponectin in eutrophic and obese children as a biomarker to predict metabolic syndrome and each of its components

BACKGROUND

Obesity is associated with the rise of noncommunicable diseases worldwide. The pathophysiology behind this disease involves the increase of adipose tissue, being inversely related to adiponectin, but directly related to insulin resistance and metabolic syndrome (MetS). Therefore, this study aimed to determine the relationship between adiponectin levels with each component of MetS in eutrophic and obese Mexican children.

METHODS

A cross sectional study was conducted in 190 school-age children classified as obese and 196 classified as eutrophic. Adiponectin, glucose, insulin, high density lipoprotein cholesterol (HDL-C) and triglycerides were determined from a fasting blood sample. Height, weight, waist circumference, systolic and diastolic blood pressures (BP) were measured; MetS was evaluated with the IDF definition. The study groups were divided according to tertiles of adiponectin, using the higher concentration as a reference. Linear regression analysis was used to assess the association between adiponectin and components of the MetS. Finally, stepwise forward multiple logistic regression analysis controlling for age, gender, basal HOMA-IR values and BMI was performed to determine the odds ratio of developing MetS according to adiponectin tertiles.

RESULTS

Anthropometric and metabolic measurements were statistically different between eutrophic and obese children with and without MetS (P <0.001). The prevalence of MetS in obese populations was 13%. Adiponectin concentrations were 15.5 ± 6.1, 12.0 ± 4.8, 12.4 ± 4.9 and 9.4 ± 2.8 μg/mL for eutrophic and obese subjects, obese without MetS, and obese with MetS, respectively (P <0.001). Obese children with low values of adiponectin exhibited a higher frequency of MetS components: abdominal obesity, 49%; high systolic BP, 3%; high diastolic BP, 2%; impaired fasting glucose, 17%; hypertriglyceridemia, 31%; and low HDL-C values, 42%. Adjusted odds ratio of presenting MetS according to adiponectin categories was 10.9 (95% CI 2.05; 48.16) when the first tertile was compared with the third.

CONCLUSION

In this sample of eutrophic and obese Mexican children we found that adiponectin concentrations and MetS components have an inversely proportional relationship, which supports the idea that this hormone could be a biomarker for identifying individuals with risk of developing MetS.

Adipocytokine associations with insulin resistance in british South asians

Aims. Adipocytokines are implicated in the pathogenesis of type 2 diabetes and may represent identifiable precursors of metabolic disease within high-risk groups. We investigated adiponectin, leptin, and TNF- α and assessed the contribution of these molecules to insulin resistance in south Asians. Hypothesis. South Asians have adverse adipocytokine profiles which associate with an HOMA-derived insulin resistance phenotype. Methods. We measured adipocytokine concentrations in south Asians with newly diagnosed impaired glucose tolerance or Type 2 Diabetes Mellitus in a case-control study. 158 (48.5% males) volunteers aged 25-75 years with risk factors for diabetes but no known vascular or metabolic disease provided serum samples for ELISA and bioplex assays. Results. Total adiponectin concentration progressively decreased across the glucose spectrum in both sexes. A reciprocal trend in leptin concentration was observed only in south Asian men. Adiponectin but not leptin independently associated with HOMA-derived insulin resistance after logistic multivariate regression. Conclusion. Diasporic south Asian populations have an adverse adipocytokine profile which deteriorates further with glucose dysregulation. Insulin resistance is inversely associated with adiponectin independent of BMI and waist circumference in south Asians, implying that adipocytokine interplay contributes to the pathogenesis of metabolic disease in this group.

Adipokines (adiponectin and plasminogen activator inhhibitor-1) in metabolic syndrome

BACKGROUND

The clustering of cardiovascular risk factors is termed the metabolic syndrome (MS), which strongly predicts the risk of diabetes and cardiovascular disease (CVD). Adipokines may contribute to the development of obesity and insulin resistance and may be a causal link between MS, diabetes and CVD. Hence, we studied the adipokines - adiponectin and plasminogen activator inhibitor-1 (PAI-1) - in subjects with MS.

MATERIALS AND METHODS

We studied 50 subjects with MS diagnosed by International Diabetes Federation (IDF) criteria and 24 healthy age- and sex-matched controls. Clinical evaluation included anthropometry, body fat analysis by bioimpedance, highly sensitive C-reactive protein, insulin, adiponectin, and PAI-1 measurement.

RESULTS

Subjects with MS had lower adiponectin (4.01 ± 2.24 vs. 8.7 ± 1.77 μg/ml; P < 0.0001) and higher PAI-1 (53.85 ± 16.45 vs. 17.35 ± 4.45 ng/ml; P < 0.0001) levels than controls. Both were related with the number of metabolic abnormalities. Adiponectin was negatively and PAI-1 was positively associated with body mass index, waist hip ratio (WHR), body fat mass, percent body fat, and all the parameters of MS, except HDL where the pattern reversed. WHR and triglycerides were independent predictors of adipokines in multiple regression analysis. Receiver operating characteristic curve analysis showed that adiponectin (6.7 μg/ml) and PAI-1 (25.0 ng/ml) levels predicted the MS with high sensitivity, specificity and accuracy in Indian population.

CONCLUSIONS

Subjects with MS have lower adiponectin and higher PAI-1 levels compared to healthy controls. Lifestyle measures have been shown to improve the various components of MS, and hence there is an urgent need for public health measures to prevent the ongoing epidemic of diabetes and CVD.

Study of beta-cell function (by HOMA model) in metabolic syndrome

INTRODUCTION

The clustering of cardiovascular risk factors is termed the metabolic syndrome (MS), which strongly predict risk of diabetes and cardiovascular disease. Many studies implicate insulin resistance (IR) in the development of diabetes, but ignore the contribution of beta-cell dysfunction. Hence, we studied beta-cell function, as assessed by HOMA model, in subjects with MS.

MATERIALS AND METHODS

We studied 50 subjects with MS diagnosed by IDF criteria and 24 healthy age- and sex-matched controls. Clinical evaluation included anthropometry, body fat analysis by bioimpedance, biochemical, and insulin measurement. IR and secretion were calculated by HOMA model.

RESULTS

Subjects with MS had more IR (HOMA-IR) than controls (3.35 ± 3.14 vs. 1.76 ± 0.53, P = 0.029) and secreted less insulin (HOMA-S) than controls (66.80 ± 69.66 vs. 144.27 ± 101.61, P = 0.0003), although plasma insulin levels were comparable in both groups (10.7 ± 10.2 vs. 8.2 ± 2.38, P = 0.44). HOMA-IR and HOMA-S were related with number of metabolic abnormalities. HOMA-IR was positively associated with body mass index, waist hip ratio, body fat mass, and percent body fat. HOMA-S was negatively associated with waist hip ratio, fasting plasma glucose and total cholesterol and positively with basal metabolic rate. Percent body fat was an independent predictor of HOMA-IR and waist hip ratio of HOMA-S in multiple regression analysis.

CONCLUSIONS

Subjects with MS have increased IR and decreased insulin secretion compared with healthy controls. Lifestyle measures have been shown to improve IR, insulin secretion, and various components and effects of MS. Hence, there is an urgent need for public health measures to prevent ongoing epidemic of diabetes and cardiovascular disease.

Ethnic variation in adiponectin and leptin levels and their association with adiposity and insulin resistance

OBJECTIVE

To investigate ethnic differences in adiponectin and leptin concentration and to determine whether these adipokines and a high-glycemic index diet account for ethnic variation in insulin resistance.

RESEARCH DESIGN AND METHODS

In 1,176 South Asian, Chinese, Aboriginal, and European Canadians, fasting blood samples were drawn, and clinical history and dietary habits including glycemic index/glycemic load were recorded using standardized questionnaires. Insulin resistance was defined using homeostasis model assessment-insulin resistance (HOMA-IR).

RESULTS

Adiponectin concentrations were significantly higher in Europeans (adjusted mean 12.94 [95% CI 2.27-13.64]) and Aboriginal people (11.87 [11.19-12.59]) than in South Asians (9.35 [8.82-9.92]) and Chinese (8.52 [8.03-9.03]) (overall P < 0.001). Serum leptin was significantly higher in South Asians (11.82 [10.72-13.04]) and Aboriginal people (11.13 [10.13-12.23]) than in Europeans (9.21 [8.38-10.12]) and Chinese (8.25 [7.48-9.10]). BMI and waist circumference were inversely associated with adiponectin in every group except the South Asians (P < 0.001 for interaction). Adiponectin was inversely and leptin was positively associated with HOMA-IR (P < 0.001). The increase in HOMA-IR for each given decrease in adiponectin was larger among South Asians (P = 0.01) and Aboriginal people (P < 0.001) than among Europeans. A high glycemic index was associated with a larger decrease in adiponectin among South Asians (P = 0.03) and Aboriginal people (P < 0.001) and a larger increase in HOMA-IR among South Asians (P < 0.05) relative to that in other groups.

CONCLUSIONS

South Asians have the least favorable adipokine profile and, like the Aboriginal people, display a greater increase in insulin resistance with decreasing levels of adiponectin. Differences in adipokines and responses to glycemic foods parallel the ethnic differences in insulin resistance.

Diabetes in Asia

Prevalence of type 2 diabetes has rapidly increased in native and migrant Asian populations. Diabetes develops at a younger age in Asian populations than in white populations, hence the morbidity and mortality associated with the disease and its complications are also common in young Asian people. The young age of these populations and the high rates of cardiovascular risk factors seen in Asian people substantially increase lifetime risk of cardiovascular disease. Several distinctive features are apparent in pathogenetic factors for diabetes and their thresholds in Asian populations. The economic burden due to diabetes at personal, societal, and national levels is huge. National strategies to raise public awareness about the disease and to improve standard of care and implementation of programmes for primary prevention are urgently needed.