Determinants of insulin-resistant phenotypes in normal-weight and obese Black African women

Validation of the Fatty Liver Index for identifying non-alcoholic fatty liver disease in a Kenyan population

BACKGROUND AND AIM

Fatty Liver Index (FLI) is a simple clinical scoring system estimating non-alcoholic fatty liver disease (NAFLD). It is validated in European-descent and Asian populations, but not in sub-Saharan Africans. The aim of this study is to evaluate the validity of the FLI for predicting NAFLD in a population from Kenya.

METHODS

Participants were recruited from a community-based study conducted in Kenya. NAFLD was diagnosed using hepatic ultrasonography. Clinical, anthropometrical, biochemical and lifestyle data were obtained. The accuracy and cut-off point of the FLI to detect NAFLD were evaluated by area under the receiver operator characteristic curve and the maximum Youden index analysis.

RESULTS

A total of 640 participants (94 with NAFLD) were included. Mean age was 37.4 ± 0.4 years and 58.7% were women. Mean body mass index (BMI) was 22.3 ± 0.2 kg/m2 and waist circumference (WC) 79.1 ± 0.4 cm. A total of 15 (2.3%) participants were diagnosed with type 2 diabetes and 65 (10.2%) with obesity (BMI ≥ 30 kg/m2 ). AUROC of FLI for predicting NAFLD was 0.80 (95% CI 0.74-0.85), which was significantly higher compared to individual components gamma-glutamyl transferase and triglycerides (p < 0.05), but not compared to anthropometric parameters BMI (AUROC of 0.83, 95% CI 0.79-0.88) and WC (AUROC of 0.81, 95% CI 0.76-0.87).

CONCLUSIONS

FLI is a simple valid scoring system to use in rural and urban Kenyan adults. However, this index might not be superior to BMI or WC to predict NAFLD, and those measurements might therefore be more appropriate in limited settings.

Metabolic phenotyping in people living with obesity: Implications for dietary prevention

Given the increasing number of people living with obesity and related chronic metabolic disease, precision nutrition approaches are required to increase the effectiveness of prevention strategies. This review addresses these approaches in different metabolic phenotypes (metabotypes) in obesity. Although obesity is typically associated with an increased cardiometabolic disease risk, some people with obesity are relatively protected against the detrimental effects of excess adiposity on cardiometabolic health, also referred to as 'metabolically healthy obesity' (MHO). Underlying mechanisms, the extent to which MHO is a transient state as well as lifestyle strategies to counteract the transition from MHO to metabolically unhealthy obesity (MUO) are discussed. Based on the limited resources that are available for dietary lifestyle interventions, it may be reasonable to prioritize interventions for people with MUO, since targeting high-risk patients for specific nutritional, lifestyle or weight-loss strategies may enhance the cost-effectiveness of these interventions. Additionally, the concept of tissue insulin resistant (IR) metabotypes is discussed, representing distinct etiologies towards type 2 diabetes (T2D) as well as cardiovascular disease (CVD). Recent evidence indicates that these tissue IR metabotypes, already present in individuals with obesity with a normal glucose homeostasis, respond differentially to diet. Modulation of dietary macronutrient composition according to these metabotypes may considerably improve cardiometabolic health benefits. Thus, nutritional or lifestyle intervention may improve cardiometabolic health, even with only minor or no weight loss, which stresses the importance of focusing on a healthy lifestyle and not on weight loss only. Targeting different metabotypes towards T2D and cardiometabolic diseases may lead to more effective lifestyle prevention and treatment strategies. Age and sex-related differences in tissue metabotypes and related microbial composition and functionality (fermentation), as important drivers and/or mediators of dietary intervention response, have to be taken into account. For the implementation of these approaches, more prospective trials are required to provide the knowledge base for precision nutrition in the prevention of chronic metabolic diseases.

Predicting mechanisms of action at genetic loci associated with discordant effects on type 2 diabetes and abdominal fat accumulation

Obesity is a major risk factor for cardiovascular disease, stroke, and type 2 diabetes (T2D). Excessive accumulation of fat in the abdomen further increases T2D risk. Abdominal obesity is measured by calculating the ratio of waist-to-hip circumference adjusted for the body-mass index (WHRadjBMI), a trait with a significant genetic inheritance. Genetic loci associated with WHRadjBMI identified in genome-wide association studies are predicted to act through adipose tissues, but many of the exact molecular mechanisms underlying fat distribution and its consequences for T2D risk are poorly understood. Further, mechanisms that uncouple the genetic inheritance of abdominal obesity from T2D risk have not yet been described. Here we utilize multi-omic data to predict mechanisms of action at loci associated with discordant effects on abdominal obesity and T2D risk. We find six genetic signals in five loci associated with protection from T2D but also with increased abdominal obesity. We predict the tissues of action at these discordant loci and the likely effector Genes (eGenes) at three discordant loci, from which we predict significant involvement of adipose biology. We then evaluate the relationship between adipose gene expression of eGenes with adipogenesis, obesity, and diabetic physiological phenotypes. By integrating these analyses with prior literature, we propose models that resolve the discordant associations at two of the five loci. While experimental validation is required to validate predictions, these hypotheses provide potential mechanisms underlying T2D risk stratification within abdominal obesity.

Role of physical activity and cardiorespiratory fitness in metabolically healthy obesity: a narrative review

Obesity has been associated with a multitude of metabolic disorders, often clustering with risk factors of cardiovascular disease and type 2 diabetes mellitus, hypertension, dyslipidaemia. Overall, obesity is a worldwide, growing health concern. However, a subgroup of obese individuals with a low burden of metabolic abnormalities have been identified and described as metabolically healthy obese (MHO). Whether the MHO phenotype is protective against obesity-related metabolic disorders in the long-term is presently unclear, and current research examining the potential transition has yielded inconsistent results. In this current narrative review, we aim to provide insights on the role of physical activity (PA) and cardiorespiratory fitness (CRF) in MHO. Lifestyle factors such as PA and CRF may influence the MHO phenotype. Limited studies have characterised energy expenditure and CRF in MHO and metabolically unhealthy obese. However, higher levels of PA, less sedentary behaviour and higher CRF have been observed in MHO individuals. Considering the multiple benefits of PA, it is high time to advocate this lifestyle change beyond its influence on energy balance in a weight loss programme to improve cardiovascular and metabolic risk factors irrespective of body weight and fat mass changes. Improved CRF via increased PA, especially exercise participation, while avoiding weight gain is not only a realistic goal, but should be the primary intervention for MHO populations to prevent the transition to an abnormal metabolic state.

Metabolically healthy obesity and unhealthy normal weight rural adults in Xinjiang: prevalence and the associated factors

BACKGROUND

This study aimed to describe the prevalence of metabolically healthy obesity (MHO) and metabolically unhealthy normal weight (MUNW) rural adults in Xinjiang and to explore their influencing factors.

METHODS

We selected 13,525 Uyghur, Kazakh and Han participants in Kashi, Yili and Shihezi areas in Xinjiang from 2009 to 2010. Weight status was classified according to body mass index. Metabolic phenotype was further defined based on the National Cholesterol Education Program Adult Treatment Panel III criteria.

RESULTS

The prevalence of normal weight, overweight, and obesity were 51.6, 30.2, and 14.4%, respectively. The mean age of the population was 45.04 years. The prevalence of MHO was 5.5% overall and was 38.5% among obese participants. The prevalence of MUNW was 15.5% overall and was 30.1% among normal weight participants. A metabolically healthy phenotype among obese individuals was positively associated with females and vegetable consumption ≥4 plates per week. However, this was inversely associated with higher age, red meat consumption ≥2 kg per week, and larger waist circumference (WC). Conversely, a metabolically unhealthy phenotype among normal-weight individuals was positively associated with higher age, red meat consumption ≥2 kg per week, and larger WC; this was however inversely associated with vegetable consumption ≥4 plates per week.

CONCLUSIONS

The prevalence of MHO among obese adults in Xinjiang is higher than that of Han adults, while the prevalence of MUNW among normal weight adults is lower than that among Han adults. In obese and normal weight participants, higher age, more red meat consumption, and larger WC increase the risk of metabolic abnormality, and more vegetable consumption reduces the risk of metabolic abnormality.

Metabolically healthy obesity and metabolically obese normal weight: a review

Despite the general relationship between obesity and its co-morbidities, there are both obese individuals who scarcely present the associated pathologies (metabolically healthy obese; MHO) and individuals who present obesity alterations despite having normal weight (metabolically obese normal weight; MONW). It is still difficult to define metabolically MHO and MONW individuals because different classifications have been used in the studies reported. Indeed, different inclusion criteria have been used to discriminate between metabolically healthy and metabolically unhealthy subjects. Due to this and other reasons, such as differences in ethnicity, genetics, and lifestyle of the populations, data concerning the prevalence of MHO and MONW are very variable. The main determinants of MHO are type of growth (hypertrophy or hyperplasia), anatomical location, inflammation of adipose tissue, ectopic fat accumulation, genetic factors, and lifestyles factors. In the case of MONW, the main determinants are genetic background and lifestyle factors. With regard to treatment, it is not clear whether MHO subjects would benefit from traditional lifestyle interventions, based on diet energy restriction and increased physical activity. For MONW subjects, there is still no specialized treatment, and the therapies are the same as those used in obese subjects.

Metabolic Syndrome Pathophysiology and Predisposing Factors

Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors with high prevalence among adult populations and elevated costs for public health systems worldwide. Despite the lack of consensus regarding the syndrome definition and diagnosis criteria, it is characterized by the coexistence of risk factors such as abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, a prothrombotic and pro-inflammatory state, insulin resistance (IR), and higher glucose levels, factors indubitably linked to an increased risk of developing chronic conditions, such as type 2 diabetes (T2D) and cardiovascular disease (CVD). The syndrome has a complex and multifaceted origin not fully understood; however, it has been strongly suggested that sedentarism and unbalanced dietary patterns might play a fundamental role in its development. The purpose of this review is to provide an overview from the syndrome epidemiology, costs, and main etiological traits from its relationship with unhealthy diet patterns and sedentary lifestyles.

Metabolically healthy obesity: facts and fantasies

Although obesity is typically associated with metabolic dysfunction and cardiometabolic diseases, some people with obesity are protected from many of the adverse metabolic effects of excess body fat and are considered "metabolically healthy." However, there is no universally accepted definition of metabolically healthy obesity (MHO). Most studies define MHO as having either 0, 1, or 2 metabolic syndrome components, whereas many others define MHO using the homeostasis model assessment of insulin resistance (HOMA-IR). Therefore, numerous people reported as having MHO are not metabolically healthy, but simply have fewer metabolic abnormalities than those with metabolically unhealthy obesity (MUO). Nonetheless, a small subset of people with obesity have a normal HOMA-IR and no metabolic syndrome components. The mechanism(s) responsible for the divergent effects of obesity on metabolic health is not clear, but studies conducted in rodent models suggest that differences in adipose tissue biology in response to weight gain can cause or prevent systemic metabolic dysfunction. In this article, we review the definition, stability over time, and clinical outcomes of MHO, and discuss the potential factors that could explain differences in metabolic health in people with MHO and MUO - specifically, modifiable lifestyle factors and adipose tissue biology. Better understanding of the factors that distinguish people with MHO and MUO can produce new insights into mechanism(s) responsible for obesity-related metabolic dysfunction and disease.

Association between obesity phenotypes of insulin resistance and risk of type 2 diabetes in African Americans: The Jackson Heart Study

OBJECTIVE

To determine whether insulin resistance (IR) measured by homeostasis model of insulin resistance (HOMA-IR) can further stratify diabetes risk in African Americans (AAs) beyond obesity and identify obese, low risk and non-obese, high risk individuals.

METHODS

Using the Jackson Heart Study cohort, we categorized participants without diabetes into four phenotypes: non-obese/insulin-sensitive, non-obese/IR, obese/insulin-sensitive and obese/IR. Obesity was defined as BMI ≥ 30 or BMI 25-30 plus an increased waist circumference. IR was defined as HOMA-IR ≥ 2. We used modified Poisson regression models to estimate the incident risk-ratios (IRR) of diabetes across these phenotypes adjusting for potential confounders and HbA1c.

RESULTS

Among 3219 AAs without diabetes, 14.0% were non-obese/insulin-sensitive, 24.6% non-obese/IR, 6.2% obese/insulin-sensitive, and 55.3% obese/IR. The overall crude incidence rate of diabetes was 29.91 cases/1000 person-years. In fully-adjusted models, compared to the non-obese/insulin-sensitive group, the relative risk of diabetes was highest in obese/IR (IRR = 2.35; 95% CI: 1.53, 3.60), followed by non-obese/IR (IRR = 1.59; 95% CI: 1.02, 2.46), and non-significant for the obese/insulin-sensitive (IRR = 1.70; 95% CI: 0.97, 2.99) group.

CONCLUSIONS

HOMA-IR can further stratify diabetes risk in AA adults beyond obesity, identifying non-obese high-risk and lower-risk obese individuals. However, diabetes risk should still be carefully monitored in obese populations despite insulin sensitivity.

HDL Subclass Distribution Shifts with Increasing Central Adiposity

Although cross-sectional studies have shown that obesity is associated with lower concentrations of large high-density lipoprotein (HDL) subclasses, it is unknown if changes in HDL subclasses are related to changes in body fat and its distribution over time. We therefore assessed changes in HDL subclass distribution over a 5.5-year free-living follow-up period in 24 black South African women. At baseline and follow-up, body composition and body fat distribution were measured using anthropometry, dual X-ray absorptiometry, and computerized tomography. HDL subclass distribution was quantified using Lipoprint®. Over the 5.5-year follow-up period, body fat (+17.3 ± 4.5 kg, p < 0.05) and trunk fat mass (+7.4 ± 1.9%, % fat mass, FM, p < 0.05) increased, while leg fat mass (-2.53 ± 0.56%, % FM, p < 0.001) and the distribution of large (-6.43 ± 2.12%, p < 0.05) HDL subclasses decreased. A percentage decrease in large HDL subclasses was associated with a percentage increase in central fat mass (visceral adipose tissue (VAT) area, p < 0.05) and a percentage decrease in peripheral fat mass (leg fat mass). These preliminary findings suggest that a relative redistribution of body fat from the periphery to the abdominal region were associated with a decrease HDL subclass size in black South African women and provide a novel link between body fat distribution and lipidology in this population.

The Prevalence of Metabolically Healthy and Unhealthy Obesity according to Different Criteria

OBJECTIVE

Obesity-related disease risks may vary depending on whether the subject has metabolically healthy obesity (MHO) or metabolically unhealthy obesity (MUO). At least 5 definitions/criteria of obesity and metabolic disorders have been documented in the literature, yielding uncertainties in a reliable international comparison of obesity phenotype prevalence. This report aims to compare differences in MHO and MUO prevalence according to the 5 most frequently used definitions.

METHODS

A random sample of 4,757 adults aged 35 years and older (male 51.1%) was enrolled. Obesity was defined either according to body mass index or waist circumference, and the definitions of metabolic abnormalities were derived from 5 different criteria.

RESULTS

In MHO, the highest prevalence was obtained when using the homeostasis model assessment (HOMA) criteria (13.6%), followed by the Chinese Diabetes Society (11.4%), Adult Treatment Panel III (10.3%), Wildman (5.2%), and Karelis (4.2%) criteria; however, the MUO prevalence had an opposite trend to MHO prevalence. The magnitude of differences in the age-specific prevalence of MHO and MUO varied greatly and ranked in different orders. The proportion of insulin resistance for MHO and MUO individuals differed significantly regardless of which metabolic criterion was used.

CONCLUSION

The prevalence of MHO and MUO in the Chinese population varies according to different definitions of obesity and metabolic disorders.

High prevalence of cardiovascular risk factors and insulin resistance 6 years after hyperglycemia first detected in pregnancy in Cape Town, South Africa

OBJECTIVE

To investigate the prevalence and associated cardiovascular risk factors 6 years after hyperglycemia first detected in pregnancy (HFDP) in Cape Town, South Africa.

RESEARCH DESIGN AND METHODS

Data were collected during the index pregnancy from all women diagnosed with HFDP at a major referral hospital in Cape Town. Participants were evaluated 6 years later using a cross-sectional study. At follow-up participants had a 75 g oral glucose tolerance test, fasting lipogram, blood pressure and anthropometric measurements, and a fieldworker administered the questionnaire. We used the Adult Treatment Panel III criteria for the diagnosis of metabolic syndrome and individual risk factors. Insulin resistance was assessed using the homeostatic model of insulin resistance.

RESULTS

At follow-up 220 women were reviewed. Their mean age at follow-up was 37.2 (SD 6.0) years. The prevalence of cardiovascular disease (CVD) risk factors was 60.9% (95% CI 54.3 to 67.2) for metabolic syndrome, 75% (95% CI 65.9 to 82.3) for insulin resistance, 62.3% (95% CI 55.6 to 68.5) for dysglycemia, 41.4% (95% CI 35.0 to 48.0) for raised blood pressure, and 74.6% (95% CI 683 to 79.9) for dyslipidemia. Women with diabetes in pregnancy compared with those with gestational diabetes during the index pregnancy had a higher prevalence of metabolic syndrome (74.3% vs 54.7%, p=0.010) and dysglycemia (88.6% vs 50.0%, p<0.001) at follow-up. Lower school education attainment, having a subsequent pregnancy, waist circumference at follow-up, and fasting blood glucose at HFDP diagnosis were associated with metabolic syndrome.

CONCLUSION

We found a high prevalence of CVD risk factors in South African women within 6 years of HFDP, which highlights the need to develop and evaluate interventions optimizing the cardiometabolic health of this vulnerable group. The main limitations of our research are the lack of a comparative group of women without HFDP and that we did not assess for CVD risk factors before HFDP.

Role of Physical Activity and Fitness in the Characterization and Prognosis of the Metabolically Healthy Obesity Phenotype: A Systematic Review and Meta-analysis

The aims of the present article are to systematically review and meta-analyze the existing evidence on: 1) differences in physical activity (PA), sedentary behavior (SB), cardiorespiratory fitness (CRF) and muscular strength (MST) between metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO); and 2) the prognosis of all-cause mortality and cardiovascular disease (CVD) mortality/morbidity in MHO individuals, compared with the best scenario possible, i.e., metabolically healthy normal-weight (MHNW), after adjusting for PA, SB, CRF or MST. Our systematic review identified 67 cross-sectional studies to address aim 1, and 11 longitudinal studies to address aim 2. The major findings and conclusions from the current meta-analysis are: 1) MHO individuals are more active, spend less time in SB, and have a higher level of CRF (yet no differences in MST) than MUO individuals, suggesting that their healthier metabolic profile could be at least partially due to these healthier lifestyle factors and attributes. 2) The meta-analysis of cohort studies which accounted for PA (N = 10 unique cohorts, 100% scored as high-quality) support the notion that MHO individuals have a 24-33% higher risk of all-cause mortality and CVD mortality/morbidity compared to MHNW individuals. This risk was borderline significant/non-significant, independent of the length of the follow-up and lower than that reported in previous meta-analyses in this topic including all type of studies, which could be indicating a modest reduction in the risk estimates as a consequence of accounting for PA. 3) Only one study has examined the role of CRF in the prognosis of MHO individuals. This study suggests that the differences in the risk of all-cause mortality and CVD mortality/morbidity between MHO and MHNW are largely explained by differences in CRF between these two phenotypes.

Phenotypic and metabolic dichotomy in obesity: clinical, biochemical and immunological correlates of metabolically divergent obese phenotypes in healthy South Asian adults

INTRODUCTION

Metabolic heterogeneity among obese individuals is thought to translate into variations in cardiovascular risk. Identifying obese people with an unfavourable metabolic profile may allow preventive strategies to be targeted at high-risk groups. This study aimed to identify clinical, biochemical and immunological differences between insulin-sensitive and insulin-resistant obese subgroups, to understand the population-specific pathophysiological basis of the adverse cardiovascular risk profile in the latter group.

METHODS

Cardiovascular risk indicators, including anthropometric parameters, blood pressure, acanthosis nigricans area, and related biochemical, endocrine and inflammatory markers, were determined in 255 healthy South Asian volunteers aged 18-45 years, with a 2:1 ratio of obese/overweight to normal-weight individuals. Lifetime atherosclerotic cardiovascular disease (ASCVD) risk was also calculated.

RESULTS

Body mass index (BMI) and insulin sensitivity-based tertiles independently showed incremental trends in waist-hip ratio, skinfold thickness, acanthosis nigricans area, blood pressure, serum lipids, hepatic enzymes, adipokines, inflammatory markers and ten-year ASCVD risk. The anthropometric, biochemical and inflammatory parameters of obese insulin-sensitive and obese insulin-resistant groups differed significantly. Extreme group analysis after excluding the middle tertiles of both insulin resistance and BMI also showed significant difference in anthropometric indicators of cardiovascular risk and estimated lifetime ASCVD risk between the two obese subgroups.

CONCLUSION

Obese insulin-sensitive individuals had a favourable metabolic profile compared to the obese insulin-resistant group. The most consistent discriminative factor between these phenotypic classes was anthropometric parameters, which underscores the importance of clinical parameters as cardiovascular risk indicators in obesity.

Prevalence and Clinical Characteristics of Metabolically Healthy Obesity in Korean Children and Adolescents: Data from the Korea National Health and Nutrition Examination Survey

Metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) are differentiated by the presence of cardiometabolic risk factors (CMRFs) and insulin resistance (IR). This study aimed to evaluate the prevalence and clinical characteristics of MHO in Korean children and adolescents and to investigate the anthropometric, laboratory, and lifestyle predictors of MHO. This study included data from 530 obese subjects, aged 10-19 years, obtained from the Fourth Korea National Health and Nutrition Examination Survey. Subjects were classified into MHO and MUO groups according to the presence of CMRF (MHO(CMRF)/MUO(CMRF)) and degree of IR (MHO(IR)/MUO(IR)). Demographic, anthropometric, cardiometabolic, and lifestyle factors were compared between the groups. Logistic regression analysis and receiver operating characteristic curve analysis were performed to identify factors that predicted MHO. The prevalence of MHO(CMRF) and MHO(IR) in obese Korean youth was 36.8% (n = 197) and 68.8% (n = 356), respectively. CMRF profiles were significantly less favorable in MUO children. Longer and more vigorous physical activity and less protein intake were associated with MHO(CMRF) phenotype. The best predictors of MHO(CMRF) and MHO(IR) were waist circumference (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.77-0.88; P < 0.001) and body mass index (BMI) standard deviation score (OR, 0.24; 95% CI, 0.15-0.39; P < 0.001), respectively. The prevalence of MHO differed depending on how it was defined. To adequately manage obesity in youth, the approach to individuals with MHO and MUO should be personalized due to variation in clinical characteristics. Longitudinal studies are needed to evaluate long-term consequences of MHO.

A randomized, double-blind clinical study to determine the effect of ANKASCIN 568 plus on blood glucose regulation

Diabetes is the fourth major cause of death in Taiwan. High blood glucose can lead to macrovascular diseases,small vessel diseases (retinopathy, kidney disease), and neuropathy. This study aimed to investigate whether Monascus-fermented products (ANKASCIN 568 plus) can regulate blood glucose and blood lipids. This study enrolled 39 patients with a fasting blood glucose level between 100 mg/dL and 180 mg/dL, and a glycated hemoglobin (HbA1c) level of <9%. All patients were randomly divided into placebo (n = 20) and experimental (n = 19) groups. Each patient received two placebo capsules (maltodextrin) or ANKASCIN 568 plus capsules daily for 12 weeks. The patients were screened during follow-up 4 weeks after the administration of sample or placebo had been discontinued. Blood and urine samples were collected at the initial, 6^th week, 12^th week, and 16^th week. The anthropometric indicators of blood pressure, fasting plasma glucose level, postprandial plasma glucose level, insulin level, insulin resistance, blood lipid changes, and liver, kidney, and thyroid function indices were measured. After 6weeks, changes in fasting blood glucose, low-density lipoprotein cholesterol (LDL-C),and total cholesterol (TC) levels showed thatANKASCIN568 plus had amore favorable effect than the placebo. Compared to baseline, a statistically significant decrease of 8.5%, 10.3%, and 7.5% was observed in fasting blood glucose, LDL-C and, TC levels, respectively (p < 0.05 for all pairs). Therefore, ANKASCIN568 plus produced by Monascus purpureus NTU 568 fermentation may be a potentially useful agent for the regulation of blood glucose and blood lipids and for treatment of coronary artery diseases.

Disparities in Cardiovascular Disease and Type 2 Diabetes Risk Factors in Blacks and Whites: Dissecting Racial Paradox of Metabolic Syndrome

Cardiovascular diseases (CVD) remain as the leading cause of mortality in the western world and have become a major health threat for developing countries. There are several risk factors that account for the CVD and the associated mortality. These include genetics, type 2 diabetes (T2DM), obesity, physical inactivity, hypertension, and abnormal lipids and lipoproteins. The constellation of these risk factors has been termed metabolic syndrome (MetS). MetS varies among racial and ethnic populations. Thus, race and ethnicity account for some of the differences in the MetS and the associated CVD and T2DM. Furthermore, the relationships among traditional metabolic parameters and CVD differ, especially when comparing Black and White populations. In this regard, the greater CVD in Blacks than Whites have been partly attributed to other non-traditional CVD risk factors, such as subclinical inflammation (C-reactive protein), homocysteine, increased low-density lipoprotein oxidation, lipoprotein a, adiponectin, and plasminogen activator inhibitor-1, etc. Thus, to understand CVD and T2DM differences in Blacks and Whites with MetS, it is essential to explore the contributions of both traditional and non-traditional CVD and T2DM risk factors in Blacks of African ancestry and Whites of Europoid ancestry. Therefore, in this mini review, we propose that non-traditional risk factors should be integrated in defining MetS as a predictor of CVD and T2DM in Blacks in the African diaspora in future studies.

Characterization of Metabolically Healthy Obese People and Metabolically Unhealthy Normal-Weight People in a General Population Cohort of the ABCD Study

There is actually no consensus about the possibility that in some instances, obesity may be a benign metabolically healthy (MH) condition as opposed to a normal-weight but metabolically unhealthy (MUH) state. The aim of this study was to characterize MH condition and to investigate possible associations with metabolic and cardiovascular complications. One thousand nineteen people (range of age 18-90 years) of the cohort of the ABCD_2 study were investigated. Participants were classified as normal weight (BMI < 24.9 kg/m²) or overweight-obese (BMI ≥25 kg/m²); they were also classified as MH in the presence of 0-1 among the following conditions: (a) prediabetes/type 2 diabetes, (b) hypertension, (c) hypertriglyceridemia or low HDL cholesterolemia, and (d) hypercholesterolemia. MUH condition was diagnosed if ≥2 of the conditions listed were found. The prevalence of overweight/obese people was 71.1%, of whom 27.4% were found to be MH. In addition, 36.7% of the normal-weight participants were MUH. HOMA-IR, high sensitivity C-reactive protein, and the carotid intima-media thickness were significantly different in the 4 subgroups (P < 0.001), with higher values observed in the MUH normal-weight and obese groups. In conclusion, this study highlights the importance of identifying a MH condition in normal-weight and in obese people in order to offer better treatment.

The Distribution of Obesity Phenotypes in HIV-Infected African Population

The distribution of body size phenotypes in people with human immunodeficiency virus (HIV) infection has yet to be characterized. We assessed the distribution of body size phenotypes overall, and according to antiretroviral therapy (ART), diagnosed duration of the infection and CD4 count in a sample of HIV infected people recruited across primary care facilities in the Western Cape Province, South Africa. Adults aged ≥ 18 years were consecutively recruited using random sampling procedures, and their cardio-metabolic profile were assessed during March 2014 and February 2015. They were classified across body mass index (BMI) categories as normal-weight (BMI < 25 kg/m²), overweight (25 ≤ BMI < 30 kg/m²), and obese (BMI ≥ 30 kg/m²), and further classified according to their metabolic status as “metabolically healthy” vs. “metabolically abnormal” if they had less than two vs. two or more of the following abnormalities: high blood glucose, raised blood pressure, raised triglycerides, and low HDL-cholesterol. Their cross-classification gave the following six phenotypes: normal-weight metabolically healthy (NWMH), normal-weight metabolically abnormal (NWMA), overweight metabolically healthy (OvMH), overweight metabolically abnormal (OvMA), obese metabolically healthy (OMH), and obese metabolically abnormal (OMA). Among the 748 participants included (median age 38 years (25th–75th percentiles: 32–44)), 79% were women. The median diagnosed duration of HIV was five years; the median CD4 count was 392 cells/mm³ and most participants were on ART. The overall distribution of body size phenotypes was the following: 31.7% (NWMH), 11.7% (NWMA), 13.4% (OvMH), 9.5% (OvMA), 18.6% (OMH), and 15.1% (OMA). The distribution of metabolic phenotypes across BMI levels did not differ significantly in men vs. women (p = 0.062), in participants below vs. those at or above median diagnosed duration of HIV infection (p = 0.897), in participants below vs. those at or above median CD4 count (p = 0.447), and by ART regimens (p = 0.205). In this relatively young sample of HIV-infected individuals, metabolically abnormal phenotypes are frequent across BMI categories. This highlights the importance of general measures targeting an overall improvement in cardiometabolic risk profile across the spectrum of BMI distribution in all adults with HIV.

Determinants of change in body weight and body fat distribution over 5.5 years in a sample of free-living black South African women

Objective

To identify socio-demographic and lifestyle determinants of weight gain in a sample of premenopasual black South African (SA) women.

Methods

Changes in body composition (dual-energy X-ray absorptiometry, computerised tomography), socio-economic status (SES) and behavioural/lifestyle factors were measured in 64 black SA women at baseline (27 ± 8 years) and after 5.5 years.

Results

A lower body mass index (BMI) and nulliparity, together with access to sanitation, were significant determinants of weight gain and change in body fat distribution over 5.5 years. In addition, younger women increased their body weight more than their older counterparts, but this association was not independent of other determinants.

Conclusion

Further research is required to examine the effect of changing SES, as well as the full impact of childbearing on weight gain over time in younger women with lower BMIs. This information will suggest areas for possible intervention to prevent long-term weight gain in these women.

Cardiorespiratory Fitness and Light-Intensity Physical Activity Are Independently Associated with Reduced Cardiovascular Disease Risk in Urban Black South African Women: A Cross-Sectional Study

BACKGROUND

Low levels of physical activity, poor cardiorespiratory fitness, and a sedentary lifestyle have been associated with increased risk for cardiovascular disease (CVD) and type 2 diabetes (T2D). Few studies have examined their independent associations in an urban black sub-Saharan African population.

OBJECTIVES

To examine the independent associations of physical activity, cardiorespiratory fitness, and sedentary time on body composition and cardiometabolic risk factors for CVD and T2D in black South African women.

MATERIALS AND METHODS

A subsample (n = 76; 18-45 years) was recruited, as part of a cross-sectional study. Accelerometry, cardiorespiratory fitness, body composition, insulin sensitivity, serum lipids, and blood pressure were measured.

RESULTS

Light- but not moderate- to vigorous intensity physical activity was inversely associated with trunk fat mass (r = -0.25, P = 0.03). Sedentary time was associated with triglyceride (TG) (r = 0.36, P = 0.01) and TG/HDL-C (r = 0.34, P = 0.04), and these relationships were independent of body fat. Cardiorespiratory fitness was inversely associated with body fat % (r = -0.34, P = 0.02), central fat mass (r = -0.31, P = 0.03), visceral adipose tissue (VAT, r = -0.47, P < 0.01), and insulin resistance (HOMA-IR; r = -0.41, P = 0.01). The association between cardiorespiratory fitness and HOMA-IR was independent of body fat and physical activity, but not VAT. Cardiorespiratory fitness was inversely associated with sedentary time (r = -0.31, P = 0.03), but not with any of the physical activity variables (P > 0.05).

CONCLUSION

Both physical activity and cardiorespiratory fitness were associated with reduced total and central fat mass, VAT, and reduced cardiometabolic risk for CVD and T2D. Longitudinal studies are required to confirm whether the promotion of increasing light physical activity, while reducing sedentary time and increasing cardiorespiratory fitness, reduces the risk for obesity, CVD and T2D.

Blood pressure in the Congolese adult population of South Kivu, Democratic Republic of Congo: Preliminary results from the Bukavu Observ Cohort Study

BACKGROUND

Providing factual data about non-communicable diseases (NCDs) is of utmost importance in the sub-Saharan African countries where NCDs and arterial hypertension data remain scattered, scarce, and less representative given the region's heterogeneous population. Within this context, the interuniversity cooperation VLIR-UOS/Catholic University of Bukavu (Democratic Republic of Congo) has established an integrated project for monitoring hypertension and cardiovascular risk factors in the population of South Kivu. The aim of the study was to present the basic results of the determinants of blood pressure in the cohort studied.

METHODS

In 2013 and 2014, trained interviewers collected the anthropometric parameters, blood pressure, and medical history of 7405 adults (3060 in urban areas and 4345 in rural areas) including 3162 males and 4243 females; the cohort is expected to be followed for 9 years.

RESULTS

The average age of the entire group was 33.0±16.7 years. Compared to men, women had significantly higher obesity indices (P<0.0001), lower blood pressure between 20 and 39 years of age (P<0.0001) but higher blood pressure at 60 years of age and older (P<0.0001). Blood pressure was positively correlated with body mass index, waist circumference, and paradoxically with consumption of vegetables, but negatively correlated with the consumption of fruit, intense physical activity, and relaxation at home.

CONCLUSIONS

These results show that a cohort study is feasible in the Democratic Republic of Congo. The factual data analysis can contribute to health policy orientation and setting up of preventive measures. Since most correlated risk factors are preventable, recommendations can already be made in the fight against high blood pressure in this population.

Prevalence, Risk Factors, and Genetic Traits in Metabolically Healthy and Unhealthy Obese Individuals

Objective. To assess prevalence of metabolically healthy individuals among patients with abdominal obesity (AO) and to determine phenotype and potential genetic traits associated with a benign metabolic status. Methods. 503 AO patients without cardiovascular diseases were examined. Waist circumference (WC), BMI, blood pressure, plasma glucose and serum insulin levels, HOMA-IR, lipid profile, and adiponectin (AN) and leptin (LEP) concentrations in serum were measured. Polymorphisms A19G and Q223R of the LEP and LEP receptor gene, and G276T and T45G of the AN gene were investigated. Results. 91.3% of patients were metabolically unhealthy obese (MUO), and 8.7% metabolically healthy obese (MHO). MHO patients were younger, and had lesser BMI and WC, while duration of obesity, frequency, and duration of physical training were greater than MUO patients (p < 0.05). In MHO and MUO patients distribution of the G19G, G19A, and A19A genotypes of the LEP gene and G276G, G276T, and T276T genotypes of AN gene did not differ. The Т45Т genotype was associated with increase of metabolic disorders' risk for patients with АО (OR = 2.331; 95%  CI = 1.121 ÷ 5.132). Conclusions. Prevalence of MHO individuals among patients with AO is low. Benign metabolic status was associated with younger age, lower waist circumference, and higher physical activity, shorter duration of obesity, and G45G adiponectin genotype carriage.

Association of metabolic syndrome components with insulin resistance in normal weight population: the Qazvin Metabolic Diseases study

PURPOSE

Metabolically obese but normal weight (MONW) is associated with higher risk of type 2 diabetes, dyslipidemia, and hypertension. The aim of this study was to evaluate the association of metabolic syndrome components with MONW in each sex in Iranian population.

METHODS

This cross-sectional study was performed on 417 normal weight subjects in Qazvin, Iran between September 2010 and April 2011. MONW was defined by insulin resistance (IR) using the homeostatic model assessment (HOMA). Cut off point for IR was defined as the lower limit of top quintile of HOMA-IR values in normal weight population without any metabolic risk factors. Data were analyzed using T test, Mann-Whitney U test, and multi-variant logistic regression analysis.

RESULTS

Of 417 subjects, 44.3 % were female. The prevalence of MONW was 33.8 % in men and 39.8 % in women. Triglycerides levels were significantly higher in both men and women with MONW. Waist circumference was significantly higher in men with MONW, while high-density lipoprotein cholesterol levels were significantly lower in women with MONW. In logistic regression analysis, hypertriglyceridemia in women (OR 3.398; 95 % CI 1.306-8.846) and waist circumference (per 5 cm increment) in men (OR 1.653; 95 % CI 1.279-2.136) had independent association with MONW.

CONCLUSION

Association of metabolic syndrome components with MONW is different in men and women. Waist circumference had an independent association with IR in men but not in women. IR and its complications should be considered in lean women with hypertriglyceridemia.

Longitudinal Changes in Body Fat and Its Distribution in Relation to Cardiometabolic Risk in Black South African Women

BACKGROUND

Ethnic differences in body composition and cardiometabolic risk have been reported in cross-sectional studies. This study aimed to investigate changes in body composition over 5.5 years, and its association with cardiometabolic risk in premenopausal black South African (SA) women.

METHODS

Changes in body composition and body fat distribution (dual-energy x-ray absorptiometry and computerized tomography), fasting glucose, insulin, and lipid concentrations, were measured in 63 black SA women at baseline (age: 27 ± 8 years), and 5.5 years later.

RESULTS

Body weight and fat mass (FM) increased by 6.9 ± 9.9 kg and 4.3 ± 6.9 kg, respectively, over the 5.5 years with a relative (%FM) increase in central and decrease in peripheral FM (all P < 0.05). Fasting glucose and lipid concentrations (except HDL-cholesterol) increased over the follow-up period (all P < 0.05). Both baseline and changes in body fat distribution were associated with cardiometabolic risk. Independent of baseline age, FM and insulin sensitivity, baseline trunk:leg was associated with reduced insulin sensitivity at follow-up (Matsuda index; β = -0.41, P = 0.002). Increasing trunk:gynoid ratio was associated with higher plasma insulin levels (β = 0.31, P = 0.023) and reduced insulin sensitivity (Matsuda index; β = -0.52, P < 0.001) at follow-up.

CONCLUSIONS

Weight gain in free-living black SA women over 5.5 years was associated with a centralization of fat mass, which predicted an increase in cardiometabolic risk.

Obesity, insulin resistance and comorbidities? Mechanisms of association

Overall excess of fat, usually defined by the body mass index, is associated with metabolic (e.g. glucose intolerance, type 2 diabetes mellitus (T2DM), dyslipidemia) and non-metabolic disorders (e.g. neoplasias, polycystic ovary syndrome, non-alcoholic fat liver disease, glomerulopathy, bone fragility etc.). However, more than its total amount, the distribution of adipose tissue throughout the body is a better predictor of the risk to the development of those disorders. Fat accumulation in the abdominal area and in non-adipose tissue (ectopic fat), for example, is associated with increased risk to develop metabolic and non-metabolic derangements. On the other hand, observations suggest that individuals who present peripheral adiposity, characterized by large hip and thigh circumferences, have better glucose tolerance, reduced incidence of T2DM and of metabolic syndrome. Insulin resistance (IR) is one of the main culprits in the association between obesity, particularly visceral, and metabolic as well as non-metabolic diseases. In this review we will highlight the current pathophysiological and molecular mechanisms possibly involved in the link between increased VAT, ectopic fat, IR and comorbidities. We will also provide some insights in the identification of these abnormalities.

A randomized controlled exercise training trial on insulin sensitivity in African American men: The ARTIIS study: Major category: study design, statistical design, study protocols

BACKGROUND

Lack of regular physical activity at prescribed intensity levels is a modifiable risk factor for insulin resistance and the development of diabetes. African American men are at increased risk for developing diabetes and most African American men are not meeting the current recommended levels of physical activity. The primary objective of the Aerobic Plus Resistance Training and Insulin Resistance in African American Men (ARTIIS) study is to determine the effectiveness of an exercise training intervention aimed at reducing diabetes risk factors in African American men at risk for developing diabetes.

METHODS

Insufficiently active 35-70 year old African American men with a family history of diabetes were eligible for the study. The 5-month randomized controlled trial assigns 116 men to an exercise training or healthy living control arm. The exercise training arm combines aerobic and resistance training according to the current national physical activity recommendations and is conducted in community (YMCA) facilities. The healthy living arm receives information promoting healthy lifestyle changes.

OUTCOMES

Insulin response to an oral glucose load is the primary outcome measure, and changes in physiological parameters, cardiorespiratory fitness, strength, body composition, and psychological well-being comprise the secondary outcomes.

CONCLUSIONS

The ARTIIS study is one of the first adequately powered, rigorously designed studies to investigate the effects of an aerobic plus resistance exercise training program and to assess adherence to exercise training in community facilities, in African American men.

Ethnic differences in the association between lipid metabolism genes and lipid levels in black and white South African women

OBJECTIVE

Dyslipidaemia can lead to the development of atherosclerosis and cardiovascular disease (CVD), however its prevalence has been shown to differ between ethnic groups in South Africa (SA). Therefore the aim of this study was to investigate ethnic differences in the association between serum lipid levels and polymorphisms within genes involved in lipid metabolism in black and white SA women.

METHODS

In a convenient sample of 234 white and 209 black SA women of Xhosa ancestry, body composition (DXA) and fasting serum lipids were measured. Participants were genotyped for the cholesteryl ester transfer protein (CETP, rs708272, B1/B2), lipoprotein lipase (LPL, rs328, S/X), hepatic lipase (LIPC, rs1800588, C/T) and proprotein convertase subtilisin/kexin type 9 (PCSK9, rs28362286, C/X) polymorphisms.

RESULTS

Compared to white women, black women had lower concentrations of serum total cholesterol (TC, P < 0.001), low density lipoprotein cholesterol (LDL-C, P < 0.001), high density lipoprotein cholesterol (HDL-C, P < 0.001) and triglycerides (TG, P < 0.001). There were significant differences in the genotype and allele frequency distributions between black and white women for the LPL S/X (P < 0.001), PCSK9 C679X (P = 0.002) and LIPC 514C/T (P < 0.001) polymorphisms. In black women only, there were genotype effects on serum lipid levels. Specifically, women with the LPL SX genotype had lower TC and LDL-C and higher HDL-C concentrations than those with the SS genotype and women with the CETP B2 allele had lower LDL-C concentrations than those with the B1B1 genotype.

CONCLUSION

Polymorphisms within the LPL and CETP genes were associated with a more protective lipid profile in black, but not white SA women. This supports the hypothesis that the more favorable lipid profile of black compared to white SA women is associated with polymorphisms in lipid metabolism genes, specifically the LPL and CETP genes.

comparative study of glucose homeostasis, lipids and lipoproteins, HDL functionality, and cardiometabolic parameters in modestly severely obese African Americans and White Americans with prediabetes: implications for the metabolic paradoxes

OBJECTIVE

To determine whether modestly severe obesity modifies glucose homeostasis, levels of cardiometabolic markers, and HDL function in African Americans (AAs) and white Americans (WAs) with prediabetes.

RESEARCH DESIGN AND METHODS

We studied 145 subjects with prediabetes (N = 61 WAs, N = 84 AAs, mean age 46.5 ± 11.2 years, mean BMI 37.8 ± 6.3 kg/m(2)). We measured fasting levels of lipids, lipoproteins, and an inflammatory marker (C-reactive protein [CRP]); HDL functionality (i.e., levels of paraoxonase 1 [PON1]); and levels of oxidized LDL, adiponectin, and interleukin-6 (IL-6). We measured serum levels of glucose, insulin, and C-peptide during an oral glucose tolerance test. Values for insulin sensitivity index (Si), glucose effectiveness index (Sg), glucose effectiveness at zero insulin (GEZI), and acute insulin response to glucose (AIRg) were derived using a frequently sampled intravenous glucose tolerance test (using MINMOD software).

RESULTS

Mean levels of fasting and incremental serum glucose, insulin, and C-peptide tended to be higher in WAs versus AAs. The mean Si was not different in WAs versus AAs (2.6 ± 2.3 vs. 2.9 ± 3.0 × 10(-4) × min(-1) [μU/mL](-1)). Mean values for AIRg and disposition index as well as Sg and GEZI were lower in WAs than AAs. WAs had higher serum triglyceride levels than AAs (116.1 ± 55.5 vs. 82.7 ± 44.2 mg/dL, P = 0.0002). Mean levels of apolipoprotein (apo) A1, HDL cholesterol, PON1, oxidized LDL, CRP, adiponectin, and IL-6 were not significantly different in obese AAs versus WAs with prediabetes.

CONCLUSIONS

Modestly severe obesity attenuated the ethnic differences in Si, but not in Sg and triglyceride levels in WAs and AAs with prediabetes. Despite the lower Si and PON1 values, AAs preserved paradoxical relationships between the Si and HDL/apoA1/triglyceride ratios. We conclude that modestly severe obesity has differential effects on the pathogenic mechanisms underlying glucose homeostasis and atherogenesis in obese AAs and WAs with prediabetes.

High Molecular Weight (HMW): total adiponectin ratio is low in hiv-infected women receiving protease inhibitors

Background

At the time of the study, the HIV-treatment policy in South Africa included highly active antiretroviral therapy (HAART) regimens 1 (nucleotide reverse transcriptase inhibitors (NRTIs) only), and 2 (protease inhibitors (PI) and NRTIs). HAART is associated with the lipodystrophy syndrome, insulin resistance and reduced total adiponectin (TA) levels. The high molecular weight (HMW):TA ratio is a superior marker of insulin resistance. The aim of this study was to establish whether HMW:TA ratios are low in patients on PIs and whether they correlate with insulin resistance.

Methods

This was a cross-sectional study undertaken in an antiretroviral clinic at a tertiary hospital. The participants were 66 HIV-infected females: 22 were on regimen 2 (PI group), 22 on regimen 1 (non-PI) and 22 treatment naïve (TN), matched for BMI and age. Patients with a history of diabetes or impaired glucose tolerance were excluded. Serum adiponectin multimers were analysed using the AlpcoTM Adiponectin (Multimeric) enzyme immunoassay. Waist hip ratios (WHR), glucose and insulin levels were assessed, and HOMA-IR and QUICKI calculated. Data were analysed non-parametrically and multivariate analysis was performed.

Results

TA and HMW levels were lower in the treatment groups than in the TN group. HMW:TA was lower in the PI than in the non-PI and TN groups, and in the non-PI than in the TN groups. HMW:TA correlated negatively with waist, insulin and HOMA-IR, independently of BMI and duration of therapy. HOMA-IR and QUICKI did not differ among the groups.

Conclusion

HMW:TA is significantly decreased with HAART (particularly with PIs, but also with non-PIs) and may be a more sensitive marker of insulin resistance in these patients than conventional markers or HMW and total adiponectin individually.

Profile of individuals who are metabolically healthy obese using different definition criteria. A population-based analysis in the Spanish population

BACKGROUND

Obesity is associated with numerous metabolic complications such as diabetes mellitus type 2, dyslipidemia, hypertension, cardiovascular diseases and several forms of cancer. Our goal was to compare different criteria to define the metabolically healthy obese (MHO) with metabolically unhealthy obese (MUHO) subjects. We applied Wildman (W), Wildman modified (WM) with insulin resistance (IR) with cut-off point ≥ 3.8 and levels of C- Reactive Protein (CRP) ≥ 3 mg/l; and Consensus Societies (CS) criteria. In these subjects cardiovascular-risk (CV-risk) was estimated by Framingham score and SCORE for MHO and MUHO.

METHODS

A cross-sectional study was conducted in Spanish Caucasian adults. A total of 3,844 subjects completed the study, 45% males, aged 35-74 years. Anthropometric/biochemical variables were measured. Obesity was defined as BMI: ≥ 30 Kg/m(2).

RESULTS

The overall prevalence of obesity in our population was 27.5%, (23.7%/males and 30.2%/females). MHO prevalence according to W, WM, and CS definition criteria were: 9.65%, 16.29%, 39.94% respectively in obese participants. MHO has lower waist circumference (WC) measurements than MUHO. The estimated CV-risks by Framingham and SCORE Project charts were lower in MHO than MUHO subjects. WC showed high specificity and sensitivity in detecting high estimated CV risk by Framingham. However, WHR showed high specificity and sensitivity in detecting CV risk according to SCORE Project. MHO subjects as defined by any of the three criteria had higher adiponectin levels after adjustment by sex, age, WC, HOMA IR and Framingham or SCORE risks. This relationship was not found for CRP circulating levels neither leptin levels.

CONCLUSIONS

MHO prevalence is highly dependent on the definition criteria used to define those individuals. Results showed that MHO subjects had less WC, and a lower estimated CV-risk than MUHO subjects. Additionally, the high adiponectin circulating levels in MHO may suggest a protective role against developing an unhealthy metabolic state.

Consequences of Abdominal Adiposity within the Metabolic Syndrome Paradigm in Black People of African Ancestry

The metabolic syndrome (MetS) is a constellation of risk factors that are associated with increased risks for coronary heart disease and type 2 diabetes. Although the cause is unknown, abdominal adiposity is considered the underpinning of these metabolic alterations. Hence, increased abdominal adiposity contributes to dyslipidemia, hyperglycemia, beta cell dysfunction, insulin resistance, hypertension and inflammation. The role of abdominal adiposity in the causation of metabolic alterations that lead to the clinical expression of the MetS has become a focus of active research. In addition, there are ethnic/racial differences in the manifestation of the MetS. Therefore, the focus of this current review is to: (1) explore the consequences of abdominal obesity within the MetS paradigm; and (2) discuss the impact of ethnicity/race on MetS in Black People of African Ancestry (PAA).

Meeting physical activity guidelines is associated with reduced risk for cardiovascular disease in black South African women; a 5.5-year follow-up study

Background

Low levels of physical activity (PA) have been associated with increased risk for cardiovascular disease (CVD) and type 2 diabetes (T2D), but few studies have examined whether meeting international PA guidelines is associated with reduced risk in a black South African (SA) population. The aims of this study were to compare body composition and cardio-metabolic risk factors for CVD and T2D between active and inactive groups (part 1, cross-sectional analysis) and, to determine whether PA level predicts changes in body composition and cardio-metabolic risk factors for CVD and T2D at follow-up after 5.5-years (part 2, longitudinal analysis).

Methods

Part 1 included a sample of 240 apparently healthy black SA women (26 ± 7 years) who underwent the following measurements at baseline: PA (Global Physical Activity Questionnaire (GPAQ)), body composition and regional fat distribution (dual-energy x-ray absorptiometry and computerised tomography), blood pressure, fasting glucose, insulin and lipid concentrations. For part 2, a sub-sample of women (n = 57) underwent the same measurements after a 5.5-year period.

Results

At baseline, 61% of women were classified as meeting the guidelines for moderate- to vigorous-intensity physical activity (MVPA) according to GPAQ. Women who were active had significantly lower body weight (p < 0.001), body fat (BMI, fat mass, % body fat, waist circumference, central and appendicular fat mass, all p < 0.001), and measures of insulin resistance (fasting serum insulin and HOMA-IR, both p = 0.01), and higher high-density lipoprotein cholesterol (p = 0.041), compared to the inactive group. At follow-up, all body fat measures increased significantly in both groups and diastolic blood pressure decreased significantly in those who were active at baseline, but did not change in those who were inactive.

Conclusions

Meeting PA guidelines was associated with decreased risk for CVD and T2D in black SA women, but did not prevent the increase in body fat over time. Interventions promoting physical activity to specifically address obesity in this high-risk group are recommended.

Body size preference among Yoruba in three Nigerian communities

Following our previous observation of an aversion to weight reduction in Nigerians with type 2 diabetes, we measured several parameters of body dimensions and preferences in otherwise healthy adults in three communities to study the phenomenon further. The study population of 524 participants (304 F) was 99.8% of Yoruba ethnic origin with a mean age of 43.9 ± 17.2 years. Females had a significantly (p > 0.001) higher body mass index (BMI), waist circumference, hip circumference compared to the males; the values being 24.55 ± 5.5 vs. 21.75 ± 3.71 kg/m(2); 84.98 ± 12.67 vs. 80.92 ± 9.85 cm; 96.32 ± 12.94 vs. 89.36 ± 8.06 cm, respectively. There was a high level of satisfaction amongst respondents with their body size (Kendall's t = 0.52, p < 0.001) which they also predicted with a high degree of certainty even without the prior use of a weighing scale. The relationship between current body size (CBI) and BMI emerged as CBI = 1.22 + 0.32 BMI. In the 41% of respondents who expressed unhappiness with their current body size, there was a strong aversion for a smaller body size and the preference was often for a bigger body figure. Strikingly, many more women than men were less dissatisfied with their bigger body sizes. Stepwise regression indicated that CBI and gender were the two most important variables that best related to casual blood sugar (RBS) among the factors entered. The mathematical relationship between these variables that emerged was: [Formula: see text] where gender = 0 for male and 1 for female. The results suggest that larger body sizes were positively viewed in these communities consistent with our previous observations in type 2 diabetes.

Insulin resistance is associated with lower acetylcholine-induced microvascular reactivity in nondiabetic women

BACKGROUND

The association between insulin resistance and microvascular dysfunction is well established in obese individuals with type 2 diabetes. It is unclear whether this relationship is dependent on obesity and body fat in insulin-resistant persons. This study investigated acetylcholine (ACh)-induced microvascular reactivity in apparently healthy women (n=37, 20-45 years), with and without insulin resistance.

METHODS

Body fat mass (dual X-ray absorptiometry), waist circumference (WC), blood pressure, fasting glucose, insulin, and free fatty acid concentrations were measured. Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR), and subjects were divided into insulin-resistant (IR, n=16) and insulin-sensitive (IS, n=21) groups. ACh-induced forearm microvascular reactivity was measured by laser Doppler imagery using iontophoresis of ACh and compared between groups adjusting for WC and skin resistance (SR).

RESULTS

The IR group had a higher body mass index (BMI) (30.7 ± 6.4 vs. 22.9 ± 7.3 kg/m(2), P < 0.01), fat mass (34.7 ± 11.9 vs. 19.7 ± 9.6 kg, P < 0.01), WC (89.9 ± 13.6 vs. 74.4 ± 9.7 cm, P < 0.01), and a lower SR (0.24 ± 0.08 vs. 0.32 ± 0.08 Ω, P < 0.05) than the IS group. Microvascular reactivity, expressed as percentage increase in perfusion from baseline, was significantly lower in IR subjects after adjusting for differences in WC and SR (420.9 ± 166.5 vs. 511.6 ± 214.8%, P < 0.05). There were associations between microvascular reactivity and SR (r=-0.34, P < 0.05) and systolic blood pressure (r=-0.36, P < 0.05), but not BMI, body fat mass, WC, or HOMA-IR.

CONCLUSION

ACh-induced microvascular reactivity was different between IR and IS apparently healthy, nondiabetic women once differences in WC and SR were accounted for.

Characterising metabolically healthy obesity in weight-discordant monozygotic twins

AIMS/HYPOTHESIS

Not all obese individuals display the metabolic disturbances commonly associated with excess fat accumulation. Mechanisms maintaining this 'metabolically healthy obesity' (MHO) are as yet unknown. We aimed to study different fat depots and transcriptional pathways in subcutaneous adipose tissue (SAT) as related to the MHO phenomenon.

METHODS

Sixteen rare young adult obesity-discordant monozygotic (MZ) twin pairs (intra-pair difference (∆) in BMI ≥ 3 kg/m(2)), aged 22.8-35.8 years, were examined for detailed characteristics of metabolic health (subcutaneous, intra-abdominal and liver fat [magnetic resonance imaging/spectroscopy]), OGTT, lipids, adipokines and C-reactive protein (CRP). Affymetrix U133 Plus 2.0 chips were used to analyse transcriptomics pathways related to mitochondrial function and inflammation in SAT.

RESULTS

Based on liver fat accumulation, two metabolically different subgroups emerged. In half (8/16) of the pairs (∆weight 17.1 ± 2.0 kg), the obese co-twin had significantly higher liver fat (∆718%), 78% increase in AUC insulin during OGTT and CRP, significantly more disturbance in the lipid profile and greater tendency for hypertension compared with the lean co-twin. In these obese co-twins, SAT expression of mitochondrial oxidative phosphorylation, branched-chain amino acid catabolism, fatty acid oxidation and adipocyte differentiation pathways were downregulated and chronic inflammation upregulated. In the other eight pairs (∆weight 17.4 ± 2.8 kg), the obese co-twin did not differ from the non-obese co-twin in liver fat (∆8%), insulin sensitivity, CRP, lipids, blood pressure or SAT transcriptomics.

CONCLUSIONS/INTERPRETATION

Our results suggest that maintenance of high mitochondrial transcription and lack of inflammation in SAT are associated with low liver fat and MHO.

Association between Lower Normal Free Thyroxine Concentrations and Obesity Phenotype in Healthy Euthyroid Subjects

We investigated whether thyroid function could identify obesity phenotype in euthyroid subjects. A cross-sectional analysis was performed among nondiabetic, euthyroid subjects. We stratified subjects into four groups by BMI and insulin resistance (IR). Of 6241 subjects, 33.8% were overweight or obese (OW/OB) and 66.2% were normal weight (NW). Free thyroxine (FT4) levels were negatively associated with body mass index, waist circumference, triglyceride, c-reactive protein, and HOMA-IR and positively with high-density lipoprotein cholesterol in both genders. In multivariate regression analysis, FT4 level, a continuous measurement, was negatively correlated with HOMA-IR (β = -0.155, P < 0.001 in men; β = -0.175, P < 0.001 in women). After adjustment for age, sex, metabolic, and life style factors, subjects in the lowest FT4 quartile had an odds ratio (OR) for IR of 1.99 (95% confidence interval 1.61-2.46), as compared to those in the highest quartile. The association between low FT4 and IR remained significant in both NW and OW/OB subgroups. In conclusion, low normal FT4 levels were independently related to IR in NW and OW/OB euthyroid subjects. Further studies are needed to investigate the mechanisms by which low FT4 levels are linked to high IR in euthyroid ranges.

Differences in body composition between metabolically healthy obese and metabolically abnormal obese adults

Potential differences in body composition between metabolically healthy obese (MHO) and metabolically abnormal obese (OA) adults were explored with 395 obese adults from the Pennington Center Longitudinal Study (18-68 years). Adults were classified as OA (≥2 risk factors: blood pressure ≥130/85 mmHg; triglycerides ≥150 mg dl(-1); high-density lipoprotein cholesterol: men <40, women <50 mg dl(-1); fasting glucose ≥100 mg dl(-1); waist circumference: ≥102 cm men, women ≥88 cm) or MHO (<2 risk factors). Whole-body bone mineral density and content, percent body fat, fat mass, lean mass and trunk adipose tissue mass were measured with dual-energy X-ray absorptiometry. Visceral (VAT), subcutaneous (SAT) and total abdominal adipose tissue (TAT) were measured with computed tomography. Gender-specific general linear regression models were used to determine differences in body composition between MHO and OA controlling for age, race, smoking status and menopause status. In men, MHO had lower fat mass (kg and %), trunk adipose tissue, VAT, SAT, TAT and lean mass compared with OA. MHO women had lower fat mass (kg), lean mass, trunk adipose tissue, VAT and TAT when compared with OA women. In conclusion, OA and MHO cardiometabolic profiles are characterized by differences in body composition consistent between genders.

A metabolically healthy obese phenotype in hispanic participants in the IRAS family study

OBJECTIVE

Some obese individuals appear to be protected from developing type 2 diabetes mellitus and cardiovascular disease (CVD). This has led to characterizing body size phenotypes based on cardiometabolic risk factors specifically as obese or overweight, and as metabolically healthy (MH) or metabolically abnormal (MA) based upon blood pressure, lipids, glucose homeostasis, and inflammatory parameters. The aim of this study was to measure the prevalence of and describe fat distribution across these phenotypes in a minority population.

DESIGN AND METHODS

Hispanic participants (N = 1054) in the IRAS Family Study were categorized into different body size phenotypes. Computed tomography (CT) abdominal scans were evaluated for measures of nonalcoholic fatty liver disease (NAFLD) and abdominal fat distribution. Statistical models adjusting for familial relationships were estimated.

RESULTS

Seventy percent (70%) of the Hispanic cohort was overweight (32%) or obese (38%). Forty-one percent (n = 138) of overweight participants and 19% (n = 74) of obese participants met criteria for MH. Adjusted analyses showed the MH phenotype was associated with lower visceral adipose tissue (VAT) and higher liver density (indicating lower fat content) in obese participants (p = 0.0005 and p = 0.0002, respectively), and lower VAT but not liver density in overweight participants (p = 0.008 and p = 0.162, respectively) compared to their MA counterparts. Odds of NAFLD were reduced in MH obese (OR = 0.34, p = 0.0007) compared to MA obese. VAT did not differ between MH obese or overweight and normal weight groups.

CONCLUSIONS

These findings suggest that lower levels of visceral and liver fat, despite overall increased total body fat, may be a defining feature of MH obesity in Hispanic Americans.

Metabolic effects of bariatric surgery in insulin-sensitive morbidly obese subjects

BACKGROUND

The effects of bariatric surgery (BS) in metabolically healthy morbidly obese (MO) subjects are not well established. Against this background, we characterized the metabolic and inflammatory profiles of MO subjects with insulin sensitivity (IS) in the normal range, and evaluated the changes on these parameters following BS in this population.

METHODS

We conducted a retrospective analysis of prospectively collected data in MO women undergoing BS between 2006 and 2010. Anthropometric, metabolic comorbidities, and inflammatory markers were compared at baseline and 12 months after BS, between 52 women (10.4%) presenting with a HOMA-IR < 2.94 (80th percentile reference population) (IS-MO group) and an age- and BMI-matched group of women (n = 52) with HOMA-IR > 2.94.

RESULTS

The IS-MO women presented a more favorable metabolic and inflammatory profile as compared to the IR-MO group. However, an enlarged waist circumference (WC), a high-sensitivity C-reactive protein (hs-CRP) > 3 mg/dL, and metabolic syndrome (MS) were present in 100%, 90%, and 51.9% of the IS-MO group at baseline. At 12 months after surgery, all the MS components and hs-CRP improved in IS-MO subjects (p < 0.01). The prevalence of the MS in the IS-MO group significantly decreased (11%, p < 0.05) despite WC and hs-CRP being abnormal respectively in 53.3% and 20.0% of women in this group.

CONCLUSIONS

In MO women, an IS in the normal range is associated with a limited protection from metabolic co-morbidities. Nonetheless, BS results in the amelioration of the altered metabolic and inflammatory profiles also in this group of subjects.

Influence of a clinical lifestyle-based weight loss program on the metabolic risk profile of metabolically normal and abnormal obese adults

OBJECTIVE

It is unclear whether all obese individuals should be prescribed weight loss (WL) treatment. The effect of a clinically significant WL of 5% on metabolic factors among metabolically normal and abnormal overweight and obese (MNO and MAO) individuals was examined.

DESIGN AND METHODS

The sample included 392 overweight and obese adults from the Wharton Medical Clinic. MAO was defined as having one or more clinically relevant aberrations in glucose, triglycerides, blood pressure (BP), high-density lipoprotein-C, low-density lipoprotein-C, preexisting, or current medication use for metabolic conditions.

RESULTS

Of the 392 patients, 21.2% of the sample was MNO at baseline and 41.3% of the sample attained a 5% WL. Regardless of initial metabolic health status, improvements in most risk factors were observed with a 5% WL in comparison with those who did not lose weight. Even MAO patients who did not achieve a 5% WL still significantly improved BP and cholesterol over the treatment period.

CONCLUSIONS

A clinically significant WL is beneficial for the cardiometabolic risk profile of both MNO and MAO. However, a 5% WL is not necessarily required to improve the cardiometabolic risk profile of MAO. Thus, lifestyle-based WL provides beneficial metabolic effects for all overweight and obese individuals, particularly those with significant metabolic aberrations.

Adiposity and insulin resistance in humans: the role of the different tissue and cellular lipid depots

Human adiposity has long been associated with insulin resistance and increased cardiovascular risk, and abdominal adiposity is considered particularly adverse. Intra-abdominal fat is associated with insulin resistance, possibly mediated by greater lipolytic activity, lower adiponectin levels, resistance to leptin, and increased inflammatory cytokines, although the latter contribution is less clear. Liver lipid is also closely associated with, and likely to be an important contributor to, insulin resistance, but it may also be in part the consequence of the lipogenic pathway of insulin action being up-regulated by hyperinsulinemia and unimpaired signaling. Again, intramyocellular triglyceride is associated with muscle insulin resistance, but anomalies include higher intramyocellular triglyceride in insulin-sensitive athletes and women (vs men). Such issues could be explained if the "culprits" were active lipid moieties such as diacylglycerol and ceramide species, dependent more on lipid metabolism and partitioning than triglyceride amount. Subcutaneous fat, especially gluteofemoral, appears metabolically protective, illustrated by insulin resistance and dyslipidemia in patients with lipodystrophy. However, some studies suggest that deep sc abdominal fat may have adverse properties. Pericardial and perivascular fat relate to atheromatous disease, but not clearly to insulin resistance. There has been recent interest in recognizable brown adipose tissue in adult humans and its possible augmentation by a hormone, irisin, from exercising muscle. Brown adipose tissue is metabolically active, oxidizes fatty acids, and generates heat but, because of its small and variable quantities, its metabolic importance in humans under usual living conditions is still unclear. Further understanding of specific roles of different lipid depots may help new approaches to control obesity and its metabolic sequelae.

Metabolically healthy but obese, a matter of time? Findings from the prospective Pizarra study

BACKGROUND

Prospective longitudinal studies evaluating the relevance of "Metabolically Healthy but Obese" (MHO) phenotype at risk for type 2 diabetes mellitus (T2D) and cardiovascular diseases are few and results are contradictory.

METHODS

As a representative of the general population, 1051 individuals were evaluated in 1997-1998 and re-evaluated after 6 years and 11 years. Subjects without known T2D were given an oral glucose tolerance test. Anthropometric and biochemical variables were measured. Four sets of criteria were considered to define MHO subjects besides body mass index ≥30 kg/m(2): A: Homeostatic Model of Assessment-Insulin Resistance Index (HOMA-IR) <90th percentile; B: HOMA-IR <90th percentile, high-density lipoprotein cholesterol >40 mg/dL in men and high-density lipoprotein cholesterol >50 mg/dL in women, triglycerides <150 mg/dL, fasting glucose <110 mg/dL, and blood pressure ≤140/90 mm Hg; C: HOMA-IR <90th percentile, triglycerides <150 mg/dL, fasting glucose <110 mg/dL, and blood pressure ≤140/90 mm Hg; D: HOMA-IR <90th percentile, triglycerides <150 mg/dL, and fasting glucose <110 mg/dL. Subjects with T2D at baseline were excluded from the calculations of incidence of T2D.

RESULTS

The baseline prevalence of MHO phenotype varied between 3.0% and 16.9%, depending on the set of criteria chosen. Metabolically nonhealthy obese subjects were at highest risk for becoming diabetic after 11 years of follow-up (odds ratio = 8.20; 95% confidence interval = 2.72-24.72; P < .0001). In MHO subjects the risk for becoming diabetic was lower than in metabolically nonhealthy obese subjects, but this risk remained significant (odds ratio = 3.13; 95% confidence interval = 1.07-9.17; P = .02). In subjects who lost weight during the study, the association between MHO phenotype and T2D incidence disappeared, even after adjusting for HOMA-IR.

CONCLUSIONS

The results suggest that MHO is a dynamic concept that should be taken into account over time. As a clinical entity, it may be questionable.

Contraception and the obese woman

PURPOSE

Obesity has reached epidemic rates among U.S. women of reproductive age, many of whom want to use contraception. However, some forms of contraception can have adverse effects on an obese woman's health. This article explores risks of contraception available in the United States and provides clinical recommendations for use by obese women.

DATA SOURCES

Information was compiled by reviewing the scientific literature on contraception and female obesity using CINAHL, MEDLINE, PubMed search engines.

CONCLUSIONS

The evidence is largely supportive of combined oral contraceptive (COC) use in carefully screened obese women without known risks factors for cardiovascular disease. The efficacy of COCs may be slightly reduced in obese women because of increased body mass. Other types of hormonal contraceptives have varying safety and efficacy reports when used by obese women. Intrauterine devices do not have reduced efficacy nor increased risks for obese women but insertion may be more difficult. Obesity has no effect on efficacy of barrier methods of contraception.

IMPLICATIONS

Clinicians should conduct a careful history and physical exam with selected supporting laboratory tests when considering prescription of hormonal contraceptives for obese women. Obese women require health counseling to carefully follow directions for contraceptive use to avoid unintended pregnancy.

Diet composition and activity level of at risk and metabolically healthy obese American adults

OBJECTIVE

Obesity often clusters with other major cardiovascular disease risk factors, yet a subset of the obese appears to be protected from these risks. Two obesity phenotypes are described, (i) "metabolically healthy" obese, broadly defined as body mass index (BMI) ≥ 30 kg/m(2) and favorable levels of blood pressure, lipids, and glucose; and (ii) "at risk" obese, BMI ≥ 30 with unfavorable levels of these risk factors. More than 30% of obese American adults are metabolically healthy. Diet and activity determinants of obesity phenotypes are unclear. We hypothesized that metabolically healthy obese have more favorable behavioral factors, including less adverse diet composition and higher activity levels than at risk obese in the multi-ethnic group of 775 obese American adults ages 40-59 years from the International Population Study on Macro/Micronutrients and Blood Pressure (INTERMAP) cohort.

DESIGN AND METHODS

In gender-stratified analyses, mean values for diet composition and activity behavior variables, adjusted for age, race, and education, were compared between metabolically healthy and at risk obese.

RESULTS

Nearly one in five (149/775 or 19%) of obese American INTERMAP participants were classified as metabolically healthy obese. Diet composition and most activity behaviors were similar between obesity phenotypes, although metabolically healthy obese women reported higher sleep duration than at risk obese women.

CONCLUSIONS

These results do not support hypotheses that diet composition and/or physical activity account for the absence of cardiometabolic abnormalities in metabolically healthy obese.

Relationship between waist circumference, visceral fat and metabolic syndrome in a Congolese community: further research is still to be undertaken

Introduction

The criteria of positivity of waist circumference to define the metabolic syndrome as currently recommended for the population of sub-Saharan Africa do not take into account specific ethnic or regional variation.

Methods

The predictive value of different values of waist circumference compared with visceral fat as determined by OMRON BF510 body composition in 360 indigenous patients from Bukavu city between June 1, 2010 and May 30, 2011 was studied.

Results

The prevalence was higher in women for enlarged waist circumference according to the pathological IDF or NCEP / ATP III threshold (p < 0.0001) contrasting with lower rates for pathological accumulation of visceral fat in men (p = 0.0001). The highest values for sensitivity and specificity were obtained for a threshold value of 95 cm for men (sensitivity = 72.4%, specificity = 91.1%, area under the curve (99% CI) = 0.899 (0.833 to 0.965)) and 99 cm in women (sensitivity = 75.0%, specificity = 78.3%, AUC (99% CI) = 0.844 (0.777 to 0.911)). This test also showed an independent effect on the probability of accumulation of visceral fat (Odd adjusted OR = 5.0 (99% CI: 2.1 to 11.7), p <0.0001).

Conclusion

The threshold value for pathological waist circumference currently used for black African populations may overpredict abdominal fat excess in women. Further studies are needed to provide adequate cutoffs in sub-Saharan populations.

Physical activity and screen time in metabolically healthy obese phenotypes in adolescents and adults

INTRODUCTION

The purpose of this study was to examine levels of physical activity (PA) and screen time (ST) in metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) adolescents and adults.

METHODS

NHANES data from obese adolescents (12-18 years, BMI z-score ≥ 95th percentile) and adults (19-85 years, BMI ≥ 30 kg/m(2)) were pooled from 2003-2005 cycles. Metabolic phenotypes were categorized as MHO (0 or 1 cardiometabolic risk factor; triglycerides, HDL-C, blood pressure, or glucose) or MUO (≥2 cardiometabolic risk factors). Logistic regression models estimated associations between phenotype and PA/ST adjusted for age, gender, BMI, race/ethnicity, menopausal status, and NHANES cycle.

RESULTS

Among adolescents, PA was not associated with MHO. In contrast, MHO adults 19-44 years were 85% more likely to engage in active transportation and 2.7 times more likely to be involved in light intensity usual daily activity versus sitting. For each minute per day, adults 45-85 years were 36% more likely to have the MHO phenotype with higher levels of moderate PA. ST was not associated with metabolic phenotypes in adolescents or adults.

CONCLUSION

The current study provides evidence that PA, but not ST, differs between MHO and MUO in adults, but not in adolescents. Future studies are needed to confirm results.