Are metabolically healthy obese individuals really healthy?

Metabolically healthy obesity: a friend or foe?

Obesity is associated with a reduced life expectancy, largely because obese individuals are at an increased risk of type 2 diabetes, cardiovascular disease, and several types of cancer. Much interest has recently focused on the concept of "all obesity is not created equally." Obese individuals without the metabolic abnormalities that commonly accompany excess adiposity, a condition known as metabolically healthy obesity (MHO), account for a substantial proportion of the obese adult population. Numerous possible mechanisms underlying MHO have been suggested, including adipose tissue distribution and inflammation. However, the prognostic value of MHO is controversial and considerably challenging. The lack of a standard definition for metabolic health and obesity as well as the dynamic properties of MHO may have contributed to these inconsistent results. This review aimed to present several current issues regarding MHO including its definition, epidemiology, natural course, suggested mechanisms, and clinical implications in the context of patient prognosis.

Metabolically Healthy Obesity and Ischemic Heart Disease: A 10-Year Follow-Up of the Inter99 Study

CONTEXT

Recent studies have suggested that a subgroup of obese individuals is not at increased risk of obesity-related complications. This subgroup has been referred to as metabolically healthy obese.

OBJECTIVE

To investigate whether obesity is a risk factor for development of ischemic heart disease (IHD) irrespective of metabolic health.

DESIGN

In all, 6238 men and women from the Danish prospective Inter99 study were followed during 10.6 (standard deviation = 1.7) years.

SETTING

General community.

PARTICIPANTS

Participants were classified according to body mass index and four metabolic risk factors (low high-density lipoprotein cholesterol, elevated blood pressure, triglycerides, and fasting plasma glucose). Metabolically healthy individuals were defined as having no metabolic risk factors, and metabolically unhealthy individuals were defined as having a minimum of one.

MAIN OUTCOME MEASURES

IHD.

RESULTS

During follow-up, 323 participants developed IHD. Metabolically healthy obese men had increased risk of IHD compared with metabolically healthy normal-weight men [hazard ratio (HR), 3.1; 95% confidence interval (CI), 1.1 to 8.2)]. The corresponding results for women were less pronounced (HR, 1.8; 95% CI, 0.7 to 4.8). Being metabolically healthy but overweight was not associated with higher risk of IHD in men (HR, 1.1; 95% CI, 0.5 to 2.4), and in women the risk was only slightly increased and insignificant (HR, 1.5; 95% CI, 0.8 to 3.0). A substantial proportion of metabolically healthy individuals became metabolically unhealthy after 5 years of follow-up. When these changes in exposure status were taken into account, slightly higher risk estimates were found.

CONCLUSIONS

Being obese is associated with higher incidence of IHD irrespective of metabolic status, and we question the feasibility of denoting a subgroup of obese individuals as metabolically healthy.

Association between metabolically healthy central obesity in women and levels of soluble receptor for advanced glycation end products, soluble vascular adhesion protein-1, and the activity of semicarbazide-sensitive amine oxidase

AIM

To determine the levels of circulating soluble receptor for advanced glycation end products (sRAGE), as a biomarker of risk of metabolic syndrome and cardiovascular disease development in centrally obese (CO) women considered metabolically healthy (COH) in comparison with those metabolically unhealthy (COU).

METHODS

47 lean healthy, 17 COH (presenting waist-to-height ratio ≥0.5 but not elevated blood pressure, atherogenic lipid profile, and insulin resistance), and 50 COU (CO presenting ≥2 risk factors) women aged 40-45 years were included. Anthropometric characteristics, blood chemistry and hematology data, adipokines, markers of inflammation, sRAGE, soluble vascular adhesion protein-1 (sVAP-1), and the activity of semicarbazide sensitive amine oxidase (SSAO) were determined.

RESULTS

Central obesity associated with low sRAGE levels (lean healthy: 1503±633 pg/mL; COH: 1103±339 pg/mL, P<0.05; COU: 1106±367 ng/mL, P<0.0.1), hyperleptinemia, and elevated markers of inflammation irrespective of the presence or absence of cardiometabolic risk factors. COU women presented high adiponectin levels. SVAP-1 concentrations and the activity of SSAO were similar in all 3 groups.

CONCLUSION

COH women present abnormalities in non-standard markers of cardiometabolic risk (sRAGE, leptin, high sensitive C-reactive protein), supporting the view that there is no healthy pattern of obesity. The clinical impact of our findings for future prognosis of metabolically healthy obese subjects remains to be elucidated in longitudinal studies.

Functional Significance and Predictive Value of MicroRNAs in Pediatric Obesity: Tiny Molecules with Huge Impact?

Obesity is a major health concern. While some children develop comorbidities such as insulin resistance and low-grade systemic inflammation upon weight gain, others stay metabolically healthy. There is an urgent need for clinically relevant markers with prognostic value related to disease development and intervention success. MicroRNAs (miRNAs) are established biomarkers for several disease states. Herein, we give a brief overview of miRNA biogenesis and function and the potential role of circulating miRNA in the context of pediatric obesity.

Risk of all-cause mortality in abdominal obesity phenotypes: Tehran Lipid and Glucose Study

BACKGROUND AND AIM

Long-term health risks in the so-called "healthy obesity" phenotypes remain controversial. Also it is unknown if "metabolically healthy abdominal obese" (MHAO) phenotype is at increased risk of all-cause mortality compared to their non-abdominally obese counterparts. In this study we assessed the risk of all-cause mortality in different abdominal obesity phenotypes.

METHODS AND RESULTS

In this large population-based cohort, 8804 participants (aged ≥ 30 years), from the Tehran Lipid and Glucose Study (TLGS) were enrolled and followed for a median of 12.0 (8.7-12.5) years. Abdominal obesity was defined using national waist circumference (WC) cut-off points of ≥89 cm for men and ≥91 cm for women. Metabolic health was defined as ≤1 components of metabolic syndrome (excluding WC), using the Joint Interim Statement (JIS) definition. Baseline prevalence of MHAO phenotype was 12.8% in the whole population and 23.4% in those with abdominal obesity. A total of 540 all-cause death occurred during the follow-up. After multivariate adjustment, all-cause mortality risk in MHAO phenotype was not significantly increased compared to "metabolically healthy non abdominal obese" (MHNAO) as the reference group (HR: 1.35, CI: 0.89-2.03).

CONCLUSION

Our results indicate that MHAO individuals were not at higher risk for all-cause mortality over a median of 12 years follow-up. However, considering inadequate power of our analysis for fully adjusted model, larger studies with more follow-ups are needed.

4-hydroxynonenal causes impairment of human subcutaneous adipogenesis and induction of adipocyte insulin resistance

OBJECTIVE

Increased adipose production of 4-hydroxynonenal (4-HNE), a bioreactive aldehyde, directly correlates with obesity and insulin resistance. The aim of this study was to elucidate the impact of 4-HNE in mediating adipocyte differentiation and function in two metabolically distinct obese groups; the insulin sensitive (IS) and the insulin resistant (IR).

METHODS

Subcutaneous (SC) adipose tissues were obtained from eighteen clinically well characterized obese premenopausal women undergoing weight reduction surgery. Cellular distribution of 4-HNE in the form of protein adducts was determined by immunohistochemistry in addition to its effect on oxidative stress, cell growth, adipogenic capacity and insulin signaling in preadipocytes derived from the IS and IR participants.

RESULTS

4-HNE was detected in the SC adipose tissue in different cell types with the highest level detected in adipocytes and blood vessels. Short and long-term in vitro treatment of SC preadipocytes with 4-HNE caused inhibition of their growth and increased production of reactive oxygen species (ROS) and antioxidant enzymes. Repeated 4-HNE treatment led to a greater reduction in the adipogenic capacity of preadipocytes from IS subjects compared to IR and caused dephosphorylation of IRS-1 and p70S6K while activating GSK3α/β and BAD, triggering an IR phenotype.

CONCLUSION

These data suggest that 4-HNE-induced oxidative stress plays a role in the regulation of preadipocyte growth, differentiation and insulin signaling and may therefore contribute to adipose tissue metabolic dysfunction associated with insulin resistance.

The Metabolic Phenotype in Obesity: Fat Mass, Body Fat Distribution, and Adipose Tissue Function

The current obesity epidemic poses a major public health issue since obesity predisposes towards several chronic diseases. BMI and total adiposity are positively correlated with cardiometabolic disease risk at the population level. However, body fat distribution and an impaired adipose tissue function, rather than total fat mass, better predict insulin resistance and related complications at the individual level. Adipose tissue dysfunction is determined by an impaired adipose tissue expandability, adipocyte hypertrophy, altered lipid metabolism, and local inflammation. Recent human studies suggest that adipose tissue oxygenation may be a key factor herein. A subgroup of obese individuals - the 'metabolically healthy obese' (MHO) - have a better adipose tissue function, less ectopic fat storage, and are more insulin sensitive than obese metabolically unhealthy persons, emphasizing the central role of adipose tissue function in metabolic health. However, controversy has surrounded the idea that metabolically healthy obesity may be considered really healthy since MHO individuals are at increased (cardio)metabolic disease risk and may have a lower quality of life than normal weight subjects due to other comorbidities. Detailed metabolic phenotyping of obese persons will be invaluable in understanding the pathophysiology of metabolic disturbances, and is needed to identify high-risk individuals or subgroups, thereby paving the way for optimization of prevention and treatment strategies to combat cardiometabolic diseases.

Are all metabolically healthy individuals with obesity at the same risk of diabetes onset?

OBJECTIVE

To examine the risk of diabetes and the development of an unhealthy status according to metabolic health. To assess the effect of changes in metabolic health among participants with metabolically healthy obesity (MHO) on the risk of diabetes.

METHODS

A total of 4,340 subjects were included. Unhealthy metabolic status was defined as having three or more risk factors of the Adult Treatment Panel-III criteria. A Cox proportional-hazard analysis was conducted to estimate the hazard ratio (HR) of developing diabetes across the change in the metabolic status of subjects with MHO.

RESULTS

After 40,622 person-years of follow-up, the risk of becoming unhealthy was 1.53 times higher for participants with MHO, compared with lean or overweight healthy subjects. A greater risk of diabetes was found in MHO, but it was attributable to those who progressed to an unhealthier status over time: HR of 4.78 (95% CI: 3.38-6.78). The combination of being metabolically unhealthy and obesity heightened the risk of diabetes: HR of 10.09 (95% CI: 4.82-21.55).

CONCLUSIONS

The increased risk of diabetes in MHO is attributed to the progression to an unhealthier state. "Healthy obesity" is not a permanent situation but a transitory state.

Metabolic Health in Relation to Body Size: Changes in Prevalence over Time between 1997-99 and 2008-11 in Germany

OBJECTIVE

The study examined potential changes in the proportion of metabolic health according to body size categories over time and across strata of sex and age, varying definitions of metabolic health.

METHODS

We analysed data from national health interview and examination surveys 1997-99 and 2008-11 for adults aged 18-79 years (GNHIES98: N = 6,565; DEGS1: 6,860). Metabolic health as defined by ATPIII criteria was examined across body mass index categories. The Plourde and Karelis criteria were applied in relation to abdominal obesity.

RESULTS

Proportions of adults with metabolic health by body size categories were largely stable over time, except for an increasing proportion of metabolically healthy persons with pre-obesity and metabolically healthy women without abdominal obesity. In both surveys proportions of adults meeting ATPIII criteria ranged from approximately 30% among men and women with obesity, to about two thirds of those with pre-obesity to about 93% among those with normal weight. According to Plourde and Karelis criteria proportions ranged from almost 30% among men and women without abdominal obesity to less than 10% among those with abdominal obesity. Proportions were consistently higher among younger than older age groups and less consistently higher among women than men.

CONCLUSIONS

Proportions of adults with metabolic health by body size categories were largely stable over time, except for an increasing proportion of metabolically healthy women without abdominal obesity. There is no evidence that metabolic health among adults with obesity increased in Germany over a period of ten years.

Insulin-sensitive adiposity is associated with a relatively lower risk of diabetes than insulin-resistant adiposity: the Bogalusa Heart Study

Obesity and insulin resistance are both closely associated with type 2 diabetes mellitus (T2DM). It is, however, not clear whether the role of obesity in the development of T2DM is dependent on insulin resistance. This study aims to assess the hypothesis that insulin-sensitive adiposity is associated with a relatively lower risk of T2DM than insulin-resistant adiposity, and the adiposity-T2DM association is modified by insulin resistance in middle-aged black and white adults. The longitudinal study cohort consisted of 1588 middle-aged normoglycemic black and white adults aged 18-44 years at baseline who were followed for 16 years on average. Overweight/obesity at baseline was defined as BMI ≥25, and insulin resistance was measured using the homeostasis model assessment of insulin resistance (HOMA). The prevalence of incident pre-diabetes and T2DM was compared between the insulin-sensitive and insulin-resistant adiposity groups. The prevalence of both incident pre-diabetes and T2DM was higher in the insulin-resistant adiposity than in the insulin-sensitive adiposity group (11.5 vs. 7.5 %, p = 0.023 for pre-diabetes; 16.7 vs. 2.7 %, p < 0.001 for T2DM). In multivariable logistic analyses, adjusted for baseline age, race, sex, follow-up years, and smoking, baseline insulin-resistant obesity was associated with incident pre-diabetes (odds ratio, OR = 2.07, p = 0.046) and T2DM (OR = 8.19, p < 0.001). ORs did not differ between blacks and whites. The ORs for the association of BMI with pre-diabetes and T2DM significantly increased across increasing quartiles of baseline HOMA (p for trend = 0.032 for pre-diabetes and <0.001 for T2DM). Slopes of increasing follow-up glucose with baseline BMI, measured as regression coefficients (β), were significantly greater in insulin-resistant than in insulin-sensitive individuals (β = 0.86 vs. 0.38, p = 0.009 for difference in slopes). These findings suggest that insulin resistance amplifies the obesity-diabetes association and underscore the importance of preventing both adiposity and insulin resistance in young adults.

From the BMI paradox to the obesity paradox: the obesity-mortality association in coronary heart disease

Despite a strong association between body weight and mortality in the general population, clinical evidence suggests better clinical outcome of overweight or obese individuals with established coronary heart disease. This finding has been termed the 'obesity paradox', but its existence remains a point of debate, because it is mostly observed when body mass index (BMI) is used to define obesity. Inherent limitations of BMI as an index of adiposity, as well as methodological biases and the presence of confounding factors, may account for the observed findings of clinical studies. In this review, our aim is to present the data that support the presence of a BMI paradox in coronary heart disease and then explore whether next to a BMI paradox a true obesity paradox exists as well. We conclude by attempting to link the obesity paradox notion to available translational research data supporting a 'healthy', protective adipose tissue phenotype. © 2016 World Obesity.

Phenotypes of prediabetes and stratification of cardiometabolic risk

Prediabetes is associated with increased risks of type 2 diabetes, cardiovascular disease, dementia, and cancer, and its prevalence is increasing worldwide. Lifestyle and pharmacological interventions in people with prediabetes can prevent the development of diabetes and possibly cardiovascular disease. However, prediabetes is a highly heterogeneous metabolic state, both with respect to its pathogenesis and prediction of disease. Improved understanding of these features and precise phenotyping of prediabetes could help to improve stratification of disease risk. In this Personal View, we focus on the extreme metabolic phenotypes of metabolically healthy obesity and metabolically unhealthy normal weight, insulin secretion failure, insulin resistance, visceral obesity, and non-alcoholic fatty liver disease. We present new analyses aimed at improving characterisation of phenotypes in lean, overweight, and obese people with prediabetes. We discuss evidence from lifestyle intervention studies to explore whether these phenotypes can also be used for individualised prediction and prevention of cardiometabolic diseases.

Does metabolic health in overweight and obesity persist? - Individual variation and cardiovascular mortality over two decades

OBJECTIVE

Overweight and obese individuals may be metabolically healthy, but attention needs to be given to long-term persistence of this trait and any associated variation in cardiovascular risk.

DESIGN

Cross-sectional and longitudinal variation in metabolic health and associated cardiovascular mortality were analysed in 1099 white European-origin normal-weight and overweight or obese males followed for 20years.

METHODS

Definitions of metabolic health were based on LDL and HDL cholesterol, triglycerides, blood pressure, fasting glucose and cardiovascular risk. Insulin resistance (e.g. HOMA-IR) and sub-clinical inflammation (ESR and white blood cell count) were explored. Cardiovascular mortality risks and persistence of metabolic health status were evaluated.

RESULTS

There were 87 cardiovascular deaths. Insulin resistance was increased in metabolically healthy overweight or obese participants (median HOMA-IR 2.63, 95% CI: 1.79-3.65, P<0.001) relative to normal-weight participants (median HOMA-IR 1.67, 95% CI: 1.08-2.67, P<0.001) as was sub-clinical inflammation but metabolically healthy overweight or obese individuals were not at increased risk of cardiovascular mortality compared with the metabolically healthy normal-weight individuals (hazard ratio 1.13, 95% CI: 0.34-3.72, P=0.8). The proportions of initially metabolically healthy overweight or obese who remained metabolically healthy for visits 2, 3 and 4 were 54, 48 and 39% respectively, and for initially normal-weight individuals, 68, 51 and 41%. A lower proportion of metabolically healthy overweight or obese individuals remained metabolically healthy at visit 2 compared with normal-weight individuals (P=0.007), but proportions converged thereafter.

CONCLUSIONS

Despite being insulin resistant and having greater sub-clinical inflammation, and despite instability in metabolic health status, metabolically healthy overweight or obese individuals were at no greater risk of cardiovascular mortality than their normal-weight equivalents.

Metabolically Healthy Overweight and Obesity Is Associated with Higher Adherence to a Traditional Dietary Pattern: A Cross-Sectional Study among Adults in Lebanon

This study aimed to examine the proportion and socio-demographic correlates of Metabolically Healthy Overweight and Obesity (MHOv/O) among Lebanese adults and to investigate the independent effect of previously identified dietary patterns on odds of MHOv/O. Data were drawn from the National Nutrition and Non-Communicable Disease Risk Factor Survey (Lebanon 2008-2009). Out of the 337 adult participants who had complete socio-demographic, lifestyle, dietary as well as anthropometric and biochemical data, 196 had a BMI ≥ 25 kg/m² and their data were included in this study. MHOv/O was identified using the Adult Treatment Panel criteria. Dietary patterns previously derived in this study population were: Fast Food/Dessert, Traditional-Lebanese and High-Protein. The proportion of MHOv/O in the study sample was 37.2%. Females, higher education and high level of physical activity were positively associated with odds of MHOv/O. Subjects with higher adherence to the Traditional-Lebanese pattern had higher odds of MHOv/O (OR: 1.83, 95% CI: 1.09-3.91). No significant associations were observed between the Fast Food/Dessert and the high-protein patterns with MHOv/O. Follow-up studies are needed to confirm those findings and understand the mechanisms by which the Traditional-Lebanese pattern may exert a protective effect in this subgroup of overweight and obese adults.

A short leucocyte telomere length is associated with development of insulin resistance

AIMS/HYPOTHESIS

A number of studies have shown that leucocyte telomere length (LTL) is inversely associated with insulin resistance and type 2 diabetes mellitus. The aim of the present longitudinal cohort study, utilising a twin design, was to assess whether shorter LTL predicts insulin resistance or is a consequence thereof.

METHODS

Participants were recruited between 1997 and 2000 through the population-based national Danish Twin Registry to participate in the GEMINAKAR study, a longitudinal evaluation of metabolic disorders and cardiovascular risk factors. Baseline and follow-up measurements of LTL and insulin resistance over an average of 12 years were performed in a subset of the Registry consisting of 338 (184 monozygotic and 154 dizygotic) same-sex twin pairs.

RESULTS

Age at baseline examination was 37.4 ± 9.6 (mean ± SD) years. Baseline insulin resistance was not associated with age-dependent changes in LTL (attrition) over the follow-up period, whereas baseline LTL was associated with changes in insulin resistance during this period. The shorter the LTL at baseline, the more pronounced was the increase in insulin resistance over the follow-up period (p < 0.001); this effect was additive to that of BMI. The co-twin with the shorter baseline LTL displayed higher insulin resistance at follow-up than the co-twin with the longer LTL.

CONCLUSIONS/INTERPRETATION

These findings suggest that individuals with short LTL are more likely to develop insulin resistance later in life. By contrast, presence of insulin resistance does not accelerate LTL attrition.

Obesity as a Disease: Current Policies and Implications for the Future

The recognition of obesity as a chronic disease is increasing. However, there is variable acknowledgment of it as a disease in health policies across the USA. The objective of this review is to describe how obesity meets the definition of a disease, explain its interpretation in current health policies, and explore implications for obesity in future health policy adoption and development. Perspectives are presented from scientific evidence, clinical practice, and health policy areas including Medicare, Medicaid, the Affordable Care Act, federal government agency guidance, and healthcare quality.

Proinflammatory and lipid biomarkers mediate metabolically healthy obesity: A proteomics study

OBJECTIVE

The metabolically healthy obesity (MHO) phenotype is an important obesity subtype in which obesity is not accompanied by any metabolic comorbidity. However, the underlying molecular mechanisms remain elusive. In this study, a shotgun proteomics approach to identify circulating biomolecules and pathways associated with MHO was used.

METHODS

The subjects were 20 African-American women: 10 MHO cases and 10 metabolically abnormal individuals with obesity (MAO) controls. Serum proteins were detected and quantified using label-free proteomics. Differential expression of proteins between the two groups was analyzed, and the list of differentially expressed proteins was analyzed to determine enriched biological pathways.

RESULTS

Twenty proteins were differentially expressed between MHO and controls. These proteins included: hemoglobin subunits (HBA1, P = 6.00 × 10(-18) ), haptoglobin-related protein (HPR, P = 1.2 × 10(-15) ), apolipoproteins (APOB-100, P = 1.50 × 10(-40) ; APOA4, P = 1.1 × 10(-14) ), retinol-binding protein 4 (RBP4, P = 7.1 × 10(-08) ), and CRP (P = 2.0 × 10(-04) ). MHO was associated with lower levels of proinflammatory and higher levels of anti-inflammatory biomarkers when compared with MAO. Pathway analysis showed enrichment of lipids and inflammatory pathways, including LXR/RXR and FXR/RXR activation, and acute phase response signaling.

CONCLUSIONS

These findings suggested that protection from dysregulated inflammatory and lipid processes were primary molecular hallmarks of MHO. The candidate biomarkers (AHSG, RBP4, and APOA4) identified in this study are potential prognostic markers for MHO.

Obesity or obesities? Controversies on the association between body mass index and premature mortality

Obesity is still defined on the basis of body mass index (BMI) and BMI in itself is generally accepted as a strong predictor of overall early mortality. However, an inverse association between BMI and mortality has been reported in patients with many disease states and in several clinical settings: hemodialysis, cardiovascular diseases, hypertension, stroke, diabetes, chronic obstructive pulmonary disease, surgery, etc. This unexpected phenomenon is usually called obesity-survival paradox (OP). The contiguous concepts of metabolically healthy obesity (MHO, a phenotype having BMI ≥ 30 but not having any metabolic syndrome component and having a homeostasis model assessment of insulin resistance, HOMA, <2.5) and metabolically obese normal weight (MONW, normal-weight individuals displaying obesity-related phenotypic characteristics) have received a great deal of attention in recent years. The interactions that link MHO, MONW and OP with body composition, fat distribution, aging and cardiorespiratory fitness are other crucial areas of research. The article is an introductory narrative overview of the origin and current use of the concepts of MHO, MONW and OP. These phenomena are very controversial and appear as a consequence of the frail current diagnostic definition of obesity based only on BMI. A new commonly established characterization and classification of obesities based on a number of variables is needed urgently.

Epidemiology of Obesity and Diabetes and Their Cardiovascular Complications

Obesity and diabetes mellitus have reached epidemic proportions in the past few years. During 2011 to 2012, more than one-third of the US population was obese. Although recent trend data indicate that the epidemic has leveled off, prevalence of abdominal obesity continues to rise, especially among adults. As seen for obesity, the past few decades have seen a doubling of the diabetes mellitus incidence with an increasing number of type 2 diabetes mellitus cases being diagnosed in children. Significant racial and ethnic disparities exist in the prevalence and trends of obesity and diabetes mellitus. In general, in both adults and children, non-Hispanic blacks and Mexican Americans seem to be at a high risk than their non-Hispanic white counterparts. Secular changes in agricultural policies, diet, food environment, physical activity, and sleep have all contributed to the upward trends in the diabesity epidemic. Despite marginal improvements in physical activity and the US diet, the food environment has changed drastically to an obesogenic one with increased portion sizes and limited access to healthy food choices especially for disadvantaged populations. Interventions that improve the food environment are critical as both obesity and diabetes mellitus raise the risk of cardiovascular disease by ≈2-fold. Among those with type 2 diabetes mellitus, significant sex differences occur in the risk of cardiovascular disease such that diabetes mellitus completely eliminates or attenuates the advantages of being female. Given the substantial burden of obesity and diabetes mellitus, future research efforts should adopt a translational approach to find sustainable and holistic solutions in preventing these costly diseases.

Attenuated atrial natriuretic peptide-mediated lipolysis in subcutaneous adipocytes of obese type 2 diabetic men

Subjects with obesity seem to display a suboptimal exercise response, which might be due to hormonal disturbances. In the present study, we show the adipose tissue of obese subjects to be less sensitive to atrial natriuretic peptide, a cardiac hormone important during exercise.

Classification and clinical characterization of metabolically "healthy" obese children and adolescents

BACKGROUND

Some obese children do not show cardiometabolic complications such as prediabetes, dyslipidemia or insulin resistance. The objective of the study was to classify obese children and adolescents as metabolically "healthy" obese (MHO) on the basis of three different definitions, and to compare cardiometabolic features with metabolically unhealthy obese (MUO) children and adolescents.

METHODS

The study included 156 obese children and adolescents aged between 10 and 18. Subjects were classified as MHO or MUO using three definitions based on the: (1) pediatric International Diabetes Federation (IDF) criteria; (2) homeostatic model assessment of insulin resistance (HOMA-IR); (3) combination of the previous two definitions. Cardiometabolic features were compared between MHO and MUO subjects.

RESULTS

Six to 19% obese children and adolescents were classified as MHO, and showed a better insulin sensitivity, lower prevalence of prediabetes, lower triglycerides and lower triglyceride-to-HDL-C ratio compared to MUO.

CONCLUSIONS

Less than 20% obese children and adolescents are identified as MHO and show a healthier cardiometabolic profile as compared to MUO. Implementation of the proposed classifications in future clinical research could contribute towards the standardization of the MHO definition and offer new insights into the manifestation of the pediatric MHO phenotype.

Metabolically healthy obesity also has risk for hyperuricemia among Chinese general population: A cross-sectional study

INTRODUCTION

The metabolically healthy obese (MHO) refers to obese individuals with a favorable metabolic profile. It is unknown whether metabolically healthy status in persons with obesity or overweight decreases the risk of hyperuricemia. This study aims to explore the association of MHO with risk of hyperuricemia.

METHODS

We performed a cross-sectional study including 11,435 (5300 men and 6135 women) general population aged ≥35 years in Liaoning Province. Anthropometric measurements, laboratory examinations and self-reported information on lifestyle factors were collected by trained personnel. Metabolically healthy overweight/obesity was defined according to body mass index and ATP-III criterion of metabolically healthy status. Hyperuricemia was defined as SUA ≥7mg/dl (420mmol/L) in men or ≥6mg/dl (360mmol/L) in women. Logistic regression analyses were performed to explore the association between overweight/obesity with different metabolic status and risk of hyperuricemia.

RESULTS

Among total subjects, 470 (4.2%) were metabolically healthy obese (MHO) and 1567 (14.0%) were metabolically unhealthy obese (MUO). For metabolically healthy female participants, the prevalence of hyperuricemia with overweight was similar to with a normal BMI (2.5% vs. 3.1%, P=0.314). Multivariate logistic regression analyses showed that MHO (OR=2.48, 95% CI: 1.81-3.41) and MUO (OR=4.81, 95% CI: 3.97-5.83) were significantly associated with hyperuricemia. However, the odds ratio in females with metabolically healthy overweight was 0.85 (95% CI: 0.53-1.37).

CONCLUSIONS

Metabolically healthy might decline the risk of hyperuricemia, but overweight and obesity with metabolically healthy had also strong associations with hyperuricemia, except in females with metabolically healthy overweight.

The normal-weight type 2 diabetes phenotype revisited

BACKGROUND

Type 2 diabetes (T2DM) is associated with obesity, insulin resistance and the metabolic syndrome (MetS). In non-diabetic populations, features of metabolic obesity (MO) are observed in a minority of normal-weight (NW) subjects. The cardiometabolic status of metabolically obese but normal-weight (MONW) individuals has not yet been phenotyped in T2DM.

PATIENTS AND METHODS

Prevalence and features of MONW were analyzed in 1244 T2DM patients, in whom MONW was identified as a BMI <25.0 and a MetS score ≥3/5. Among NW (n=262; 21%), those without MetS (n=152; NW-MetS[-]) were compared to NW-MetS[+] (n=110; i.e. 42% of NW and 9% of all T2DM).

RESULTS

There were no differences between groups in age; gender; diabetes duration; smoking; BP; and LDL-C. NW-MetS[+] had higher BMI; waist; fat mass; visceral fat; liver steatosis and HbA1c, and lower insulin sensitivity. Non-right-handedness was twice-higher (18%) in NW-MetS[-]. NW-MetS[+] had higher apoB100 and triglycerides, and lower HDL-C and LDL size. Macroangiopathy was present in 39% of NW-MetS[+] vs. 22% of NW-MetS[-], as coronary (23% vs. 14%) or peripheral artery disease (14% vs. 5%) and TIA/stroke (15% vs. 7%). Microangiopathy was present in 54% of NW-MetS[+] vs. 32% of NW-MetS[-], as retinopathy (25% vs. 13%); neuropathy (29% vs. 18%); and albuminuria (39% vs. 20%).

CONCLUSIONS

MONW among T2DM represents a significant minority (about 1 in 10). Their cardiometabolic phenotype deserves attention due to multiple comorbidities, including a twice-higher prevalence of micro-/macrovascular damage in patients wrongly perceived at lower risk due to normal BMI. Unexpectedly, non-right-handedness was over-represented among metabolically healthy patients.

Risk of diabetes in combined metabolic abnormalities and body mass index categories

AIM

The present study was designed to estimate the progression rates from combination of normal weight, overweight, obesity, and number of metabolic abnormalities (MA) to type 2 diabetes (T2D) in a non-diabetic high risk population in Isfahan, Iran.

METHODS

A total of 1869 non-diabetic first-degree relatives (FDR) of patients with T2D 30-70 years old were examined and followed for a mean (SD) of 7.3 (2.2) years for T2D incidence. At baseline and through follow-up, participants underwent a standard 75-g 2-h oral glucose tolerance test.

RESULTS

The metabolically healthy overweight and obese at baseline were associated with incidence of T2D, independently of age and gender. Any one MA increased the risk of developing T2D among normal weight, overweight and obese individuals. Those with normal weight and ≥3 MA were over 20 times (odds ratios (OR) 20.21; 95% confidence intervals (CI) 2.4, 170.4) and those with overweight and ≥3 MA 22.5 times (OR 22.5; 95% CI 3.0, 167.0) and obese with ≥3 MA were 25.4 times (OR 25.4; 95% CI 3.4, 187) more likely to develop T2D than those with normal weight and without MA. Compared with participants without MA, obese individuals with concomitant MA were not significantly more likely to progress to T2D.

CONCLUSION

Our data provide further evidence that normal weight, overweight and obese individuals with MA had a higher risk of incident T2D than normal weight individuals without MA.

Obesity, metabolic abnormality, and health-related quality of life by gender: a cross-sectional study in Korean adults

PURPOSE

This study sought to compare the association between health-related quality of life (HRQoL) and four body health types by gender.

METHODS

The study included 6217 men and 8243 women over 30 years of age chosen from a population-based survey. Participants were grouped by body mass index and metabolic abnormality into four types: metabolically healthy normal weight, metabolically abnormal but normal weight (MANW), metabolically healthy obesity (MHO), and metabolically abnormal obesity (MAO). HRQoL was measured using the EQ-5D health questionnaire. The outcomes encompassed five dimensions (mobility, self-care, usual activity, pain/discomfort, and anxiety/depression), and the impaired HRQoL dichotomized by the EQ-5D preference score. Complex sample multivariate binary logistic regression analyses were conducted to adjust for sociodemographic variables, lifestyle factors, and disease comorbidity.

RESULTS

Among men, those in the MANW group presented worse conditions on all dimensions and the impaired HRQoL compared to other men. However, no significant effect remained after adjusting for relevant covariates. For women, those in the MAO group had the most adversely affected HRQoL followed by those females in the MHO group. The domain of mobility and impaired HRQoL variable of the MAO and MHO groups remained significant when controlling for all covariates in the model.

CONCLUSIONS

The MANW is the least favorable condition of HRQoL for men, suggesting that metabolic health may associate with HRQoL more than obesity for males. In women, the MAO and MHO groups had the most adversely affected HRQoL, implying that MHO is not a favorable health condition and that obesity, in general, may be strongly associated with HRQoL in women.

Features of endometrial cancer in patients with 'metabolically healthy' versus 'standard' obesity: the decreasing frequency of metabolically healthy obesity

Background:

As endometrial cancer (EC) prevalence increases with obesity, we aimed to determine whether EC characteristics depend upon obesity type: ‘standard’ (SO) or ‘metabolically healthy obesity’ (MHO).

Patients & methods:

258 EC patients were included. Data on anthropometry, blood hormones, lipids and glucose, and tumor features were collected.

Results:

EC clinicopathologic characteristics and clinical stage correlate differently with BMI and obesity type. BMI is related inversely with tumor grade while SO patients are characterized by a more advanced clinical stage than those with MHO. Besides typical insulin resistance signs, EC patients with SO often display a higher serum leptin/adiponectin ratio compared with MHO patients. Historical data suggest a gradual increase in EC patient height and weight, and a decrease in MHO prevalence.

Conclusion:

It is currently unknown whether the latter observation reflects the evolution of EC, or obesity alongside the current epidemic. Regardless, the reduced MHO prevalence demonstrates the need for more intensive preventive measures aimed at obesity and obesity-associated conditions, including different EC subtypes.

Worldwide prevalence of uterine body or endometrial cancer (EC) has increased notably. Recently, the WHO documented an obesity epidemic in several countries. Concurrently, many studies showed a high (37–66%) obesity rate in EC patients. There is currently no mention of a potentially distinctive correlation of EC with obesity types. In general, these types of obesity can be subdivided into ‘standard’ (SO; with metabolic disturbances, initially with insulin resistance signs) and ‘nonstandard’, or metabolically healthy obesity (MHO; without mentioned disturbances). The present paper concludes, first, that EC patients with SO (especially if BMI is ≥30) generally have more advanced tumor stage than patients with MHO. Second, in an EC group (2012–2014) a decrease in MHO frequency versus 1998–2000 group was observed. Altogether, this underlines the need for additional cancer preventive efforts in the obese female population.

PPP2R5C Couples Hepatic Glucose and Lipid Homeostasis

In mammals, the liver plays a central role in maintaining carbohydrate and lipid homeostasis by acting both as a major source and a major sink of glucose and lipids. In particular, when dietary carbohydrates are in excess, the liver converts them to lipids via de novo lipogenesis. The molecular checkpoints regulating the balance between carbohydrate and lipid homeostasis, however, are not fully understood. Here we identify PPP2R5C, a regulatory subunit of PP2A, as a novel modulator of liver metabolism in postprandial physiology. Inactivation of PPP2R5C in isolated hepatocytes leads to increased glucose uptake and increased de novo lipogenesis. These phenotypes are reiterated in vivo, where hepatocyte specific PPP2R5C knockdown yields mice with improved systemic glucose tolerance and insulin sensitivity, but elevated circulating triglyceride levels. We show that modulation of PPP2R5C levels leads to alterations in AMPK and SREBP-1 activity. We find that hepatic levels of PPP2R5C are elevated in human diabetic patients, and correlate with obesity and insulin resistance in these subjects. In sum, our data suggest that hepatic PPP2R5C represents an important factor in the functional wiring of energy metabolism and the maintenance of a metabolically healthy state.

After a meal, dietary glucose travels through the hepatic portal vein to the liver. A substantial part of this glucose is taken up by liver, which converts it to glycogen which is stored, and lipids which are in part stored and in part secreted as VLDL particles. The rest of the organs receive whatever glucose the liver leaves in circulation, plus the secreted lipids. Hence the liver plays a crucial role in determining the balance of sugar versus lipids in the body after a meal. This balance is very important, because too much glucose in circulation leads to diabetic complications whereas too much VLDL increases risk of atherosclerosis. Little is known about how the liver strikes this balance. We identify here a phosphatase—the PP2A holoenzyme containing the PPP2R5C regulatory subunit—as a regulator of this process. We find that knockdown of PPP2R5C in mouse liver specifically causes it to uptake elevated levels of glucose, and secrete elevated levels of VLDL into circulation. This leads to a phenotype of improved glucose tolerance and insulin sensitivity. The prediction from these functional studies in mice is that elevated levels of PPP2R5C expression should lead to insulin resistance. Indeed, we find that PPP2R5C expression levels are elevated in diabetic patients, or healthy controls with visceral obesity, raising the possibility that dysregulation of PPP2R5C expression in humans may contribute towards metabolic dysfunction.

[Pharmacological therapy versus bariatric surgery for patients with obesity and type 2 diabetes]

There is strong epidemiological evidence for an association between increased body weight and a higher incidence of type 2 diabetes. Moreover, reduction in body weight may delay the onset of type 2 diabetes. The basic therapy of type 2 diabetes includes lifestyle modifications, such as education, nutritional advice, increased physical activity, non-smoking and strategies to cope with stress. If lifestyle modifications are not successful, antidiabetic pharmacotherapy is stepwise intensified to achieve individual therapeutic targets; however, pharmacological treatment of type 2 diabetes frequently fails to prevent the progress of the disease and the manifestation of diabetes complications. Sustained weight reduction belongs to the individual treatment targets for patients with obesity and type 2 diabetes. Because conservative weight reduction strategies are frequently not successful, bariatric surgery has emerged as an effective treatment particularly for those patients with obesity-associated type 2 diabetes in whom a glycosylated hemoglobin (HbA1c) target < 7.5% could not be achieved with pharmacological therapy. Bariatric surgery should no longer be considered as the last option for patients with obesity-associated type 2 diabetes.

Biology of upper-body and lower-body adipose tissue--link to whole-body phenotypes

The distribution of adipose tissue in the body has wide-ranging and reproducible associations with health and disease. Accumulation of adipose tissue in the upper body (abdominal obesity) is associated with the development of cardiovascular disease, insulin resistance, type 2 diabetes mellitus and even all-cause mortality. Conversely, accumulation of fat in the lower body (gluteofemoral obesity) shows opposite associations with cardiovascular disease and type 2 diabetes mellitus when adjusted for overall fat mass. The abdominal depots are characterized by rapid uptake of predominantly diet-derived fat and a high lipid turnover that is easily stimulated by adrenergic receptor activation. The lower-body fat stores have a reduced lipid turnover with a capacity to accommodate fat undergoing redistribution. Lower-body adipose tissue also seems to retain the capacity to recruit additional adipocytes as a result of weight gain and demonstrates fewer signs of inflammatory insult. New data suggest that the profound functional differences between the upper-body and lower-body tissues are controlled by site-specific sets of developmental genes, such as HOXA6, HOXA5, HOXA3, IRX2 and TBX5 in subcutaneous abdominal adipose tissue and HOTAIR, SHOX2 and HOXC11 in gluteofemoral adipose tissue, which are under epigenetic control. This Review discusses the developmental and functional differences between upper-body and lower-body fat depots and provides mechanistic insight into the disease-protective effects of lower-body fat.

[Insulin or surgery? : the perspective of a diabetologist]

Obesity significantly increases the risk of developing type 2 diabetes by a factor of up to 9. Medical treatment of type 2 diabetes with lifestyle and pharmacological interventions frequently fails to prevent the progress of the disease and the manifestation of diabetes complications. In recent years bariatric metabolic surgery has emerged as an effective treatment for patients with obesity and type 2 diabetes. Compared to medical treatment alone, metabolic surgery has been shown to be more effective in reducing mortality, improving hyperglycemia, hypertension and dyslipidemia in randomized clinical trials among patients with obesity and type 2 diabetes. However, surgery also has the risk for acute perioperative complications, long-term micronutrient deficiencies and psychological problems. Weighing these risks against the benefits of significant weight loss and improved glycemic control, metabolic surgery seems to be a promising treatment option for obesity-associated type 2 diabetes. However, current guidelines and treatment algorithms for the treatment of type 2 diabetes either ignore or underestimate the potential of metabolic surgery. In my opinion, metabolic surgery should be considered earlier in the treatment of type 2 diabetes and obesity and no longer be considered as the last therapeutic option for patients with obesity-associated type 2 diabetes.