Metabolically healthy obesity and risk of mortality: does the definition of metabolic health matter?

Metabolically-healthy obesity is associated with higher prevalence of colorectal adenoma

Background

The risk of colorectal adenoma (CRA), an important precursor of colorectal cancer, is largely unknown among obese individuals without obesity-related metabolic abnormalities, a condition described as metabolically-healthy obese (MHO). The aim of this study was to examine the association among metabolic status, the different categories of body mass index (BMI), and CRA in a large cohort of adults.

Methods

We analyzed the association among metabolic status, BMI categories and CRA in asymptomatic adults who underwent a first-time colonoscopy as part of the comprehensive health check-up program at the Health Promotion Center of Samsung Medical Center, from January 2005 to December 2012. Being metabolically healthy was defined as lacking any metabolic syndrome components and having a homeostasis model assessment of insulin resistance <2.5.

Results

The prevalence of “any,” “multiple,” and “high-risk” CRA was 25.6%, 8.3%, and 4.4% among 9,182 metabolically-healthy participants, and 35.9%, 12.5%, and 7.0% among 17,407 metabolically-unhealthy participants, respectively. Increased BMI showed a significant dose-dependent relationship with the prevalence of “any,” “multiple,” and “high-risk” CRA, in both metabolically-healthy and unhealthy participants. In multivariable-adjusted models that accounted for potential confounders including age, sex, smoking, alcohol, first-degree family history of colorectal cancer, and aspirin use, the odds ratio (OR) for any CRA comparing MHO with metabolically-healthy normal-weight (MHNW) participants was 1.25 (95% confidence interval (CI), 1.09–1.43). Further adjustment for metabolic components associated with obesity did not significantly change the association. Similarly, the ORs for multiple CRAs and high risk CRA were higher in MHO participants than MHNW participants [ORs (95% CI), 1.63 (1.31–2.04) and 1.53 (1.14–2.04), respectively].

Conclusions

The MHO phenotype was closely associated with higher prevalence of CRA, including high-risk adenoma. This finding supports the conclusion that MHO increases the risk of colorectal cancer.

Physical health-related quality of life in relation to metabolic health and obesity among men and women in Germany

Background

This study examined sex-specific differences in physical health-related quality of life (HRQoL) across subgroups of metabolic health and obesity. We specifically asked whether (1) obesity is related to lower HRQoL independent of metabolic health status and potential confounders, and (2) whether associations are similar in men and women.

Methods

We used cross-sectional data from the German Health Interview and Examination Survey 2008–11. Physical HRQoL was measured using the Short Form-36 version 2 physical component summary (PCS) score. Based on harmonized ATPIII criteria for the definition of the metabolic health and a body mass index ≥ 30 kg/m² to define obesity, individuals were classified as metabolically healthy non-obese (MHNO), metabolically unhealthy non-obese (MUNO), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). Sex-specific analyses including multivariable linear regression analyses were based on PCS as the dependent variable, metabolic health and obesity category as the independent variable with three categories and MHNO as the reference, and age, education, lifestyle and comorbidities as confounders.

Results

This study included 6860 participants (3298 men, 3562 women). Compared to MHNO, all other metabolic health and obesity categories had significantly lower PCS in both sexes. As reflected by the beta coefficients [95% confidence interval] from bivariable linear regression models, a significant inverse association with PCS was strongest for MUO (men: −7.0 [−8.2; −5.8]; women: −9.0 [−10.2; −7.9]), intermediate for MUNO (men: −4.2 [−5.3; −3.1]; women: −5.6 [−6.8; −4.4]) and least pronounced for MHO (men: −2.2 [−3.6; −0.8]; women −3.9 [−5.4; −2.5]). Differences in relation to MHNO remained statistically significant for all groups after adjusting for confounders, but decreased in particular for MUNO (men:–1.3 [−2.3; −0.3]; women: −1.5 [−2.7; −0.3].

Conclusions

Obesity was significantly related to lower physical HRQoL, independent of metabolic health status. Potential confounders including age, educational status, health-related behaviors, and comorbidities explained parts of the inverse relationship. Associations were evident in both sexes and consistently more pronounced among women than men.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-017-0688-7) contains supplementary material, which is available to authorized users.

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.

Fatty liver disease determines the progression of coronary artery calcification in a metabolically healthy obese population

OBJECTIVES

Metabolically healthy obese (MHO) phenotype describes an obese state with a favorable metabolic profile. However, the prognosis of this subpopulation remains controversial. We aimed to examine whether MHO phenotype is associated with progression of atherosclerotic activity, reflected as the changes in coronary artery calcification (CAC) over time. If so, we sought to determine the role of fatty liver disease (FLD), the hallmark of hepatic steatosis, in this progression.

METHODS

We enrolled 1,240 asymptomatic subjects who underwent repeated CAC score measurement during routine health examinations. CAC score progression was defined as either incident CAC in a population free of CAC at baseline, or an increase by ≥2.5 units between the baseline and final square root of CAC scores in participants with detectable CAC at baseline. Subjects were stratified by body mass index (cut-off, 25.0 kg/m2) and metabolic health state using Adult Treatment Panel-III criteria. FLD was assessed via ultrasonography.

RESULTS

Over 2.9 years of follow-up, 25.2% of total subjects exhibited CAC score progression. The MHO phenotype was not significantly associated with CAC score progression (multivariate adjusted-odds ratio [OR], 1.45; 95% confidence interval [CI], 0.93-2.25), as compared to the metabolically healthy non-obese (MHNO) phenotype. However, subgroup analysis indicated that the MHO/FLD phenotype was significantly associated with CAC score progression (multivariate adjusted-OR, 2.37; 95% CI, 1.34-4.16), as compared to the MHNO/no FLD phenotype, whereas the MHO/no FLD phenotype was not (multivariate adjusted OR, 1.25; 95% CI, 0.71-2.24).

CONCLUSIONS

Obese individuals with FLD have an increased risk of atherosclerosis progression, despite their healthy metabolic profile. Preventive interventions targeting cardiometabolic risk factors should be considered in such individuals, regardless of the weight status.

Metabolically healthy obesity and depressive symptoms: 16-year follow-up of the Gazel cohort study

Aims

The health correlates of the metabolically healthy obese (MHO) phenotype, particularly in relation to depressive symptoms remains unclear. Accordingly, we examined the risk of depressive symptoms in this phenotype using a 16-year follow-up prospective study.

Methods

A sample of 14 475 participants (75% men), aged 44–59 years in 1996, was drawn from the Gazel cohort. Obesity was defined as body mass index (BMI) ≥ 30 kg/m² and metabolic health as having none of the self-reported following cardiovascular risk factors: hypertension, type 2 diabetes and dyslipidemia. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression (CES-D) scale in 1996, 1999, 2002, 2005, 2008 and 2012. Generalized Estimating Equations (GEE) were used to estimate the risk of depressive symptoms during a follow-up of 16 years.

Results

In multivariate analyses, metabolically unhealthy normal weight [Odds Ratio (OR) = 1.37; 95% Confidence Interval (CI): 1.25–1.51], overweight [1.44 (1.31–1.59)] and obese [1.30 (1.10–1.54)] but not MHO participants [1.04 (0.81–1.32)] had higher risk of depressive symptoms at the start of follow-up compared to metabolically healthy normal weight individuals. Depressive symptoms decreased over time in metabolically healthy normal weight individuals [0.52 (0.50–0.55)], this decrease was less marked only in metabolically unhealthy obese participants [1.22 (1.07–1.40)]. Compared to MHO participants, metabolically unhealthy obese individuals were at increased risk of depression at the start of follow-up, but with a similar reduction of this risk over time.

Conclusion

Poor metabolic health, irrespective of BMI was associated with greater depressive symptoms at the start of follow-up, whereas a poorer course of depressive symptoms over time was observed only in those with both obesity and poor metabolic health.

The impact of maternal obesity on inflammatory processes and consequences for later offspring health outcomes

Obesity is a global epidemic, affecting both developed and developing countries. The related metabolic consequences that arise from being overweight or obese are a paramount global health concern, and represent a significant burden on healthcare systems. Furthermore, being overweight or obese during pregnancy increases the risk of offspring developing obesity and other related metabolic complications in later life, which can therefore perpetuate a transgenerational cycle of obesity. Obesity is associated with a chronic state of low-grade metabolic inflammation. However, the role of maternal obesity-mediated alterations in inflammatory processes as a mechanism underpinning developmental programming in offspring is less understood. Further, the use of anti-inflammatory agents as an intervention strategy to ameliorate or reverse the impact of adverse developmental programming in the setting of maternal obesity has not been well studied. This review will discuss the impact of maternal obesity on key inflammatory pathways, impact on pregnancy and offspring outcomes, potential mechanisms and avenues for intervention.

Metabolically healthy obesity and incident chronic kidney disease: The role of systemic inflammation in a prospective study

OBJECTIVE

To investigate the association between the metabolically healthy obesity (MHO) phenotype and incident chronic kidney disease (CKD) in a Chinese population and whether systemic inflammation affects this association.

METHODS

A cohort study was performed with 2,491 Chinese adults. Body mass index ≥ 25.0 kg/m² was defined as obesity. CKD was defined as estimated glomerular filtration rate < 60 mL/min per 1.73 m² or urinary albumin-to-creatinine ratio ≥ 30 mg/g. High-sensitivity C-reactive protein (hsCRP) was used as a surrogate marker of systemic inflammation.

RESULTS

Over a median follow-up period of 3.9 years, 243 of 2,491 participants developed incident CKD (9.8%). Compared with metabolically healthy nonobesity (MHNO), MHO was associated with incident CKD (odds ratio [OR] = 1.65, 95% confidence interval [CI] 1.01-2.69), but not after adjustment for hsCRP. The MHO/hsCRP ≥ 0.20 mg/L group, but not the MHO/hsCRP < 0.20 mg/L group, had an increased OR for incident CKD (OR = 2.66, 95% CI 1.37-5.14), with the MHNO/hsCRP < 0.20 mg/L group as the reference.

CONCLUSIONS

MHO was significantly associated with incident CKD, and the level of systemic inflammation partially explained this association.

Prevalence of polycystic ovary syndrome in Chinese obese women of reproductive age with or without metabolic syndrome

OBJECTIVE

To compare the prevalence of polycystic ovary syndrome (PCOS) and related clinical characteristics between metabolically unhealthy obese (MUO) and metabolically healthy obese (MHO) women of reproductive age.

DESIGN

Cross-sectional clinical study.

SETTING

Tertiary hospital.

PATIENT(S)

We studied 299 MUO and 122 MHO Chinese women matched on body mass index. Metabolically healthy obese was defined as obesity with no more than one metabolic abnormality. Diagnosis of PCOS was based on the revised Rotterdam criteria.

INTERVENTION(S)

Each subject underwent physical examination, laboratory evaluation, and gynecologic ultrasound for a diagnosis of PCOS or metabolic syndrome (MetS).

MAIN OUTCOME MEASURE(S)

Prevalence of PCOS was calculated in both groups. Insulin resistance was determined by homeostasis model assessment of insulin resistance or by the insulin sensitivity index derived from Bergman's minimal model. Fat distribution was measured with computerized tomography scan.

RESULT(S)

Prevalence of PCOS and its components did not differ between MUO and BMI-matched MHO groups (67.89% and 66.96%, respectively). In logistic regression analysis, MetS did not predict the presence of PCOS after adjusting for confounding factors. The MHO group had lower visceral adipose tissue, relatively higher insulin sensitivity, and better β-cell function, compared with those in the MUO group; but there were no significant differences in sex hormones (except for free T and sex hormone-binding globulin) and ultrasound manifestations between MHO and MUO women.

CONCLUSION(S)

For the first time, our findings suggest that MetS does not add additional risk for PCOS. In addition, we found that both MUO and MHO are associated with insulin resistance to some extent.

Metabolic Phenotype and Risk of Colorectal Cancer in Normal-Weight Postmenopausal Women

BACKGROUND

The prevalence of metabolically unhealthy phenotype in normal-weight adults is 30%, and few studies have explored the association between metabolic phenotype and colorectal cancer incidence in normal-weight individuals. Our aim was to compare the risk of colorectal cancer in normal-weight postmenopausal women who were characterized by either the metabolically healthy phenotype or the metabolically unhealthy phenotype.

METHODS

A large prospective cohort, the Women's Health Initiative, was used. The analytic sample included 5,068 postmenopausal women with BMI 18.5 to <25 kg/m2 Metabolic phenotype was defined using the Adult Treatment Panel-III definition, excluding waist circumference; therefore, women with one or none of the four components (elevated triglycerides, low high-density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose) were classified as metabolically healthy. Multivariable Cox proportional hazards regression was used to estimate adjusted HRs for the association between metabolic phenotype and risk of colorectal cancer.

RESULTS

Among normal-weight women, those who were metabolically unhealthy had higher risks of colorectal cancer (HR, 1.49; 95% CI, 1.02-2.18) compared with those who were metabolically healthy.

CONCLUSIONS

A metabolically unhealthy phenotype was associated with higher risk of colorectal cancer among normal-weight women.

IMPACT

Normal-weight women should still be evaluated for metabolic health and appropriate steps taken to reduce their risk of colorectal cancer. Cancer Epidemiol Biomarkers Prev; 26(2); 155-61. ©2017 AACR.

Obesity is more closely related with hepatic steatosis and fibrosis measured by transient elastography than metabolic health status

OBJECTIVE

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) involves multiple concomitant events induced by obesity and metabolic health condition. This study aimed to assess the risk of NAFLD according to metabolic health and obesity status using transient elastography (TE).

MATERIALS AND METHODS

A total of 2198 asymptomatic adults without chronic liver disease and who underwent a medical health check-up were recruited. Subjects were categorized into four groups according to metabolic health and obesity statuses: metabolically healthy non-obese (MHNO); metabolically unhealthy non-obese (MUNO); metabolically healthy obese (MHO); and metabolically unhealthy obese (MUO). Hepatic steatosis was defined as controlled attenuation parameter (CAP)≥238dB/m, and significant liver fibrosis was defined as liver stiffness measurement (LSM) >7.0kPa, as defined by TE.

RESULTS

Compared with MHNO group, the odds ratios (ORs) [95% confidence interval (CI)] for hepatic steatosis were 2.94 [2.32-3.71], 4.62 [3.52-6.07], and 12.02 [9.08-15.92] in the MUNO, MHO, and MUO groups, respectively (P<0.001) in crude model. Regarding liver fibrosis, there was no significant difference in the ORs in MUNO group (ORs: 0.95 [95% CI, 0.33-2.78], P value = 0.929), whereas there was a significant increase in the ORs in MHO group compared with MHNO group (ORs: 4.32 [95% CI, 1.73-10.76], P=0.002) in the fully adjusted model.

CONCLUSION

Our results show that MHO was associated with both liver steatosis and fibrosis assessed by transient elastography. Our results suggest that a healthy metabolic profile does not protect obese adults from hepatic steatosis or fibrosis, indicating that obesity itself might contribute to liver fibrosis.

Fat Matters: Understanding the Role of Adipose Tissue in Health in HIV Infection

More than one-third of adults in the USA are obese and obesity-related disease accounts for some of the leading causes of preventable death. Mid-life obesity may be a strong predictor of physical function impairment later in life regardless of body mass index (BMI) in older age, highlighting the benefits of obesity prevention on health throughout the lifespan. Adipose tissue disturbances including lipodystrophy and obesity are prevalent in the setting of treated and untreated HIV infection. This article will review current knowledge on fat disturbances in HIV-infected persons, including therapeutic options and future directions.

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.

A indicator of visceral adipose dysfunction to evaluate metabolic health in adult Chinese

Visceral adipose dysfunction is a major cause of metabolic disorders. However, there is lack of a clinical index for prediction of visceral fat dysfunction in Asians. The present study aims to establish a visceral adiposity index for evaluation of metabolic health status in Chinese, the largest Asian ethnic group. 485 subjects were recruited from Lianqian Community, Xiamen and received abdominal computed tomography(CT) for visceral fat area. A Chinese visceral adiposity index (CVAI) was created using multivariate linear regression analyses, and was further validated in 6495 subjects recruited from Changfeng Community, Shanghai. CVAI was well associated with visceral obesity (r = 0.68, P < 0.001) and HOMA-IR (r = 0.60, P < 0.001). The AUROCs were 0.89(0.88–0.90), 0.72(0.71–0.73), 0.69(0.68–0.71) and 0.67(0.65–0.68) for determination of metabolic syndrome, hypertension, diabetes and prediabetes, respectively. CVAI was more valuable compared to BMI and waist circumference in evaluation of metabolic risks (all P < 0.001), even in subjects with metabolically unhealthy normal weight (MUNW) and metabolically healthy obese/overweight (MHO). This study demonstrates that CVAI is a reliable and applicable index for evaluation of visceral fat dysfunction in Chinese. It might be used to evaluate metabolic health status in Asians.

Disability, Physical Inactivity, and Impaired Health-Related Quality of Life Are Not Different in Metabolically Healthy vs. Unhealthy Obese Subjects

BACKGROUND

Obesity represents a major health hazard, affecting morbidity, psychological status, physical functionality, quality of life, and mortality. The aim of the present study was to explore the differences between metabolically healthy (MHO) and metabolically unhealthy (MUO) obese subjects with regard to physical activity, disability, and health-related quality of life (HR-QoL).

METHODS

All subjects underwent a multidimensional evaluation, encompassing the assessment of body composition, metabolic biomarkers and inflammation, physical activity level (IPAQ questionnaire), disability (TSD-OC test), and HR-QoL (SF-36 questionnaire). MHO and MUO were defined based on the absence or the presence of the metabolic syndrome, respectively.

RESULTS

253 subjects were included (54 men and 199 women; age: 51.7 ± 12.8 vs. 50.3 ± 11.7 years, p = 0.46; BMI: 38.1 ± 5.7 vs. 38.9 ± 6.7 kg/m², p = 0.37). No significant difference was observed in body composition. There was no difference between MHO and MUO considering inflammation (hs-CRP: 6517.1 ± 11,409.9 vs. 5294.1 ± 5612.2 g/L; p = 0.37), physical inactivity (IPAQ score below 3000 METs-min/week in 77.6% of MHO vs. 80% of MUO subjects; p = 0.36), obesity-related disability (TSD-OC score > 33%, indicating a high level of obesity-related disability, in 20.2% of MHO vs. 26.5% of MUO subjects; p = 0.28), and the HR-QoL (SF-36 total score: 60 ± 20.8 vs. 62.8 ± 18.2, p = 0.27).

DISCUSSION AND CONCLUSION

The metabolic comorbidity and the impairment of functional ability and psycho-social functioning may have a different timing in the natural history of obesity. Alterations in the physical activity level and mobility disabilities may precede the onset of metabolic abnormalities. (Trial registration 2369 prot 166/12-registered 23 February 2012; Amendment 223/14-registered 13 February 2014).

Peripheral invariant natural killer T cell deficiency in metabolically unhealthy but normal weight versus metabolically healthy but obese individuals

Objective

To investigate the proportion of circulating invariant natural killer T (iNKT) cells in four body health types.

Methods

In this cross-sectional study, participants were classified into four body health types according to the body mass index and metabolic status: metabolically healthy and normal weight (MHNW), metabolically unhealthy but normal weight (MUNW), metabolically healthy but obese (MHO), or metabolically unhealthy and obese (MUO). Demographic and clinical characteristics were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR) and visceral adiposity index (VAI) were calculated. The proportion of circulating iNKT cells was also evaluated by flow cytometry.

Results

The study enrolled 41 MHNW, 37 MUNW, 30 MHO, and 43 MUO participants. Compared with the MHNW group, the MUNW, MHO, and MUO groups had significantly lower iNKT cell proportions. The iNKT cell proportion was significantly higher in the MHO group than the MUNW and MUO groups. The iNKT cell proportion was inversely correlated with high-sensitivity C-reactive protein, HOMA-IR, and VAI values.

Conclusion

The proportion of iNKT cells was lower in people (lean or obese) with excessive visceral fat accumulation, suggesting that iNKT cell deficiency may be involved in the pathophysiology of obesity-related metabolic disorders.

Calorie restriction and reversal of type 2 diabetes

Type 2 diabetes causes major global health problems and has been believed to be a lifelong condition with inevitable worsening. Steadily increasing numbers of drugs appeared to be required to achieve even modest control. Early type 2 diabetes has now been shown to be reversed by substantial weight loss and this has allowed temporal tracking of the underlying pathophysiological changes. Areas covered: In early type 2 diabetes, negative calorie balance decreases liver fat within days, and allows return of normal control of hepatic glucose production. Over 8 weeks, the negative calorie balance allows the raised levels of intra-pancreatic fat and simultaneously first phase insulin secretion to normalise. These findings are consistent with the 2008 Twin Cycle Hypothesis of the etiology and pathogenesis of type 2 diabetes. Individuals develop type 2 diabetes when they exceed their personal fat threshold for safe storage of fat and there is no difference in pathophysiology between those with BMI above or below 30 kg/m². Expert commentary: Type 2 diabetes can now be understood as a state of excess fat in liver and pancreas, and remains reversible for at least 10 years in most individuals.

Clinical implication of body size phenotype on heart rate variability

We compared heart rate variability (HRV) values according to the following body size phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy but normal weight (MUNW), metabolically healthy but obese (MHO), and metabolically unhealthy obese (MUO). We retrospectively analyzed a dataset from 1200 participants who had visited the Cardiovascular Center at Korea University Guro Hospital between March 2009 and February 2014 and underwent Holter monitoring for 24h. HRV was calculated from standard deviation of normal-to-normal R-R intervals (SDNN), standard deviation of the average normal-to-normal intervals (SDANN), and root mean square of successive differences (rMSSD) measurements, and study subjects were classified according to body mass index (BMI) and presence or absence of metabolic syndrome. Various HRV indices, including SDNN, SDANN, and rMSSD, were significantly lower in MUNW subjects than in MHNW or MHO subjects, while there were no significant differences between MUNW and MUO subjects. Although BMI had no significant correlation with any HRV indices, SDNN, SDANN, and rMSSD values had significant negative correlations with waist circumference and levels of C-reactive proteins, AST, ALT, fasting glucose, and HOMA-IR. A significant positive correlation was observed between HRV index and HDL level. Furthermore, the SDNN value significantly decreased with an increase in the number of metabolic syndrome components after adjusting for other covariates. Compared to MHNW or MHO subjects, Korean men and women with the MUNW phenotype exhibited decreased HRV, suggesting that low HRV is related to adverse cardiovascular outcomes in MUNW individuals.

Metabolic phenotypes of obesity: frequency, correlates and change over time in a cohort of postmenopausal women

OBJECTIVE

The possibility that a subset of persons who are obese may be metabolically healthy-referred to as the 'metabolically healthy obese' (MHO) phenotype-has attracted attention recently. However, few studies have followed individuals with MHO or other obesity phenotypes over time to assess change in their metabolic profiles. The aim of the present study was to examine transitions over a 6-year period among different states defined simultaneously by body mass index (BMI) and the presence/absence of the metabolic syndrome (MetS).

METHODS

We used repeated measurements available for a subcohort of participants enrolled in the Women's Health Initiative (N=3512) and followed for an average of 6 years to examine the frequency of different metabolic obesity phenotypes at baseline, the 6-year transition probabilities to other states and predictors of the risk of different transitions. Six phenotypes were defined by cross-tabulating BMI (18.5-<25.0, 25.0-<30.0, ⩾30.0 kg m^-2) by MetS (yes, no). A continuous-time Markov model was used to estimate 6-year transition probabilities from one state to another.

RESULTS

Over the 6 years of follow-up, one-third of women with the healthy obese phenotype transitioned to the metabolically unhealthy obese (MUO) phenotype. Overall, there was a marked tendency toward increased metabolic deterioration with increasing BMI and toward metabolic improvement with lower BMI. Among MHO women, the 6-year probability of becoming MUO was 34%, whereas among unhealthy normal-weight women, the probability of 'regressing' to the metabolically healthy normal-weight phenotype was 52%.

CONCLUSIONS

The present study demonstrated substantial change in metabolic obesity phenotypes over a 6-year period. There was a marked tendency toward metabolic deterioration with greater BMI and toward metabolic improvement with lower BMI.

Metabolically healthy obesity across the life course: epidemiology, determinants, and implications

In recent years, different subphenotypes of obesity have been described, including metabolically healthy obesity (MHO), in which a proportion of obese individuals, despite excess body fat, remain free of metabolic abnormalities and increased cardiometabolic risk. In the absence of a universally accepted set of criteria to classify MHO, the reported prevalence estimates vary widely. Our understanding of the determinants and stability of MHO over time and the associated cardiometabolic and mortality risks is improving, but many questions remain. For example, whether MHO is truly benign is debatable, and whether risk stratification of obese individuals on the basis of their metabolic health status may offer new opportunities for more personalized approaches in diagnosis, intervention, and treatment of diabetes remains speculative. Furthermore, as most of the research to date has focused on MHO in adults, little is known about childhood MHO. In this review, we focus on the epidemiology, determinants, stability, and health implications of MHO across the life course.

Identifying metabolic syndrome in a clinical cohort: Implications for prevention of chronic disease

In the clinical setting, calculating cardiovascular disease (CVD) risk is commonplace but the utility of the harmonised equation for metabolic syndrome (MetS) (Alberti et al., 2009) is less well established. The aims of this study were to apply this equation to an overweight clinical cohort to identify risk factors for being metabolically unhealthy and explore associations with chronic disease.

Baseline data were analysed from a lifestyle intervention trial of Illawarra residents recruited in 2014/2015. Participants were aged 25–54 years with a BMI 25–40 kg/m². Data included MetS, CVD risk, insulin sensitivity, weight, body fat, diet, peripheral artery disease (PAD), physical activity, socio-economic position and psychological profile. Backward stepwise regression tested the association of covariates with MetS status and linear or logistic regression tested associations between MetS and risk of CVD, coronary heart disease, PAD and insulin resistance. 374 participants were included in the analysis with 127 (34.0%) categorised with MetS. Covariates significantly and positively associated with MetS were higher BMI (odds 1.26, p < 0.01) and older age (odds 1.08, p < 0.01). MetS participants (n = 351) had a 4.50% increase in CVD risk and were 8.1 and 12.7 times (respectively) more likely to be at risk of CHD and insulin resistance, compared to participants without MetS.

The utility of the harmonised equation in the clinical setting was confirmed in this overweight clinical cohort. Those classified as having MetS were more likely to be older, overweight/obese individuals and they had a substantially higher risk of developing CVD and insulin resistance than those without MetS.

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Older, obese individuals at greatest risk of having Metabolic Syndrome (MetS)

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Stress, socioeconomic, fitness and diet factors were not associated with MetS.

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MetS individuals had increased cardiovascular risk of 4.50%.

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MetS were 12.7 times more likely to be insulin resistant.

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Study identifies those at risk in order to implement early lifestyle changes.

Weight for gestational age and metabolically healthy obesity in adults from the Haguenau cohort

BACKGROUND

An obesity subphenotype, named 'metabolically healthy obese' (MHO) has been recently defined to characterise a subgroup of obese individuals with less risk for cardiometabolic abnormalities. To date no data are available on participants born with small weight for gestational age (SGA) and the risk of metabolically unhealthy obesity (MUHO).

OBJECTIVE

Assess the risk of MUHO in SGA versus appropriate for gestational age (AGA) adult participants.

METHODS

129 young obese individuals (body mass index ≥30 kg/m²) from data of an 8-year follow-up Haguenau cohort (France), were identified out of 1308 participants and were divided into 2 groups: SGA (n=72) and AGA (n=57). Metabolic characteristics were analysed and compared using unpaired t-test. The HOMA-IR index was determined for the population and divided into quartiles. Obese participants within the first 3 quartiles were considered as MHO and those in the fourth quartile as MUHO. Relative risks (RRs) and 95% CI for being MUHO in SGA versus AGA participants were computed.

RESULTS

The SGA-obese group had a higher risk of MUHO versus the AGA-obese group: RR=1.27 (95% CI 1.10 to 1.6) independently of age and sex.

CONCLUSIONS

In case of obesity, SGA might confer a higher risk of MUHO compared with AGA.

The association of incident hypertension with metabolic health and obesity status: definition of metabolic health does not matter

OBJECTIVE

Metabolically healthy obese (MHO) phenotype refers to obese individuals with a favourable metabolic profile. Its prognostic value remains controversial and may partly depend on differences in how the phenotype is defined. We aimed to investigate whether the MHO phenotype is associated with future development of incident hypertension in a Korean population according to various definitions of metabolic health.

SUBJECTS AND METHODS

The study population comprised 31 033 Koreans without hypertension. Participants were stratified into metabolically healthy nonobese (MHNO), metabolically unhealthy nonobese (MUNO), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) by body mass index (cut-off value, 25·0 kg/m(2) ) and metabolic health state, using four different definitions: Adult Treatment Panel (ATP)-III, Wildman, Karelis and the homoeostasis model assessment (HOMA) criteria.

RESULTS

Over the median follow-up period of 35·0 months (range, 4·5-81·4 months), 4589 of the 31 033 individuals (14·8%) developed incident hypertension. Compared with the MHNO group, the MHO group showed increased association with incident hypertension with multivariate-adjusted odds ratios of 1·56 (95% confidence interval [CI], 1·41-1·72), 1·58 (95% CI 1·42-1·75), 1·52 (95% CI 1·35-1·71) and 1·46 (95% CI 1·33-1·61), when defined by ATP-III, Wildman, Karelis and HOMA criteria, respectively.

CONCLUSION

MUO individuals showed the highest association with the incident hypertension (adjusted odds ratios up to 2·00). MHO subjects showed an approximately 1·5-fold higher association with incident hypertension than their nonobese counterpart regardless of the definition of metabolic health used. Thus, considering both metabolic health and obesity is important for the assessment of potential cardiovascular outcomes.

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.

Obesity, metabolic health, and mortality in adults: a nationwide population-based study in Korea

BMI, metabolic health status, and their interactions should be considered for estimating mortality risk; however, the data are controversial and unknown in Asians. We aimed to investigate this issue in Korean population. Total 323175 adults were followed-up for 96 (60–120) (median [5–95%]) months in a nationwide population-based cohort study. Participants were classified as “obese” (O) or “non-obese” (NO) using a BMI cut-off of 25 kg/m². People who developed ≥1 metabolic disease component (hypertension, diabetes, dyslipidaemia) in the index year were considered “metabolically unhealthy” (MU), while those with none were considered “metabolically healthy” (MH). The MUNO group had a significantly higher risk of all-cause (hazard ratio, 1.28 [95% CI, 1.21–1.35]) and cardiovascular (1.88 [1.63–2.16]) mortality, whereas the MHO group had a lower mortality risk (all-cause: 0.81 [0.74–0.88]), cardiovascular: 0.73 [0.57–0.95]), compared to the MHNO group. A similar pattern was noted for cancer and other-cause mortality. Metabolically unhealthy status was associated with higher risk of all-cause and cardiovascular mortality regardless of BMI levels, and there was a dose-response relationship between the number of incident metabolic diseases and mortality risk. In conclusion, poor metabolic health status contributed more to mortality than high BMI did, in Korean adults.

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.

Natural Course of Metabolically Healthy Overweight/Obese Subjects and the Impact of Weight Change

Few studies have described the characteristics of metabolically healthy individuals with excess fat in the Chinese population. This study aimed to prospectively investigate the natural course of metabolically healthy overweight/obese (MH-OW/OB) adults, and to assess the impact of weight change on developing metabolic abnormalities. During 2009–2010, 525 subjects without any metabolic abnormalities or other obesity-related diseases were evaluated and reevaluated after 5 years. The subjects were categorized into two groups of overweight/obese and normal weight based on the criteria of BMI by 24.0 at baseline. At follow-up, the MH-OW/OB subjects had a significantly increased risk of developing metabolically abnormalities compared with metabolically healthy normal-weight (MH-NW) individuals (risk ratio: 1.35, 95% confidence interval: 1.17–1.49, p value < 0.001). In the groups of weight gain and weight maintenance, the MH-OW/OB subjects was associated with a larger increase in fasting glucose, triglycerides, systolic blood pressure, diastolic blood pressure and decrease in high-density lipoprotein cholesterol comparing with MH-NW subjects. In the weight loss group, no significant difference of changes of metabolic parameters was observed between MH-OW/OB and MH-NW adults. This study verifies that MH-OW/OB are different from MH-NW subjects. Weight management is needed for all individuals since weight change has a significant effect on metabolic health without considering the impact of weight change according to weight status.

Bariatric surgery is associated with improvement in kidney outcomes

Severe obesity is associated with increased risk of kidney disease. Whether bariatric surgery reduces the risk of adverse kidney outcomes is uncertain. To resolve this we compared the risk of estimated glomerular filtration rate (eGFR) decline of ≥30% and doubling of serum creatinine or end-stage renal disease (ESRD) in 985 patients who underwent bariatric surgery with 985 patients who did not undergo such surgery. Patients were matched on demographics, baseline body mass index, eGFR, comorbidities, and previous nutrition clinic use. Mean age was 45 years, 97% were white, 80% were female, and 33% had baseline eGFR <90 ml/min per 1.73 m(2). Mean 1-year weight loss was 40.4 kg in the surgery group compared with 1.4 kg in the matched cohort. Over a median follow-up of 4.4 years, 85 surgery patients had an eGFR decline of ≥30% (22 had doubling of serum creatinine/ESRD). Over a median follow-up of 3.8 years, 177 patients in the matched cohort had an eGFR decline of ≥30% (50 had doubling of serum creatinine/ESRD). In adjusted analysis, bariatric surgery patients had a significant 58% lower risk for an eGFR decline of ≥30% (hazard ratio 0.42, 95% confidence interval 0.32-0.55) and 57% lower risk of doubling of serum creatinine or ESRD (hazard ratio 0.43, 95% confidence interval: 0.26-0.71) compared with the matched cohort. Results were generally consistent among subgroups of patients with and without eGFR <90 ml/min per 1.73 m(2), hypertension, and diabetes. Thus, bariatric surgery may be an option to prevent kidney function decline in severely obese individuals.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.

TyG Index Change Is More Determinant for Forecasting Type 2 Diabetes Onset Than Weight Gain

The risk of type 2 diabetes associated with obesity appears to be influenced by other metabolic abnormalities, and there is controversy about the harmless condition of the metabolically healthy obese (MHO) state. The aim of this study is to assess the risk of diabetes and the impact of changes in weight and in triglyceride-glucose index (TyG index), according to the metabolic health and obesity states.We analyzed prospective data of the Vascular Metabolic CUN cohort, a population-based study among a White European population (mean follow-up, 8.9 years). Incident diabetes was assessed in 1923 women and 3016 men with a mean age at baseline of 55.33 ± 13.68 and 53.78 ± 12.98 years old.A Cox proportional-hazard analysis was conducted to estimate the hazard ratio (HR) of diabetes on metabolically healthy nonobese (MHNO), metabolically healthy obese, metabolically unhealthy nonobese (MUNO), and metabolically unhealthy obese (MUO). A continuous standardized variable (z-score) was derived to compute the HR for diabetes per 1-SD increment in the body mass index (BMI) and the TyG index.MHO, MUNO, and MUO status were associated with the development of diabetes, HR of 2.26 (95% CI: 1.25-4.07), 3.04 (95% CI: 1.69-5.47), and 4.04 (95% CI: 2.14-7.63), respectively. MUNO individuals had 1.82 greater risk of diabetes compared to MHO subjects (95% CI: 1.04-3.22). The HRs for incident diabetes per 1-SD increment in BMI and TyG indexes were 1.23 (95% CI: 1.04-1.44) and 1.54 (95% CI: 1.40-1.68). The increase in BMI did not raise the risk of developing diabetes among metabolically unhealthy subjects, whereas increasing the TyG index significantly affect the risk in all metabolic health categories.Metabolic health is more important determinant for diabetes onset than weight gain. The increase in weight does not raise the risk of developing diabetes among metabolically unhealthy subjects.

The long-term prognosis of cardiovascular disease and all-cause mortality for metabolically healthy obesity: a systematic review and meta-analysis

BACKGROUND

Metabolically healthy obese phenotype (MHO) refers to obese individuals with absence of metabolic abnormalities such as dyslipidaemia, insulin resistance and hypertension. Many studies reported the long-term prognosis of MHO on diseases and mortality with inconsistent results.

METHODS

We performed a meta-analysis to assess the risks of cardiovascular (CV) events and all-cause mortality for MHO individuals. Original prospective observational studies were searched in Medline, EMBASE, Web of Science and Cochrane library up to 30 September 2015. In this meta-analysis, the relative risk (RR) calculated on the basis of the incident number of disease events and deaths in participants and the corresponding multivariable-adjusted HR were both extracted to calculate pooled risk estimates. A random-effects model was used if there was heterogeneity among studies; otherwise, the fixed-effects model was used.

RESULTS

22 prospective studies, involving 584 799 participants, were archived in the analyses. With metabolically healthy normal weight as the reference, the MHO phenotype was associated with a higher risk of CV events (RR 1.50, 95% CI 1.27 to 1.77; HR 1.60, 95% CI 1.38 to 1.84). However, MHO individuals were not associated with increased risk of all-cause mortality (RR 1.18, 95% CI 0.83 to 1.66; HR 1.07, 95% CI 0.92 to 1.25).

CONCLUSIONS

The meta-analysis confirms a positive association between a metabolically healthy obese phenotype and the risk of CV events. However, higher risk for all-cause mortality is not evident in metabolically healthy obese individuals.

Reappraisal of waist circumference cutoff value according to general obesity

BACKGROUND

Current criterion of waist circumference (WC) for abdominal obesity is not enough to demonstrate characteristics of obese and non-obese populations defined by BMI. The aim of this study was to redefine the cutoff values of WC according to general obesity (BMI ≥ 25 kg/m(2)).

METHODS

The receiver operating characteristic curve analysis was performed to determine cutoff values of WC for predicting atherosclerosis according to BMI in 1,063 non-diabetic subjects. To validate this new criterion, diabetic patients (n = 3,690) were divided into three groups based on the current (WC of 90/80 cm for men/women) and new cutoff values of WC: 1) group with WC below the lowest value of two criteria; 2) intermediate group defined as having a WC between them; and 3) group with WC more than the highest value of them.

RESULTS

The new cutoff values of WC for predicting atherosclerosis in non-diabetic subjects were 84/76 cm for non-obese men/women, and 93/87 cm for obese men/women, respectively. Of non-obese diabetic patients, the intermediate group (WC 84 ~ 90/76 ~ 80 cm for men/women) was more insulin resistant and showed elevated odds ratio (OR) for having 2 or more metabolic risk factors compared to group with WC below 84/76 cm for men/women [OR 2.48 (95 % CI 1.89-3.25) in men, 2.01 (95% CI 1.45-2.78) in women]. In contrast, among obese diabetic patients, insulin resistance and the likelihood of having 2 or more metabolic risk factors were not different from the intermediate group (WC 90 ~ 93/80 ~ 87 cm for men/women) and group with WC below 90/80 cm for men/women.

CONCLUSIONS

The current universal cutoff values of WC may under- or over-estimate the metabolic risks of intermediate groups. Therefore, the WC criteria for abdominal obesity should be applied differently depending on the BMI.

Prevalence of biopsy-proven non-alcoholic fatty liver disease in severely obese subjects without metabolic syndrome

Obesity is a major risk factor for non-alcoholic fatty liver disease (NAFLD). NAFLD encompasses simple fatty liver (FL) and non-alcoholic steatohepatitis (NASH) in its spectrum. NASH can progress to liver cirrhosis and is associated with liver cancer. Not all obese subjects have insulin resistance (IR) or develop metabolic syndrome (MS). This study evaluates the prevalence of NAFLD in severely obese subjects without MS. We retrospectively reviewed 445 charts from our database of severely obese subjects with clinical suspicion of NAFLD and who were selected for laparoscopic Roux-en-Y gastric bypass surgery. One hundred five subjects who did not have MS, as defined by the International Diabetes Foundation, based on comprehensive pre-operative metabolic evaluation were included. Liver biopsy specimens were evaluated for NAFLD. 24% of morbidly obese (mean body mass index [BMI] 48 kg m(-2) ) adult subjects (mean age 38 years) who underwent bariatric surgery did not have MS. NAFLD was identified in 77 (73%) on liver biopsy, out of which 59 (56%) were labelled as FL and 18 (17%) had histological diagnosis of NASH. Age, gender, race and BMI were the same among all groups. Among NAFLD subjects, 22% did not have any additional metabolic component of MS, while 36% had low high-density lipoprotein, 27% had hypertension, 8% had high triglycerides and 6% had hyperglycaemia. IR calculated by HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) and diagnosis of hyperglycaemia was statistically higher in NASH group compared to those who did not have NASH. NAFLD is highly prevalent in morbidly obese individuals who undergo bariatric surgery despite the absence of MS. Diagnosis of hyperglycaemia in such subjects suggests the presence of IR and may have underlying NASH, which is a progressive form of NAFLD.

UPDATING THE CONCEPT OF METABOLICALLY HEALTHY OBESITY

Obesity is a well-recognized risk factor for type 2 diabetes, cardiovascular disease, and several types of cancer. However, a proportion of the obese individuals display a significantly lower risk for metabolic complications than expected for their degree of body mass index, and this subtype of obesity was described as "metabolically healthy obesity" (MHO). No universally accepted criteria for the diagnosis of MHO exists and the prevalence of this subtype of obesity varies largely according to criteria used. Broadly, MHO is characterized by a lower amount of visceral fat, a more favorable inflammatory profile, and less insulin resistance as compared to the metabolically unhealthy obesity. Currently, controversies exist regarding the risk of cardiovascular events and all-cause mortality associated with MHO as compared to metabolically-healthy non-obese individuals. Further research is needed in order to identify the MHO phenotype and if MHO is truly healthy for a long period of time or if it is a transient state from normal metabolic/normal weight to abnormal metabolic/obese state. This review will discuss the MHO definition criteria; the differences between MHO and metabolically unhealthy obesity; the possible underlying mechanisms and clinical implications of MHO.

Individuals with Metabolically Healthy Overweight/Obesity Have Higher Fat Utilization than Metabolically Unhealthy Individuals

The mechanisms underlying the change in phenotype from metabolically healthy to metabolically unhealthy obesity are still unclear. The aim of this study is to investigate whether a difference in fasting fat utilization exists between overweight/obese individuals with a favorable cardiovascular risk profile and those with Metabolic Syndrome and Type 2 diabetes. Furthermore, we sought to explore whether there is an association between fasting fat utilization and insulin resistance. In this cross-sectional study, 172 overweight/obese individuals underwent a nutritional assessment. Those with fasting glucose ≥ 126 mg/dL or antidiabetic treatment were considered to be diabetics. If at least three of the NCEP criteria were present, they had Metabolic Syndrome, while those with less criteria were considered to be healthy overweight/obese. An indirect calorimetry was performed to estimate Respiratory Quotient, an index of nutrient utilization. A lower Respiratory Quotient (i.e., higher fat utilization) was found in healthy overweight/obese individuals than in those with Metabolic Syndrome and Type 2 diabetes (0.85 ± 0.05; 0.87 ± 0.06; 0.88 ± 0.05 respectively, p = 0.04). The univariate and multivariable analysis showed a positive association between the Respiratory Quotient and HOMA-IR (slope in statistic (B) = 0.004; β = 0.42; p = 0.005; 95% Confidence interval = 0.001-0.006). In this study, we find, for the first time, that the fasting Respiratory Quotient is significantly lower (fat utilization is higher) in individuals who are metabolically healthy overweight/obese than in those with metabolically unhealthy obesity. In addition, we demonstrated the association between fat utilization and HOMA-IR, an insulin resistance index.

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.

Metabolically healthy obesity and cardiovascular events: A systematic review and meta-analysis

AIMS

Previous studies have provided inconsistent results about the cardiovascular risks for participants with metabolically healthy obesity (MHO). These uncertainties might partly reflect the lack of a uniform definition of MHO. We conducted a systematic review and meta-analysis to examine whether there is a suitable approach that identifies obese participants who are not at an increased risk of cardiovascular events compared with healthy normal-weight participants.

METHODS AND RESULTS

Twenty-two prospective studies were eligible for the meta-analysis. Using random-effect models, pooled relative risks (RRs) were calculated for the combined effects of obesity with the presence or absence of metabolic syndrome, insulin resistance, hypertension, diabetes, hyperlipidaemia and any of these metabolic factors. Participants with MHO defined by the absence of metabolic syndrome were at increased risk for cardiovascular events compared with healthy normal-weight participants (pooled RR 1.45, 95% confidence interval (CI) 1.20-1.70), but had lower risks than unhealthy normal-weight (RR 2.07, 95% CI 1.62-2.65) and obese (RR 2.31, 95% CI 1.99-2.69) participants. The risk associated with participants who had MHO was particularly high over the long term. Similar risk estimates were observed when MHO was defined by other approaches.

CONCLUSIONS

None of the approaches clearly identified an obese subgroup not at increased risk of cardiovascular events compared with normal-weight healthy participants. A benign obese phenotype might be defined by strict definitions, but insufficient studies exist to support this. More research is needed to better define MHO.

Estimation of risk for diabetes according to the metabolically healthy status stratified by degree of obesity in Korean men

Although obesity is clearly identified as a risk factor for diabetes, the relationship between diabetes and metabolically healthy status of obesity is less clear. This study was aimed to evaluate the incidental risk of diabetes according to metabolically healthy status of obesity. 31,834 Korean men without diabetes categorized into six groups according to their metabolically healthy status stratified by degree of obesity were followed up for 5 years: metabolically healthy normal weight (MH-NW), metabolically healthy overweight (MH-OW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MU-NW), metabolically unhealthy overweight (MU-OW), and metabolically unhealthy obese (MUO). Cox proportional hazards analysis was used to measure the risk for diabetes according to their categories. While overall incidence was 9.0 %, incidence of diabetes was in proportion to the degree of obesity and metabolically healthy status (MH-NW: 6.3 %, MH-OW: 7.5 %, MHO: 9.2 %, MU-NW: 11.8 %, MU-OW: 14.9 %, MUO: 20.1 %). When MH-NW was set as reference, the adjusted HRs (95 % CI) for diabetes of the MH-OW, MHO, MU-NW, MU-OW, MUO compared to MH-NW were 1.18 (1.06-1.32), 1.58 (1.03-2.41), 1.81 (1.61-2.04), 2.36 (2.11-2.63), and 3.47 (2.84-4.24), respectively. In conclusion, risk for diabetes was in proportion to the degree of obesity in both metabolically healthy and unhealthy group. Metabolically healthy status was more significant determinant for incident diabetes than obesity itself.

Epidemiological modifiers of non-alcoholic fatty liver disease: Focus on high-risk groups

An improved understanding of non-alcoholic fatty liver disease epidemiology would lead to identification of individuals at high risk of developing chronic liver disease and extra-hepatic complications, thus contributing to more effective case finding of non-alcoholic fatty liver disease among selected groups. We aimed to illustrate the epidemiology of non-alcoholic fatty liver disease in high-risk groups, which were identified based on existing literature. To this end, PubMed was searched to retrieve original articles published until May 2015 using relevant and pertinent keywords "nonalcoholic fatty liver disease" and "diabetes", "obesity", "hyperlipidaemia", "familial heterozygous hypobetalipoproteinaemia", "hypertension", "metabolic syndrome", "ethnicity", "family history" or "genetic polymorphisms". We found that age, sex and ethnicity are major physiological modifiers of the risk of non-alcoholic fatty liver disease, along with belonging to "non-alcoholic fatty liver disease families" and carrying risk alleles for selected genetic polymorphisms. Metabolic syndrome, diabetes, obesity, mixed hyperlipidaemia and hypocholesterolaemia due to familial hypobetalipoproteinaemia are the major metabolic modifiers of non-alcoholic fatty liver disease risk. Compared with these metabolic conditions, however, arterial hypertension appears to carry a relatively more modest risk of non-alcoholic fatty liver disease. A better understanding of the epidemiology of non-alcoholic fatty liver disease may result in a more liberal policy of case finding among high-risk groups.

Metabolic Abnormalities Are Common among South American Hispanics Subjects with Normal Weight or Excess Body Weight: The CRONICAS Cohort Study

Objective

We aimed to characterize metabolic status by body mass index (BMI) status.

Methods

The CRONICAS longitudinal study was performed in an age-and-sex stratified random sample of participants aged 35 years or older in four Peruvian settings: Lima (Peru’s capital, costal urban, highly urbanized), urban and rural Puno (both high-altitude), and Tumbes (costal semirural). Data from the baseline study, conducted in 2010, was used. Individuals were classified by BMI as normal weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), and obese (≥30 kg/m²), and as metabolically healthy (0–1 metabolic abnormality) or metabolically unhealthy (≥2 abnormalities). Abnormalities included individual components of the metabolic syndrome, high-sensitivity C-reactive protein, and insulin resistance.

Results

A total of 3088 (age 55.6±12.6 years, 51.3% females) had all measurements. Of these, 890 (28.8%), 1361 (44.1%) and 837 (27.1%) were normal weight, overweight and obese, respectively. Overall, 19.0% of normal weight in contrast to 54.9% of overweight and 77.7% of obese individuals had ≥3 risk factors (p<0.001). Among normal weight individuals, 43.1% were metabolically unhealthy, and age ≥65 years, female, and highest socioeconomic groups were more likely to have this pattern. In contrast, only 16.4% of overweight and 3.9% of obese individuals were metabolically healthy and, compared to Lima, the rural and urban sites in Puno were more likely to have a metabolically healthier profile.

Conclusions

Most Peruvians with overweight and obesity have additional risk factors for cardiovascular disease, as well as a majority of those with a healthy weight. Prevention programs aimed at individuals with a normal BMI, and those who are overweight and obese, are urgently needed, such as screening for elevated fasting cholesterol and glucose.

[Modifications of immunity in obesity: The impact on the risk of infection]

Incidence of obesity is constantly rising all over the world; obesity has developed into an important problem of public health. Clinical experience, supported by many clinical trials, shows that obesity constitutes a risk factor for numerous cardiovascular, metabolic, cancer and even infectious diseases. In this revue we summarize the present knowledge on immunological properties and functions of adipose tissue and their modifications in obese subjects, with a bending to a potentially deleterious chronic inflammatory state. We will discuss the negative impact of this chronic inflammation on physiological acute inflammatory reaction during infectious episodes. However, the modifications of anti-infectious immune response in obese subjects are not well known at present and need further investigations.

Metabolically healthy and unhealthy obesity: differential effects on myocardial function according to metabolic syndrome, rather than obesity

BACKGROUND

The term 'metabolically healthy obese (MHO)' is distinguished using body mass index (BMI), yet BMI is a poor index of adiposity. Some epidemiological data suggest that MHO carries a lower risk of cardiovascular disease (CVD) or mortality than being normal weight yet metabolically unhealthy.

OBJECTIVES

We aimed to undertake a detailed phenotyping of individuals with MHO by using imaging techniques to examine ectopic fat (visceral and liver fat deposition) and myocardial function. We hypothesised that metabolically unhealthy individuals (irrespective of BMI) would have adverse levels of ectopic fat and myocardial dysfunction compared with MHO individuals.

SUBJECTS

Individuals were categorised as non-obese or obese (BMI ⩾30 kg m(-2)) and as metabolically healthy or unhealthy according to the presence or absence of metabolic syndrome.

METHODS

Sixty-seven individuals (mean±s.d.: age 49±11 years) underwent measurement of (i) visceral, subcutaneous and liver fat using magnetic resonance imaging and proton magnetic resonance spectroscopy, (ii) components of metabolic syndrome, (iii) cardiorespiratory fitness and (iv) indices of systolic and diastolic function using tissue Doppler echocardiography.

RESULTS

Cardiorespiratory fitness was similar between all groups; abdominal and visceral fat was highest in the obese groups. Compared with age- and BMI-matched metabolically healthy counterparts, the unhealthy (lean or obese) individuals had higher liver fat and decreased early diastolic strain rate, early diastolic tissue velocity and systolic strain indicative of subclinical systolic and diastolic dysfunction. The magnitude of dysfunction correlated with the number of components of metabolic syndrome but not with BMI or with the degree of ectopic (visceral or liver) fat deposition.

CONCLUSIONS

Myocardial dysfunction appears to be related to poor metabolic health rather than simply BMI or fat mass. These data may partly explain the epidemiological evidence on CVD risk relating to the different obesity phenotypes.

The Relationship between Dietary Patterns and Metabolic Health in a Representative Sample of Adult Australians

Studies assessing dietary intake and its relationship to metabolic phenotype are emerging, but limited. The aims of the study are to identify dietary patterns in Australian adults, and to determine whether these dietary patterns are associated with metabolic phenotype and obesity. Cross-sectional data from the Australian Bureau of Statistics 2011 Australian Health Survey was analysed. Subjects included adults aged 45 years and over (n = 2415). Metabolic phenotype was determined according to criteria used to define metabolic syndrome (0-2 abnormalities vs. 3-7 abnormalities), and additionally categorized for obesity (body mass index (BMI) ≥30 kg/m2 vs. BMI <30 kg/m2). Dietary patterns were derived using factor analysis. Multivariable models were used to assess the relationship between dietary patterns and metabolic phenotype, with adjustment for age, sex, smoking status, socio-economic indexes for areas, physical activity and daily energy intake. Twenty percent of the population was metabolically unhealthy and obese. In the fully adjusted model, for every one standard deviation increase in the Healthy dietary pattern, the odds of having a more metabolically healthy profile increased by 16% (odds ratio (OR) 1.16; 95% confidence interval (CI): 1.04, 1.29). Poor metabolic profile and obesity are prevalent in Australian adults and a healthier dietary pattern plays a role in a metabolic and BMI phenotypes. Nutritional strategies addressing metabolic syndrome criteria and targeting obesity are recommended in order to improve metabolic phenotype and potential disease burden.

Comparison of Serum Adipocytokine Levels according to Metabolic Health and Obesity Status

BACKGROUND

Metabolic health is an emerging concept that is highly correlated with various metabolic complications, and adipocytokines have been causally linked to a wide range of metabolic diseases. Thus, this study compared serum adipocytokine levels according to metabolic health and obesity status.

METHODS

Four hundred and fifty-six nondiabetic subjects (mean age, 40.5 years) were categorized into four groups according to metabolic health and obesity status: metabolically healthy nonobese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy nonobese (MUHNO), and metabolically unhealthy obese (MUHO). Being metabolically healthy was defined as the presence of fewer than two of the following five metabolic abnormalities: high blood pressure, high fasting blood glucose, high triglyceride, low high density lipoprotein cholesterol, and being in the highest decile of the homeostatic model assessment of insulin resistance index. Obesity status was assessed using body mass index (BMI), with obesity defined as a BMI higher than 25 kg/m². Levels of serum interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor α (TNF-α), and adipocyte fatty acid binding protein (A-FABP) were also evaluated.

RESULTS

Of the 456 subjects, 247 (54.2%) were in the MHNO group, 66 (14.5%) were in the MHO group, 66 (14.5%) were in the MUHNO group, and 77 (16.9%) were in the MUHO group. There were no significant differences in IL-6 or MCP-1 levels among the groups, but levels of TNF-α and A-FABP were significantly higher in the MUHNO group compared to the MHNO group.

CONCLUSION

High TNF-α and A-FABP levels are significantly associated with metabolically unhealthiness in nonobese Korean individuals.