Obesity and prognosis: Time to forget about metabolically healthy obesity

Transitions in Metabolic Health Status and Obesity Over Time and Risk of Diabetes: The Dongfeng-Tongji Cohort Study

CONTEXT

Evidence regarding the association between metabolically healthy overweight or obesity (MHOO) and diabetes is controversial, and mostly ignores the dynamic change of metabolic health status and obesity.

OBJECTIVE

To explore the association between transitions of metabolic health status and obesity over 5 years and diabetes incidence.

METHODS

We examined 17 309 participants derived from the Dongfeng-Tongji cohort and followed from 2008 to 2018 (median follow-up 9.9 years). All participants were categorized into 4 phenotypes based on body mass index (BMI) and metabolic health status: metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), MHOO, and metabolically unhealthy overweight or obesity (MUOO). The associations of changes in BMI-metabolic health status (2008-2013) with diabetes incidence (2018) were performed among 12 206 individuals with 2 follow-up examinations.

RESULTS

Compared with stable MHNW, stable MHOO (hazard ratio [HR] 1.76; 95% CI 1.26, 2.45) and transition from MHOO to metabolically unhealthy phenotypes were associated with higher risk for diabetes (HR 2.97; 95% CI 1.79, 4.93 in MHOO to MUNW group and HR 3.38; 95% CI 2.54, 4.49 in MHOO to MUOO group). Instead, improvements to metabolic healthy phenotypes or weight loss occurring in MUOO reduced the risk of diabetes compared with stable MUOO, changing from MUOO to MHNW, MUNW, and MHOO resulted in HRs of 0.57 (95% CI 0.37, 0.87), 0.68 (95% CI 0.50, 0.93), and 0.45 (95% CI 0.34, 0.60), respectively.

CONCLUSION

People with MHOO, even stable MHOO, or its transition to metabolically unhealthy phenotypes were at increased risk of diabetes. Metabolic improvements and weight control may reduce the risk of diabetes.

The role of the gut microbiota on the metabolic status of obese children

Background

The term “metabolically healthy obese (MHO)” denotes a hale and salutary status, yet this connotation has not been validated in children, and may, in fact, be a misnomer. As pertains to obesity, the gut microbiota has garnered attention as conceivably a nosogenic or, on the other hand, protective participator.

Objective

This study explored the characteristics of the fecal microbiota of obese Chinese children and adolescents of disparate metabolic statuses, and the associations between their gut microbiota and circulating proinflammatory factors, such as IL-6, TNF-α, lipopolysaccharide-binding protein (LBP), and a cytokine up-regulator and mediator, leptin.

Results

Based on weight and metabolic status, the 86 Chinese children (ages 5–15 years) were divided into three groups: metabolically healthy obese (MHO, n = 42), metabolic unhealthy obese (MUO, n = 23), and healthy normal weight controls (Con, n = 21). In the MUO subjects, the phylum Tenericutes, as well as the alpha and beta diversity, were significantly reduced compared with the controls. Furthermore, Phylum Synergistetes and genus Bacteroides were more prevalent in the MHO population compared with controls. For the MHO group, Spearman’s correlation analysis revealed that serum IL-6 positively correlated with genus Paraprevotella, LBP was positively correlated with genus Roseburia and Faecalibacterium, and negatively correlated with genus Lactobacillus, and leptin correlated positively with genus Phascolarctobacterium and negatively with genus Dialister (all p < 0.05).

Conclusion

Although there are distinct differences in the characteristic gut microbiota of the MUO population versus MHO, dysbiosis of gut microsystem is already extant in the MHO cohort. The abundance of some metabolism-related bacteria associates with the degree of circulating inflammatory compounds, suggesting that dysbiosis of gut microbiota, present in the MHO children, conceivably serves as a compensatory or remedial response to a surfeit of nutrients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01548-9.

Prevalence of NASH/NAFLD in people with obesity who are currently classified as metabolically healthy

BACKGROUND

While metabolic health in obesity may confer a protective status, recent studies indicate that nonalcoholic fatty liver disease (NAFLD) or even nonalcoholic steatohepatitis (NASH) may exist in this category of individuals. Although cardiovascular and diabetic risks have been well described, the risk of NAFLD and NASH among this population requires further investigation.

OBJECTIVE

Our goal was to compare the prevalence of steatosis, NAFLD, and NASH between individuals with metabolically healthy obesity (MHO) and individuals with metabolically abnormal obesity (MAO) and to identify preoperative risk factors for these conditions in a prospective cohort with morbid obesity scheduled for bariatric surgery.

SETTINGS

Tertiary referral university hospital in France.

METHODS

The prospective cohort included 837 bariatric patients who also had an intraoperative liver biopsy between 2002 and 2015. Obese individuals fulfilling none of the criteria in the strict definition of metabolic syndrome were considered metabolically healthy. Preoperative blood samples and liver pathology examinations were reviewed. Steatosis, NAFLD, and NASH were carefully identified allowing comparison of prevalence and risk factors between the 2 cohorts.

RESULTS

In total, 149 patients (17.8%) had MHO and the remaining 688 (82.2%) had MAO. The cohort with MHO was significantly younger, had a significantly lower glycosylated hemoglobin, a lower homeostasis model assessment of insulin resistance, and increased C-reactive protein. In individuals with MHO, 44 patients (29.5%) had at least moderate steatosis (>33% macrovesicular steatosis) and 5.4% had NASH. Using logistic regression, waist circumference was positively associated with NASH, whereas body mass index and alanine aminotransferase were significantly associated with severe steatosis (>66%).

CONCLUSION

Our study indicates that obese individuals without metabolic syndrome may develop subclinical liver involvement. Therefore, the occurrence of NAFLD and NASH in this population needs further investigation.

Fatty acid profile and estimated desaturase activities in whole blood are associated with metabolic health

BACKGROUND

The aim was to investigate if fatty acid profile and estimated desaturase activities; stearoyl CoA-desaturase (SCD), delta-5-desaturase and delta-6-desaturase (D5D; D6D), differ between individuals with metabolically healthy (MH) and unhealthy (MU) phenotypes. We also explored these associations according to BMI categories.

METHODS

Men and women at moderately elevated risk of cardiovascular disease were included in this cross-sectional study (n = 321). If subjects met ≥4 out of 5 criteria (elevated triglycerides, total and LDL-cholesterol, HbA1c and low HDL-cholesterol), they were classified as MU (n = 52). If levels were within reference ranges for ≥3 of the same criteria, subjects were classified as MH (n = 150). Utilizing the entire population, a score ranging from 0 to 5 denoting the number of MU criteria met was computed. Estimated desaturase activities were calculated as product-to-precursor ratio of fatty acids in whole blood (SCD16 [16:1n7/16:0], SCD18 [18:1n9/18:0], D5D [18:3n6/18:2n6], D6D [20:4n6/20:3n6]).

RESULTS

Individuals with MH had lower estimated SCD16 and SCD18 activities, whereas estimated D6D activity was higher compared to MU. Similar, SCD16 and SCD18 increased, whereas D6D decreased with increasing criteria of MU. Trends were similar across BMI categories.

CONCLUSIONS

This study supports the notion of estimated desaturase activities as possible novel biomarkers of metabolic health irrespectively of BMI.

Metabolically Healthy Obesity and Bariatric Surgery

A peculiar category of persons with obesity lacking common metabolic disturbances has been depicted and termed as metabolically healthy obesity (MHO). Yet, although MHO patients are free of obesity-associated complications, they might not be entirely precluded from developing cardio-metabolic disorders. Among patients with morbid obesity (MO) who are referred to bariatric surgery, a subset of metabolically healthy MO (MHMO) has been identified and the question arises if these patients would benefit from surgery in terms of mitigating the peril of cardio-metabolic complications. We revisited the pathophysiological mechanisms that define MHO, the currently available data on the cardio-metabolic risk of these patients and finally we reviewed the benefits of bariatric surgery and the urge to better characterize MHMO before submission to surgery.

The control of cardiovascular risk factors – an essential component of the rehabilitation of patients with ischemic heart disease. What are the current targets?

Cardiovascular diseases continue to cause the highest mortality in Europe, among both men and women. Ischemic heart disease is responsible for most of these deaths. An important role in decreasing mortality and improving the prognosis of patients diagnosed with this disorder is played by cardiovascular rehabilitation programs. The short hospitalization period of patients with acute coronary syndromes who undergo revascularization procedures (in-hospital rehabilitation) becomes extremely useful to determine the cardiovascular risk factors underlying the development of these diseases and to implement lifestyle changing measures. Patients with ischemic heart disease included in rehabilitation programs will not only have the advantage of an increased exercise capacity, but they will also be monitored by qualified medical personnel for the evolution of cardiovascular risk factors. We aim to summarize the objectives to be targeted regarding these risk factors in the presence of a patient with ischemic heart disease included in cardiovascular rehabilitation programs. Key words: cardiovascular risk factors, cardiovascular rehabilitation,

Impact of sex and myocardial function on association of obesity with mortality in Asian patients with acute heart failure: a retrospective analysis from the STRATS-AHF registry

OBJECTIVES

Impact of sex and myocardial function on the obesity paradox in heart failure (HF) is unknown. We explored whether sex, myocardial function, and left ventricular (LV) geometry explains the protective association of body mass index (BMI) with mortality, and investigated whether metabolic health status affects this association.

DESIGN

A multicentre cohort study with patients with acute HF admitted from January 2009 to December 2016 with a median follow-up of 33.7 months.

SETTING

Three tertiary hospitals.

PARTICIPANTS

A total of 2021 overweight-to-obese (OW) and 1543 normal-weight (NW) patients with acute HF.

MEASUREMENTS

The primary outcome was all-cause mortality. Patients were categorised as either OW (BMI≥23kg/m²) or NW (BMI<23kg/m²). BMI was used as both categorical and continuous variables. Clinical, laboratory and echocardiographic measures, including LV global longitudinal strain (LV-GLS), LV-ejection fraction, LV geometry, were obtained.

RESULTS

During the follow-up period, 1392 patients died (685 OW and 707 NW). BMI was significantly associated with mortality in univariate (HR=0.929 per kg/m², p<0.001) and multivariate analyses (HR=0.954 per kg/m², p<0.001). In multivariable fractional polynomials, higher BMIs were associated with lower mortality overall and in subgroups by sex, LV-GLS and LV geometry, with a steeper association in men (p-interaction <0.001). In women, there were significant interactions of BMI with LV-GLS (p-interaction=0.044) and age (p-interaction=0.040) for mortality; the protective association of BMI with mortality was confined to subgroups with high LV-GLS (>10.1%) or elderly patients (≥75 years). In men, this association was found in all subgroups without significant interaction. Metabolically healthy obese patients had better survival than metabolically unhealthy obese patients (log-rank p<0.001).

CONCLUSIONS

In women, a significant interaction was observed between BMI and age or LV-GLS in association with mortality, suggesting that sex, ageing and myocardial dysfunction can affect the magnitude of the obesity paradox in HF. Metabolic health status provides prognostic information beyond obesity status.

TRIAL REGISTRATION NUMBER

Registry: ClinicalTrials.gov Number: NCT03513653 (https://clinicaltrials.gov/ct2/show/NCT03513653).

Segmenting Young Adult University Student's Eating Behaviour: A Theory-Informed Approach

The purpose of this paper is to extend behavioural theory and segmentation application. Specifically, this paper draws on three segmentation bases and behavioural theory that extends focus beyond individual psychological predispositions to form segments within the healthy eating context for young adult university students (20–35 years) in Queensland, Australia. Participants were invited to take part in an online survey via email and through face to face intercept to ensure a diverse cross section was obtained. Structural equation modelling revealed that the Motivation, Opportunity, and Ability (MOA) framework can be utilised to explain healthful eating behaviour and two-step cluster analysis uncovered two distinct segments with education, motivation to eat healthily and Turconi’s eating behaviour scores being the most important variables within the wider multivariate segment formation. This paper contributes to literature in the following ways. First, it confirms the importance of behavioural bases in segment formation and supports inclusion of other bases, namely demographics and psychographics. Next, it provides evidence of the value of including behavioural theory, which extends focus beyond what individuals think to understand how the environment may support them. Finally, this paper demonstrates that the MOA framework together with eating behaviour and demographic factors (education) can produce theoretically informed segments.

Metabolically healthy versus unhealthy obesity and risk of fibrosis progression in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Little is known about the impact of metabolically healthy obesity on fibrosis progression in non-alcoholic fatty liver disease (NAFLD). We investigated the association of body mass index (BMI) category, body fat percentage and waist circumference with worsening of noninvasive fibrosis markers in metabolically healthy and unhealthy individuals with NAFLD.

METHODS

A cohort study was performed on 59 957 Korean adults with NAFLD (13 285 metabolically healthy and 46 672 metabolically unhealthy individuals) who were followed for a median of 7.7 years. Being metabolically healthy was defined as not having any metabolic syndrome component and having a homoeostasis model assessment of insulin resistance <2.5. Progression from low to intermediate or high probability of advanced fibrosis was assessed using the NAFLD fibrosis score (NFS).

RESULTS

During 339 253.1 person-years of follow-up, 9857 subjects with low NFS at baseline progressed to intermediate or high NFS. Among metabolically healthy individuals, the multivariable-adjusted HRs (95% CI) for NFS worsening comparing BMIs 23-24.9, 25-29.9 and ≥30 with a BMI of 18.5-22.9 kg/m² were 1.19 (1.00-1.42), 1.79 (1.52-2.10) and 3.52 (2.64-4.69), respectively, whereas the corresponding HRs (95% CI) in metabolically unhealthy individuals were 1.37 (1.24-1.52), 2.18 (1.99-2.39) and 4.26 (3.83-4.75). A similar trend was observed in the analyses using body fat and waist circumference.

CONCLUSION

In the large-scale cohort of young and middle-aged individuals with NAFLD, BMI was positively associated with worsening of noninvasive fibrosis marker regardless of metabolic health status. Excess adiposity per se, even without accompanying metabolic health status, may contribute to fibrosis progression in NAFLD.

Heterogeneity of obesity phenotypes in relation to cardiovascular risk

Obesity is associated with numerous metabolic disorders, the development and progression of a wide range of conditions and diseases, primarily cardiovascular disease and type 2 diabetes. One of the widely discussed phenomena of the association of obesity with cardiovascular diseases, their complications and mortality is the phenomenon of “heterogeneity of obesity phenotypes in relation to cardiovascular risk”. Currently, two main phenotypes have been identified — metabolically healthy and metabolically unhealthy obesity. At the same time, not only the expediency of separation, but also the existence of this phenotype is widely discussed today. The article provides an overview of existing approaches to the verification of metabolic phenotypes of obesity and data relating to the epidemiology and the association of metabolically healthy obesity with the risk of cardiovascular diseases and death, and also discusses the factors that determine the features of the obesity phenotype.

Heterogeneity of obesity phenotypes in relation to cardiovascular risk

Obesity is associated with numerous metabolic disorders, the development and progression of a wide range of conditions and diseases, primarily cardiovascular disease and type 2 diabetes. One of the widely discussed phenomena of the association of obesity with cardiovascular diseases, their complications and mortality is the phenomenon of “heterogeneity of obesity phenotypes in relation to cardiovascular risk”. Currently, two main phenotypes have been identified — metabolically healthy and metabolically unhealthy obesity. At the same time, not only the expediency of separation, but also the existence of this phenotype is widely discussed today. The article provides an overview of existing approaches to the verification of metabolic phenotypes of obesity and data relating to the epidemiology and the association of metabolically healthy obesity with the risk of cardiovascular diseases and death, and also discusses the factors that determine the features of the obesity phenotype.

Single-nucleotide polymorphisms in a cohort of significantly obese women without cardiometabolic diseases

BACKGROUND/OBJECTIVES

Obesity is an important risk factor for the development of diseases such as diabetes mellitus, hypertension, and dyslipidemia; however, a small number of individuals with long-standing obesity do not present with these cardiometabolic diseases. Such individuals are referred to as metabolically healthy obese (MHO) and potentially represent a subgroup of the general population with a protective genetic predisposition to obesity-related diseases. We hypothesized that individuals who were metabolically healthy, but significantly obese (BMI ≥ 35 kg/m2) would represent a highly homogenous subgroup, with which to investigate potential genetic associations to obesity. We further hypothesized that such a cohort may lend itself well to investigate potential genotypes that are protective with respect to the development of cardiometabolic disease.

SUBJECTS/METHODS

In the present study, we implemented this novel selection strategy by screening 892 individuals diagnosed as Class 2 or Class 3 obese and identified 38 who presented no manifestations of cardiometabolic disease. We then assessed these subjects for single-nucleotide polymorphisms (SNPs) that associated with this phenotype.

RESULTS

Our analysis identified 89 SNPs that reach statistical significance (p < 1 × 10-5), some of which are associated with genes of biological pathways that influences dietary behavior; others are associated with genes previously linked to obesity and cardiometabolic disease as well as neuroimmune disease. This study, to the best of our knowledge, represents the first genetic screening of a cardiometabolically healthy, but significantly obese population.

All-cause mortality of metabolically healthy or unhealthy obese: risk stratification using myocardial perfusion imaging

Introduction

There is still controversy about the favorable prognosis of "metabolically healthy" (MH) obese. This study evaluated mortality and the use of myocardial perfusion scintigraphy (MPS) for risk stratification of MH or metabolically unhealthy (MU) obese or nonobese patients.

Material and methods

Patients without dyslipidemia, hypertension, or diabetes were considered MH, and those with ≥ 1 of these risk factors were considered MU. The MPS was categorized as normal, abnormal or ischemic. Patients were followed for 4.0 ±1.0 years for all-cause death.

Results

Of 2450 patients, 613 were obese. The MH obese patients less often had ischemia than MU obese, but there was no significant difference in the prevalence of ischemia compared to all nonobese. The annualized death rate of MH obese was 1.3% and of nonobese 1.0% (p = 0.4). An abnormal MPS and the MU status were independently associated with death, with hazard ratios of 1.85 and 1.72, respectively. A normal MPS identified patients with low risk among all subgroups; annualized rates of death were 1.0%, 1.1% and 1.0% for all nonobese, MH obese and MU obese, respectively (p = 0.63).

Conclusions

The annualized death rate of MH obese patients was not significantly different from that of nonobese individuals. Myocardial perfusion scintigraphy was able to stratify prognosis in the overall patient population. These data may be helpful to identify high-risk individuals, thereby improving patient management.