Healthy obesity

Lay beliefs about the perceived harmfulness of excess weight: Influence of weight status and the cause of weight

Health campaigns often emphasise the association between excess weight and poor health. Past research suggests that whether an individual's excess weight is viewed as harmful is partially explained by the quantity of excess weight. The present research explored whether the purported cause of excess weight also influences its perceived harmfulness. Across two studies (total N = 577), participants read information about target individuals whose excess weight was caused by different factors (unhealthy lifestyle vs. medical condition). Participants rated the extent to which the target's weight was harmful and also recommended health-related behaviours to the target. For the target with overweight, when her weight was described as being caused by unhealthy behaviours as opposed to a medical condition, her weight was rated as more harmful, and she was recommended to engage in more healthy behaviours. For the target with obesity, her weight was viewed as harmful irrespective of its described cause. Compared with the target with overweight, the weight of the target with obesity was rated as more harmful and she was recommended to diet more. Perceptions of the harmfulness of 'overweight' are influenced by the purported cause of that overweight, whereas obesity itself is viewed as harmful, regardless of the cause.

Disentangling the effects of obesity and high-fat diet on glucose homeostasis using a photoperiod induced obesity model implicates ectopic fat deposition as a key factor

OBJECTIVE

Obesity in laboratory rodents is generally induced by feeding them a high fat diet (HFD). This model does not permit separation of the impact of the HFD from the resultant obesity on metabolic defects such as impaired glucose homeostasis. In Brandt's voles we have previously shown that exposure to long photoperiod (LD: 16L: 8D) induces obesity even when they are fed a low fat diet. We show here that these voles are largely resistant to HFD. This model therefore permits some separation of the effects of HFD and obesity on glucose homeostasis. The objective was therefore to use this model to assess if glucose homeostasis is more related to diet or obesity METHODS: Male voles, which were 35 days old and born in LD, were exposed to SD and a low fat diet for 70 days. We then randomly separated the animals into 4 groups for another 63 days: SL (short day and low fat diet: n = 19) group; SH (short day and high-fat diet, n = 20) group; LL (long day and low-fat diet, n = 20) group; LH (long day and high-fat diet, n = 18) group. Glucose tolerance tests (GTT) were performed after treatment for 56 days, and body compositions of the voles were quantified at the end by dissection.

RESULTS

Consistent with our previous work LD voles were more obese than SD voles. Although total body weight was independent of dietary fat content, HFD did have an effect on fat storage. Photoperiod induced obesity had no effect on glucose homeostasis, and the fat content in both the liver and muscle. In contrast, HFD induced adiposity was linked with elevated fat deposition in muscle (but not in liver) and led to impaired glucose tolerance.

CONCLUSIONS

The contrasting effects of diet and photoperiod were consistent with the predictions of the 'lipotoxicity hypothesis'. This may contribute to our understanding of why some human individuals are able to be obese yet remain metabolically healthy.

Association between dietary fatty acid patterns and obesity indices in Jordanian adults: A cross-sectional study

Background

The ratios of fatty acids in different diets and their connection to chronic diseases including obesity and CVD have been researched. The current study set out to detect the dietary fatty acid patterns among Jordanian adults and their relationships with obesity indices.

Methods

The data of 1096 adults were extracted from a household food consumption patterns survey study. Food intake was analyzed, and fatty acid patterns were determined. After anthropometric measurements, obesity indices were calculated.

Results

Two fatty acid patterns were determined (High fatty acids from Protein and Olive Oil sources pattern, and the low Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) pattern), explaining an overall variance of 41.78% and 24.31%, respectively. A significant difference in obesity scores through fatty acids pattern quartiles was only seen among female participants. Q4 of the "High fatty acids from Protein and Olive Oil sources" pattern had a significantly higher means of body mass index (25.12 ± 0.46; p = 0.015), waist-to-height-ratio (0.51 ± 0.01; p = 0.002), weight-adjusted waist index (10.13 ± 0.09; p = 0.021) and body roundness index (3.61 ± 0.15; p = 0.007) compared to Q1, while Q4 of "Low EPA and DHA" pattern had significantly higher means of waist circumference (WC) (86.28 ± 1.34) and a body shape index (ABSI) (10.12 ± 0.30) in comparison to Q1 (WC = 81.55 ± 1.08 and ABSI = 9.07 ± 0.22; p = 0.025, 0.013; respectively). In females, there was a significant association between the "High fatty acids from Protein and Olive Oil sources" pattern and all the obesity indices.

Conclusion

Our results suggest that an increase in the high fatty acids from Protein and Olive Oil sources pattern is associated with a reduction in obesity indices, which is opposite to the low EPA and DHA pattern. This was a sex-specific association.

Factors Associated with White Fat Browning: New Regulators of Lipid Metabolism

Mammalian adipose tissue can be divided into white and brown adipose tissue based on its colour, location, and cellular structure. Certain conditions, such as sympathetic nerve excitement, can induce the white adipose adipocytes into a new type of adipocytes, known as beige adipocytes. The process, leading to the conversion of white adipocytes into beige adipocytes, is called white fat browning. The dynamic balance between white and beige adipocytes is closely related to the body’s metabolic homeostasis. Studying the signal transduction pathways of the white fat browning might provide novel ideas for the treatment of obesity and alleviation of obesity-related glucose and lipid metabolism disorders. This article aimed to provide an overview of recent advances in understanding white fat browning and the role of BAT in lipid metabolism.

Serum Fatty Acid-Binding Protein 4 Levels in Adolescents: Effect of Insulin Resistance

Background: Fatty acid-binding protein 4 (FABP4) is an adipokine that plays a causative role in obesity and diabetes. In a stratified cross-sectional study with adolescents, we explored whether changes in FABP4 are already present in lean adolescents, provided they display elements of insulin resistance (IR). Methods: Adolescents were divided in four groups according to body mass index and homeostasis model assessment-IR. Results: In metabolically unhealthy lean (MUL) adolescents (MUL, lean with IR), FABP4 was 33% higher than in healthy counterparts (metabolically healthy lean [MHL]). Obese adolescents without IR (metabolically healthy obesity [MHO]) had 50% higher levels of FABP4 than their lean counterparts (MHL), while levels of FABP4 in obese adolescents with IR (metabolically unhealthy obese [MUO]) were 220% higher than those of MUL adolescents. The differences were significant at least with P < 0.005. MUO > MHO > MUL. Our data demonstrate that the known FABP4 defect in adults with obesity also occurs in youth and even in lean adolescents, suggesting an early association between impaired glucose metabolism and FABP4 irrespective of body weight. FABP4 was more sensitive in discerning each of our 4 subgroups than either adiponectin or leptin. Moreover, evidence for a putative early adiponectin resistance in MUL suggests a combined defect in these adolescents that call for early detection and prevention of the metabolic disturbance that should stay away from concentrating only in subjects with obesity. Conclusions: Our data may serve to draw the considerable attention that is currently paid to FABP4 to the adolescent population, irrespective of the presence of obesity. Further studies with larger cohorts and analyses of visceral and liver fat are warranted.

Association of Visceral Adipose Tissue and Insulin Resistance with Incident Metabolic Syndrome Independent of Obesity Status: The IRAS Family Study

OBJECTIVE

Although increasing evidence suggests that visceral adipose tissue (VAT) is a major underlying cause of metabolic syndrome (MetS), few studies have measured VAT at multiple time points in diverse populations. VAT and insulin resistance were hypothesized to differ by MetS status within BMI category in the Insulin Resistance Atherosclerosis Study (IRAS) Family Study and, further, that baseline VAT and insulin resistance and increases over time are associated with incident MetS.

METHODS

Generalized estimating equations were used for differences in body fat distribution and insulin resistance by MetS status. Mixed effects logistic regression was used for the association of baseline and change in adiposity and insulin resistance with incident MetS across 5 years, adjusted for age, sex, race/ethnicity, and family correlation.

RESULTS

VAT and insulin sensitivity differed significantly by MetS status and BMI category at baseline. VAT and homeostatic model assessment of insulin resistance (HOMA-IR) at baseline (VAT odds ratio [OR] = 1.16 [95% CI: 1.12-2.31]; HOMA-IR OR = 1.85 [95% CI: 1.32-2.58]) and increases over time (VAT OR = 1.55 [95% CI: 1.22-1.98]; HOMA-IR OR = 3.23 [95% CI: 2.20-4.73]) were associated with incident MetS independent of BMI category.

CONCLUSIONS

Differing levels of VAT may be driving metabolic heterogeneity within BMI categories. Both overall and abdominal obesity (VAT) may play a role in the development of MetS. Increased VAT over time contributed additional risk.

Comparison of the Incidence of Cardiovascular Diseases in Weight Groups with Healthy and Unhealthy Metabolism

BACKGROUND

We aimed to identify the relationship between metabolically healthy obesity (MHO), a special subtype of obesity, and the incidence of cardiovascular disease (CVD) in rural Xinjiang.

METHODS

Body mass index (BMI) and the Joint Interim Statement criteria were utilized to define obesity and metabolic status, respectively. A baseline survey was conducted between 2010 and 2012. The cohort was followed-up until 2017, including 5059 participants (2953 Uyghurs and 2106 Kazakhs) in the analysis.

RESULTS

During 6.78 years of follow-up, 471 individuals developed CVD, 10.8% (n=545) of whom were obese, and the prevalence of MHO and MHNW was 5.2% and 54.5%, respectively. Compared with metabolically healthy normal weight subjects, the subjects with MHO had an increased risk of CVD (hazard ratio [HR]=1.76, 95% confidence interval [CI]: 1.23-2.51), while the metabolically unhealthy obesity (MUO) group had an even higher risk (HR=3.80, 95% CI: 2.87-5.03). Additionally, there were sex differences in the relationship between BMI-metabolic status and incident CVD (P _interaction =0.027). Compared with the subjects with MHO, those with MUO had an increased risk of CVD (HR=1.84, 95% CI: 1.26-2.71).

CONCLUSION

MHO was associated with a high risk of CVD among adults in rural Xinjiang. In each BMI category, metabolically unhealthy subjects had a higher risk of developing CVD than did metabolically healthy subjects.

Impact of bariatric surgery on subclinical atherosclerosis in patients with morbid obesity

BACKGROUND

The main cause of death in obese individuals is cardiovascular disease precipitated by atherosclerosis. Endothelial dysfunction and inflammation are considered early events in the development of the disease.

OBJECTIVES

The aim of this study was to identify biomarkers of subclinical atherosclerosis in patients with morbid obesity by comparing clinical, vascular, and biochemical parameters indicative of endothelial dysfunction in patients with and without atheromatous plaque and monitoring changes after bariatric surgery.

SETTINGS

Multicenter collaboration between Biochemistry and Biomedicine Department in Barcelona University and University Hospital Arnau de Vilanova in Lleida.

METHODS

Plasma samples from 66 patients with morbid obesity were obtained before bariatric surgery and at 6 and 12 months after. Patients were divided into 2 groups based on the presence of atheromatous plaque. We used contrast-enhanced carotid ultrasound, enzyme-linked immunosorbent assay, Griess, and EndoPAT-2000 methods.

RESULTS

Patients with plaque showed the worst profile of cardiovascular risk factors. Carotid intima-media thickness and plasminogen activator inhibitor-1 were higher in plaque group (P < .0001). After bariatric surgery, vasa vasorum, oxidized low-density lipoprotein, and plasminogen activator inhibitor-1 decreased (P < .0001 in all cases).

CONCLUSIONS

Obesity promotes atherogenesis, leading to vascular endothelial damage. Bariatric surgery reduces cardiovascular risk and the prognosis is better for patients without plaque. The increase in plasminogen activator inhibitor-1, carotid intima-media thickness, and vasa vasorum proliferation might be the first alterations in the atheromatous process in obesity and could serve as good biomarkers of subclinical atherosclerosis.

Is fatness or fitness key for survival in older adults with intellectual disabilities?

BACKGROUND

Overweight/obesity and poor physical fitness are two prevalent lifestyle-related problems in older adults with intellectual disabilities, which each require a different approach. To improve healthy ageing, we assessed whether fatness or fitness is more important for survival in older adults with intellectual disabilities.

METHODS

In the HA-ID study, we measured obesity and fitness of 874 older adults with intellectual disabilities (61.4 ± 7.8 years). All-cause mortality was assessed over a 5-year follow-up period.

RESULTS

Fitness, but not obesity, was significantly related to survival (HR range of 0.17-0.22). People who were unfit were 3.58 (95% CI = 1.72-7.46) to 4.59 (95% CI = 1.97-10.68) times more likely to die within the follow-up period than people who were fit, regardless of obesity.

CONCLUSION

This was the first study to show that being fit is more important for survival than fatness in older adults with intellectual disabilities. The emphasis should, therefore, shift from weight reduction to improving physical fitness.

Lifetime predictors of stroke in subjects without a diagnosis of hypertension: the aerobics center longitudinal study

BACKGROUND AND PURPOSE

Although several studies have assessed the importance of traditional risk factors in predicting stroke, none have concurrently addressed the stroke-predicting ability of these risk factors across the lifespan of subjects without a hypertension (HTN) diagnosis. Thus, this study aimed to assess the importance of blood-pressure-related risk indicators, cardiorespiratory fitness (CRF), weight status, diabetes mellitus (DM), and lifestyle factors as predictors of stroke in different stages of life among non-hypertensive subjects.

MATERIALS AND METHODS

This study was a long-term follow-up study including 33,254 men and 10,598 women from the Aerobics Center Longitudinal Study (ACLS) who were 18-100 years old and did not have a HTN diagnosis at baseline. Logistic regression models were constructed using forward selection procedures for each age category, with stroke occurrence as the dependent variable, and pulse pressure (PP), mean arterial pressure (MAP), systolic blood pressure (SBP), smoking status, CRF, drinking behavior, DM status, and weight status as potential predictors.

RESULTS

In total, 507 subjects had a stroke during an average follow-up period of 17 years (range=1-34 years). Logistic regression models showed that MAP values (P=0.043) in those aged 19-39 years; SBP (P<0.001), CRF (P=0.001), weight status (P=0.005), and alcohol consumption (P=0.001) in those 40-60 years old; and CRF (P=0.002), weight status (P=0.005), and DM status (P=0.037) in those over 60 years old were predictors of stroke.

CONCLUSION

These findings suggest that, among individuals without a baseline HTN diagnosis, classic modifiable risk factors for stroke change across different stages of life.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

NAFLD Related-HCC: The Relationship with Metabolic Disorders

Obesity increases death rates of all cancers including non-alcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (NAFLD-HCC). NAFLD is considered as hepatic manifestation of metabolic syndrome and is a multi-system disease. Recent prevalence studies have intensively reported the association of obesity, metabolic risk factors and HCC incidence and mortality. Mechanistic studies suggested that immune response, PI3K/AKT/mTOR/PTEN pathway, mitochondrial dysfunction and genetic alterations are important mediators in the progression of NAFLD-HCC from metabolic disorder. In this book chapter, we attempt to collate current research on NAFLD-HCC that lead to our understandings on how metabolic disorders may intersect with cancer development. We also discussed the prevention options of NAFLD-HCC in view of obesity and metabolic disorder. These studies have extended our knowledge on the complicated mechanism of NAFLD and HCC, and provided the prevention options of NAFLD-HCC in patients with obesity and metabolic diseases.

Adipokines are Associated With Hypertension in Metabolically Healthy Obese (MHO) Children and Adolescents: A Prospective Population-Based Cohort Study

Background

The potential mechanism underlying the relationship between the risk of cardiovascular diseases and metabolically healthy obese (MHO) individuals remains unclear. The aim of the study was to prospectively investigate the potential role of the adipokines in the association between the MHO phenotype and hypertension in children and adolescents.

Methods

A total of 1184 participants at baseline were recruited from a cohort of the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) study. The participants were classified according to their body mass index (BMI) and metabolic syndrome (MS) components. The levels of the adipokines, including leptin, adiponectin, and resistin, were measured.

Results

MHO individuals had higher leptin levels (11.58 ug/L vs 1.20 ug/L), leptin/adiponectin ratio (1.18 vs 0.07), and lower adiponectin (11.65 ug/L vs 15.64 ug/L) levels compared to metabolically healthy normal-weight individuals (all P < 0.05). Compared to metabolically healthy normal-weight individuals, the prevalence of high leptin levels (26.5% vs 0.4%), low adiponectin levels (17.9% vs 6.3%) and a high leptin/adiponectin ratio (26.0% vs 2.1%) was higher in MHO individuals (all P < 0.01). The MHO individuals with abnormal adipokines were significantly more likely to developing hypertension (high leptin, relative risk 11.04; 95% confidence interval, 1.18–103.35; and high leptin/adiponectin ratio, relative risk 9.88; 95% confidence interval, 1.11–87.97) compared to metabolically healthy normal-weight individuals with normal adipokine levels.

Conclusions

The abnormal adipokine levels contribute to the increased hypertension risk in MHO children and adolescents. The non-traditional risk factors should be highlighted in MHO children and adolescents in clinical practice and research.

Time to redefine body mass index categories in chronic diseases? Spotlight on obesity paradox

Obesity is a complex condition classically characterised by excessive body fat accumulation and represents one of the most important public health problems worldwide. Although several epidemiological studies have shown that elevated BMI is associated with higher morbidity, and with increased rate of death from all causes and from cardiovascular disease, accumulating evidence suggests that being overweight or obese may be protective (the so-called obesity paradox), at least in chronic diseases. These observations, not only question the validity of the BMI system, but also raise the intriguing question of whether we should redefine what the normal range of BMI is in individuals suffering from a chronic disease. In the present article, we review the available information on the association between elevated BMI and increased morbidity and mortality including obesity-related paradoxes, explore key aspects of the role and limitations of BMI as a measure of increased adiposity and outline potential solutions to address the current controversies regarding the impact of obesity on human health.

Cardiometabolic healthy obesity paradigm and all-cause mortality risk

OBJECTIVE

To examine the cardiometabolic healthy obesity paradigm as it relates to all-cause mortality risk, with effect moderation evaluated for physical activity and demographic characteristics.

METHODS

Data from the 1999-2006 NHANES were used. The analytic sample included 7579 dietary fasting adults (20+ yrs). All-cause mortality was linked with participant data from the National Death Index. Metabolic health was based on fasting levels of triglycerides, high-density lipoprotein cholesterol, glucose and blood pressure. Weight status was determined from measured height and weight. Physical activity was assessed via self-report. Six mutually exclusive groups were evaluated, including 1) Metabolically Healthy and Normal Weight (Referent), 2) Metabolically Healthy and Overweight, 3) Metabolically Healthy and Obese, 4) Metabolically Abnormal and Normal Weight, 5) Metabolically Abnormal and Overweight, and 6) Metabolically Abnormal and Obese. A Cox proportional hazards model was used to evaluate the association between these 6 groups and all-cause mortality.

RESULTS

The unweighted median follow-up was 103months; 770,568 person-months occurred with an incidence rate of 1.18 deaths per 1000 person-months. When compared to those who were metabolically healthy and of normal BMI, all other metabolic and weight configurations had an increased mortality risk. There was no evidence of effect modification by physical activity or demographic characteristics.

CONCLUSIONS

These findings emphasize the importance of optimizing body habitus and increasing public awareness of the detrimental effects of metabolic abnormalities.

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.

Leptin as a cardiovascular risk marker in metabolically healthy obese: Hyperleptinemia in metabolically healthy obese

Adipokines contribute to the inflammatory process which can lead to obesity-associated cardiometabolic complications. Metabolically healthy obese individuals seem to be protected or more resistant to develop these complications and it is intriguing why some individuals develop comorbidities and others do not. Thus, we questioned whether the differences between metabolically healthy and unhealthy obese relied on the alterations in metabolic profile, characterized by serum leptin and adiponectin. A total of 142 obese adults were divided into 2 groups - metabolically healthy obese (MHO) or unhealthy obese (MUO) - and they were evaluated for anthropometric measures, body composition, blood pressure, dietary intakes and plasma levels of leptin and adiponectin. Leptin/adiponectin ratio (L/A) was calculated. Age, BMI and blood pressure were higher in the MUO. No differences in anthropometric measurements, body composition, dietary intake and dietary quality were observed between groups. Leptin were significantly higher in the MUO (53.07 ± 34.56 versus 36.27 ± 24.02 ng/ml in the MHO, r < 0.04). The logistic regression analysis demonstrated that leptin was an important factor associated with not being healthy, independent of age, body weight and BMI. There were no differences between groups for adiponectin and L/A. Leptin correlated positively with body weight (r = 0.25, r < 0.05), BMI (r = 0.38, r < 0.05) and BF (r = 0.74, r < 0.05), and negatively with FFM (r = -0.74, r < 0.05). Our findings suggest that leptin is an important cardiovascular disease marker to obese population and can contribute to evaluate metabolic risks in these 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.

Does youth adiposity, or change in adiposity from youth to adulthood, predict metabolically healthy obesity in adulthood?

BACKGROUND

Individuals with metabolically healthy obesity (MHO) do not have the metabolic complications usually associated with obesity.

OBJECTIVE

To examine whether youth adiposity, or change in adiposity from youth to adulthood, predicts MHO 20 years later.

METHODS

A national sample of 2410 Australian participants had height, weight and waist circumference (WC) measured in 1985 (7-15 years old) and 2004-2006 (26-36 years old). A fasting blood sample was taken in 2004-2006. MHO was defined as body mass index (BMI) ≥30 kg m(-2) , normal fasting glucose (<5.6 mmol L(-1) ), triglycerides (<1.695 mmol L(-1) ), high-density lipoprotein-cholesterol (>1.036 mmol L(-1) men, > 1.295 mmol L(-1) women), blood pressure (<130/85 mmHg) and no medication for these conditions. Relative risks (RR) were calculated using log binomial regression and expressed per unit of youth BMI (or WC) z-score or change in BMI (or WC) z-score from youth to adulthood, adjusted for sex and youth age.

RESULTS

In total 323 individuals were obese at follow-up, 79 (24.5%) were MHO. Adult MHO was not associated with youth BMI (RR: 1.00, 95%CI: 0.85-1.19) or WC (RR: 0.93, 95%CI: 0.79-1.11). Individuals were less likely to be MHO if they had larger increases in BMI (BMI RR: 0.74, 95%CI: 0.57-0.97) or WC (RR: 0.70, 95%CI: 0.55-0.90) from youth to adulthood.

CONCLUSIONS

Change in adiposity from youth to adulthood predicted adult MHO better than youth adiposity alone.

Polymorphisms in stearoyl coa desaturase and sterol regulatory element binding protein interact with N-3 polyunsaturated fatty acid intake to modify associations with anthropometric variables and metabolic phenotypes in Yup'ik people

SCOPE

n-3 polyunsaturated fatty acid (n-3 PUFA) intake is associated with protection from obesity; however, the mechanisms of protection remain poorly characterized. The stearoyl CoA desaturase (SCD), insulin-sensitive glucose transporter (SLC2A4), and sterol regulatory element binding protein (SREBF1) genes are transcriptionally regulated by n-3 PUFA intake and harbor polymorphisms associated with obesity. The present study investigated how consumption of n-3 PUFA modifies associations between SCD, SLC2A4, and SREBF1 polymorphisms and anthropometric variables and metabolic phenotypes.

MATERIALS AND METHODS

Anthropometric variables and metabolic phenotypes were measured in a cross-sectional sample of Yup'ik individuals (n = 1135) and 33 polymorphisms were tested for main effects and interactions using linear models that account for familial correlations. n-3 PUFA intake was estimated using red blood cell nitrogen stable isotope ratios. SCD polymorphisms were associated with ApoA1 concentration and n-3 PUFA interactions with SCD polymorphisms were associated with reduced fasting cholesterol levels and waist-to-hip ratio. SLC2A4 polymorphisms were associated with hip circumference, high-density lipoprotein and ApoA1 concentrations. SREBF1 polymorphisms were associated with low-density lipoprotein and HOMA-IR and n-3 PUFA interactions were associated with reduced fasting insulin and HOMA-IR levels.

CONCLUSION

The results suggest that an individual's genotype may interact with dietary n-3 PUFAs in ways that are associated with protection from obesity-related diseases in Yup'ik people.

Gender-Related Differential Effects of Obesity on Health-Related Quality of Life via Obesity-Related Comorbidities: A Mediation Analysis of a French Nationwide Survey

BACKGROUND

Negative effects of obesity on health-related quality of life (HRQoL) have been reported, especially in women, but the relative contribution of cardiometabolic and other obesity-related comorbidities to such effects remains unclear. Our objective was to model the association by sex between body mass index and HRQoL and to precisely quantify the indirect effects mediated by obesity-related comorbidities.

METHODS AND RESULTS

Data were drawn from the latest French Decennial Health Survey, a nationwide cross-sectional study conducted in 2003 (21 239 adults aged 25-64 years analyzed). HRQoL was measured by the 36-item short-form health survey questionnaire. A mediation analysis based on the counterfactual framework was performed to quantify the proportion of obesity effects on HRQoL mediated by related comorbidities, including cardiometabolic risk factors (diabetes mellitus, hypertension, dyslipidemia) and diseases (ischemic heart disease, cerebrovascular, and peripheral vascular disease), musculoskeletal disorders, and asthma. After multiple linear regression, inverse associations were found between increasing body mass index category and physically oriented and most mentally oriented 36-item short-form health survey dimensions, with evidence of greater effects in women. Mediation analysis revealed that obesity effects were significantly mediated by several comorbidities, more apparently in men (eg, proportion of obesity class II total effect mediated via cardiometabolic factors: general health 27.0% [men] versus 13.6% [women]; proportion of obesity class II total effect mediated via total count of comorbidities: physical functioning 17.8% [men] versus 7.7% [women] and general health 37.1% [men] versus 20.3% [women]).

CONCLUSIONS

Women have a greater overall impact of obesity on HRQoL, but with proportionally lower effects mediated by cardiometabolic and other obesity-related conditions, suggesting the possible role of other specific psychosocial processes.

Physical Activity and Sedentary Behavior in Metabolically Healthy versus Unhealthy Obese and Non-Obese Individuals - The Maastricht Study

Background

Both obesity and the metabolic syndrome are associated with increased risk of cardiovascular diseases and type 2 diabetes. Although both frequently occur together in the same individual, obesity and the metabolic syndrome can also develop independently from each other. The (patho)physiology of “metabolically healthy obese” (i.e. obese without metabolic syndrome) and “metabolically unhealthy non-obese” phenotypes (i.e. non-obese with metabolic syndrome) is not fully understood, but physical activity and sedentary behavior may play a role.

Objective

To examine objectively measured physical activity and sedentary behavior across four groups: I) “metabolically healthy obese” (MHO); II) “metabolically unhealthy obese” (MUO); III)”metabolically healthy non-obese” (MHNO); and IV) “metabolically unhealthy non-obese” (MUNO).

Methods

Data were available from 2,449 men and women aged 40–75 years who participated in The Maastricht Study from 2010 to 2013. Participants were classified into the four groups according to obesity (BMI≥30kg/m²) and metabolic syndrome (ATPIII definition). Daily activity was measured for 7 days with the activPAL physical activity monitor and classified as time spent sitting, standing, and stepping.

Results

In our study population, 562 individuals were obese. 19.4% of the obese individuals and 72.7% of the non-obese individuals was metabolically healthy. After adjustments for age, sex, educational level, smoking, alcohol use, waking time, T2DM, history of CVD and mobility limitation, MHO (n = 107) spent, per day, more time stepping (118.2 versus 105.2 min; p<0.01) and less time sedentary (563.5 versus 593.0 min., p = 0.02) than MUO (n = 440). In parallel, MHNO (n = 1384) spent more time stepping (125.0 versus 115.4 min; p<0.01) and less time sedentary (553.3 versus 576.6 min., p<0.01) than MUNO (n = 518).

Conclusion

Overall, the metabolically healthy groups were less sedentary and more physically active than the metabolically unhealthy groups. Therefore, physical activity and sedentary time may partly explain the presence of the metabolic syndrome in obese as well as non-obese individuals.

A biopsychosocial approach to the interrelation between motherhood and women's excessive weight

Portugal is characterized by a high prevalence of overweight and obesity among women, whose weight increases most rapidly in early adulthood. Individual genetic features and behaviours, along with social, cultural and environmental factors interact in complex relationships with body weight and with its variation throughout time. Motherhood may trigger an increase in weight, potentially influencing the associations between excessive weight and several other health determinants. Taking into account the quality of prenatal care within Portugal's health care system, regarding coverage and success in improved outcomes, we theoretically demonstrate why pregnancy and motherhood should be seen as opportunities for prevention and why a deeper knowledge about the interplay of biological, social and psychological determinants of weight at this stage of life can be useful to design more effective weight control interventions towards this population.

Metabolically Healthy Obesity and the Risk of Cardiovascular Disease in the Elderly Population

Background

Whether being metabolically healthy obese (MHO)—defined by the presence of obesity in the absence of metabolic syndrome—is associated with subsequent cardiovascular disease (CVD) remains unclear and may depend on the participants’ age. We examined the association of being MHO with CVD risk in the elderly.

Methods and Findings

This study included 5,314 individuals (mean age 68 years) from the prospective population-based Rotterdam Study. We categorized our population in groups according to body mass index (BMI) and presence and absence of metabolic syndrome, and estimated the hazard ratio (HR) and 95% confidence interval (95%CI) for every group by using Cox proportional hazard models. Among 1048 (19.7%) obese individuals we identified 260 (24.8%) MHO subjects. Over 14 years of follow-up there were 861 incident CVD cases. In the multivariable adjusted analysis, we did not observe an increased CVD risk in MHO individuals (HR 1.07, 95%CI 0.75–1.53), compared to normal weight individuals without metabolic syndrome. CVD risk was increased by the presence of metabolic syndrome in normal weight (HR 1.35, 95%CI 1.02–1.80), overweight (HR 1.32, 95%CI 1.09–1.60) and obese (HR 1.33, 95%CI 1.07–1.66) individuals, compared to those with normal weight without metabolic syndrome. In a mediation analysis, 71.3% of the association between BMI and CVD was explained by the presence of metabolic syndrome.

Conclusions

In our elderly population, we found that the presence of obesity without metabolic syndrome did not confer a higher CVD risk. However, metabolic syndrome was strongly associated with CVD risk, and was associated with an increased risk in all BMI categories. Therefore, preventive interventions targeting cardiometabolic risk factors could be considered in elderly, regardless of weight status.

Metabolic syndrome: genetic insights into disease pathogenesis

PURPOSE OF REVIEW

Metabolic syndrome (MetS) is a cluster of interrelated and heritable metabolic traits, which collectively impart unsurpassed risk for atherosclerotic cardiovascular disease and type 2 diabetes. Considerable work has been done to understand the underlying disease mechanisms by elucidating its genetic cause.

RECENT FINDINGS

Genome-wide association studies have been widely utilized albeit with modest success in identifying variants that are associated with more than two metabolic traits. Another limitation of this approach is the inherent small effect of the common variants, a major barrier for dissecting their cognate pathways. Modest advances in this venue have been also made by genetic studies of kindreds at the extreme ends of quantitative distributions. These efforts have led to the discovery of a number of disease genes with large effects that underlie the association of diverse traits of this syndrome.

SUMMARY

Substantial progress has been made over the last decade in identification of genetic risk factors associated with the various traits of MetS. The heterogeneity and multifactorial heritability of MetS, however, has been a challenge toward understanding the factors underlying the association of these traits. Genetic investigations of outlier kindreds or homogenous populations with high prevalence for the disease can potentially improve our knowledge of the disease pathophysiology.

Morbidly "Healthy" Obese Are Not Metabolically Healthy but Less Metabolically Imbalanced Than Those with Type 2 Diabetes or Dyslipidemia

BACKGROUND

We have investigated the differences between metabolically "healthy" morbidly obese patients and those with comorbidities.

MATERIALS AND METHODS

Thirty-two morbidly obese patients were divided by the absence ("healthy": DM-DL-) or presence of comorbidities (dyslipidemic: DM-DL+, or dyslipidemic and with type 2 diabetes: DM+DL+). We have studied various plasma parameters and gene expression adipose tissue, before and after gastric bypass.

RESULTS

The group DM+DL+ tends to have lower values than the other two groups for anthropometric parameters. Regarding the satiety parameters, only leptin (p = 0.0024) showed a significant increase with comorbidities. Lipid parameters showed significant differences among groups, except for phospholipids and NEFA. For insulin resistance parameters, only glucose (p < 0.0001) was higher in DM+DL+ patients, but not insulin or homeostasis model assessment of insulin resistance (HOMA-IR). The gene expression of adiponectin, insulin receptor (INSR) and glucose receptor-4 (GLUT4), in the subcutaneous fat, decreased in all groups vs. a non-obese control. Interleukin-6 (IL6) and the inhibitor of plasminogen activator type 1 (PAI-1) genes decreased only in DM-DL+ and DM+DL+, but not in "healthy" patients. Leptin increased in all groups vs. the non-obese control. The visceral fat from DM+DL+ patients showed a sharp decrease in adiponectin, GLUT4, IL6 and PAI-1. All parameters mentioned above improved very significantly by surgery, independent of the occurrence of comorbidities.

CONCLUSIONS

The morbidly obese "healthy" individual is not really metabolically healthy, but morbidly obese individuals with diabetes and dyslipidemia are more metabolically imbalanced.

The impact of low-protein high-carbohydrate diets on aging and lifespan

Most research on nutritional effects on aging has focussed on the impact of manipulating single dietary factors such as total calorie intake or each of the macronutrients individually. More recent studies using a nutritional geometric approach called the Geometric Framework have facilitated an understanding of how aging is influenced across a landscape of diets that vary orthogonally in macronutrient and total energy content. Such studies have been performed using ad libitum feeding regimes, thus taking into account compensatory feeding responses that are inevitable in a non-constrained environment. Geometric Framework studies on insects and mice have revealed that diets low in protein and high in carbohydrates generate longest lifespans in ad libitum-fed animals while low total energy intake (caloric restriction by dietary dilution) has minimal effect. These conclusions are supported indirectly by observational studies in humans and a heterogeneous group of other types of interventional studies in insects and rodents. Due to compensatory feeding for protein dilution, low-protein, high-carbohydrate diets are often associated with increased food intake and body fat, a phenomenon called protein leverage. This could potentially be mitigated by supplementing these diets with interventions that influence body weight through physical activity and ambient temperature.

Diabetic and dyslipidaemic morbidly obese exhibit more liver alterations compared with healthy morbidly obese

Background & aims

To study the origin of fat excess in the livers of morbidly obese (MO) individuals, we analysed lipids and lipases in both plasma and liver and genes involved in lipid transport, or related with, in that organ.

Methods

Thirty-two MO patients were grouped according to the absence (healthy: DM − DL −) or presence of comorbidities (dyslipidemic: DM − DL +; or dyslipidemic with type 2 diabetes: DM + DL +) before and one year after gastric bypass.

Results

The livers of healthy, DL and DM patients contained more lipids (9.8, 9.5 and 13.7 times, respectively) than those of control subjects. The genes implicated in liver lipid uptake, including HL, LPL, VLDLr, and FAT/CD36, showed increased expression compared with the controls. The expression of genes involved in lipid-related processes outside of the liver, such as apoB, PPARα and PGC1α, CYP7a1 and HMGCR, was reduced in these patients compared with the controls. PAI1 and TNFα gene expression in the diabetic livers was increased compared with the other obese groups and control group. Increased steatosis and fibrosis were also noted in the MO individuals.

Conclusions

Hepatic lipid parameters in MO patients change based on their comorbidities. The gene expression and lipid levels after bariatric surgery were less prominent in the diabetic patients. Lipid receptor overexpression could enable the liver to capture circulating lipids, thus favouring the steatosis typically observed in diabetic and dyslipidaemic MO individuals.

•

The criteria used to define the “metabolically healthy” obese is not applicable to morbidly obese patients.

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Virtually no studies of how bariatric surgery affects depending on comorbidities and less how affect to the liver.

•

Anthropometrics, fat, lipid profile and inflammation parameters are different depending of comorbidities, not only in plasma but also in liver.

•

The extent of lipases and lipids in the liver biopsies could help not only the diagnosis but also to follow the course of recovery after surgery.

•

The morbidly obese individuals with diabetes and dyslipidemia have more altered metabolic profiles than the other two groups.

The associations of "fatness," "fitness," and physical activity with all-cause mortality in older adults: A systematic review

OBJECTIVE

This review explored whether cardiorespiratory fitness or physical activity act as either confounders or effect modifiers of the relationship between adiposity markers and all-cause mortality in older adults.

METHODS

Systematic searches were carried out to identify observational studies that examined the association of adiposity markers (BMI, waist circumference, and waist-hip ratio) with all-cause mortality in adults aged ≥ 60 which took into account cardiorespiratory fitness or physical activity. Data from each included study was analyzed to produce a graphical representation of this relationship.

RESULTS

Fourteen of the fifteen identified studies found that increasing BMI had a non-positive association with all-cause mortality, with persistence of the obesity paradox despite adjustment for physical activity or cardiorespiratory fitness. Physical activity measurement methods were all subjective and often unvalidated. The two studies stratifying for cardiorespiratory fitness did not find that fitness had a significant impact on the relationship between excess adiposity and mortality but found that overweight and fit people had better survival than normal-weight unfit people,

CONCLUSIONS

The predominant use of poor physical activity measurement suggests that studies are currently not adequately accounting for possible physical activity confounding. More studies are needed for addressing the modification of the relationship between adiposity markers and mortality by cardiorespiratory fitness.

Healthy excessive weight in Portuguese women 4 years after delivery of a liveborn

OBJECTIVE

To quantify the prevalence of healthy excessive weight and determinants of metabolic profile, considering women's reproductive life.

METHODS

We evaluated 1847 mothers of a birth cohort assembled after delivery and reevaluated 4years later. A healthy profile was defined as the absence of hypertension, diabetes, dyslipidemia, C-reactive protein <3mg/l and being below the second tertile of HOMA-IR. Adjusted odds ratios (OR) and confidence intervals (95% CI) were computed using multinomial logistic regression, taking women with normal BMI as the reference category of the outcome.

RESULTS

Four years after delivery, 47% of women had normal BMI, 33% were overweight and 20% obese. In each BMI class, 61%, 33% and 12% presented a healthy metabolic profile, respectively. Family history of CVD/cardiometabolic risk factors was associated with a higher probability of obesity with a not healthy metabolic profile (OR=1.39 95% CI: 0.98-1.98). Women who breastfed the enrolled child for >26weeks and practiced physical exercise were less likely to be obese and metabolically unhealthy (OR=0.39 95% CI: 0.23-0.68; OR=0.48 95% CI: 0.33-0.70, respectively), with no effect on healthy excessive weight.

CONCLUSIONS

These results support the existence of a healthy excessive weight phenotype in women after motherhood, influenced by anthropometrics, genetic and lifestyles characteristics.

Platelet-derived microparticle count and surface molecule expression differ between subjects with and without type 2 diabetes, independently of obesity status

This study investigated the impact of either type 2 diabetes or obesity, separately or in combination, on the absolute amounts of microparticles (MP) and the pathways by which these are associated with either condition. The concentrations of circulating MP derived from platelets (PMP), leukocytes (LMP) and monocytes (MMP), together with their specific activation markers, were compared in 30 subjects who were characterised across 4 cohorts as obese or type 2 diabetes. The subjects with type 2 diabetes had elevated concentrations of total PMP (P = 0.003), and PMP that were fibrinogen-positive (P = 0.04), tissue factor-positive (P < 0.001), P-selectin-positive (P = 0.03). Type 2 diabetes did not alter either total or activated LMP or MMP. Obesity per se did not impact on any MP measurement. Elevated concentrations of plasma PMP occurred in subjects with type 2 diabetes, whether they were obese or non-obese. In contrast, obesity in the absence of type 2 diabetes had no effect. The increased concentrations of specific marker-positive PMP in the subjects with diabetes might reflect potential pathways by which PMP may contribute to the pathogenesis of atherosclerosis and type 2 diabetes.

Deleted in breast cancer 1 limits adipose tissue fat accumulation and plays a key role in the development of metabolic syndrome phenotype

Obesity is often regarded as the primary cause of metabolic syndrome. However, many lines of evidence suggest that obesity may develop as a protective mechanism against tissue damage during caloric surplus and that it is only when the maximum fat accumulation capacity is reached and fatty acid spillover occurs into to peripheral tissues that metabolic diseases develop. In this regard, identifying the molecular mechanisms that modulate adipocyte fat accumulation and fatty acid spillover is imperative. Here we identify the deleted in breast cancer 1 (DBC1) protein as a key regulator of fat storage capacity of adipocytes. We found that knockout (KO) of DBC1 facilitated fat cell differentiation and lipid accumulation and increased fat storage capacity of adipocytes in vitro and in vivo. This effect resulted in a "healthy obesity" phenotype. DBC1 KO mice fed a high-fat diet, although obese, remained insulin sensitive, had lower free fatty acid in plasma, were protected against atherosclerosis and liver steatosis, and lived longer. We propose that DBC1 is part of the molecular machinery that regulates fat storage capacity in adipocytes and participates in the "turn-off" switch that limits adipocyte fat accumulation and leads to fat spillover into peripheral tissues, leading to the deleterious effects of caloric surplus.

Visceral adiposity index may be a surrogate marker for the assessment of the effects of obesity on arterial stiffness

Objective

The relationship between obesity and cardiovascular disease (CVD) remains unclear. This study aims to describe the relationship between arterial stiffness and obesity in order to investigate the effects of obesity on CVD.

Methods

We collected data from 5,158 individuals over 40 years of age from a cross-sectional study in Nanjing, China. Anthropometric, demographic, hemodynamic measurements and arterial stiffness measured through brachial-ankle pulse wave velocity (baPWV) were obtained. Subjects were grouped by body mass index (BMI), waist circumference (WC) and visceral adiposity index (VAI), a sex-specific index based on BMI, WC, triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C).

Results

The multivariate regression analysis revealed a negative but weak effect of BMI (β = −0.047, P<0.001) on baPWV, but failed to demonstrate any significant effect of WC on baPWV while VAI was a positive independent indicator of baPWV (β = 0.023, P = 0.022). The unadjusted baPWV significantly increased across groups with higher obesity categories (P<0.01). Although the positive association was lost after adjustments for confounding factors in the BMI or WC categories (P>0.05), it was still obtained between baPWV and VAI quartile (P<0.01). No differences were observed among the metabolically healthy groups or the metabolically abnormal groups in the BMI and WC categories (P>0.05). However, baPWV significantly increased across groups with higher VAI categories even in the same metabolic category (P<0.01).

Conclusions

This study supports the concept of heterogeneity of metabolic status among individuals within the same obesity range. Obese individuals are at an increased risk of arterial stiffness regardless of their metabolic conditions. VAI may be a surrogate marker for the assessment of obesity and the effects of obesity on arterial stiffness.

Metabolically healthy obesity and risk of incident type 2 diabetes: a meta-analysis of prospective cohort studies

The risk of type 2 diabetes among obese adults who are metabolically healthy has not been established. We systematically searched Medline (1946-August 2013) and Embase (1947-August 2013) for prospective studies of type 2 diabetes incidence (defined by blood glucose levels or self-report) among metabolically healthy obese adults (defined by body mass index [BMI] and normal cardiometabolic clustering, insulin profile or risk score) aged ≥18 years at baseline. We supplemented the analysis with an original effect estimate from the English Longitudinal Study of Ageing (ELSA), with metabolically healthy obesity defined as BMI ≥ 30 kg m(-2) and <2 of hypertension, impaired glycaemic control, systemic inflammation, adverse high-density lipoprotein cholesterol and adverse triglycerides. Estimates from seven published studies and ELSA were pooled using random effects meta-analyses (1,770 healthy obese participants; 98 type 2 diabetes cases). The pooled adjusted relative risk (RR) for incident type 2 diabetes was 4.03 (95% confidence interval = 2.66-6.09) in healthy obese adults and 8.93 (6.86-11.62) in unhealthy obese compared with healthy normal-weight adults. Although there was between-study heterogeneity in the size of effects (I(2)  = 49.8%; P = 0.03), RR for healthy obesity exceeded one in every study, indicating a consistently increased risk across study populations. Metabolically healthy obese adults show a substantially increased risk of developing type 2 diabetes compared with metabolically healthy normal-weight adults. Prospective evidence does not indicate that healthy obesity is a harmless condition.

Metabolically healthy obesity and the risk of cardiovascular disease and type 2 diabetes: the Whitehall II cohort study

AIM

The metabolically healthy obese (MHO) phenotype refers to obese individuals with a favourable metabolic profile. Its prognostic value is unclear and may depend on the health outcome being examined. We examined the association of MHO phenotype with incident cardiovascular disease (CVD) and type 2 diabetes.

METHODS AND RESULTS

Body mass index and metabolic health, assessed using the Adult Treatment Panel-III (ATP-III) criteria, were assessed on 7122 participants (69.7% men) from the Whitehall II study, aged 39-63 years in 1991-93. Incident CVD (coronary heart disease or stroke) and type 2 diabetes were ascertained from medical screenings (every 5 years), hospital data, and registry linkage until 2009. A total of 657 individuals (9.2% of the cohort) were obese and 42.5% of these were classified as MHO in 1991-93. Over the median follow-up of 17.4 years, there were 828 incident cases of CVD and 798 incident cases of type 2 diabetes. Compared with metabolically healthy normal weight individuals, MHO subjects were at increased risk for CVD (HR = 1.97, 95% CI: 1.38-2.80) and type 2 diabetes (3.25, 95% CI: 2.32-4.54). There was excess risk in metabolically unhealthy obese compared with MHO for type 2 diabetes (1.98, 95% CI: 1.39-2.83) but not CVD (1.23, 95% CI: 0.81-1.87). Treating all measures as time varying covariates produced similar findings.

CONCLUSION

For type 2 diabetes, the MHO phenotype is associated with lower risk than the metabolically unhealthy obese, but for CVD the risk is as elevated in both obesity phenotypes.

All-cause mortality risk of metabolically healthy abdominal obese individuals: the EPIC-MORGEN study

OBJECTIVE

It appears that a certain proportion of obese individuals have a normal metabolic profile despite having excess weight. Whether these so-called "metabolically healthy" obese express lower disease and mortality risks than "metabolically unhealthy" obese is still unclear. The mortality risk of "metabolically healthy" abdominal obese (MHAO) individuals was investigated.

DESIGN AND METHODS

Prospective cohort study (EPIC-MORGEN) among 22,654 individuals aged 20-59 years followed for an average of 13.4 years (SD 2.3). MHAO was assessed at baseline (1993-1997) and defined as abdominal obesity (waist circumference ≥102 cm/≥88 cm (men/women)) with normal glucose, blood pressure, and plasma lipids. All-cause mortality risks adjusted for age and sex were estimated using Cox proportional hazards models.

RESULTS

Individuals who were "metabolically healthy" nonabdominal obese (MHNAO) comprised the reference group. As compared to MHNAO, mortality risk for MHAO was around 40% higher (Hazard ratio (HR) 1.43; 95% confidence interval (CI): 1.00-2.04) and of the same magnitude as that for "metabolically unhealthy" nonabdominal obese (MUNAO) (HR 1.31; 95% CI: 1.08-1.59). The HR for MUAO was 1.99 (95% CI: 1.62-2.43).

CONCLUSIONS

Mortality risk of MHAO individuals was significantly higher than that of MHNAO individuals and lower than, but not statistically significantly different from, that of MUAO individuals.

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

OBJECTIVE

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

DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Defining metabolically healthy obesity: role of dietary and lifestyle factors

BACKGROUND

There is a current lack of consensus on defining metabolically healthy obesity (MHO). Limited data on dietary and lifestyle factors and MHO exist. The aim of this study is to compare the prevalence, dietary factors and lifestyle behaviours of metabolically healthy and unhealthy obese and non-obese subjects according to different metabolic health criteria.

METHOD

Cross-sectional sample of 1,008 men and 1,039 women aged 45-74 years participated in the study. Participants were classified as obese (BMI ≥ 30 kg/m(2)) and non-obese (BMI < 30 kg/m(2)). Metabolic health status was defined using five existing MH definitions based on a range of cardiometabolic abnormalities. Dietary composition and quality, food pyramid servings, physical activity, alcohol and smoking behaviours were examined.

RESULTS

The prevalence of MHO varied considerably between definitions (2.2% to 11.9%), was higher among females and generally increased with age. Agreement between MHO classifications was poor. Among the obese, prevalence of MH was 6.8% to 36.6%. Among the non-obese, prevalence of metabolically unhealthy subjects was 21.8% to 87%. Calorie intake, dietary macronutrient composition, physical activity, alcohol and smoking behaviours were similar between the metabolically healthy and unhealthy regardless of BMI. Greater compliance with food pyramid recommendations and higher dietary quality were positively associated with metabolic health in obese (OR 1.45-1.53 unadjusted model) and non-obese subjects (OR 1.37-1.39 unadjusted model), respectively. Physical activity was associated with MHO defined by insulin resistance (OR 1.87, 95% CI 1.19-2.92, p = 0.006).

CONCLUSION

A standard MHO definition is required. Moderate and high levels of physical activity and compliance with food pyramid recommendations increase the likelihood of MHO. Stratification of obese individuals based on their metabolic health phenotype may be important in ascertaining the appropriate therapeutic or intervention strategy.

Metabolically healthy obesity: definitions, determinants and clinical implications

Obesity is associated with increased risk of developing metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) leading to higher all-cause mortality. However accumulating evidence suggests that not all obese subjects are at increased cardiometabolic risk and that the "metabolically healthy obese" (MHO) phenotype may exist in the absence of metabolic abnormalities. Despite the knowledge of the existence of obese metabolic phenotypes for some time now there is no standard set of criteria to define metabolic health, thus impacting on the accurate estimation of the prevalence of the MHO phenotype and making comparability between studies difficult. Furthermore prospective studies tracking the development of cardiometabolic disease and mortality in MHO have also produced conflicting results. Limited data regards the determinants of the MHO phenotype exist, particularly in relation to dietary and lifestyle behaviours. In light of the current obesity epidemic it is clear that current "one size fits all" approaches to tackle obesity are largely unsuccessful. Whether dietary, lifestyle and/or therapeutic interventions based on stratification of obese individuals according to their metabolic health phenotype are more effective remains to be seen, with limited and conflicting data available so far. This review will present the current state of the art including the epidemiology of MHO and its definitions, what factors may be important in determining metabolic health status and finally, some potential implications of the MHO phenotype in the context of obesity diagnosis, interventions and treatment.

Body composition determinants of metabolic phenotypes of obesity in nonobese and obese postmenopausal women

OBJECTIVE

Although obesity is typically associated with increased cardiovascular risk, a subset of obese individuals display a normal metabolic profile ("metabolically healthy obese," MHO) and conversely, a subset of nonobese subjects present with obesity-associated cardiometabolic abnormalities ("metabolically obese nonobese," MONO). The aim of this cross-sectional study was to identify the most important body composition determinants of metabolic phenotypes of obesity in nonobese and obese healthy postmenopausal women.

DESIGN AND METHODS

We studied a total of 150 postmenopausal women (age 54 ± 7 years, mean ± 1 SD). Based on a cardiometabolic risk score, nonobese (body mass index [BMI] ≤ 27) and obese women (BMI > 27) were classified into "metabolically healthy" and "unhealthy" phenotypes. Total and regional body composition was assessed with dual-energy X-ray absorptiometry (DXA).

RESULTS

In both obese and nonobese groups, the "unhealthy" phenotypes were characterized by frequent bodyweight fluctuations, higher biochemical markers of insulin resistance, hepatic steatosis and inflammation, and higher anthropometric and DXA-derived indices of central adiposity, compared with "healthy" phenotypes. Indices of total adiposity, peripheral fat distribution and lean body mass were not significantly different between "healthy" and "unhealthy" phenotypes. Despite having increased fat mass, MHO women exhibited comparable cardiometabolic parameters with healthy nonobese, and better glucose and lipid levels than MONO. Two DXA-derived indices, trunk-to-legs and abdominal-to-gluteofemoral fat ratio were the major independent determinants of the "unhealthy" phenotypes in our cohort.

CONCLUSIONS

The "metabolically obese phenotype" is associated with bodyweight variability, multiple cardiometabolic abnormalities and an excess of central relative to peripheral fat in postmenopausal women. DXA-derived centrality ratios can discriminate effectively between metabolic subtypes of obesity in menopause.

Diabetes and cardiovascular disease outcomes in the metabolically healthy obese phenotype: a cohort study

OBJECTIVE

To determine the correlates of the "metabolically healthy obese" (MHO) phenotype and the longitudinal risks of diabetes and cardiovascular disease (CVD)/stroke associated with this phenotype.

RESEARCH DESIGN AND METHODS

The North West Adelaide Health Study is a prospective cohort study of 4,056 randomly selected adults aged ≥ 18 years. Participants free of CVD/stroke and not underweight (n = 3,743) were stratified by BMI categories and metabolic risk, defined as having two or more International Diabetes Federation metabolic syndrome criteria, excluding waist circumference.

RESULTS

Correlates of the MHO (n = 454 [12.1%]) included smoking, socioeconomic disadvantage, and physical inactivity. Compared with metabolically healthy normal-weight subjects (n = 1,172 [31.3%]), the MHO were more likely to develop metabolic risk (15.5 vs. 33.1%, P < 0.001) and incident diabetes (odds ratio 2.09 [95% CI 0.87-5.03]) but not CVD/stroke (1.16 [0.58-2.29]) during 5.5-10.3 years of follow-up. These risks were not seen in MHO subjects maintaining metabolic health (n = 188 [67%]). Sustained metabolic health in obese participants was associated with age ≤ 40 years and lower waist circumference. Compared with the metabolically at-risk obese, MHO women demonstrated a significantly higher (mean [SE]) percentage of leg fat (49.9 [0.5] vs. 53.2 [0.7]) and lower waist circumference (104 [0.6] vs. 101 cm [0.8]), despite no significant differences in overall adiposity.

CONCLUSIONS

"Healthy" obesity was a transient state for one-third of subjects. Persistence of a MHO phenotype, which was associated with favorable outcomes, was related to younger age and a more peripheral fat distribution. The MHO phenotype may be sustained by promoting lower waist circumferences.

Physical activity, measures of obesity, and cardiometabolic risk: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The influence of higher physical activity on the relationship between adiposity and cardiometabolic risk is not completely understood.

METHODS

Between 2000-2002, data were collected on 6795 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Self-reported intentional physical activity in the lowest quartile (0-105 MET-minutes/week) was categorized as inactive and the upper three quartiles (123-37,260 MET-minutes/week) as active. Associations of body mass index (BMI) and waist circumference categories, stratified by physical activity status (inactive or active) with cardiometabolic risk factors (dyslipidemia, hypertension, upper quartile of homeostasis model assessment of insulin resistance [HOMA-IR] for population, and impaired fasting glucose or diabetes) were assessed using logistic regression analysis adjusting for age, gender, race/ethnicity, and current smoking.

RESULTS

Among obese participants, those who were physically active had reduced odds of insulin resistance (47% lower; P < .001) and impaired fasting glucose/diabetes (23% lower; P = .04). These associations were weaker for central obesity. However, among participants with a normal waist circumference, those who were inactive were 63% more likely to have insulin resistance (OR [95% CI] 1.63 [1.24-2.15]) compared with the active reference group.

CONCLUSIONS

Physical activity was inversely related to the cardiometabolic risk associated with obesity and central obesity.

Development of metabolic syndrome components in adults with a healthy obese phenotype: a 3-year follow-up

OBJECTIVE

There is a lack of data on the progression from a healthy obese phenotype toward an unhealthy obese phenotype and the development of metabolic syndrome (MetS). Our aim was to assess the development of MetS 3 years after screening in centrally obese individuals with a healthy obese phenotype and to evaluate the usefulness of repeated screening.

DESIGN AND METHODS

Eighty-eight individuals (mean age 47 years, 88% female) with central obesity as their only MetS component (ATP III criteria) at baseline screening were re-evaluated for MetS status after 3 years.

RESULTS

At follow-up, the cardiometabolic risk profile in centrally obese individuals with a healthy phenotype showed a tendency toward deterioration. Thirty-two percent developed at least one additional MetS component, 7% had developed MetS. Nobody had developed type 2 diabetes. An increased triglyceride level (n = 16) and an increased blood pressure (n = 18) were the components most often present at follow-up. The people developing additional MetS components had a lower education level compared with the group that preserved the healthy centrally obese phenotype (80 vs. 71% lower educated, P = 0.35). They also had slightly worse baseline levels of the risk factors.

CONCLUSION

The number of centrally obese individuals developing an unhealthy phenotype in this relatively short follow-up period emphasizes the need for a regular surveillance of cardiometabolic parameters in centrally obese individuals. However, it is questionable whether a repeated screening for type 2 diabetes every 3 years, as recommended by the American Diabetes Association, in this category of patients is appropriate.

A mixture of trans-galactooligosaccharides reduces markers of metabolic syndrome and modulates the fecal microbiota and immune function of overweight adults

Metabolic syndrome is a set of disorders that increases the risk of developing cardiovascular disease. The gut microbiota is altered toward a less beneficial composition in overweight adults and this change can be accompanied by inflammation. Prebiotics such as galactooligosaccharides can positively modify the gut microbiota and immune system; some may also reduce blood lipids. We assessed the effect of a galactooligosaccharide mixture [Bi2muno (B-GOS)] on markers of metabolic syndrome, gut microbiota, and immune function in 45 overweight adults with ≥3 risk factors associated with metabolic syndrome in a double-blind, randomized, placebo (maltodextrin)-controlled, crossover study (with a 4-wk wash-out period between interventions). Whole blood, saliva, feces, and anthropometric measurements were taken at the beginning, wk 6, and end of each 12-wk intervention period. Predominant groups of fecal bacteria were quantified and full blood count, markers of inflammation and lipid metabolism, insulin, and glucose were measured. B-GOS increased the number of fecal bifidobacteria at the expense of less desirable groups of bacteria. Increases in fecal secretory IgA and decreases in fecal calprotectin, plasma C-reactive protein, insulin, total cholesterol (TC), TG, and the TC:HDL cholesterol ratio were also observed. Administration of B-GOS to overweight adults resulted in positive effects on the composition of the gut microbiota, the immune response, and insulin, TC, and TG concentrations. B-GOS may be a useful candidate for the enhancement of gastrointestinal health, immune function, and the reduction of metabolic syndrome risk factors in overweight adults.

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

OBJECTIVE

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

DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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