Lancet Diabetes & Endocrinology Commission on the Definition and Diagnosis of Clinical Obesity

Differentiating monogenic and syndromic obesities from polygenic obesity: Assessment, diagnosis, and management

Background

Obesity is a multifactorial neurohormonal disease that results from dysfunction within energy regulation pathways and is associated with increased morbidity, mortality, and reduced quality of life. The most common form is polygenic obesity, which results from interactions between multiple gene variants and environmental factors. Highly penetrant monogenic and syndromic obesities result from rare genetic variants with minimal environmental influence and can be differentiated from polygenic obesity depending on key symptoms, including hyperphagia; early-onset, severe obesity; and suboptimal responses to nontargeted therapies. Timely diagnosis of monogenic or syndromic obesity is critical to inform management strategies and reduce disease burden. We outline the physiology of weight regulation, role of genetics in obesity, and differentiating characteristics between polygenic and rare genetic obesity to facilitate diagnosis and transition toward targeted therapies.

Methods

In this narrative review, we focused on case reports, case studies, and natural history studies of patients with monogenic and syndromic obesities and clinical trials examining the efficacy, safety, and quality of life impact of nontargeted and targeted therapies in these populations. We also provide comprehensive algorithms for diagnosis of patients with suspected rare genetic causes of obesity.

Results

Patients with monogenic and syndromic obesities commonly present with hyperphagia (ie, pathologic, insatiable hunger) and early-onset, severe obesity, and the presence of hallmark characteristics can inform genetic testing and diagnostic approach. Following diagnosis, specialized care teams can address complex symptoms, and hyperphagia is managed behaviorally. Various pharmacotherapies show promise in these patient populations, including setmelanotide and glucagon-like peptide-1 receptor agonists.

Conclusion

Understanding the pathophysiology and differentiating characteristics of monogenic and syndromic obesities can facilitate diagnosis and management and has led to development of targeted pharmacotherapies with demonstrated efficacy for reducing body weight and hunger in the affected populations.

Adiposity, type 2 diabetes and atherosclerotic cardiovascular disease risk: Use and abuse of the body mass index

The worldwide prevalence of individuals with an elevated body weight has increased steadily over the past five decades. Billions of research dollars have been invested to improve our understanding of the causes and consequences of having an elevated body weight. All this knowledge has, however, failed to influence populational body weight trajectories of most countries around the world. Research on the definition of "obesity" has also evolved. Body mass index (BMI), the most commonly used tool to make its diagnosis, has major limitations. In this review article, we will highlight evidence from observational studies, genetic association studies and randomized clinical trials that have shown the remarkable inter-individual differences in the way humans store energy as body fat. Increasing evidence also suggests that, as opposed to weight inclusive, lifestyle-based approaches, weight-centric approaches advising people to simply eat less and move more are not sustainable for most people for long-term weight loss and maintenance. It is time to recognize that this outdated approach may have produced more harm than good. On the basis of pathophysiological, genetic and clinical evidence presented in this review, we propose that it may be time to shift away from the traditional clinical approach, which is BMI-centric. Rather, emphasis should be placed on actionable lifestyle-related risk factors aiming at improving overall diet quality and increasing physical activity level in the general population.

Phenotyping of Obesity Treatment Candidates: A Narrative Review

PURPOSE OF REVIEW

This review explores characterizing candidates for obesity treatments including pharmacotherapy, endoscopic bariatric therapies, and metabolic bariatric surgery (MBS), focusing on established clinical parameters for diagnosing obesity beyond body mass index alone.

RECENT FINDINGS

Existing literature primarily provides rates for fat mass percentage (i.e., a marker for adiposity quantity), waist circumference (i.e., a marker for adiposity distribution), and C-reactive protein levels (i.e., a marker for adiposity functionality) among obesity treatment candidates. Limited data on abnormal values and sex-based differentiation exist. The literature indicates high central-tendency measures for fat mass percentage and waist circumference, while C-reactive protein levels vary. Data on the Edmonton Obesity Staging System (i.e., a marker for adiposity-related disease severity) is predominantly available for MBS candidates. Future studies in obesity interventions should improve screening and diagnosis of obesity by incorporating sex-specific considerations and providing abnormal value rates for measurements to enhance understanding of patients' characteristics.

Screening Accuracy of BMI for Adiposity Among 8- to 19-Year-Olds

BACKGROUND AND OBJECTIVES

Although the limitations of BMI have long been recognized, there are recent concerns that it is not a good screening tool for adiposity. We therefore examined the cross-sectional relation of BMI to adiposity among 6923 8- to 19-year-olds in the National Health and Nutrition Survey from 2011 through 2018.

METHODS

Participants were scanned with dual-energy x-ray absorptiometry. Adiposity was expressed as fat mass index (FMI, fat mass kg ÷ m2) and percentage of body fat (%fat). Lean mass was expressed as lean mass index (LMI, lean mass ÷ m2). Regression models and 2 × 2 tables were used to assess the relation of BMI to FMI, %fat, and LMI.

RESULTS

Age and BMI accounted (R2) for 90% to 94% of the variability of FMI and LMI in each sex. Associations with %fat were weaker (R2s ∼0.70). We also examined the screening abilities of a BMI ≥ Centers for Disease Control and Prevention 95th percentile for high levels of adiposity and LMI. Cut points were chosen so that prevalences of high values of these variables would be similar to that for high BMI. Of participants with a high BMI, 88% had a high FMI, and 76% had a high %fat. Participants with a high BMI were 29 times more likely to have a high FMI than those with lower BMIs; comparable relative risks were 12 for high %fat and 14 for high LMI.

CONCLUSIONS

Despite its limitations, a high BMI is a very good screening tool for identifying children and adolescents with elevated adiposity.

Breaking Academic Silos: Pedagogical Recommendations for Equitable Obesity Prevention Training and Research During an Age of Nutrition Polarization

Introduction

Obesity is a preventable chronic condition and a risk factor for poor health and early mortality. Weight stigma and weight-neutral medicine are popular topics in social media that are often at odds with current medical guidelines on obesity treatment and prevention. This conflict may erode the public's trust in science, impede research progress on preventing obesity in marginalized groups, and uphold the ongoing and historical lack of diversity among nutrition trainees.

Methods

The authors conducted a series of student-led dialogue sessions with nutrition graduate students in Boston, Massachusetts, from March to May 2023 to understand perceptions of obesity research, health equity, and racism and discrimination. This article summarizes the lessons learned and provides pedagogical recommendations for jointly addressing obesity at the population level and the recruitment, training, and retention of diverse scholars, clinicians, and public health practitioners.

Results

Dialogue sessions revealed that students perceive a disproportionate focus on the harms of obesity as a chronic disease, highlighting that inadequate attention is given to weight stigma and discrimination. Some participants believed that weight-based discrimination is equally detrimental to individual health and wellbeing as having obesity. Discussions also emphasized the need to pinpoint the multidimensional and cultural manifestations of weight stigma, which necessitates collaboration across social sectors and academic disciplines. Students recognized the urgent need to apply an equity lens to obesity research and teaching but felt limited in their access to experts within nutrition science who specialize in racism, discrimination, eating disorders, and weight stigma.

Conclusions

This study identified concrete opportunities for urgently needed new training and research in population-level obesity prevention, emphasizing antiracism, harm reduction, and elimination of stigma and bias across multiple levels of science and society. Overall, the decision to use the BMI within pedagogy and training must be explicitly stated-research, population surveillance, decision-making, or treatment pedagogy and training-while acknowledging its strengths and limitations across diverse settings. Finally, the social determinants of obesity should incorporate not only weight stigma but also racism and multiple forms of discrimination.

Unraveling the Variability of Human Satiation: Implications for Precision Obesity Management

Satiation is the physiologic process that regulates meal size and termination, and it is quantified by the calories consumed to reach satiation. Given its role in energy intake, changes in satiation contribute to obesity's pathogenesis. Our study employed a protocolized approach to study the components of food intake regulation including a standardized breakfast, a gastric emptying study, appetite sensation testing, and a satiation measurement by an ad libitummeal test. These studies revealed that satiation is highly variable among individuals, and while baseline characteristics, anthropometrics, body composition and hormones, contribute to this variability, these factors do not fully account for it. To address this gap, we explored the role of a germline polygenic risk score, which demonstrated a robust association with satiation. Furthermore, we developed a machine-learning-assisted gene risk score to predict satiation and leveraged this prediction to anticipate responses to anti-obesity medications. Our findings underscore the significance of satiation, its inherent variability, and the potential of a genetic risk score to forecast it, ultimately allowing us to predict responses to different anti-obesity interventions.

Investigating the Role of FABP4 in Diabetes and Obesity and the Influence of Age and Ethnicity: A Comprehensive Analysis of a Cohort from the KEDP-Study

Adipocyte P2 (aP2), also known as FABP4, is an adipokine that adipose tissue produces and expresses in macrophages. Its primary role is to facilitate the transportation of fatty acids across cell membranes. Numerous studies have reported associations between FABP4 and the development of metabolic disorders. However, there is limited knowledge regarding FABP4 expression in diabetes and obesity, especially about different age groups, genders, and ethnicities. This study aims to investigate the association between FABP4 levels, diabetes mellitus, and obesity within various ethnic groups. We measured plasma FABP4 concentrations in a cohort of 2083 patients from the KDEP study and gathered anthropometric data. Additionally, we collected and analyzed clinical, biochemical, and glycemic markers using multivariate regression analysis. The average FABP4 concentration was significantly higher in female participants than in males (18.8 ng/mL vs. 14.4 ng/mL, p < 0.001, respectively), and in those over 50 years old compared to those under 50 years of age (19.3 ng/mL vs. 16.2 ng/mL, p < 0.001, respectively). In this study, significant positive associations were found between the plasma level of FABP4 and obesity markers: BMI (r = 0.496, p < 0.001), hip circumference (r = 0.463, p < 0.001), and waist circumference (WC) (r = 0.436, p < 0.001). Similar observations were also seen with glycemic markers, which included HbA1c (r = 0.126, p < 0.001), fasting blood glucose (FBG) (r = 0.184, p < 0.001), fasting insulin (r = 0.326, p < 0.001), and HOMA-IR (r = 0.333, p < 0.001). Importantly, these associations remained significant even after adjusting for age, gender, and ethnicity. Furthermore, FABP4 levels were negatively associated with male gender (β: -3.85, 95% CI: -4.92, -2.77, p < 0.001), and positively associated with age (β: 0.14, 95% CI: 0.096, 0.183, p < 0.001), BMI (β: 0.74, 95% CI: 0.644, 0.836, p < 0.001), and fasting insulin (β: 0.115, 95% CI: 0.091, 0.138, p < 0.001). In this study, plasma FABP4 levels were significantly higher in diabetic and obese participants, and they were strongly influenced by age, gender, and ethnicity. These findings suggest that FABP4 may serve as a valuable prognostic and diagnostic marker for obesity and diabetes, particularly among female patients, individuals over 50 years old, and specific ethnic groups.

Obesity and body mass index: Past and future considerations in osteoarthritis research

Obesity is an important topic for the osteoarthritis (OA) scientific community. However, the predominant use of body mass index (BMI) to define obesity in OA research is associated with uncertainties and limitations. These include an inability to discern fat and muscle mass, account for sex-differences in fat distribution, or identify adiposity-related health impairments. A focus on BMI in OA research may influence weight bias in clinical practice and impact disparities in access to effective OA treatments. To ensure that our understanding and approaches to improve health outcomes for individuals with or at risk for OA continues to advance in the next decade, future research will need to consider alternative measures beyond BMI for obesity identification and align with evolving obesity science. OA researchers must be aware of issues associated with weight stigma and work to minimize negative generalizations based on BMI.

Approach to Obesity Treatment in Primary Care: A Review

Importance

More than 40% of US adults have obesity, which increases the risks for multiple chronic diseases and premature mortality. Historically, nonsurgical interventions often have not led to sufficient weight loss and maintenance to improve health, but highly effective antiobesity medications (AOMs) have recently become available, and additional effective therapeutics are under development. Given that most medical care for adults with obesity is delivered in primary care settings, guidance for integrating weight-management approaches is needed.

Observations

Lifestyle interventions can lead to a mean weight loss of 2% to 9% of initial weight at 1 year and increase the likelihood of weight loss of 5% or more, but weight regain over time is common even with continued treatment. Adjunctive treatments, including AOMs and surgical approaches, can lead to larger, more sustained weight loss and improvements in numerous obesity-associated medical conditions. Highly effective AOMs, including nutrient-stimulated hormone-based therapies, induce mean weight loss of 15% or more. Barriers to intervention, including access to care, have a disproportionate influence on populations most affected by obesity and its consequences.

Conclusions and Relevance

Primary care clinicians play a vital role in the assessment, management, and support of patients with obesity. With careful clinical assessment and shared decision-making, a flexible treatment plan can be developed that reflects evidence of treatment efficacy, patient preference, and feasibility of implementation. Adjunctive therapies to lifestyle interventions, including more effective pharmacotherapeutics for obesity, offer hope to patients and the potential for considerable improvements in health and quality of life.

A multifaceted training tool to reduce weight bias among healthcare students: A randomized controlled trial

BACKGROUND

Weight bias toward people with obesity (PwO) is common in healthcare settings. Efforts to address weight bias in healthcare settings should begin during university studies. This study aimed to explore the effect of a multifaceted intervention on weight bias among undergraduate healthcare students.

METHODS

An open label randomized controlled trial. The intervention tool consisted of short video lectures on obesity, vignettes simulating interactions between health professionals and PwO, and open discourse with a PwO. The control group received a short-written document on obesity. Online questionnaires on Anti-Fat Attitudes ('AFA'), short form of the Fat-Phobia Scale ('FPS'), Weight Implicit Association Test ('Weight-IAT'), and knowledge about obesity were administered at baseline, 1-week, and 6-week post-intervention.

RESULTS

A total of 162, 152, and 146 students participated in the study at baseline, 1-week, and 6-week post-intervention, respectively. Their mean age was 25.8 ± 6.7 years and 88.3% were women. Means of AFA total scores and FPS scores decreased significantly over time only within the intervention group (P Time*Group = 0.002 and 0.014). Both groups showed a similar trend over time in mean scores of Weight-IAT (P Time*Group = 0.868) and knowledge about obesity (P Time*Group = 0.115).

CONCLUSIONS

A multifaceted intervention resulted in a significant reduction in explicit weight bias but did not yield any additional advantages over the control group in implicit weight bias and knowledge about obesity.

CLINICALTRIALS

GOV NUMBER

NCT05482802.

8. Obesity and Weight Management for the Prevention and Treatment of Type 2 Diabetes: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

"Anti-obesity medications" or "medications to treat obesity" instead of "weight loss drugs" - why language matters - an official statement of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM)

Obesity is largely undertreated, in part because of the stigma surrounding the disease and its treatment. The use of the term "weight loss drugs" to refer to medications for the treatment of obesity may contribute to this stigma, leading to the idea that anyone who wants to lose weight could use them and that short-term use, only in the active weight loss phase would be enough. On the contrary, the use of terms such as "medications to treat obesity" or "anti-obesity medications" conveys the idea that the treatment is directed at the disease rather than the symptom. This joint statement by the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM) intends to alert the press, healthcare professionals and scientific community about the importance of the appropriate use of language, with the aim of improving obesity care.

Achieving consensus on the language of obesity: a modified Delphi study

BACKGROUND

Obesity is recognized by the World Health Organization as a chronic disease. As such, it should be referred to using the language of chronic diseases, with correct and established terminology and definitions. This study was designed to map the current language used to discuss obesity and to compare this with the standard language used for chronic disease.

METHODS

We performed a modified Delphi study to identify the language of chronic disease that is being used in the context of obesity, and to identify discrepancies and potential use of inadequate language with respect to the standard language used for chronic diseases. Participants (n = 24) were identified from relevant stakeholder groups and desk research, and included patients, healthcare professionals, policymakers, researchers, industry, and payers (social insurers) of 18 nationalities/regions in Europe, North/South America, and South Africa. Participants were enrolled between 20.10.2020 and 30.10.2020. The study comprised two rounds of qualitative surveys. In Round 1, participants responded to six open-ended questions. Round 2 comprised 38 statements based on key terms/themes identified in Round 1 and covered the definition, causes, progression, treatment, management, and complications of obesity. Consensus was defined as ≥70% participant agreement on a statement.

FINDINGS

All participants completed Round 1 and 23 participants completed Round 2. In Round 2, consensus was reached for 28 of the 38 statements. Participants reached a consensus regarding the use of statements that acknowledge the heterogeneous nature of obesity, but not on the use of statements that: defined obesity based on body mass index; regarded psychological, physical, or physiological factors among the main causes of obesity; or implied that weight loss should be the aim of obesity treatment.

INTERPRETATION

This study uses expert consensus to provide insight into the language used to describe obesity as a chronic disease, and forms the basis for a unified language of obesity.

FUNDING

Innovative Medicines Initiative, Novo Nordisk A/S.

Addressing child and adolescent obesity management in Ireland: identifying facilitators and barriers in clinical practice

Background

Ireland's Model of Care for the Management of Overweight and Obesity outlines a plan for treating adolescent and child obesity (CO). However, engagement with key stakeholders is required to support its implementation and improve health services.

Aim

This study aims to map the perceived barriers and facilitators related to CO management across healthcare settings, professional disciplines, and regions in the Republic of Ireland (ROI).

Materials and methods

An online cross-sectional survey of registered healthcare professionals (HPs), designed to adhere to the Consolidated Framework for Implementation Research (CFIR), was co-developed by a project team consisting of researchers, healthcare professionals, and patient advocates. The survey was pilot tested with project stakeholders and distributed online to professional groups and via a social media campaign, between September 2021 and May 2022, using "SurveyMonkey." Data were summarised using descriptive statistics and thematic analyses. Themes were mapped to the CFIR framework to identify the type of implementation gaps that exist for treating obesity within the current health and social care system.

Results

A total of 184 HPs completed the survey including nurses (18%), physicians (14%), health and social care professionals (60%), and other HPs (8%). The majority were female (91%), among which 54% reported conducting growth monitoring with a third (32.6%) giving a diagnosis of paediatric/adolescent obesity as part of their clinical practice. Nearly half (49%) of the HPs reported having the resources needed for clinical assessment. However, 31.5% of the HPs reported having enough "time," and almost 10% of the HPs reported having no/limited access to suitable anthropometric measurement tools. Most HPs did not conduct obesity-related clinical assessments beyond growth assessment, and 61% reported having no paediatric obesity training. CFIR mapping identified several facilitators and barriers including time for clinical encounters, suitable materials and equipment, adequate training, perceived professional competency and self-efficacy, human equality and child-centredness, relative priorities, local attitudes, referral protocols, and long waiting times.

Conclusions

The findings provide actionable information to guide the implementation of the Model of Care for the Management of Overweight and Obesity in Ireland. Survey findings will now inform a qualitative study to explore implementation barriers and facilitators and prioritise actions to improve child and adolescent obesity management.

Assessment of obesity

Obesity is a chronic, progressive and relapsing disease, characterised by the presence of abnormal or excess adiposity that impairs health and social wellbeing. It is associated with obesity-related disease complications, health inequalities and premature death. Clinical evaluation of obesity requires a thorough history and examination. Assessment should focus not only on anthropometric measurements, but also on the mental, metabolic, mechanical and monetary impact of adiposity, including multiple health conditions. Increased awareness and knowledge will help reduce weight stigma and biases. A focused non-judgemental assessment will help guide further investigations, timely referral and management.

Neural differences of food-specific inhibitory control in people with healthy vs higher BMI

Consistent with the idea that deficits in inhibition limit resistance to tempting, tasty, high-calorie foods, and might result in a higher BMI, we test whether people with higher BMIs (BMI >25 kg/m²) present inefficient inhibitory control over food-related responses. To unpack this association, we also examine individual differences in the neural mechanisms of food inhibitory control in healthy vs higher BMI individuals. We test these aspects with a sample of 109 participants (49 with higher BMI and 60 with healthy BMI) and the food stop-signal task, which was used to examine individuals' inhibitory control. Results demonstrated that people with higher BMI had significantly poorer food inhibitory control than healthy BMI individuals. fMRI results showed that, in both Go (Go_food vs Go_nature) and Stop conditions (Stop_food vs Stop_nature), compared to healthy BMI individuals, individuals with higher BMI had lower activation in the superior frontal gyrus, precuneus, precentral gyrus, and supramarginal gyrus in the food stimulus condition. Moreover, ROI analysis results showed that under the Stop_food condition, the activation in the inferior frontal gyrus in the higher BMI group was significantly negatively correlated with inhibitory control abilities. These results suggest that people with a higher BMI have limited ability to inhibit food impulsions, and that the prefrontal regions and parietal cortex may contribute to the progression of inhibitory control limitations in relation to food.