A new framework for diagnosing obesity that incorporates anthropometric measures beyond body mass index and clinical comorbidities has reclassified nearly 1 in 5 U.S. adults previously considered overweight as having obesity, though the mortality risk associated with this group remains uncertain.
The European Association for the Study of Obesity (EASO) framework—analyzed in a study of 44,030 adults from the National Health and Nutrition Examination Survey (NHANES)—defines obesity as a body mass index (BMI) of 30 kg/m² or higher, or a BMI between 25 and 29.9 kg/m² combined with a waist-to-height ratio (WHtR) over 0.5 and the presence of medical, functional, or psychological complications.
Key Findings on Reclassification and Mortality
The analysis showed that 18.8% of adults previously classified as overweight based on BMI alone were reclassified as persons with obesity (PWO) under the new EASO framework. However, these newly identified PWO demonstrated similar mortality risk to individuals with normal weight (hazard ratio [HR], 0.98; 95% CI, 0.87–1.10), whereas a higher risk was observed among those with BMI ≥30 kg/m² (HR, 1.19; 95% CI, 1.08–1.32).
When compared to individuals with normal weight and without major comorbidities, the newly identified PWO showed elevated mortality risk (HR, 1.50; 95% CI, 1.20–1.88), but this risk was comparable to that seen among normal-weight adults with comorbidities (HR, 1.74; 95% CI, 1.34–2.22).
Among persons classified as overweight based solely on BMI (n = 14,627), 56.4% were reclassified as PWO under the EASO definition. Among those with at least one illness (n = 8,910), 96.8% were reclassified as PWO.
When compared to overweight individuals who were not reclassified, the newly identified PWO had a 77% higher hazard of death (HR, 1.77; 95% CI, 1.36–2.32), a risk nearly identical to that observed in persons with BMI-defined obesity (HR, 1.76; 95% CI, 1.36–2.29).
Demographic and Clinical Characteristics
The newly classified PWO were older (mean age, 51.3 years; SD, 14.5) compared with those defined as overweight (36.5 years; SD, 12.2) or PWO (45.4 years; SD, 15.0) based on BMI alone. Women comprised 41.0% of newly classified PWO compared with 52.3% of BMI-defined PWO.
The most prevalent complications among newly identified PWO were hypertension (79.9%), arthritis (33.2%), diabetes (15.6%), and cardiovascular disease (10.5%). These rates exceeded those among BMI-defined PWO: hypertension (60.3%), arthritis (28.2%), diabetes (19.0%), and cardiovascular disease (8.6%).
Among overweight individuals not reclassified under the EASO framework (n = 6001), 87.7% met the WHtR threshold of 0.5 or higher but lacked the required morbidity component, while only 4.3% met the morbidity criterion without meeting the WHtR threshold.
Framework Components and Methodology
The EASO framework was developed through a Delphi consensus process involving 29 international obesity experts across three iterative rounds. The final framework comprises 28 statements addressing obesity diagnosis, staging, treatment targets, and initial interventions.
In this study, medical complications included hypertension (defined as self-reported hypertension or systolic blood pressure ≥130 mm Hg or diastolic blood pressure ≥80 mm Hg or use of antihypertensive medication), cardiovascular disease, diabetes, arthritis, renal disease, chronic obstructive pulmonary disease, and depression.
The analysis included NHANES participants aged 18–79 years from 1999 to 2018, with mortality data linked through 31 December 2019. Participants were excluded if they had BMI <18 kg/m², cancer, pregnancy, or missing anthropometric data. Cox proportional hazards models evaluated mortality associations, adjusting for age, sex, ethnicity, education, marital status, income-to-poverty ratio, health insurance coverage, smoking status, and alcohol misuse.
The study received funding from Ariel University and the Holon Institute of Technology, Israel. Authors reported no relevant financial conflicts of interest.
Clinical Implications and Limitations
The study authors noted that “the new EASO framework may provide a more sensitive tool to diagnose obesity than the traditional BMI definition,” but acknowledged that it remains unclear whether newly identified adults with obesity would benefit comparably from treatment as those traditionally included in clinical trials.
Limitations included the cross-sectional design, which precluded longitudinal analysis of clinical trajectories. Additionally, 1,602 participants (3.5%) were excluded due to missing BMI and/or waist circumference data.
Editorial Perspective on Risk Stratification
In an accompanying editorial, Christina C. Wee, MD, MPH, and colleagues contextualized the findings within broader efforts to improve obesity risk assessment beyond BMI. They noted that current treatment guidelines already incorporate waist circumference and comorbidities into treatment decisions, often lowering BMI thresholds for interventions in patients with type 2 diabetes or other major conditions.
The editorial emphasized that the excess mortality risk observed among newly reclassified individuals “may simply reflect greater illness burden rather than higher risk posed by excess adiposity above what is captured by BMI and preexisting comorbidities alone.” Accordingly, they questioned the added value of the EASO framework, given existing clinical practice guidelines.
The study received funding from Ariel University and the Holon Institute of Technology, Israel, with authors reporting no relevant financial conflicts of interest.
Source: Annals of Internal Medicine Editorial, Original Research