Redefining Obesity and Risk: Extending the 2024 EASO Framework with Morbidity Stratification in the UK Biobank.

Area of Science:

• Cardiology
• Endocrinology
• Public Health

Background:

• The 2024 European Association for the Study of Obesity (EASO) framework redefines obesity using central adiposity and morbidity.
• Previous understanding lacked detailed risk stratification across the Body Mass Index (BMI) spectrum under this new framework.
• Prognostic implications for mortality and cardiovascular outcomes required elucidation.

Purpose of the Study:

• To evaluate the EASO framework's ability to improve phenotypic stratification.
• To describe risk heterogeneity across BMI categories using the EASO framework.
• To assess the framework's impact on mortality and major adverse cardiovascular events (MACE).

Main Methods:

• Utilized UK Biobank data from 451,615 participants with a median follow-up of 15.1 years.
• Defined obesity using the EASO framework, including Waist-to-Height Ratio (WHtR) and morbidity presence.
• Employed Cox proportional hazards models to estimate hazard ratios (HRs) for mortality and MACE.

Main Results:

• The EASO framework reclassified 15.62% of individuals, increasing obesity prevalence from 24.50% to 40.12%.
• All-cause mortality showed a V-shaped association with adiposity, while MACE risk increased linearly.
• EASO overweight individuals had the lowest mortality (HR 0.82), while EASO new obesity and BMI obesity had the highest MACE risks (HRs 1.35 and 1.38, respectively).

Conclusions:

• The EASO framework significantly increases obesity prevalence and better identifies individuals with adverse profiles.
• Morbidity consistently amplifies absolute risk across adiposity levels, supporting its integration into risk assessment.
• The study supports a morbidity-integrated approach for obesity phenotyping and risk stratification.