Implications of the European Association for the Study of Obesity's New Framework Definition of Obesity: Prevalence and Association With All-Cause Mortality.

Abstract

Background: The European Association for the Study of Obesity (EASO) recently introduced a new framework to define obesity that incorporates anthropometric measures beyond body mass index (BMI) and clinical comorbidities. However, this framework has not been validated.

Objective: To describe the distribution of overweight and obesity and determine the prevalence of complications and association of obesity with all-cause mortality using BMI categories and the new EASO framework.

Design: Cross-sectional and longitudinal analysis.

Setting: NHANES (National Health and Nutrition Examination Survey) from 1999 to 2018 linked to mortality data.

Participants: A representative sample of the adult population in the United States aged 18 to 79 years.

Measurements: Obesity defined using BMI categories was compared with the new EASO definition.

Results: The study population included 44 030 adults. On the basis of the new EASO definition, 18.8% of adults who were previously defined as overweight based on BMI alone were now considered persons with obesity (PWO). Similar mortality risk was found among the newly identified PWO and persons with normal weight (hazard ratio [HR], 0.98 [95% CI, 0.87 to 1.10]), whereas higher risk was seen among persons with BMI of 30 kg/m² or greater (HR, 1.19 [CI, 1.08 to 1.32]). However, when compared with persons with normal weight who did not have major morbidities, a higher risk was seen among the newly identified PWO (HR, 1.50 [CI, 1.20 to 1.88]), although this higher risk was no greater than the higher risk seen among persons with normal weight and comorbidities (HR, 1.74 [CI, 1.34 to 2.22]). Excess risk was seen among PWO compared with persons with overweight according to both the new EASO framework and the traditional BMI definition. The most prevalent complications among the newly identified PWO were hypertension (79.9%), arthritis (33.2%), diabetes (15.6%), and cardiovascular disease (10.5%).

Limitation: Residual confounding; body weight assessed at a single time point.

Conclusion: The new EASO framework may provide a more sensitive tool to diagnose obesity than the traditional BMI definition, but whether these newly identified adults with obesity would benefit comparably to obesity treatment as those traditionally included in treatment trials is uncertain.

Primary funding source: Ariel University and the Holon Institute of Technology, Israel.