EASO's New Obesity Framework and Incident Type 2 Diabetes: A Prospective Cohort Study

We prospectively investigated the association between the European Association for the Study of Obesity (EASO) modified obesity definition and the incidence of type 2 diabetes mellitus (T2DM).

We analysed data from the NAfld in the Gifu Area Longitudinal Analysis (NAGALA) cohort, an ongoing community-based health screening program in Japan. Obesity was defined using both traditional body mass index (BMI) categories and the new EASO definition (BMI 23-27.5 kg/m² plus waist-to-height ratio ≥ 0.5 and at least one obesity-related comorbidity). T2DM was identified during follow-up based on haemoglobin A1c (HbA1c) ≥ 6.5%, fasting plasma glucose ≥ 7.0 mmol/L, or self-reported physician diagnosis of diabetes.

The study included 13 825 adults without diabetes at baseline. According to the new EASO definition, 10.3% of the study population (1424 individuals, representing 31.3% of those originally classified as overweight by BMI) were reclassified as having obesity. Compared with individuals with normal weight, those with EASO-defined overweight showed an increased risk of T2DM [hazard ratio (HR): 1.48, 95% confidence interval (CI): 1.10-2.00], while those with EASO-defined new obesity demonstrated a significantly elevated risk (HR: 5.06, 95% CI: 3.86-6.62). After multivariable adjustment for age, sex, smoking status, alcohol consumption, physical activity, and HbA1c, the adjusted HR for EASO-defined new obesity remained significantly elevated at 2.68 (95% CI: 2.03-3.54). When compared with normal-weight individuals without comorbidities, EASO-defined new obesity was associated with a higher T2DM risk (HR: 4.14, 95% CI: 2.77-6.19) than normal-weight individuals with comorbidities (HR: 1.95, 95% CI: 1.30-2.92).

The new EASO framework may improve the identification of individuals at high risk of incident type 2 diabetes mellitus compared with traditional BMI criteria alone.