Supplementary file 1_Hidden metabolic obesity phenotypes and risk of incident type 2 diabetes among BMI-defined non-obese adults: a secondary analysis of the NAGALA cohort.pdf

Incidence rates were 1.70, 2.61, 8.20, and 21.37 per 1,000 person-years across the four phenotypes, respectively. In the fully adjusted model, isolated abdominal obesity was not significantly associated with T2DM (HR 1.47, 95% CI 0.66–3.31), whereas isolated fatty liver (HR 3.43, 95% CI 2.41–4.87) and combined abdominal obesity and fatty liver (HR 8.10, 95% CI 4.65–14.12) were strongly associated with higher risk. Risk increased progressively with the number of non-BMI adiposity components (P for trend <0.001).

Associations with fatty liver were observed in both sexes, with no clear evidence of effect modification by sex (P for interaction=0.176), and remained robust in sensitivity analyses, including restriction to BMI <23 kg/m². Adding abdominal obesity, fatty liver, or the four-level phenotype to a comprehensive clinical model did not clearly improve 5-year predictive performance.</p>Conclusions<p>Among BMI-defined non-obese adults, fatty liver—especially when accompanied by abdominal obesity—identified substantial heterogeneity in incident T2DM risk.

These findings highlight the limitations of BMI alone for characterizing adiposity-related metabolic risk, while not establishing incremental predictive utility beyond established clinical risk factors.</p>