Central obesity is more closely associated with type 2 diabetes in the middle-aged and elderly population in China than body mass index.

Abstract

Background: the appropriate anthropometric indicator for identifying prevalent type 2 diabetes mellitus (T2DM) in Chinese adults, who often develop the disease at lower BMI levels, remains uncertain.

Methods: we conducted a dual-study analysis integrating longitudinal and cross-sectional evidence. First, using the Global Burden of Disease (GBD) 2023 data, we assessed the long-term trends (1990-2023) in T2DM burden attributable to high BMI among Chinese adults aged ≥ 45 years. Second, using cross-sectional data from the China Health and Retirement Longitudinal Study (CHARLS, 2015 wave, n = 8,841), we evaluated and compared the associations of eight anthropometric indices-BMI, waist circumference (WC), waist-to-height ratio (WHtR), body roundness index (BRI), conicity index (CI), weight-adjusted waist index (WWI), tri-ponderal mass index (TMI), and a body shape index (ABSI)-with prevalent T2DM.

Results: GBD analysis showed a sustained increase in the age-standardized burden of high BMI-attributable T2DM from 1990 to 2023, with greater rises in men than in women. In the CHARLS analysis, central obesity-related indices-particularly BRI, WC, and WHtR-showed relatively strong associations with prevalent T2DM and slightly higher discriminative performance (areas under the curve [AUC] ≈ 0.67) than BMI (AUC = 0.66) and other indices. BRI, WC, and WHtR demonstrated robust, stable associations across all demographic and lifestyle subgroups. ABSI showed the lowest discriminative ability (AUC = 0.59).

Conclusion: central obesity-related anthropometric indices, especially BRI, WC, and WHtR, showed slightly better performance than BMI in identifying prevalent T2DM among middle-aged and older Chinese adults. These findings, against the backdrop of a longitudinally increasing population-level burden, highlight the value of incorporating simple waist-based indices into diabetes screening and prevention strategies in China.