Body mass index (BMI) and lipid parameters are commonly assessed in the clinical evaluation of older adults with type 2 diabetes mellitus (T2DM). A large cohort analysis published in Diabetology & Metabolic Syndrome evaluated whether low BMI (BMI <22 kg/m²) and core lipid parameters were associated with all-cause mortality in older adults with T2DM and evaluated potential mediation by lipid markers.
The analysis included 372,559 participants aged ≥60 years from the Shanghai Center for Disease Control and Prevention diabetes management cohort. Participants were stratified according to BMI <22 kg/m². Linear regression models evaluated associations between low BMI and lipid parameters, while Cox regression models assessed relationships between BMI, lipid parameters, and mortality risk. Restricted cubic spline models were used to examine nonlinear trends, and Bayesian mediation models quantified potential mediation effects.
Compared with participants with BMI ≥22 kg/m², those with BMI <22 kg/m² had a higher risk of all-cause mortality (hazard ratio [HR] 1.10; 95% confidence interval [CI] 1.06-1.13). Nonlinear associations were observed between lipid parameters and mortality risk. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) demonstrated U-shaped relationships, while high-density lipoprotein cholesterol (HDL-C) showed an L-shaped association. Optimal thresholds were identified at 5.03 mmol/L for TC, 0.98 mmol/L for HDL-C, and 3.39 mmol/L for LDL-C. Mediation analysis demonstrated significant negative mediation effects for TC (proportion mediated −16.68%), HDL-C (−111.99%), and LDL-C (−4.12%), with HDL-C showing the strongest masking effect (βACME 1.44; 95% CI 1.33-1.56).
These findings indicate that low BMI was independently associated with a higher risk of all-cause mortality in older adults with type 2 diabetes mellitus. Lipid parameters, particularly HDL-C, accounted for part of this association in mediation analyses, highlighting the relevance of lipid metabolic disturbances among underweight older adults with T2DM.
