Association between metabolic dysfunction-associated steatotic liver disease and insulin resistance in individuals with normoglycemia

Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly prevalent, especially among individuals with type 2 diabetes mellitus. Insulin resistance (IR) is a key shared mechanism. This study aimed to investigate the association between MASLD and IR in individuals with normal glucose levels. We recruited participants from communities and outpatient clinics in central and northern Taiwan, excluding those with impaired fasting glucose or type 2 diabetes mellitus. Data collected included body mass index, blood pressure, body fat percentage, and lifestyle factors. After overnight fasting, blood samples were taken. MASLD was diagnosed via abdominal ultrasonography. IR was calculated using the homeostasis model assessment of insulin resistance formula and categorized into tertiles (T1-T3). Statistical analyses included analysis of variance and multivariate logistic regression. Among 485 participants (mean age 42.0 ± 11.4 years), MASLD prevalence increased with IR levels (T1: 34.1%, T2: 40.1%, T3: 47.8%; P < .001). Fasting glucose remained within normal limits but rose with IR (T1: 81.9 ± 7.4, T2: 85.1 ± 7.6, T3: 87.3 ± 6.5 mg/dL; P < .0001). After adjusting for age, sex, body mass index, exercise, alcohol use, and smoking, MASLD risk was significantly higher in T3 (odds ratio: 3.87, 95% confidence interval: 2.08-7.21) and T2 (odds ratio: 1.83, 95% confidence interval: 1.11-3.00) compared to T1. Even among individuals with normal glucose levels, elevated IR is significantly associated with higher MASLD risk. Early identification and intervention for IR may help prevent MASLD progression.