Sarcopenic Obesity and Risk of Incident Type 2 Diabetes: A Prospective Cohort Study and Landmark Analysis From the UK Biobank

OBJECTIVE: To examine whether sarcopenic obesity (SO) is associated with incident type 2 diabetes (T2D) beyond obesity or sarcopenia alone and whether associations differ by sex, age, and transitions in body composition phenotypes over time. RESEARCH DESIGN AND METHODS: We studied 479,607 diabetes-free UK Biobank participants. SO was defined using handgrip strength, skeletal muscle mass-to-weight ratio, and fat mass percentage. Cox models estimated hazard ratios (HRs). A landmark analysis (n = 53,107) examined phenotype transitions. RESULTS: Over a median follow-up of 14.2 years, T2D developed in 32,948 participants. SO conferred the highest risk (HR 3.54 [95% CI 3.34-3.74]), exceeding obesity alone and sarcopenia alone. Transitioning to SO (HR 2.90 [95% CI 2.07-4.07]) and persistent SO (HR 3.07 [95% CI 1.63-5.79]) both elevated risks. CONCLUSIONS: SO was associated with higher T2D risk than obesity or sarcopenia alone, supporting integrated assessment of muscle health and adiposity in T2D risk stratification.