Accelerometer-derived physical activity, sarcopenia, and grip strength as modifiers of type 2 diabetes risk

Physical activity (PA) represents a modifiable protective factor against type 2 diabetes mellitus (T2DM), whereas sedentary behavior is recognized as a significant risk factor. However, uncertainties remain regarding the dose-response relationships across different PA intensities, the impact of sarcopenia status, and potential interactions between muscle function and PA. This prospective cohort study included 89,532 UK Biobank participants. PA and sedentary behavior were measured by wrist accelerometers. PA included total volume of PA, moderate-to-vigorous PA (MVPA), and light-intensity PA (LPA). Sarcopenia status was defined using EWGSOP2 criteria including grip strength, muscle mass, and walk pace. Cox proportional hazards models estimated associations with incident T2DM over median seven years of follow-up, adjusting for sociodemographic, lifestyle, and clinical factors. Higher levels of total PA and guideline-recommended MVPA were associated with reduced T2DM risk. Sedentary time showed a positive linear association (P for linearity < 0.001, P for nonlinearity = 0.969). A slow walking pace (HR = 1.82, 95% CI: 1.57-2.10) and severe muscle mass deficit (HR = 1.15, 95% CI: 1.00-1.32) were independent risk factors. Crucially, grip strength modified PA-T2DM associations: higher PA reduced risk significantly only in participants with normal grip strength (HR = 0.60, 95% CI: 0.53-0.69) but not in those with low grip strength (HR = 1.06, 95% CI: 0.74-1.51; P for interaction < 0.05). Accelerometer-measured PA demonstrated dose-dependent protective effects against T2DM, whereas components of sarcopenia were independently associated with an increased risk. Notably, preserved grip strength enhances these benefits, suggesting that muscle function assessment can optimize personalized prevention strategies.