Glow Up: a single-centre observational study protocol to develop digital biomarkers for prediabetes screening and digital phenotyping

Introduction: Prediabetes, a key precursor to type 2 diabetes, is highly prevalent and underdiagnosed, particularly among adults aged ≥45 years with elevated body mass index (BMI). Early detection is critical because lifestyle interventions can delay or prevent progression to type 2 diabetes. The Glucose Observation and Wearable Use for Prevention (Glow Up) study aims to (1) test the feasibility of a digital biomarker for pre-diabetes screening using wearable- and smartphone-derived lifestyle factors (eg, sleep, physical activity and nutrition patterns) in daily life and to (2) characterise individual- and metabolic subgroup-level variability in lifestyle factors and glycaemic control. Specifically, we aim to examine how lifestyle factors relate to glycaemic status and identify personalised predictors of early metabolic dysregulation.