Continuous Glucose Monitoring in Prediabetes

The current research landscape shows Type 2 diabetes (T2D) as a major public health challenge, affecting more than 10% of Americans with staggering annual costs of $327 billion. Research has clearly established the protective role of physical activity in T2D prevention, with studies showing that even modest increases in daily activity (14 minutes) can reduce T2D risk by 9%, while sedentary behavior like television viewing can significantly increase risk by 30%. These findings underscore the critical importance of physical activity in diabetes prevention strategies.

Continuous Glucose Monitoring (CGM) technology has emerged as a valuable tool in diabetes management, with the American Diabetes Association now recommending its use for diabetes self-management. While CGM's effectiveness in improving blood sugar control among diagnosed T2D patients is well-documented, there's a notable gap in research regarding its potential as a preventive tool. Specifically, no studies have examined whether real-time glucose feedback from CGM devices might encourage increased physical activity among people at risk for developing T2D.

Individuals at risk for type 2 diabetes, such as with prediabetes, were chosen as the study population for several strategic reasons. First, this aligns with a prevention-focused approach, as research shows that lifestyle interventions can effectively delay or prevent diabetes onset in high-risk populations. Second, there's a significant knowledge gap regarding CGM use in prevention - while its benefits for diagnosed diabetes patients are well-documented, its potential as a preventive tool remains unexplored. The study specifically targets individuals with pre-diabetes diagnosis and BMI > 25, while excluding those with prior CGM experience or who use glucose-affecting medications to ensure valid results. This population choice also addresses health equity concerns, as type 2 diabetes disproportionately affects underserved communities, making prevention strategies particularly valuable for these groups.

Inclusion criteria

Adults aged 18 years or older Prediabetes confirmed by the recent lab tests (within three month). If not available, it will be confirmed at lab Body mass index (BMI) >= 25 kg/m2 Ability to provide informed consent Ownership of a smartphone compatible with Dexcom G6 application Willing and able to comply with study procedures for 20 days

Exclusion criteria

Diabetes and Glycemic Management:

• Diagnosed type 1 or type 2 diabetes mellitus
• Current use of glucose-lowering medications (metformin, sulfonylureas, GLP-1 agonists, SGLT2 inhibitors, insulin, etc.)
• HbA1c >= 6.5% or fasting plasma glucose >= 126 mg/dL

Cardiovascular Conditions:

• History of cardiovascular disease (myocardial infarction, stroke, heart failure, coronary artery disease)
• Peripheral artery disease
• Uncontrolled hypertension (systolic BP > 160 mmHg or diastolic BP > 100 mmHg)
• Raynaud phenomenon or other conditions affecting peripheral vascular assessment
• Atrial fibrillation or other arrhythmias affecting pulse wave velocity measurement

Medications Affecting Vascular Function:

• Current use of vasoactive medications (nitrates, phosphodiesterase inhibitors)
• Recent changes (< 4 weeks) in antihypertensive medications
• Chronic use of non-steroidal anti-inflammatory drugs (NSAIDs)
• Systemic corticosteroid use

Physical Activity Limitations:

• Physical disability or musculoskeletal condition preventing normal ambulation
• Use of mobility aids (wheelchair, walker, cane)
• Medical advice to limit physical activity

Other Exclusions:

• Pregnancy or lactation
• Active cancer or cancer treatment within the past 5 years (excluding non-melanoma skin cancer)
• Chronic kidney disease (eGFR < 60 mL/min/1.73m2)
• Liver disease (ALT or AST > 3x upper limit of normal)
• Thyroid disease (unless stable on treatment for > 3 months)
• Current participation in a weight loss program or clinical trial
• Skin conditions preventing CGM sensor placement
• Known allergy to CGM adhesive
• Shift work or irregular sleep schedule (may affect CGM patterns)
• Planned travel during study period that would interfere with study visits