Digital Lifestyle Coaching for Alzheimer's Disease Prevention in APOE4 Carriers

Plasma phosphorylated tau 217 (pTau217) concentration will be measured from self-collected dried blood spot samples at three timepoints across the 12-month active monitoring period. Both absolute concentration at each time point and change from baseline will be assessed.

A composite proteomic brain-aging score will be derived from proteomic biomarkers associated with biological brain aging, measured via dried blood spot samples collected from participants. The score represents estimated biological brain age relative to chronological age; lower scores indicate a younger biological brain. Analysis will be restricted to participants who return all required dried blood spot samples.

A composite neuropsychological score will be derived from repeated administration of validated online cognitive assessments, including the Stroop Test, Processing Speed Assessment Test (PSAT), and Trail Making Test, spanning cognitive domains of attention, processing speed, executive function, and cognitive flexibility over time. The direction of the composite score will be defined in the statistical analysis plan. Both composite score at each time point and change from baseline will be assessed.

Physical activity will be assessed continuously via Oura Ring throughout the 12-month study period. Metrics may include daily movement, step count, activity volume, energy expenditure, and overall activity score. Both metric values at each time point and change from baseline will be assessed.

Self-reported physical activity will be assessed monthly via participant questionnaire measuring average duration, frequency, and intensity of physical activity performed during each assessment period.

Sleep health will be assessed continuously via Oura Ring wearable device throughout the 12-month study period. Sleep metrics include total sleep duration, sleep efficiency, REM sleep, deep sleep, sleep latency, sleep timing, restlessness, breathing regularity, blood oxygen saturation, and heart rate variability (HRV), which are combined to generate the Oura Sleep Score (range: 0-100; higher scores indicate better sleep quality). Both Sleep Score at each time point and change from baseline will be assessed.

Subjective sleep quality will be assessed monthly via an 11-point rating scale (range: 0-10) measuring how refreshed participants feel upon waking. Higher scores indicate better subjective sleep quality.

Heart rate variability (HRV) will be assessed continuously via Oura Ring wearable device throughout the 12-month study period. Higher HRV trends over time are interpreted as indicative of better cardiovascular health. Both HRV values at each time point and change from baseline will be assessed.

Self-reported dietary behaviors will be assessed monthly via participant questionnaire. Measures include dietary pattern adherence (e.g., specific diet type followed), macronutrient and food group intake changes (e.g., protein and vegetable consumption), and self-reported weight changes throughout the study period.