Glucose Observation and Wearable Use for Prevention (GlowUp)

GLOW UP: A Single-Center Observational Study Developing Digital Biomarkers for Prediabetes Screening and Lifestyle Phenotyping

The GLOW UP study is a single-center, prospective, observational case-control study conducted in St. Gallen, Switzerland. The primary aim of the study is to examine to what degree lifestyle data collected from wearable devices and a smartphone app can identify individuals with prediabetes (vs. normoglycemic) in a real-world setting. The study also aims to characterize variability in lifestyle and glycemic patterns and to examine how between- and within-person differences relate to diabetes risk; to identify personalized predictors of early metabolic dysregulation. The study also evaluates new image-based meal tracking algorithms for predicting glycemic control and examines how reminder messages influence adherence to a ~4-week meal logging protocol.

The study aims to enroll 200 adults aged 45 years and older with a BMI of at least 25 kg/m² and no known diagnosis of diabetes, including 100 participants with prediabetes and 100 normoglycemic (metabolically healthy) controls. Participants will be classified at the baseline visit using HbA1c and fasting plasma glucose (FPG) tests, with prediabetes defined as HbA1c 5.7-6.4% and/or FPG 5.6-6.9 mmol/L, and normoglycemia defined as HbA1c <5.7% and FPG <5.6 mmol/L, following clinical standards. During the ~4-week observational period, participants will be asked to wear a smart ring, a wrist-worn smartwatch, and a blinded continuous glucose monitor (CGM). Participants will be asked to log/take-images of their meals via a study app and to complete brief questionnaires (e.g., tracking mood, stress, and contextual meal annotations) via ecological momentary assessments. FPG and HbA1c samples will be collected at baseline to classify participants as prediabetic or normoglycemic, and again at follow-up (~4 weeks), which will serve as the primary outcome to evaluate associations between lifestyle and wearable-derived data and diabetes risk status.

Study Overview

• Status: Recruiting
• Conditions: Prevention

• Study Type: Observational
• Enrollment (Estimated): 200

Contacts and Locations

• Study Contact: Name: Mia Jovanova, Dr.; Phone Number: +41 44 632 05 41; Email: mia.jovanova@unisg.ch

Study Locations

• Switzerland
  • Sankt Gallen, Switzerland, 9000
    • Recruiting
    • HOCH Health and School of Medicine, University of St. Gallen
    • Contact: Mia Jovanova, Dr.; Phone Number: +41 44 632 05 41
    • Contact: Email: mia.jovanova@unisg.ch
    • Principal Investigator: Mia Jovanova, Dr.
    • Principal Investigator: Tobias Kowatsch, Prof. Dr.
    • Principal Investigator: Michael Brändle, Prof. Dr. med

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults ≥45 years with BMI ≥25 kg/m², German-speaking residents of Switzerland, without known diabetes, recruited from GP practices, community and workplace channels, and general public advertisements.

Description

Inclusion Criteria:

• Citizens or residents of Switzerland who are German-speaking (main place of living or employment in Switzerland).
• Age ≥45 years.
• BMI ≥25 kg/m² (overweight or obese).
• Regular access to a smartphone (iOS or Android) with a data plan.
• Able to use smartphone applications.
• Able to walk independently.

Exclusion Criteria:

• History of stroke, heart disease, renal failure, cancer, or diabetes (type 1 or type 2).
• Past vascular bypass surgery or angioplasty.
• Current or planned use of glucose-lowering medications during the upcoming 4 weeks (e.g., GLP-1 receptor agonists, metformin).
• Pregnant or breastfeeding.
• Relevant skin conditions at wearable placement sites (e.g., upper arm).
• BMI <25 kg/m² confirmed at enrollment.
• FPG ≥7.0 mmol/L and/or HbA1c ≥6.5% (newly identified type 2 diabetes); Individuals who meet type-2 diabetes criteria at enrollment, based on Swiss/ADA diagnostic criteria will be informed of blood test results and referred to a GP. These individuals will be deemed ineligible and excluded from the study.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Prediabetic; Adults aged ≥45 years with BMI ≥25 kg/m². FPG 5.6-6.9 mmol/L and/or HbA1c 5.7-6.4% (clinical prediabetes thresholds). No known type-2 diabetes diagnosis.
Normoglycemic; Adults aged ≥45 years with BMI ≥25 kg/m². FPG <5.6 mmol/L and HbA1c <5.7% (normoglycemic; no prediabetes). No known type-2 diabetes diagnosis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diabetes risk status (prediabetic vs. normoglycemic)	Prediabetic (FPG levels 5.6-6.9mmol/L and/or HbA1c levels 5.7%-6.4%) Normoglycemic (FPG levels <5.6mmol/L and HbA1c levels <5.7%)	At follow-up, week 4

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diabetes risk at alternative FPG and HbA1c thresholds	Participants will also be classified using alternative FPG and HbA1c thresholds based on the observed distribution of glycemic values in the resulting study sample (e.g., high-risk prediabetes FPG ≥6.0 mmol/L, HbA1c ≥6.0%). Additionally, continuous FPG and HbA1c values will be analyzed.	At follow-up, week 4
Metabolic phenotypes	Metabolic phenotypes defined based on a combination of FPG, HbA1c, body mass index (BMI) and visceral fat levels.	At follow-up, week 4
Continuous glycemic control	Continuous glucose levels (mmol/L) over the ~4-week period to characterize dynamic glucose patterns.	Up to 4 weeks
Lifestyle profiles	Lifestyle patterns derived based on nutrition (e.g., macro-nutrient composition), physical activity, sleep, stress levels (e.g., survey-based, HR/HRV).	Up to 4 weeks
Adherence to image-based food tracking	Number of meal logs completed	Up to 4 weeks

Collaborators and Investigators

• Sponsor: University of St.Gallen

Study record dates

Study Major Dates

• Study Start (Actual): December 8, 2025
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: January 9, 2026
• First Submitted That Met QC Criteria: January 19, 2026
• First Posted (Actual): January 28, 2026

Study Record Updates

• Last Update Posted (Actual): January 28, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2025-00972

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No