Effects of Wearable Device Functions and Health Coaching on Device-measured Movement Behaviours and Cardiometabolic Risk Factors in Adults With Central Obesity

Effects of Wearable Device Functions and Health Coaching on Device-measured Movement Behaviours and Cardiometabolic Risk Factors in Adults With Central Obesity: a Randomised Controlled Trial

This study is a randomized controlled trial. The objective of this study is to investigate:

1. the effects of 1-year evidence-based interventions incorporating wearable device functions alone on device-measured movement behaviours and cardiometabolic risk factors among adults with central obesity; and
2. the effects of 1-year evidence-based interventions incorporating wearable device functions combined with health coaching on device-measured movement behaviours and cardiometabolic risk factors among adults with central obesity.

We hypothesise that the use of wearable device functions in combination with health coaching will lead to significantly greater improvements in device-measured movement behaviours and cardiometabolic risk factors compared with no intervention and wearable device functions alone, both after the 12-month intervention and at the 6-month follow-up.

This study will implement a parallel-group, open-label, 1-year randomized controlled trial involving 133 adults aged 40 years or older with central obesity. The trial will examine the effects of a cutting-edge intervention using evidence-based wearable device functions alone or in combination with evidence-based health coaching on movement behaviours and cardiometabolic risk factors.

All participants will provide written informed consent prior to participation and will be informed that they may withdraw from the study at any time during the study period. A staff member without access to participant information will generate a computer-based randomization list using permuted blocks of six, with two participants allocated to each of the three groups (two intervention groups and one control group) per block, in a 2:2:2 allocation ratio.

The control group will not receive a Fitbit device and will be asked to continue their usual lifestyle. The two intervention groups will use four evidence-based Fitbit functions: step goal setting, sleep goal setting, activity prompts, and community functions. The key difference between the two intervention groups is that one group will additionally receive a structured health coaching program adapted from the U.S. Centers for Disease Control and Prevention (CDC) National Diabetes Prevention Program (NDPP), as used in our prior trial.

The CDC NDPP recommends that at least 22 health coaching sessions be delivered over a 1-year period, depending on participants' needs, and provides corresponding curricula and handouts outlining session content. Coaching sessions will be delivered by trained research staff who have received appropriate professional training in health coaching delivery.

The lifestyle change program will include, but not be limited to:

1. education on cardiometabolic disease risk factors (e.g., type 2 diabetes, coronary heart disease, and stroke);
2. goal planning and goal setting;
3. strategies for self-monitoring physical activity, sleep, diet, and stress;
4. strategies for initiating and maintaining favourable levels of physical activity, diet, and sleep;
5. strategies for obtaining support from family, friends, and co-workers; and
6. review of achievements and challenges during the intervention period, with goal setting and planning for the subsequent 6-month follow-up period.

Participants will attend the research laboratory on three occasions: at baseline, immediately after the 12-month intervention, and at the 6-month follow-up. Assessments will include demographic information, standing height, body weight, body mass index, waist circumference, hip circumference, waist-to-hip ratio, systolic and diastolic blood pressure, and questionnaires.

At each laboratory visit, one EDTA blood sample and one clotted blood sample will be collected by a trained phlebotomist and analysed by an accredited medical diagnostic centre to assess cardiometabolic risk markers, including total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides.

An Axivity AX6 device will be used as a research-grade accelerometer to assess movement behaviours, including sleep, sedentary time, light physical activity, moderate-to-vigorous physical activity (MVPA), steps, energy expenditure, and resting heart rate. Participants will also be asked to wear the Axivity device on the dominant wrist for seven consecutive days at baseline and post-intervention.

Research staff will access participants' Fitbit web accounts to extract Fitbit data, activate Fitbit functions for the intervention groups, and monitor device battery life. Reminders to wear and charge the Fitbit and research-grade accelerometer will be sent every seven days via WhatsApp to promote protocol compliance. To further support adherence, participants who complete all study assessments will receive a HKD 500 supermarket voucher.

Study Overview

• Status: Recruiting
• Conditions: Exercise; Fitness Trackers; Cardio Vascular Disease; Physical Activities; Health Coaching
• Intervention / Treatment: Device: Fitbit Wearable Device; Behavioral: Lifestyle Coaching Program

• Study Type: Interventional
• Enrollment (Estimated): 133
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Youngwon Kim; Phone Number: 852 28315252; Email: youngwon.kim@hku.hk

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong
    • Recruiting
    • Exercise Physiology Lab, The University of Hong Kong
    • Contact: Youngwon Kim; Phone Number: 852 28315252; Email: youngwon.kim@hku.hk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 40 years or older
• Central obesity, defined as waist circumference: ≥90 cm for men; ≥80 cm for women
• Insufficient physical activity based on World Health Organization (WHO) guidelines
• Physical activity assessed using the International Physical Activity Questionnaire (IPAQ) - Short Form
• Ownership of a smartphone
• Able to read and understand English or Chinese

Exclusion Criteria:

• unable to perform daily-life activities, based on the Physical Activity Readiness-Questionnaire (PAR-Q) (24) and/or participation in another lifestyle-change intervention study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Usual Care Control; Participants will continue their usual lifestyle without receiving a wearable device or behavioral intervention.
Experimental: Fitbit Only; Participants will receive a Fitbit wearable device and use selected Fitbit functions related to physical activity and sleep.	Device: Fitbit Wearable Device; Participants will use a Fitbit wearable device with the following evidence-based functions enabled: step goal setting (10% higher than baseline daily steps), sleep goal setting (8 hours per day), activity prompts (vibration alert when fewer than 250 steps are accumulated per hour), and community features such as activity or exercise challenges. These functions support self-monitoring, goal setting, prompts, feedback, and social support.
Experimental: Fitbit + Lifestyle Coaching; Participants will receive a Fitbit wearable device and participate in a structured lifestyle coaching program adapted from the U.S. CDC National Diabetes Prevention Program (NDPP).	Behavioral: Lifestyle Coaching Program; Participants will receive a structured lifestyle coaching program adapted from the U.S. Centers for Disease Control and Prevention National Diabetes Prevention Program (NDPP). The program includes at least 22 coaching sessions delivered over approximately 12 months. Sessions focus on cardiometabolic disease risk factors, goal setting, self-monitoring of physical activity, sleep, diet, and stress, strategies to initiate and maintain healthy behaviors, social support, and review of progress and challenges.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
24-hour Movement Behavior Composition (Accelerometer-derived)	The primary outcome is the 24-hour composition of movement behaviors, defined as the relative distribution of time spent in sedentary behavior, light physical activity, moderate-to-vigorous physical activity (MVPA), and sleep within a 24-hour period. These components will be derived from accelerometer data and jointly analyzed as a single compositional outcome using compositional data analysis methods.	Baseline, 12-month post-intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Weight	Body weight measured using a calibrated digital scale. Unit of Measure: Kilograms (kg)	Baseline, 12 months
Waist Circumference	Waist circumference measured at the midpoint between the lowest rib and the iliac crest. Unit of Measure: Centimeters (cm)	Baseline, 12 months
Blood Pressure	Systolic and diastolic blood pressure measured using a standardized BP monitor. Unit of Measure: mmHg	Baseline, 12 months
Blood Lipid Profile	Total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides measured from fasting blood samples. Unit of Measure: mmol/L	Baseline, 12 months

Collaborators and Investigators

• Sponsor: The University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2025
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: January 15, 2026
• First Submitted That Met QC Criteria: January 23, 2026
• First Posted (Actual): February 2, 2026

Study Record Updates

• Last Update Posted (Actual): February 2, 2026
• Last Update Submitted That Met QC Criteria: January 23, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: randomized controlled trial; wearable technology; movement behavior; NDPP Program
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: healthcoachingrct

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The datasets analysed during the current study and statistical code are available from the corresponding author on reasonable request, as is the full protocol.
• IPD Sharing Time Frame: The datasets analysed during the current study and statistical code will be available after the completion of the study
• IPD Sharing Access Criteria: IPD data can be accessed based on reasonable request by contacting the corresponding author.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

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