Financial Incentives to Exercise for Adolescents

Study Overview
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Brief Summary
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Among youth populations, American Indians have the highest prevalence of diabetes in the United States. This study will use exercise as the principal lifestyle modification approach to reduce the risk of diabetes in this population. The Choctaw Nation of Oklahoma has several excellent, but underutilized wellness facilities in their Health Services Area in rural Southeast Oklahoma, a low socioeconomic region. It has been established that exercise lowers diabetes risk, and many overweight/obese, insulin resistant American Indian youth who live in this region would benefit from an increase in regular exercise. The challenge is to modify behavior so that routine exercise is established and maintained. The proposed study will test whether monetary incentives can elicit greater frequency and duration of exercise in American Indian youth when transportation and access barriers are reduced.

Detailed Description
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Study participants in the intervention arm of the study will be asked to exercise on 3 days per week for 48 weeks. Clinical and physical assessments will be performed at baseline and after 16, 32 and 48 weeks. Participants will be randomized into one of two groups. Each group will receive payment for exercise sessions completed but one group will be on a fixed schedule of compensation and the other will have a schedule that incentivizes frequency or duration of exercise. In addition, two reference groups of age-matched participants who are normal weight and subclassified as having either low or high levels of physical activity and fitness will be tested. The reference groups will complete baseline tests and will not enter the exercise intervention program.

Official Title
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Incentivizing Behavior: Promoting More Physical Activity in American Indian Youth

Conditions
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Obesity, Sedentary Lifestyle, Insulin Resistance

Intervention / Treatment
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* Behavioral: Exercise training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria for exercise intervention cohort: 11.0-20.9 years old overweight or obese family history of diabetes (primary or secondary relative) not in sports or exercise program (3 or fewer days per week of moderate-to-vigorous intensity physical activity, MVPA) for prior 3 months Tanner stage 2 or above Inclusion Criteria for reference group cohort: 11.0-20.9 years old normal weight For low physical activity subgroup: not in sports or exercise program (3 or fewer days per week of MVPA) for prior 3 months For high physical activity subgroup: >30 minutes of structured MVPA on >3 days/week over the preceding 3 months Tanner stage 2 or above Exclusion Criteria for all participants: metabolic, endocrine, cardiovascular, kidney disease orthopedic problems that limit physical activity medications or treatments that would interfere with the outcomes and interpretations smoking or tobacco use alcohol or illicit drug use pregnancy

Ages Eligible for Study
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Minimum Age: 11 Years
Maximum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard payment, phase 1<br>All participants will perform exercise training. Participants in this arm will receive a fixed amount of money for exercise session lasting at least 20 minutes during weeks 1-16 (phase 1). All exercise recommendations and outcome tests will be same for this group as the experimental group so that the two groups differ only in the financial incentives they receive for exercise behavior. | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| Active Comparator: Standard payment, phase 2<br>All participants will perform exercise training. Participants in this arm will receive a fixed amount of money for exercise session lasting at least 20 minutes during weeks 17-32 (phase 2). All exercise recommendations and outcome tests will be same for this group as the experimental group so that the two groups differ only in the financial incentives they receive for exercise behavior. | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| Active Comparator: Ramp-down payment, phase 3<br>All participants will perform exercise training. This phase will last from weeks 33-48 (phase 3). Participants in this arm will receive a fixed amount of money for exercise session lasting at least 20 minutes, but the value of the payments will decrease weekly (ramp-down) until reaching zero in week 41. All exercise recommendations and outcome tests will be same for this group as the experimental group so that the two groups differ only in the financial incentives they receive for exercise behavior. | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| Experimental: Incentivized payment, phase 1<br>All participants will perform exercise training. Participants in this arm will receive an increasing amount of money when they increase exercise frequency (number of days) during weeks 1-16 (phase 1). All exercise recommendations and outcome tests will be same for this group as the active comparator group so that the two groups differ only in the financial incentives they receive for exercise behavior | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| Experimental: Incentivized payment, phase 2<br>All participants will perform exercise training. Participants in this arm will receive an increasing amount of money when they exercise for longer than 20 minutes per session during weeks 17-32 (phase 2). All exercise recommendations and outcome tests will be same for this group as the active comparator group so that the two groups differ only in the financial incentives they receive for exercise behavior | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| Experimental: Raffle payment, phase 3<br>All participants will perform exercise training. In weeks 33-48 (phase 3)participants in this arm will receive fewer financial incentives than in the prior 32 weeks but they will be delivered through a raffle system to utilize a variable reinforcement approach. All exercise recommendations and outcome tests will be same for this group as the active comparator group so that the two groups differ only in the financial incentives they receive for exercise behavior. | Behavioral: Exercise training<br>* All participants will perform exercise training at the wellness center. Exercise duration and intensity will be recorded with heart rate monitors.<br>|
| No Intervention: Normal weight, low activity group<br>This group of participants will complete only the baseline tests and assessments and will serve as a reference group. They will be selected to have low physical activity and fitness like the intervention group. Therefore differences in their results with the intervention group will reflect the effects of overweight/obesity on the variables of interest. | |
| No Intervention: Normal weight, high activity group<br>This group of participants will complete only the baseline tests and assessments and will serve as a reference group. They will be selected to have higher physical activity and fitness than the intervention group. They will therefore serve as a healthy reference group and differences in their results with the intervention group will reflect the effects of both overweight/obesity and physical activity on the variables of interest. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Volume of Exercise (Total Time) | Frequency and duration of moderate-to-vigorous physical activity will be measured using heart rate monitors. The monitors will be worn each exercise session. Participants are asked to complete 3 exercise sessions per week throughout the 48-week period of enrollment. The primary comparison between the experimental and active comparator groups will be the volume of exercise (total time) accumulated. Comparisons will be made for accumulated exercise volume at 16, 32, and 48 weeks and the change from baseline (week 0). | at baseline (week 0) and weeks 16, 32, and 48. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin Resistance | Fasting blood glucose and insulin concentration will be measured and used to calculate the homeostatic model of assessment for insulin resistance (iHOMA2, %S). Testing will be performed at baseline (week 0) and weeks 16, 32, and 48. Data analysis will focus on the change from baseline and whether that change differs between groups. | at baseline (week 0) and weeks 16, 32, and 48. | 
| Exercise Fitness | Peak oxygen uptake (VO2max) during a progressive intensity bicycle test to fatigue. Testing will be performed at baseline (week 0) and weeks 16, 32, and 48. Data analysis will focus on the change from baseline and whether that change differs between groups. | at baseline (week 0) and weeks 16, 32, and 48. | 
| Body Composition | Body fat content. Testing will be performed at baseline (week 0) and weeks 16, 32, and 48. Data analysis will focus on the change from baseline and whether that change differs between groups. | at baseline (week 0) and weeks 16, 32, and 48. |