PreDiabetes
Conditions
Keywords
Delay Discounting, Episodic Future Thinking
Brief summary
The proposed research will translate research on delay discounting to the prevention of Type 2 diabetes (T2D) in persons with prediabetes. In this study, the investigators will verify target engagement (DD) by examining if EFT improves DD under conditions shown to increase discounting of the future. Prediabetics will be randomized to receive EFT/ERT in a factorial design when experiencing simulated poverty/neutral conditions, respectively. The effects will be measured on DD. The investigators predict that poverty conditions will increase discounting of the future for ERT subjects, but those receiving EFT will show levels of DD similar to levels observed for participants in the wealth condition.
Detailed description
The prevention of Type 2 diabetes in an obese person with prediabetes requires developing a healthier lifestyle. The rational approach for someone with prediabetes would be to eat healthier, be more active, lose weight, and manage their comorbidities. However, preliminary research suggests that individuals with Type 2 diabetes discount the future and engage in behaviors that maximize current pleasure and short-term gain; thus, daily choices needed to improve future health are rare in this population. Delay discounting (DD) describes the choice of smaller immediate versus larger delayed rewards. This behavioral process is related to a wide variety of health choices, ranging from preventive health to behavioral and medical regimen adherence, including regimens used for Type 2 diabetes. The investigators believe that DD provides a target for one type of self-regulation that can improve a wide variety of health behaviors and medical adherence. Research from our laboratories has shown that episodic future thinking (EFT), a form of prospection which reduces the bias towards immediate gratification, activates brain regions involved in planning and prospection such that future rewards have increased value and the extent of delay discounting is reduced. Cueing individuals to think about future events during inter-temporal decision-making reduces the rate of DD, eating in and outside of the laboratory, and smoking behavior. The overarching goal of this research is to use an experimental medicine approach to translate basic research on DD and EFT into clinical interventions to prevent the transition from prediabetes to a diagnosis of Type 2 diabetes.
Interventions
BEHAVIORALEpisodic Future Thinking
Participants will be instructed to use their episodic future cues as they engage in different decision making tasks.
BEHAVIORALEpisodic Recent Thinking
Participants will be instructed to use their episodic recent cues as they engage in different decision making tasks.
BEHAVIORALScarcity Narrative
Participants will read a narrative to induce a scarcity mindset, in which they are asked to imagine a scenario in which they have lost their job and have no current secondary income.
BEHAVIORALNeutral Narrative
Participants will read a narrative in which they are asked to imagine a scenario in which they have been transferred between departmental jobs, with little change in salary/commute.
Sponsors
Virginia Polytechnic Institute and State University
Leonard Epstein
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
Participants will be assigned to complete an episodic future or recent thinking task and asked to describe positive events for different time periods.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Prediabetes: Participants must have a diagnosis of prediabetes within the last 2 years or meet criteria for prediabetes. The American Diabetes Association guidelines defines prediabetes as Fasting Plasma Glucose (FPG) 100-125 mg/dl, 2h glucose 140-199 mg/dl after Oral Glucose Tolerance Test (OGTT), or hemoglobin A1c (HbA1c) approximately 5.7-6.4%. * Comorbidities: Participants must have a history of comorbid diagnosis such as hypertension and/or hyperlipidemia to participate in the behavioral portion of this study. Hypertension is defined as blood pressure greater than 140/90 on two separate occasions at least one week apart, or medical management for hypertension (i.e. medications including Lisinopril and Diovan). Dyslipidemia is defined by LDL greater than 130 mg/dl, or non-fasting non HDL cholesterol ≥160mg/dL or medical management for dyslipidemia (medications including Niacin, Lovastatin).
Exclusion criteria
* Type 2 Diabetes: Individuals will be excluded if they have Type 2 Diabetes. * Pregnancy: Women who are pregnant or lactating will be excluded from participation. * Conditions that affect adherence: Participants should not have a condition that would limit participation which include medical conditions that would affect individuals' ability to use the computer for prolonged period of time; leave the individual unable to ambulate; or current diagnoses of an eating disorder (anorexia, bulimia,), unmanaged psychiatric disorder (depression, anxiety, attention deficit hyperactivity disorder (ADHD), schizophrenia), or an intellectual impairment that would impact study adherence. * Abnormal glucose related to medications: Participants should not be taking medications that would limit participation and cause abnormal glucose levels (e.g. atypical antipsychotic medications or glucocorticoids) including diabetic drugs such as Metformin. * Unwilling or unable to eat study food: Participants who are unwilling or not able to eat the study food (a PowerBar) will not be able to take part in this study. Prior participation in similar studies: Individuals who have recently participated in a laboratory study using similar methods may also be excluded. * Do not meet discounting criteria: Individuals who do not meet discounting criteria (e.g. nonsystematic discounting) on a delay discounting task may be excluded.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Delay Discounting | Delay Discounting will be measured at baseline (session 1) and after receiving EFT/ERT and Scarcity/Narrative (within about 2 weeks) | Delay Discounting will be measured using monetary Delay Discounting tasks with $100 as the delayed reward. Delay discounting is assessed using Area Under the Curve (AUC), or time\*indifference point/delay. AUC for delay discounting included time (x-axis) and indifference point (y-axis), or the amount of money at which the immediate and delayed options are approximately equal. Indifference points are a percentage of the max amount (range 0 - 100). AUC adds the calculated areas for each timepoint from the previous timepoint. Ordinal AUC was used as the measure. Ordinal AUC normalizes the horizontal axis time points to have equal distances between them. AUC ranges from 0 (most impulsive, did not choose delay) to 100 (least impulsive, always chose delay). This is the difference in delay discounting between session 2 and session 1. Larger numbers indicate a decrease in discounting, or less impulsive, while smaller/negative numbers indicate an increase in discounting, or more impulsive. |
| Reinforcing Value of Food | Session 2 | Reinforcing value of food was measured using the relative reinforcing efficacy questionnaire in which participants are asked how many portions of food they would purchase at various prices. Intensity is the number of portions they would purchase and consume when the price is $0. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Working Memory Span | Working Memory will be measured at baseline (session 1) and after receiving EFT/ERT Scarcity/Neutral intervention (up to 2 weeks post-baseline) | Backwards Corsi is a task that assesses visuo-spatial short term working memory. Participants are asked to watch a series of squares on a computer screen and repeat the sequence backwards. This is done several times and the highest number of correctly remembered locations is the span score, with a possible score of 2 - 9 locations total. Span score represents the number of locations that can be recalled backwards. Larger span scores indicate more locations can be remembered and recalled correctly backwards. This is the difference in score between session 2 and session 1. Larger numbers indicate greater change during the experimental manipulation or better working memory, while smaller or negative numbers indicates lower working memory during the experimental manipulation versus baseline. Numbers close to 0 represent little to no change. |
Countries
United States
Participant flow
Pre-assignment details
Participants completed a screening session prior to randomization (n = 149), in which they completed baseline measures of delay discounting and food reinforcement. 78 participants were eligible and randomized
Participants by arm
| Arm | Count |
|---|---|
| Episodic Future Thinking (EFT) & Scarcity Narrative Episodic Future Thinking: Participants will be instructed to use their episodic cues as they engage in different decision making tasks
Narrative: Participants will read a narrative to induce a scarcity mindset, in which they are asked to imagine a scenario in which they have lost their job and have no current secondary income. | 21 |
| Episodic Future Thinking (EFT) & Neutral Narrative Episodic Future Thinking: Participants will be instructed to use their episodic cues as they engage in different decision making tasks
Narrative: Participants will read a narrative in which they are asked to imagine a scenario in which they have been transferred between departmental jobs, with little change in salary/commute. | 20 |
| Episodic Recent Thinking (ERT) & Scarcity Narrative Episodic Recent Thinking: Participants will be instructed to use their episodic cues as they engage in different decision making tasks
Narrative: Participants will read a narrative to induce a scarcity mindset, in which they are asked to imagine a scenario in which they have lost their job and have no current secondary income. | 18 |
| Episodic Recent Thinking (ERT) & Neutral Narrative Episodic Recent Thinking: Participants will be instructed to use their episodic cues as they engage in different decision making tasks
Narrative: Participants will read a narrative in which they are asked to imagine a scenario in which they have been transferred between departmental jobs, with little change in salary/commute. | 19 |
| Total | 78 |
Baseline characteristics
| Characteristic | Episodic Future Thinking (EFT) & Neutral Narrative | Total | Episodic Recent Thinking (ERT) & Neutral Narrative | Episodic Future Thinking (EFT) & Scarcity Narrative | Episodic Recent Thinking (ERT) & Scarcity Narrative |
|---|---|---|---|---|---|
| Age, Continuous | 50.55 years STANDARD_DEVIATION 34.45 | 50.33 years STANDARD_DEVIATION 12.51 | 52.89 years STANDARD_DEVIATION 11.38 | 47.57 years STANDARD_DEVIATION 12.72 | 50.61 years STANDARD_DEVIATION 10.41 |
| Delay discounting $1000 Delay Discounting | 0.57 time*indifference point/delay STANDARD_DEVIATION 0.21 | 0.59 time*indifference point/delay STANDARD_DEVIATION 0.21 | 0.59 time*indifference point/delay STANDARD_DEVIATION 0.2 | 0.61 time*indifference point/delay STANDARD_DEVIATION 0.19 | 0.60 time*indifference point/delay STANDARD_DEVIATION 0.23 |
| Delay discounting $100 Delay Discounting | 0.49 time*indifference point/delay STANDARD_DEVIATION 0.17 | 0.51 time*indifference point/delay STANDARD_DEVIATION 0.17 | 0.51 time*indifference point/delay STANDARD_DEVIATION 0.2 | 0.54 time*indifference point/delay STANDARD_DEVIATION 0.16 | 0.52 time*indifference point/delay STANDARD_DEVIATION 0.18 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 2 Participants | 0 Participants | 2 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 19 Participants | 73 Participants | 19 Participants | 19 Participants | 16 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 1 Participants | 3 Participants | 0 Participants | 0 Participants | 2 Participants |
| hbA1c HbA1c % 5.4-5.6 | 10 Participants | 40 Participants | 9 Participants | 11 Participants | 10 Participants |
| hbA1c HbA1c %5.7-6.4 | 10 Participants | 38 Participants | 10 Participants | 10 Participants | 8 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 2 Participants | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 1 Participants | 1 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 8 Participants | 28 Participants | 9 Participants | 5 Participants | 6 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 3 Participants | 0 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) White | 11 Participants | 43 Participants | 10 Participants | 14 Participants | 8 Participants |
| Region of Enrollment United States | 20 participants | 78 participants | 19 participants | 21 participants | 18 participants |
| Reinforcing Value of Food; Intensity | 10.7 number of food portions STANDARD_DEVIATION 15.1 | 9.6 number of food portions STANDARD_DEVIATION 10.6 | 7.4 number of food portions STANDARD_DEVIATION 7.1 | 9.9 number of food portions STANDARD_DEVIATION 6.9 | 106 number of food portions STANDARD_DEVIATION 11.7 |
| Sex: Female, Male Female | 15 Participants | 61 Participants | 16 Participants | 17 Participants | 13 Participants |
| Sex: Female, Male Male | 5 Participants | 17 Participants | 3 Participants | 4 Participants | 5 Participants |
| Site Enrollment University at Buffalo | 13 Participants | 47 Participants | 11 Participants | 12 Participants | 11 Participants |
| Site Enrollment Virginia Tech Carilon | 7 Participants | 31 Participants | 8 Participants | 9 Participants | 7 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 21 | 0 / 20 | 0 / 18 | 0 / 19 |
| other Total, other adverse events | 0 / 21 | 0 / 20 | 0 / 18 | 0 / 19 |
| serious Total, serious adverse events | 0 / 20 | 0 / 21 | 0 / 18 | 0 / 19 |
Outcome results
Primary
Change in Delay Discounting
Delay Discounting will be measured using monetary Delay Discounting tasks with $100 as the delayed reward. Delay discounting is assessed using Area Under the Curve (AUC), or time\*indifference point/delay. AUC for delay discounting included time (x-axis) and indifference point (y-axis), or the amount of money at which the immediate and delayed options are approximately equal. Indifference points are a percentage of the max amount (range 0 - 100). AUC adds the calculated areas for each timepoint from the previous timepoint. Ordinal AUC was used as the measure. Ordinal AUC normalizes the horizontal axis time points to have equal distances between them. AUC ranges from 0 (most impulsive, did not choose delay) to 100 (least impulsive, always chose delay). This is the difference in delay discounting between session 2 and session 1. Larger numbers indicate a decrease in discounting, or less impulsive, while smaller/negative numbers indicate an increase in discounting, or more impulsive.
Time frame: Delay Discounting will be measured at baseline (session 1) and after receiving EFT/ERT and Scarcity/Narrative (within about 2 weeks)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Episodic Future Thinking (EFT) & Scarcity Narrative | Change in Delay Discounting | -0.002 time*indifference point/delay | Standard Deviation 0.032 |
| Episodic Future Thinking (EFT) and Neutral Narrative | Change in Delay Discounting | 0.108 time*indifference point/delay | Standard Deviation 0.032 |
| Episodic Recent Thinking (ERT) and Scarcity Narrative | Change in Delay Discounting | -0.069 time*indifference point/delay | Standard Deviation 0.034 |
| Episodic Recent Thinking (ERT) & Neutral Narrative | Change in Delay Discounting | 0.035 time*indifference point/delay | Standard Deviation 0.033 |
p-value: 0.0034ANOVA
Primary
Reinforcing Value of Food
Reinforcing value of food was measured using the relative reinforcing efficacy questionnaire in which participants are asked how many portions of food they would purchase at various prices. Intensity is the number of portions they would purchase and consume when the price is $0.
Time frame: Session 2
Population: Two participants did not complete Reinforcing value measures
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Episodic Future Thinking (EFT) & Scarcity Narrative | Reinforcing Value of Food | 9.9 number of food portions purchased at $0 | Standard Deviation 2.4 |
| Episodic Future Thinking (EFT) and Neutral Narrative | Reinforcing Value of Food | 10.7 number of food portions purchased at $0 | Standard Deviation 2.5 |
| Episodic Recent Thinking (ERT) and Scarcity Narrative | Reinforcing Value of Food | 10.6 number of food portions purchased at $0 | Standard Deviation 2.5 |
| Episodic Recent Thinking (ERT) & Neutral Narrative | Reinforcing Value of Food | 7.4 number of food portions purchased at $0 | Standard Deviation 2.5 |
p-value: 0.76ANOVA
Secondary
Change in Working Memory Span
Backwards Corsi is a task that assesses visuo-spatial short term working memory. Participants are asked to watch a series of squares on a computer screen and repeat the sequence backwards. This is done several times and the highest number of correctly remembered locations is the span score, with a possible score of 2 - 9 locations total. Span score represents the number of locations that can be recalled backwards. Larger span scores indicate more locations can be remembered and recalled correctly backwards. This is the difference in score between session 2 and session 1. Larger numbers indicate greater change during the experimental manipulation or better working memory, while smaller or negative numbers indicates lower working memory during the experimental manipulation versus baseline. Numbers close to 0 represent little to no change.
Time frame: Working Memory will be measured at baseline (session 1) and after receiving EFT/ERT Scarcity/Neutral intervention (up to 2 weeks post-baseline)
Population: Five participants did not complete both measures of the spatial span task.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Episodic Future Thinking (EFT) & Scarcity Narrative | Change in Working Memory Span | 0.05 number of locations | Standard Deviation 0.48 |
| Episodic Future Thinking (EFT) and Neutral Narrative | Change in Working Memory Span | 0.41 number of locations | Standard Deviation 0.51 |
| Episodic Recent Thinking (ERT) and Scarcity Narrative | Change in Working Memory Span | 0.72 number of locations | Standard Deviation 0.49 |
| Episodic Recent Thinking (ERT) & Neutral Narrative | Change in Working Memory Span | 0.16 number of locations | Standard Deviation 0.48 |
p-value: 0.77ANOVA