Diabetes Mellitus
Conditions
Keywords
genetic screening
Brief summary
In this 6-month randomized, controlled trial, we examined whether providing participants with genetic test results and counseling regarding their risk for type 2 diabetes would motivate them to improve their health behaviors and lose weight to reduce their diabetes risk. We hypothesized that participants who received conventional diabetes counseling plus genetic test results and counseling would have at least 6 lb greater weight loss at 3 months than participants who received conventional diabetes counseling without genetic test results.
Detailed description
In this 6-month randomized, controlled trial, we evaluated the impact of genetic testing for type 2 diabetes on psychological, health behavior, and clinical outcomes. Eligibility criteria included age 21 to 65 years, overweight or obese (body mass index \[BMI\] \>27 kg/m2), and no prior diagnosis of type 2 diabetes. At baseline, participants (N=601) had conventional risk factors assessed, including demographics, fasting plasma glucose (FPG), and family history. They also provided blood samples for genetic testing of TCF7L2, PPARG, and KCNJ11, three genes that confer elevated risk for development of type 2 diabetes. Participants were then randomized to receive conventional counseling plus control eye disease counseling (CR+EYE) or conventional counseling plus genetic test results (CR+G). Two to four weeks following the baseline visit, when the genetic test results were available, participants returned for a visit with a genetic counselor. All participants received conventional risk counseling based on their lifetime population risk, FPG results, and family history. Next, participants were informed of their randomization assignments; CR+EYE participants received counseling on eye diseases, whereas CR+G participants received genetic counseling. Then perceived risk, affect, self-efficacy, and readiness to change were assessed. All other outcomes were also assessed at 3 and 6 months.
Interventions
GENETICgenetic testing for type 2 diabetes
TCF7L2, PPARG, or KCNJ11
BEHAVIORALConventional risk counseling
Risk based on lifetime risk, fasting plasma glucose results, and family history.
BEHAVIORALeye disease counseling
addresses risk for age-related macular degeneration, glaucoma, cataracts
Sponsors
Duke University
US Department of Veterans Affairs
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
21 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* body mass index \>27 kg/m2 * baseline fasting plasma glucose \<=125 mg/dL
Exclusion criteria
* prior diagnosis of type 2 diabetes * fasting plasma glucose \>125 mg/dL on more than one occasion * HbA1c \> 7% * taking diabetes medication * actively losing weight * enrolled in research study focusing on lifestyle changes * unable to provide informed consent or answer survey questions unassisted * residing in nursing home or receiving home health care * active diagnosis of psychosis or dementia * at least one error on 6-item cognitive screener
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Weight | 3 months | weight 3 months post-enrollment |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Insulin Resistance (HOMA2-IR) | 3 months | Calculated using the updated homeostasis model assessment (HOMA) calculator at http://www.dtu.ox.ac.uk/homacalculator/ Higher numbers indicate higher insulin resistance. There are no established cutoffs indicating impaired resistance. |
| Perceived Lifetime Risk of Type 2 Diabetes | 3 months | measured on 1-7 scale (definitely will not get diabetes to definitely will get diabetes) |
| Daily Caloric Intake | 3 months | Estimated daily caloric intake based on self-reported frequency and amount of intake of specific foods over the past 3 months as assessed by the Block Brief Food Frequency Questionnaire |
| Moderate Intensity Physical Activity | 3 months | self-report based on the long version of the International Physical Activity Questionnaire. Moderate physical activity was queried in the domains of work (e.g., carrying light loads), transportation (e.g., bicycling), domestic chores and gardening (e.g., sweeping, raking), and leisure-time (e.g., bicycling, swimming). |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| CR+G conventional risk counseling (lifetime risk, fasting plasma glucose, and family history) plus genetic testing for type 2 diabetes | 303 |
| CR+EYE conventional risk counseling (lifetime risk, fasting plasma glucose, and family history) plus eye disease counseling | 298 |
| Total | 601 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Death | 2 | 1 |
| Overall Study | Lost to Follow-up | 52 | 43 |
| Overall Study | Physician Decision | 0 | 1 |
| Overall Study | Withdrawal by Subject | 10 | 20 |
Baseline characteristics
| Characteristic | CR+G | CR+EYE | Total |
|---|---|---|---|
| Age, Continuous | 53.9 years STANDARD_DEVIATION 9.1 | 54.4 years STANDARD_DEVIATION 8.4 | 54.1 years STANDARD_DEVIATION 8.7 |
| Body mass index (BMI) stratification BMI<35 kg/m^2 | 208 participants | 213 participants | 421 participants |
| Body mass index (BMI) stratification BMI >= 35 kg/m^2 | 95 participants | 85 participants | 180 participants |
| Education High school graduate or less | 82 participants | 72 participants | 154 participants |
| Education Some post-high school education | 221 participants | 226 participants | 447 participants |
| Family history risk high | 79 participants | 60 participants | 139 participants |
| Family history risk low | 141 participants | 140 participants | 281 participants |
| Family history risk moderate | 79 participants | 94 participants | 173 participants |
| Family history risk unknown | 4 participants | 4 participants | 8 participants |
| Genetic risk high | 74 participants | NA participants | NA participants |
| Genetic risk low | 114 participants | NA participants | NA participants |
| Genetic risk moderate | 113 participants | NA participants | NA participants |
| Genetic risk unknown | 2 participants | NA participants | NA participants |
| Lifetime risk high | 213 participants | 193 participants | 406 participants |
| Lifetime risk low | 8 participants | 5 participants | 13 participants |
| Lifetime risk moderate | 81 participants | 99 participants | 180 participants |
| Lifetime risk unknown | 1 participants | 1 participants | 2 participants |
| Race/Ethnicity, Customized Non-Hispanic White | 137 participants | 115 participants | 252 participants |
| Race/Ethnicity, Customized Other | 166 participants | 183 participants | 349 participants |
| Region of Enrollment United States | 303 participants | 298 participants | 601 participants |
| Sex: Female, Male Female | 55 Participants | 63 Participants | 118 Participants |
| Sex: Female, Male Male | 248 Participants | 235 Participants | 483 Participants |
| Weight | 103.8 kg STANDARD_DEVIATION 17.7 | 100.7 kg STANDARD_DEVIATION 18.9 | 101.8 kg STANDARD_DEVIATION 18.3 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 303 | 1 / 298 |
| serious Total, serious adverse events | 1 / 303 | 2 / 298 |
Outcome results
Primary
Weight
weight 3 months post-enrollment
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CR+G | Weight | 103.8 kg | Standard Deviation 17.7 |
| CR+EYE | Weight | 100.7 kg | Standard Deviation 18.9 |
p-value: 0.4495% CI: [-0.3, 0.7]Mixed Models Analysis
Secondary
Daily Caloric Intake
Estimated daily caloric intake based on self-reported frequency and amount of intake of specific foods over the past 3 months as assessed by the Block Brief Food Frequency Questionnaire
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CR+G | Daily Caloric Intake | 1487 kcal | Standard Deviation 1127 |
| CR+EYE | Daily Caloric Intake | 1573 kcal | Standard Deviation 894 |
p-value: 0.0595% CI: [-0.2, 0]Mixed Models Analysis
Secondary
Insulin Resistance (HOMA2-IR)
Calculated using the updated homeostasis model assessment (HOMA) calculator at http://www.dtu.ox.ac.uk/homacalculator/ Higher numbers indicate higher insulin resistance. There are no established cutoffs indicating impaired resistance.
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CR+G | Insulin Resistance (HOMA2-IR) | 4.1 units on a scale | Standard Deviation 3.6 |
| CR+EYE | Insulin Resistance (HOMA2-IR) | 4.1 units on a scale | Standard Deviation 4.5 |
p-value: 0.1995% CI: [-0.1, 0.3]Mixed Models Analysis
Secondary
Moderate Intensity Physical Activity
self-report based on the long version of the International Physical Activity Questionnaire. Moderate physical activity was queried in the domains of work (e.g., carrying light loads), transportation (e.g., bicycling), domestic chores and gardening (e.g., sweeping, raking), and leisure-time (e.g., bicycling, swimming).
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CR+G | Moderate Intensity Physical Activity | 568 minutes per week | Standard Deviation 650 |
| CR+EYE | Moderate Intensity Physical Activity | 633 minutes per week | Standard Deviation 794 |
p-value: 0.6895% CI: [0.7, 1.2]generalized linear model for count data
Secondary
Perceived Lifetime Risk of Type 2 Diabetes
measured on 1-7 scale (definitely will not get diabetes to definitely will get diabetes)
Time frame: 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CR+G | Perceived Lifetime Risk of Type 2 Diabetes | 3.1 units on a scale | Standard Deviation 1.6 |
| CR+EYE | Perceived Lifetime Risk of Type 2 Diabetes | 3.1 units on a scale | Standard Deviation 1.6 |
p-value: 0.3895% CI: [-0.4, 0.1]Mixed Models Analysis