Adolescent Behavior, Obesity, Adolescent
Conditions
Keywords
adolescent, obesity, relative reinforcing value, physical activity, weight change
Brief summary
While a substantial body of research suggests that RRV is related to obesity, there is very little research on factors that contribute to the RRV of food, particularly how patterns of eating can increase or decrease the motivation to eat specific foods. Previous work has demonstrated that a subset of individuals with obesity show increases in RRV of food after repeated consumption of large portions of high energy density (HED) snack foods, which has been conceptualized as sensitization. Preliminary data suggest that sensitization of the RRV of HED food is a predictor of weight gain over time. However, more work needs to be done to address this relationship using a planned, prospective study design, using adolescent research subjects, and examining potential moderators of this relationship. The purpose of this study is to identify risk and protective factors to excess zBMI change in adolescents over time. Aim 1 was to measure the relative reinforcing value (RRV) of a preferred HED and low energy density (LED) snack food before and after 2-weeks of daily exposure. Aim 2 was to assess the RRV of exercise and sedentary activity. Hypotheses include 1) sensitization to HED food will be associated with greater zBMI at the time of testing as well as greater zBMI change over time 2) sensitization to LED food will be associated with lower zBMI at the time of testing in adolescents and less zBMI change over time. 3) Greater RRV of exercise will be protective against zBMI increases over time.
Interventions
OTHERReinforcing value of HED and LED foods in response to snack food monotony
Each child will be asked to eat two different snack foods over the course of two weeks each. The RRV of that food (vs alternative reinforcer) will be tested and baseline and post exposure. Increases in RRv for food after monotony will be considered sensitization to that food. All children will be followed to observe weight change over time for 2 years each.
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
State University of New York at Buffalo
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
12 Years to 14 Years
Healthy volunteers
Yes
Inclusion criteria
* between 12-14yoa (male and female) * zBMI: -1.5 to +2.0 (\*determined by Height/weight measurement at Visit 1) * neutral or higher liking of the study foods * Willingness to complete 9 study visits over 2 years.
Exclusion criteria
* -metabolic or endocrine disorder * use of medications known to effect appetite (Ritalin, Adderall, Concerta, Wellbutrin, Prednisone, etc) * Unwilling to complete the study visits * allergy to study foods * dislike of study foods (\*determined via Preference for Study foods forms at Visit 1) * parent report that child reads below 4th grade reading level * parent report that child cannot complete light physical activity without assistance * No English Speaking parent or legal guardian (therefore cannot provide consent in English nor answer questionnaires for this study) \* all other
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| zBMI Change | through study completion, an average of 24 months from baseline. | BMI z-score change over time. zBMI is a standardized index of body mass index used in children that is standardized to age and sex specific measurements from a national sample. 0 represents the national average. A positive number reflects a body mass index that is higher than the national average and a negative number reflects a body mass index that is lower than the national average. |
Participant flow
Recruitment details
Participants were 201 boys and girls aged 12 - 14 years without obesity recruited using flyers, e-mail and social media, personal referrals, and advertisements distributed in schools in the Buffalo, NY area.
Participants by arm
| Arm | Count |
|---|---|
| Satiators Participants who decreased responding for high energy density food after consuming it every day for 2 weeks. | 165 |
| Sensitizers Participants who increased responding for high energy density food after consuming it every day for 2 weeks. | 36 |
| Total | 201 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Lost to Follow-up | 20 | 4 |
| Overall Study | Physician Decision | 1 | 0 |
| Overall Study | Protocol Violation | 2 | 1 |
| Overall Study | Withdrawal by Subject | 13 | 2 |
Baseline characteristics
| Characteristic | Sensitizers | Total | Satiators |
|---|---|---|---|
| Age, Continuous | 13.2 years STANDARD_DEVIATION 0.845 | 13.3 years STANDARD_DEVIATION 0.828 | 13.3 years STANDARD_DEVIATION 0.827 |
| Race/Ethnicity, Customized Race American Indian/Alaska Native | 0 Participants | 1 Participants | 1 Participants |
| Race/Ethnicity, Customized Race Asian/Pacific Islander | 0 Participants | 3 Participants | 3 Participants |
| Race/Ethnicity, Customized Race Black/African American | 3 Participants | 23 Participants | 20 Participants |
| Race/Ethnicity, Customized Race Other/Mixed Race | 0 Participants | 14 Participants | 14 Participants |
| Race/Ethnicity, Customized Race White or Caucasian | 33 Participants | 160 Participants | 127 Participants |
| Region of Enrollment United States | 36 participants | 201 participants | 165 participants |
| Sex: Female, Male Female | 16 Participants | 104 Participants | 88 Participants |
| Sex: Female, Male Male | 20 Participants | 97 Participants | 77 Participants |
| zBMI | 0.48 z score STANDARD_DEVIATION 0.84 | 0.40 z score STANDARD_DEVIATION 0.99 | 0.38 z score STANDARD_DEVIATION 1.02 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 165 | 0 / 36 |
| other Total, other adverse events | 0 / 165 | 0 / 36 |
| serious Total, serious adverse events | 0 / 165 | 0 / 36 |
Outcome results
Primary
zBMI Change
BMI z-score change over time. zBMI is a standardized index of body mass index used in children that is standardized to age and sex specific measurements from a national sample. 0 represents the national average. A positive number reflects a body mass index that is higher than the national average and a negative number reflects a body mass index that is lower than the national average.
Time frame: through study completion, an average of 24 months from baseline.
Population: We began with 165 and 36, but we lost several participants in each group for various reasons which are outlined in an earlier section.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Satiators | zBMI Change | 6 months | 0.433 z-score | Standard Error 0.073 |
| Satiators | zBMI Change | 15 months | 0.376 z-score | Standard Error 0.093 |
| Satiators | zBMI Change | 24 months | 0.416 z-score | Standard Error 0.11 |
| Sensitizers | zBMI Change | 6 months | 0.55 z-score | Standard Error 0.14 |
| Sensitizers | zBMI Change | 15 months | 0.61 z-score | Standard Error 0.18 |
| Sensitizers | zBMI Change | 24 months | 0.593 z-score | Standard Error 0.25 |