- Click here for explanation of classification scheme.

The present study was designed to evaluate the acceptability and efficacy of a multi-component behavioral intervention for weight control among overweight adolescents. The intervention includes computer interaction and physician counseling in the pediatric primary care clinic, followed by 4 months of telephone-and mail-based behavioral counseling

Being between 12 and 16 yrs old, 20% to 100% above the median for body mass index for sex and age, interested in weight control, but not currently engaged in another weight control program, and otherwise healthy as determined by a pediatrician.

Three adolescents did not meet BMI inclusion

Definitions:

Treatment Group: Healthy Habits (HH) adolescents, typical care (TP) adolescents.

Protocol:

Immediately after baseline assessment in the clinic, HH adolescents engaged in a computer program adapted from PACE+ (Patient-Centered Assessment and Counseling for Exercise plus Nutrition) software designed for adolescents and modified for overweight adolescents. The computer program assessed eating, physical activity, and sedentary behavior and guided adolescents through individualized plans generated to increase physical activity or decrease sedentary behavior and decrease dietary fat or increase fruits/vegetables or decrease overeating/snacking. Plan generation included identifying benefits, barriers, and specific strategies to achieve goals. The program generated printed action plan summaries and produced a provider summary form that helped identify for pediatricians which behaviors were targeted by the adolescent and whether problematic eating behaviors were reported (e.g., taking laxatives or other purging). HH adolescents then met with a pediatrician to discuss and finalize their individualized action plans. This tailored physician counseling was based on the computer responses of the adolescents.

Counselors worked with subjects in follow-up telephone conversations to reduce calories to between 1200-1500 kcal per day.

Approximately 1 week after the clinic visit, each HH adolescent and his/her parent met in-person with the first author (B.E.S.) to discuss upcoming mail and phone contacts and to learn food self-monitoring. Calls from a phone counselor began 1 week after this meeting. Telephone counselors had at least a bachelor’s degree in psychology or nutrition and received weekly supervision in the provision of behavioral weight control treatment by the first author. Calls were intermittently monitored for compliance with call scripts. For each HH adolescent, the telephone counselor remained constant throughout intervention. Telephone contact was structured to last 10 to 20 minutes and scheduled weekly for the first eight calls and biweekly for the last three calls, thus, lasting a total of 14 to 16 weeks. Telephone counselors used detailed telephone scripts to address adolescents’ weight change since the last call (adolescents were encouraged to weigh once weekly), the link between weight change and eating and physical activity behaviors, instruction and feedback on previous self-monitoring, eating and physical activity goals, and the use of behavioral skills relevant to goal achievement. A participant manual designed to help adolescents acquire various behavioral skills for weight control was developed and distributed to HH adolescents. Initial manual sections were provided at the in-person meeting with the first author, with subsequent sections mailed after the 5th, 8th, and 10th calls. Counselors referred adolescents to the computer printouts generated in clinic and relevant manual sections to help adolescents formulate strategies for meeting goals.

HH adolescents were encouraged to self-monitor all food and beverage intake and the amount and calories consumed. Adolescents were given self-monitoring booklets, one booklet for each week, to record daily: time foods/beverages consumed, description of foods/beverages, food/beverage amounts, calories, and whether a food/beverage was a RED or GREEN food (described below). Stamped envelopes were provided with each self-monitoring booklet, so adolescents could mail booklets to their telephone counselor after the call in which the self-monitoring was reviewed. Calories were estimated using The Fat Counter, which was provided. Telephone counselors helped HH adolescents gradually reduce calories from baseline levels to 1200 to 1500 kcal/d, although this goal was flexible upward dependent on initial weight.

Adapted from Epstein and Squires’ Stoplight Diet, foods were also categorized into GREEN, RED, or no color foods. GREEN foods were defined as having 1 or fewer fat grams per serving, <150 calories per serving, and providing a good source of one or more valuable dietary components (e.g., calcium, fiber, or protein). RED foods were defined as having 5 or more grams of fat per serving or were diet versions of high-fat foods. The eventual GREEN food goal was 40 GREEN food servings (based on standard serving sizes) or more per week, and the RED food goal was <15 RED food servings per week. Telephone counselors did not encourage or discourage eating any prescribed foods but encouraged reduction in food quantity and more healthful eating, within established eating preferences and food availability. For example, if an adolescent liked eating tacos, he/she was not discouraged from eating tacos, but rather encouraged to eat fewer tacos and to reduce or eliminate the high-fat high-calorie food items often in tacos (e.g., fried tortilla, sour cream, and guacamole). This procedure allowed for flexibility in addressing adolescents’ individual food preferences within a given adolescent’s family and cultural context. Telephone counselors provided calorie and macronutrient information for foods not listed in The Fat Counter (e.g., carne asada).

Beginning at the fifth call, HH adolescents were encouraged to self-monitor physical activity daily. The physical activity goal was a minimum of 60 minutes of at least moderate intensity physical activity on 5 days per week, with gradual increases from baseline levels. Telephone counselors encouraged adolescents to increase time in preferred physical activities and to add new types of physical activity. Conversely, adolescents were encouraged to decrease time spent in least preferred sedentary behaviors and to reallocate that time to being more active.

Adolescents were awarded 1 point each for meeting self-monitoring, physical activity, calorie, GREEN food, and RED food goals each week (total maximum of 5 points/wk), based solely on the counselor’s review of self-monitoring booklets. Points were accumulated for tickets for a study-based lottery (1 point = 1 ticket). The lottery occurred after all adolescents had completed post-treatment assessment, and the adolescent with the randomly selected ticket received $50.

Parents of HH adolescents were sent information sheets when adolescents were sent manual sections. Parent information sheets highlighted ways parents could be most helpful with their adolescents’ behavior change. Recommended parental skills included stimulus/environmental control, positive reinforcement, and preplanning. There was no telephone contact with parents during the HH intervention.

TC Intervention.
Immediately after baseline assessment, TC adolescents met with a pediatrician. Based on expert committee recommendations regarding pediatric obesity that were given to pediatricians, pediatricians were instructed to assess/encourage adolescent’s motivation for weight-related behavior change, provide information about short- and long-term health consequences of high weight status and benefits of better weight control, make recommendations for healthful eating consistent with the Food Guide Pyramid, review physical activity recommendations for adolescents (60 min/d of at least moderate intensity physical activity), and encourage consistency and persistence with health behavior changes. Pediatricians used a worksheet outlining these topics to facilitate thorough discussion with each TC adolescent. TC adolescents were encouraged to implement recommended behavior changes on their own and with the help of their family. After this non-tailored physician-counseling session, TC adolescents were not contacted again until scheduling for the post-treatment assessment 4 months later.

The same pediatricians provided counseling for HH and TC adolescents. Pediatricians had participated in previous intervention studies for dietary and physical activity change among non-overweight adolescents. Pediatricians met with the first author (B.E.S.) once before the study beginning to review the training and procedural materials.

After completing post-treatment assessment, neither HH nor TC adolescents were contacted until scheduling for follow-up assessment. Adolescents received $25 for post-treatment and $25 for follow-up assessment.

Weight and Height.
Weight was measured at baseline in the pediatric clinic using a calibrated standard digital scale. Weight was measured at post-treatment and follow-up on a calibrated balance beam scale. Height was measured by stadiometer at all assessments. BMI was calculated as kilograms per square meters. For purposes of determining study inclusion, population data from Rosner and colleagues were used to calculate percent overweight. Updated national norms published during the course of this study were used to calculate the BMI z scores and percentage of overweight presented and used in data analysis. BMI z scores were calculated using age- (to the nearest month) and sex-specific median, SD, and power of the Box-Cox transformation.

Dietary Intake.
Dietary intake was assessed by the 2-day dietary recall interview. Among youth, the recall procedure has evidenced high levels of between-interviewer reliability for total calories recalled (coefficient of variation < 17%), and moderate correlations between observed and recalled total calories consumed (0.47 to 0.57),  with similar associations for calories from fat. Foods and beverages were entered into Nutritionist-V software to determine total average daily energy intake and percentage of calories from dietary fat. Consistency estimates across the two recalled days were similar at different assessment time-points for calories (0.59 to 0.65) and the percentage of dietary fat (0.31 to 0.51).

Physical Activity.
Physical activity was assessed by the Seven-Day Physical Activity Recall (PAR) interview. 1-week test–retest reliability for total physical activity estimates obtained by PAR are 0.47 to 0.59 for adolescent samples, with correlations of 0.44 to 0.53 between PAR physical activity estimates and heart rate monitoring and similar correlations between PAR and accelerometer estimates of physical activity among adults. Standardized scoring procedures  were used to estimate daily physical activity-related energy expenditure, independent of body weight (kcal/kg per day), that was at least moderate in intensity (i.e., energy expenditure by sleeping and light activity was not included).

Sedentary Behavior.
Sedentary behavior was measured through self-report questionnaire that queried participation in various discretionary sedentary behaviors (e.g., television watching, but not homework) during the past 7 days. Adolescents indicated the number of days engaged in and amount of time typically spent in each sedentary behavior over the past week. This methodology is similar to that used to assess television watching but to date has unknown reliability and validity. Mean daily time in individual sedentary behaviors was calculated by multiplying the number of days by the typical time spent doing that sedentary behavior and then dividing by seven. Total daily sedentary behavior was the sum of these daily individual sedentary behavior estimates.

Problematic Eating and Weight-Related Behaviors and Beliefs.
Cognitive dietary restraint and eating disinhibition were assessed by the Three-Factor Eating Questionnaire. The restraint and disinhibition subscales have demonstrated internal consistency >0.79 across adult dieters and free eaters and were 0.81 to 0.87 for restraint and 0.63 to 0.75 for disinhibition at different assessment time-points in this study. The total score from the Children’s Eating Attitude Test (26-item CHEAT) was used to obtain a continuous measure of eating disorder psychopathology. The CHEAT has previous internal consistency coefficients between 0.76 and 0.87 and current study internal consistency of 0.70 to 0.81 at different assessment time-points, a previous test–retest estimate of 0.81, and seems related to body dissatisfaction and problematic weight management behaviors. The Killen Weight Concerns scale, with present internal consistency of 0.75 to 0.79 at different assessment time-points, assessed concern about weight and weight change and is related to the development of eating disorders.

N = 44. Randomized participants were on average 14.2 years old with a BMI of 30.7, 59.1% were boys and self identified as 70.05% white, 15.9% Hispanic, 4.5% African American, 2.3% Asian, and 6.8% multi-ethnic.

Healthy Habits (HH) adolescents evidenced better change in body mass index z scores to post-treatment than typical care (TP) adolescents. Body mass index z scores changed similarly in the conditions from post-treatment through follow-up.  Behavioral skills use was higher among HH than TC adolescents, and higher behavioral skills use was related to better weight outcome.  Energy intake, percentage of calories from fat, physical activity, sedentary behavior, and problematic weight-related or eating behavior/beliefs did not differ by condition or significantly change over time independent of condition.  The behavioral intervention evidenced good feasibility and participant satisfaction.

There were no significant differences by condition on demographic variables or baseline weight status variables (e.g., BMI z-scores), physical activity, dietary intake, or problematic eating and weight-related behaviors or beliefs.  In addition, there were no significant site or sex by condition effects or three-way interactions with time on BMI z scores, so data were collapsed across site and sex for all analyses.

There was a significant group by interaction from baseline to post-treatment for BMI z scores among post treatment completers (F _(1,37) = 6.04, p<0.02; effect size f-0.40).  As seen in Figure 2, mean BMI z scores significantly increased among TC adolescents compared with the slight decrease of BMI z scores among HH adolescents during the intervention period.  Intent-to-treat analyses did not markedly alter these results (F_(1,42) = 5.59, p<0.03).  More HH adolescents had reduced their BMI z score by post-treatment than TC adolescents (40.5% vs. 10.5%, respectively; x² ₍₁₎ = 4.44, p<0.04).   Despite differential weight status outcomes, there were no significant differential changes by condition from baseline to post-treatment or main effects of time in the secondary outcomes of total energy or dietary fat intake, physical activity, sedentary behavior or problematic eating and weight-related behaviors or beliefs.

With the inclusion of the follow-up assessment, the overall condition by time interaction for BMI z scores remained statistically significant (F _(2,70) = 4.08, p< 0.03, effect size f = 0.35; Figure 2).  However, the baseline to follow-up contrast for BMI z scores only approached statistical significance (F_(1,35) = 3.50, p = 0.070, effect size f = 0.32).  Linear contrasts suggested no differential change in BMI z scores by condition from post-treatment to follow-up, with mean BMI z scores remaining generally stable from post-treatment to follow-up in both conditions.  Intent-to-treat analyses only slightly attenuated the overall follow-up results (F_(2,84) = 3.60, p<0.04) and the baseline to follow-up contrast (F_1,42) = 3.11, p<0.09).  From baseline to follow-up, more HH adolescents had decreased BMI z score from baseline values than TC adolescents (55.6% vs. 15.8%; x²₍₁₎ actions of condition by time or main effects of time for any secondary outcomes from baseline to post-treatment to follow-up.

The HH and TC condition did not significantly differ in the amount of time adolescents (3.6 vs. 4.9 minutes, respectively) or pediatricians (6.3 vs. 8.1 minutes, respectively) perceived the physician counseling session lasted (both F_(1,44) < 4.0, p > 0.05).  There were no significant condition differences in how adolescents and physicians perceived the effectiveness, specificity, or extent of tailoring of the physician counseling.  At post-treatment, HH adolescents reported higher rates of total and eating and physical activity-specific behavioral skills use than TC adolescents (all F_(1,37) > 5.17, p < 0.03).  Parents of HH adolescents also reported that their adolescents used more overall and specifically eating-related behavioral skills than parents of TC adolescents (both F_(1,37) > 4.50, p < 0.04).  HH adolescents continued to report higher overall and eating-related behavioral skills use at the follow-up assessment compared with TC adolescents (both F_(1,33) > 7.88, p < 0.01), but parent reports of adolescent behavioral skills use were no longer significantly different between HH and TC conditions at follow-up.

The median number of HH intervention calls completed was 9.0 of the planned 11 calls among all adolescents randomized to HH, with calls lasting on average 16.4 minutes (SD = 4.6).  Approximately 70% of the HH adolescents completed 9 or more calls.  HH adolescents were significantly more satisfied with the telephone counseling component than all other intervention components (mean of 4.05 of 5, SD = 0.87; all t₍₁₈₎ > 3.33, p< 0.01).  HH adolescents reported significantly greater satisfaction for mailed materials/manual (mean = 3.57, SD  1.13) and the physician counseling (mean = 3.39, SD = 0.92) and between physician counseling and the computer interaction (mean = 2.98, SD = 1.06).

This study provides preliminary evidence for the acceptability and short-term efficacy of a multi-component intervention for adolescent weight control beginning in primary care. The small sample size and response variability limited power to detect statistically significant condition differences through follow-up, because the effect size of condition differences in BMI z scores to follow-up were moderate in size.  Studies including larger sample sizes, longer follow-up, and more thorough process evaluation would inform more comprehensive examination of efficacy and identify the most potent components of this multi-component approach.  This could help formulate stepped-care treatment models for intervening with overweight adolescents.  Innovative adolescent interventions that do not involve weekly clinic-based visits have the potential to decrease provider and participant cost, increase the number and diversity of treated overweight youth, and perhaps increase participants’ acceptability of greater length of therapeutic contact.  This may help treatment providers capitalize on the positive relationship between length of provider contact and weight loss/maintenance success, consistent with a continuous care model of obesity intervention.

Very well-designed study.