Acceptability of a School-Based Intervention for the Prevention of Adolescent Obesity

INTRODUCTION

The prevalence of overweight adolescents has nearly tripled since 1980 and is now more than triple the Healthy People 2010 goal of 5% (U.S. Department of Health and Human Services [USDHHS], 2000). Overweight adolescents are at risk for numerous health problems, including type 2 diabetes, asthma, hypertension, and high blood lipids, as well as psychological vulnerabilities such as lower self-esteem and depression (Must & Strauss, 1999; Neumark-Sztainer, Story, Hannan, & Rex, 2003). There is strong evidence that obesity tracks from childhood to adulthood, particularly from adolescence to adulthood (Kvaavik, Tell, & Klepp, 2003). In fact, being overweight during adolescence is the single best predictor of adult obesity (Whitaker, Wright, Pepe, Seidel, & Dietz, 1997). The probability that childhood obesity will persist into adulthood increases from 20% at age 4 to 80% by adolescence (Kvaavik et al.). In addition, behaviors related to obesity prevention such as physical activity and fruit and vegetable consumption decline with age, especially during adolescence (Munoz, Krebs-Smith, Ballard-Barbash, & Cleveland, 1997; Pate et al., 2002). Thus, adolescence is a particularly important time for obesity prevention efforts. Despite the tremendous need, there are few programs found to be acceptable or effective for adolescent obesity prevention.

Two recent reviews of obesity prevention programs for children and adolescents concluded that the majority were not successful, many were not population-based, and in each review only one study targeted an adolescent population (Baranowski, Cullen, Nicklas, Thompson, & Baranowski, 2002; Fowler-Brown & Kahwati, 2004). Most obesity prevention work conducted with adolescents has been limited to small-scale, hands-on, or curriculum-based interventions for overweight or at-risk-for-overweight students (Neumark-Sztainer et al., 2003; Resnicow et al., 2000). For example, 200 adolescent girls participated in a trial of an innovative approach to physical education. Six schools were randomized into treatment or control groups, and overweight or at-risk-for-overweight girls participated in the specialized gym class for 16 weeks. Although feasibility was high, at the conclusion of the program, most outcome variables were not statistically significant (Neumark-Sztainer et al.). Despite evidence that tailored communications is one of the most promising approaches to health promotion, this avenue for intervention has not been applied to adolescent obesity prevention (Dijkstra, De Vries, & Roijackers, 1999; Kreuter, Farrell, Olevitch, & Brennan, 2000; Kreuter, Strecher, & Glassman, 1999).

Researchers have concluded that effective strategies for obesity prevention are ones that affect both energy intake and energy expenditure (Dietz & Gortmaker, 2001). Multiple behavior interventions involving diet, exercise, and TV viewing are necessary to comprehensively address the problem of obesity. In addition, approaches targeting entire populations with healthy lifestyle messages serve as primary, secondary, and tertiary prevention by educating all students about healthy behaviors, identifying those not engaged in the healthy behaviors, and encouraging behavior change toward the healthy behaviors. Thus, new cases of obesity potentially can be prevented and existing cases of obesity can be reduced. Although obese children represent a high-risk group, many people who will become obese are not overweight as children. A population-based approach can help modify behaviors that may contribute to developing or to maintaining obesity. This approach also helps to avoid potential harmful effects, such as labeling and stigmatization, which could occur if targeting only those children who are overweight.

The intervention described here, Health in Motion, is a population-based, multiple-behavior approach to obesity prevention that targets the recommended guidelines for getting physical activity (60 minutes or more on at least 5 days of the week), limiting TV viewing (2 hours or less per day), and eating fruits and vegetables (at least five servings per day). The support for the inclusion of each of these three behaviors for obesity prevention is clear.

Physical activity is the largest component of the current intervention, because of its importance for long-term weight management (Steinbeck, 2001) and the dramatic declines in activity during high school (Pate et al., 2002), which have been shown to predict risk of being overweight as an adult (Kvaavik et al., 2003). In addition, after repeated findings on the relationship between TV viewing and body mass index (BMI), the American Academy of Pediatrics (2003) advocates the restriction of TV viewing as a specific strategy for preventing pediatric overweight and obesity risk. Research has linked TV viewing to increased consumption of high-fat foods (Robinson & Killen, 1995), decreased fruit and vegetable consumption (Boynton-Jarrett et al., 2003), and decreased energy expenditure (Klesges, Shelton, & Klesges, 1993). Increased fruit and vegetable consumption also has been found to be a negative predictor of BMI (McCrory, Fuss, Saltzman, & Roberts, 2000); research has found that adding more fruits and vegetables to a diet results in a reduction of dietary fat (Epstein et al., 2001).

This article reports on the development and acceptability testing of a Transtheoretical Model (TTM)–based intervention that offers tailored feedback on physical activity, fruit and vegetable consumption, and limited TV viewing. Although the long-term goal of Health in Motion is obesity prevention, its objective is to help all students, regardless of weight, adopt and maintain these three healthy behaviors. This computer-delivered program has the potential to be incorporated into health and physical education curricula, to be used as part of a fitness and wellness program, or to be recommended by school nurses, administrators, or teachers on an individual basis. An effectiveness trial of Health in Motion begins in September 2006 in eight high schools.

APPLICATION OF THE TRANSTHEORETICAL MODEL

The TTM is an integrative model of behavior change that incorporates process-oriented variables to explain and predict how and when individuals change health behaviors (Prochaska & DiClemente, 1983). There are four constructs central to change. Each is addressed in the Health in Motion intervention: stage of change, decisional balance, self-efficacy, and processes of change.

Stage of change, the central organizing construct of the TTM, delineates readiness to engage in the healthy behavior. A description of the five stages of change is presented in Table 1. Stage of change is a powerful predictor of behavior; a single intervention that helps individuals progress one stage doubles their chances of taking action in the next 6 months (Prochaska, DiClemente, & Norcross, 1992).

Decisional balance represents an individual’s relative weighing of the pros and cons of making a health behavior change. Research has shown that the cons of changing to a health-promoting behavior tend to outweigh the pros in the early stages, the pros surpass the cons in the middle stages, and the pros outweigh the cons in the later stages (Prochaska et al., 1994).

Self-efficacy represents the degree to which an individual believes he or she has the ability to perform the behavior change in various tempting situations. Self-efficacy is operationalized in this program as confidence to make and sustain changes. Individuals in the early stages tend to report the lowest confidence levels, whereas those in later stages report increasing levels (DiClemente et al., 1991).

Processes of change are 10 covert and overt activities that research has identified as the common strategies that people employ when making a behavior change. A definition of each of the processes of change is shown in Table 2. These 10 processes are related integrally with the stages of change, with individuals in early stages relying more on experiential, or cognitive, affective, and evaluative, processes of change (e.g., raising consciousness about the healthy behavior). Those in later stages rely more on behavioral techniques (e.g., stimulus control, or adding cues to make it easier to engage in healthy behaviors; Prochaska et al., 1992).

The TTM has been applied successfully to the diet and exercise fields among adults and young adults (Ma et al., 2002; Sarkin, Johnson, Prochaska, & Prochaska, 2001), as well as various behaviors in adolescent populations (Hollis, Polen, & Whitlock, in press; Mauriello et al., 2002). However, to our knowledge, this is the first TTM-based intervention directed at obesity prevention. The two main goals of the project reported in this article were to develop a multiple-behavior obesity prevention intervention for adolescents and to assess its acceptability in a pilot test.

METHODS

DESCRIPTION OF THE INTERVENTION COMPONENTS

In a baseline intervention session of Health in Motion, participants are assessed on TTM constructs and are given individualized feedback on how their responses compare with the responses of a sample of successful individuals making the same behavior change (normative comparisons). The content of the program reflects the different constructs of the TTM; the program is separated into different sections based on the behavior being targeted and the construct being covered.

For the pilot test, participants received a baseline intervention for physical activity, which included distinct assessments and individualized feedback in the following five sections:

Stage of change: a description of the participant’s current stage of change for doing 60 minutes or more of physical activity on at least 5 days of the week.

Throughout the program, the feedback a user receives is tailored to his or her stage for each behavior and to his or her responses in the assessment for a given construct for that behavior. For example, a student in the Action stage for physical activity is given specific strategies for keeping up the behavior and is reminded to recognize the benefits gained from performing the behavior. Further, if that student reports low confidence for maintaining exercise during difficult times, he or she will be given specific tips for increasing confidence and planning ahead to maintain his or her exercise routine. However, if a student is in the Precontemplation stage for physical activity, the suggestions he or she receives will focus on raising awareness of the importance of increasing physical activity, informing the student of the benefits of physical activity and providing opportunities to think about how self-image would change if he or she made progress by getting more activity.

In addition to physical activity, pilot test participants received optimally tailored feedback for consuming fruits and vegetables and limiting TV time. Optimally tailored feedback is limited feedback representing the most important TTM constructs; the constructs that are most important for behavior change progress for each stage of those behaviors were determined empirically from the measurement development data. Thus, the fruit and vegetable and TV-time components were condensed to only two TTM constructs—stage of change and decisional balance—so that the Health in Motion program could be delivered within a single class period.

The Health in Motion program begins with an introduction to the program and several screens to capture participants’ attention about the healthy behaviors for obesity prevention. For example, the program begins with quotes from teens shown on-screen to portray how other teens feel about the target behaviors. The program proceeds with alternating assessments and feedback about physical activity, then fruit and vegetable consumption, and finally, TV viewing. The program compiles text paragraphs and images on-screen as the participant progresses through the interactive session. Approximately 160 paragraphs are used in the pilot computer program, resulting in more than 1,200 unique feedback combinations. Interactive exercises and narratives from high school students were incorporated into the pilot version and were expanded upon during the completion of the final intervention.

PILOT TESTING

RESULTS

As reflected in Table 4, pilot test participants rated the program positively. Table 4 shows the distribution of responses by item, as well as the mean response for each item. Students gave the program an average score of at least 3.60 on all 12 dimensions. The accessibility of the program was its strongest feature, with an overwhelming majority of participants “strongly agreeing” or “agreeing” that the program was easy to use (97.8%) and that the questions (88.9%) and feedback (86.7%) were easy to understand. Participants also liked the way the program looked and found the program to be interesting, with 77.3% and 66.6% “strongly agreeing” or “agreeing” to those statements, respectively. The participants endorsed the content of the program, with 65.9% of the participants believing the program could help them be healthier. Overall, the participants “agreed” or “strongly agreed” that the program was designed for people their age (80%) and reported that they would recommend the program to a friend (73.3%).

The 12 evaluation items were summed into a composite score (possible range of 12–60), and demographic differences were investigated. Because of the small numbers of female students and 12th-graders, no significant gender or grade differences in the evaluation of the intervention were found. However, girls evaluated the program more positively overall (M = 51.15, SD = 6.09) than did boys (M = 46.52, SD = 9.35), and 11th-graders gave a higher rating overall (M = 48.45, SD = 6.76) compared with 12th-graders (M = 46.11, SD = 14.08). Interestingly, girls had a higher mean than boys for each evaluation item, and 11th-graders had a higher mean than 12th-graders on all items except one.

Pilot test participants also offered qualitative feedback to four open-ended questions. In an effort to obtain more in-depth information, participants were asked to explain why they would or would not recommend the program to a friend. Eighty percent of respondents offered positive responses, 11% gave neutral responses, and 9% gave negative responses. Participants offered a variety of reasons as to why they would recommend the program, such as it is educational, it tells how to be healthy, it is easy to use, and it provides something to think about. Neutral or negative responses focused on the repetition of questions and that some people do not want to be helped.

When asked the second open-ended question, “What did you like the most about the program?” most participants focused on the interactivity, the individualized feedback, the useful information that was presented, and that the program was easy to navigate and understand. When asked, “What did you like least about the program?” several participants indicated that there was too much text and suggested making the program flashier with more graphics and sound.

Finally, when asked, “How would you improve the program?” 24% of respondents did not have any improvements to suggest (e.g., “No complaints” and “I wouldn’t change it”). Suggestions for improvement included the addition of audio, the incorporation of more graphics, and the inclusion of more specific information or tips about specific behaviors (e.g., “examples of working out and a chart of foods you could eat daily”).

DISCUSSION

This pilot study demonstrated that a computer-administered, TTM-based multiple-behavior intervention is acceptable to high school students. Adolescents in various stages of change for physical activity, fruit and vegetable consumption, and limiting TV time participated in the pilot test. An average rating of 3.0 or better on each dimension was our goal for showing acceptability of the intervention and determining whether the program should move forward to a more rigorous effectiveness trial. Given that the mean of each evaluation item was more than 3.5, we demonstrated acceptability, have enhanced the program, and are testing its effectiveness compared with a control group. Qualitative feedback from students and consultants also contributed to the success of the pilot program and the ability for further testing. The majority enjoyed the program and found it interesting, easy to use, and easy to understand. Furthermore, most Health in Motion users agreed that the program gave them new ideas about being more active and eating healthier and thought the program could help them be healthier. Experts and teachers also found the program engaging, acceptable, and “much needed” in high schools.

The successful recruitment of program users, implementation of the parental consent procedure, and completion of the intervention within a 30-minute class period demonstrate the feasibility of executing the intervention in a school setting. These features suggest that the Health in Motion program is well suited for the school environment. Additionally, it is population-based, appropriate for all students, including students at all weights and at all stages of readiness to adopt healthy behaviors for obesity prevention. It provides useful behavior-change strategies for individuals at all stages of change for physical activity, fruit and vegetable consumption, and limiting TV time. The program is self-directed, requires little to no staff training, and allows for low-cost and consistent delivery across classes and individuals.

In addition, Health in Motion is theory-based. The TTM has proven effective at intervening on a variety of behaviors, including diet (Prochaska, Velicer, Rossi, Redding, Greene, & Rossi, in press) and exercise (Marcus, Simkin, Rossi, & Pinto, 1996). This support has extended to successful multiple-behavior interventions targeting smoking cessation, limiting sun exposure, and low-fat eating among adults (Prochaska et al.) and targeting smoking and condom use among adolescents (Redding et al., 2002). Additionally, bullying prevention interventions that were designed and implemented similarly to Health in Motion have been shown to be effective in large, randomized trials and are now being marketed to schools nationally. These TTM-based, computer-delivered, tailored interventions showed significant treatment effects, with bullying behavior being reduced by 30% among middle school students and 40% among high school students. These results provide great promise that the acceptability of the Health in Motion program will lead to effectiveness upon completion of an effectiveness trial (Evers, Prochaska, Van Marter, Johnson, & Prochaska, under review; Prochaska, Evers, Prochaska, Van Marter, & Johnson, in press).

This study has limitations characteristic of many pilot studies. The pilot was conducted in one New England high school with a small convenience sample from the school’s career and vocational center. Most of the participants were White boys and presumably all had considerable experience with computers. However, given that girls rated the program even more positively than did boys and that 89.6% of school-age children have access to computers (U.S. Census Bureau, 2001), these factors should not have influenced acceptability ratings.

Additionally, although the pilot testing was limited to 45 students, a total of 1,574 high school students participated in the development of the intervention, 52.4% of them girls and 29.6% non-White. Finally, the staging distribution of the pilot sample is similar to that of the sample of 1,459 high school students who completed the measurement development survey used to develop the measures used in the program. In that sample, 63% were in pre-Action stages for physical activity, 89% for fruit and vegetable consumption, and 46.7% for limiting TV time (Driskell, Mauriello, & Johnson, 2005).

The enhancement of the intervention is under way and will be completed for the launch of an effectiveness trial in September 2006. A demonstration of this program can be viewed at http://www.prochange.com/obesity. As recommended by the pilot test participants, the final enhanced Health in Motion program includes more graphics, audio, and video, and more opportunities for participants to engage in activities relevant to their individualized strategies. For example, users receiving feedback on helping relationships can type in the names of people who they can ask to support their efforts to get physical activity. For decisional balance in the limiting TV time section, users can check off, from a long list of the benefits of limiting TV time, which benefits are personally most relevant and important to them.

The final program provides follow-up sessions, in addition to the baseline session tested in this pilot test. In follow-up intervention sessions, comparisons will be made between time points as individuals make stage transitions. Participants will receive feedback on how their responses compare with the responses of individuals in the normative group and with their own previous responses. In the effectiveness trial, participants will be assigned to (a) the intervention group that receives the final enhanced Health in Motion intervention once a month over 3 months, or (b) the control group that receives assessments only. Both groups will be followed and will be assessed two more times over 1 year and compared on changes in physical activity, fruit and vegetable consumption, and TV viewing. The trial will take place in eight high schools nationwide, selected to compose an economically and ethnically diverse sample. If proven effective, the Health in Motion intervention can be disseminated in schools as an efficient, low-cost, population-based approach to preventing adolescent obesity and to curbing the epidemic of obesity.

IMPLICATIONS FOR SCHOOL NURSING PRACTICE

The results of the present study indicate that a TTM-based approach to intervening on the important behaviors for obesity prevention is acceptable to high school students. Teens are amenable to hearing stage-appropriate intervention messages about improving their physical activity, fruit and vegetable consumption, and TV time. Because adolescents spend much of their time at school, this venue is a great opportunity for health promotion and obesity prevention. As the “health representatives” at school, school nurses are in a position to initiate the delivery of such health promotion messages, either individually or school-wide.

At the individual level, school nurses can determine a student’s risk via assessment of BMI and the student’s stage of change for physical activity, fruit and vegetable consumption, and limiting TV time. Based on these assessments, nurses could prescribe Health in Motion to students individually and also encourage families to work on behavior change together with their adolescents. With their knowledge and expertise in areas such as nutrition and weight, school nurses could follow up with students and families about their progress with the target behaviors and offer specific medical advice on diet and weight.

At the school level, school nurses can determine the prevalence of unhealthy behaviors and of overweight among their students, thereby assessing the overall need for intervention in their schools. Nurses can advocate for a school-wide approach to encouraging healthy behaviors and for adopting a program like Health in Motion as part of a health education curriculum. Further, understanding the stage distribution of the students’ target behaviors can help focus health promotion efforts appropriately.

School nurses are in a unique position to effect change in the unhealthy behaviors that contribute to the epidemic of adolescent obesity. Whether on an individual basis or school-wide, school nurses can advocate for obesity prevention efforts via the adoption of a TTM-based approach such as Health in Motion.