Growth curve modeling indicated that participants in PHAT had significantly more gains in health knowledge than participants in FOY, however the effects on behavior were modest. Although this program was a brief intervention, participation in PHAT was associated with greater scores for health knowledge for at least one year after implementation. Furthermore, individuals with greater health knowledge demonstrated healthier behaviors.
Improving knowledge is an integral part of Health Education intervention research. Although PHAT participants had knowledge increases, it may differentially impact dietary, physical activity, and substance use behaviors.34-42
Although the PHAT program was brief, it elicited greater scores for health knowledge for at least one year after implementation. Moreover, people with greater knowledge scores demonstrated significantly more positive health behaviors. Results indicate that although behavioral outcomes were modest, improving knowledge is an effective first step in improving behavior if minor modifications to the curriculum are implemented. Continued research on this program and other health promotion interventions should evaluate the effectiveness of knowledge increases on specific health risk behaviors.
Results for the growth curve analysis between participants in PHAT and FOY were not significantly different for dietary behaviors. However, PHAT participants had significantly greater increases in vigorous physical activity. Several school-based studies have observed higher fruit and vegetable intake, lower fat-intake, and greater engagement of physical activity among experimental participants.16,19,20,24-26,28
However, community-based programs have generally been less successful than school-based efforts in facilitating healthy dietary behavior and physical activity initiation and maintenance.28-31
These findings are not surprising given the brevity of length and lower intervention dosages associated with community-based studies. Additionally, the methodology of school-based studies are dissimilar than that of brief, community-based research studies. For example, CATCH and the Minnesota Heart Health Project both modified access and availability of healthy food options for students, however these efforts are beyond the scope of this project.18,20
Taken together, these findings suggest that this study was similar to other community-based studies that produced modest intervention effects with regard to improving dietary behavior but was more effective in improving physical activity.
There were no significant changes for most substance use behaviors in this study. There have been a variety of studies that have observed significant differences in substance abuse among experimental and control participants.16,19,21,23,25,27
In a summary of the “elements of prevention” from meta-analyses, Sloboda55-58
suggests that the components of effective substance use prevention programs for adolescents include: addressing normative adolescent beliefs about the prevalence of substance use by peers; reinforcing perceived negative consequences of substance use for adolescents; providing life skills such as communication, decision-making and resistance opportunities; opportunities to practice these skills around real-life situations; and active engagement of adolescents in the education process. The PHAT curriculum had some of these elements (see ) however the opportunities to practice decision-making and resistance skills were limited with the brief nature of the PHAT intervention.
Unlike these programs however, PHAT was considerably shorter and had less intervention dosage. Given the complexity of modifying drug use behavior among adolescents, higher intervention dosages may be more effective in reducing substance abuse among youth. In addition, caution is noted in two somewhat recent reports59,60
that suggest more limited effect sizes from adolescent substance use prevention interventions from the 1980's and 1990's that may not achieve the same effects for adolescents for the 21st
century. In addition, in randomized trials, when comparisons are drawn from control groups, often the widespread availability of prevention programs means that controls may have been exposed to some drug prevention efforts. Thus, the comparisons are not as dramatic (statistically significant) with far smaller differences detected.58-60
A notable finding was that slopes for lifetime marijuana use were greater for PHAT participants. Although this finding was unexpected, it may be partially explained by the recognition that the control condition also addressed substance abuse behaviors within the context of HIV prevention (less dramatic comparisons).58-60
Additionally, meta-analysis suggests that knowledge level is correlated with marijuana use albeit less highly correlated than other predictors (prior drug use, poorer mental health, victimization).42
Further research should explore the effects of community-based programming on substance use for adolescents.
Though the results of this study indicate that PHAT had modest effects in improving dietary, physical activity, and substance abuse behaviors, there are strategies to elicit more favorable behavior change. First, it may be necessary to increase intervention dose for participants. Behavior change may not have been observed because appropriate doses of intervention were not applied to secure appropriate effects. A review of school-based dietary behavior literature suggests that higher dosages of intervention are associated with behavior change.61
Additionally, the PHAT intervention period may have been too brief for: 1) facilitators to develop rapport and gain the trust of participants, and 2) for participants to practice behaviors and develop the level of self-efficacy to effectively execute and sustain them. A longer intervention period may help encourage more favorable PHAT intervention effects.
Alternatively, another promising approach would be to maintain the dosage of the intervention but implement it beyond two Saturdays. The integrity of the program would remain if the content and dosage of the intervention were expanded over a longer period of time using this strategy. This approach shows potential, as the length of intervention may have been insufficient to allow participants time to process newly acquired information and fully execute cognitive and decision-making processes to stimulate behavior change. Spacing the same dose of an intervention over several sessions may allow more opportunities for validation and reinforcement of new beliefs and perceptions as well as granting opportunities to practice, enhance, and refine skills pertaining to improving health behavior.61,62
Research on interventions comparing programs of similar dosage and content but differing lengths found greater effectiveness among programs with longer implementation periods.63-66
These studies also suggest that condensing these programs decrease efficacy and inhibit more positive effects.63-66
Although programmatic efforts to improve dietary behavior among African American adolescents are critical, public health researchers must recognize the structural challenges (i.e. limited access and availability of healthy food options) to implement favorable dietary behaviors. Programs to improve healthy eating behavior may encounter challenges if there is a lack of healthy food available. Therefore, an emphasis on harm reduction strategies (coupled with larger advocacy efforts to promote health equity) may be advantageous in eliciting dietary behavior change among the population of interest. For instance, participants should be encouraged to select the healthiest foods available in the midst of a variety of unfavorable choices. Furthermore, greater benefit may be realized by emphasizing small, incremental changes to dietary behavior instead of large, sweeping modifications. For example, participants can be encouraged to increase water consumption by starting with small increases per day and gradually building to recommended amounts of intake.
Participants in this study may have encountered a variety of challenges in performing physical activity behaviors. For example, participants in both PHAT and FOY may have demonstrated less physical activity owing to a lack of safe areas to exercise, gang activity in local neighborhoods, or distance from gymnasiums or other facilities to exercise. However, there are several modifications that could strengthen execution of the PHAT curriculum. For example, emphasis can be placed on encouraging participants to engage in enjoyable activities (i.e. basketball, dancing, cheerleading, marching band) instead of more traditional physical activity (jogging, bike riding). Also, emphasis can be placed on incremental strategies to improve physical activity.
In order for researchers to observe greater benefit in substance abuse prevention with PHAT, it may be advantageous to expand the content regarding substance abuse as well as continuing its emphasis on the negative physiological, social, familial, and legal consequences of drug use. Additionally, the program should maintain its focus on reducing abuse of the most commonly used drugs among this population (i.e. alcohol, tobacco, and marijuana).
Limitations of this study should be noted. All demographic variables were self reported. However, several measures were performed to improve the quality of responses including use of identification numbers to increase confidentiality and using ACASI assessments to generate psychosocial questionnaire data. Also, there may have been varying levels of experience and effectiveness of the facilitators for this program. Several measures were taken to limit the differences between curriculum interventionists. All facilitators underwent standardized curriculum training. Also, 65% of the intervention sessions were observed and scored for fidelity of implementation. The fidelity of implementation scoring system suggests that 95% of curriculum sessions were correctly implemented. Finally, this study was executed among socioeconomically disadvantaged African American adolescents in four mid-sized cities the eastern United States and the findings may not be generalizable to other racial/ethnic populations, age groups, or geographic locales.