Smoking Prevalence Rates
The results of the study by Pentz and colleagues (1989) provided evidence that the Midwestern Prevention Program (MPP) significantly reduced cigarette smoking prevalence among treatment youths relative to control youths. Analyses indicated that, at 2-year follow-up, program schools had approximately 13 percent fewer cigarette users in the last month than would be expected without MPP intervention. The 13 percent net decrease in smoking in program schools translates to a 30 percent rate of decline in program schools relative to control schools.
The results of the study by Chou and colleagues (1998) provided evidence that the MPP significantly reduced cigarette use among treatment youths relative to control youths. However, such effects were present only at the initial 6-month follow-up, and significant effects were not sustained throughout the remaining follow-up assessments.
The results of the study indicated significant reductions in alcohol use among treatment youth at the first two follow-ups—that is, up to 1½ years, relative to the control group. Significant effects were not sustained throughout the remaining follow-up assessments.
The results of the study did not indicate sufficient evidence of a significant reduction in marijuana use among treatment youths relative to control youths during any of the four follow-up assessments.
Pentz and colleagues (1989) conducted a randomized control trial of the Midwestern Prevention Project (MPP) in Kansas City, Missouri, a longitudinal study that spanned 6 years. The experiment began in fall 1984, and the study concentrated on providing an evaluation of the program’s impact on cigarette use prevalence among middle school students. Schools were assigned to either a program group—which received school, booster, parent, and mass media program components—or a control group that received regular health education programming in school as usual. As there was no realistic way to prevent access to the mass media component, the control group was assumed to have access to this component of the intervention. The sample included eight schools, totaling 1,122 sixth and seventh grade students. The sample was 50 percent male and 82 percent white, 14 percent African American, and 4 percent other races. To evaluate the effectiveness of MPP, the program’s impact on smoking prevalence rates was analyzed. Smoking prevalence rates were measured through an analysis of self-reported cigarette use, supplemented with a biochemical analysis of monoxide in students’ breath. Both measures were combined to determine an overall impact on smoking prevalence rates.
Self-reported cigarette use among students was measured through the administration of a questionnaire regarding smoking behavior. Students completed a self-administered questionnaire about 1½ months before the intervention, between early November 1984 and early January 1985, to provide baseline data. Three follow-ups were conducted to monitor the progress of the intervention’s effects; these occurred at 6 months, after 1 year, and after 2 years. The questionnaire included items regarding smoking behaviors, drug use, and psychological factors related to drug use, and four categories of questions were used as indicators of program effects: lifetime use, last-month use, last-week use, and current use of cigarettes.
A biochemical measure of smoking was used to enhance the accuracy of the data collected from the survey results, which entailed the collection and analysis of carbon monoxide in students’ breath. During this procedure, each student was instructed to inhale deeply and hold his or her breath for 10 seconds. Students then exhaled through a straw to blow up the balloon, after which indicator readings were recorded. The instrument was calibrated before its use, to account for levels of carbon monoxide in the air that could be from heating systems or other sources. These recordings were used to estimate the concentration of carbon monoxide in expired air from the lungs, to estimate whether cigarette use was evident.
Chou and colleagues (1998) conducted a randomized controlled trial of MPP in Indianapolis, Indiana, beginning in fall 1987. The evaluation concentrated on the impact MPP made in reducing tobacco, alcohol, and marijuana use among middle school students. A cohort of adolescents from 57 schools in 12 school districts was identified for inclusion in the study, and schools were randomly assigned to either a treatment condition or control condition. Thirty-two schools were placed in the treatment condition and used all components of the MPP curriculum. Twenty-five schools were placed in the control group and were assigned to a health-education-as-usual condition. To be eligible for participation in the study, adolescents must have reported use of cigarettes, alcohol, or marijuana in the month before baseline data collection. The number of students included in the study totaled 3,412, with 1,904 in the treatment group and 1,508 in the control group. Students were tracked for four follow-ups at 6 months, 1½ years, 2½ years, and 3½ years after baseline data collection.
The study used the administration of a self-report questionnaire regarding students’ recent substance use. The questionnaire consisted of 100 items that measured substance abuse behavior as well as demographic characteristics, attitudes, and social influences related to substance abuse. Responses regarding cigarette, alcohol, and marijuana use were evaluated separately to determine the potential impact of MPP on each behavior.
The cost to implement the Midwestern Prevention Program (MPP) over a 3-year period is estimated at $175,000, which includes the costs of teacher, parent, and community leader training and curriculum materials for the school-based program. This calculation is based on a minimum of 20 teachers trained in one group for the school program, 20 parent group members trained in one group for the parent program (about 3 or 4 principals, 4 student peer leader, 12 parents), and 1,000 participating middle school students. Beyond this threshold, costs increase to approximately $4,000 per additional group trained on the same day or trip, $100–$125 per additional trainer manual, and $7 per additional student workbook.
To facilitate successful implementation of the Midwestern Prevention Program (MPP), the community frequently donated available resources such as office space, technical support, media coverage, or other various materials. Additionally, strong support from parents and school principals helped to bolster implementation of the family and school components of the program. It was important that all participants put forth necessary effort, as trainers and leaders were required to make a 2- to 2½-year commitment to the program.
Training of all participants facilitated proper implementation of MPP. Teachers were required to participate in a 2-day training session before implementation of the school component, and were also required to attend yearly ½-day refinement sessions. It was recommended that program implementation occurred within 2 weeks of training, or teachers could forget techniques and information from training sessions. Community leaders and school superintendents were also required to complete a series of training sessions to facilitate effective implementation of the program. Initial sessions included familiarizing leaders with effective prevention techniques, and setting general goals for the task force or council. Later sessions entailed the review of prevention and intervention research to guide further direction of program goals. Finally, the parent program component involved a 1-day training that included discussion and collaboration between parents and principals. During this session, groups conducted a policy needs assessment that was tailored to the needs of specific schools to plan long-term prevention efforts.