Combined Diet and Physical Activity Promotion Programs to Prevent Type 2 Diabetes Among People at Increased Risk

Part I. Community Guide Update and Rationale for Intervention

As of July 2014, this strategy is “Recommended” based on strong evidence that diet and physical activity reduce the onset of new Type 2 Diabetes cases. It is also recommended because it reduces other risk factors that contribute to diabetes such as body weight and blood pressure.  Based on the previous research of 53 studies reviewed by the Community Guide Task Force and the studies that were presented in the table, diet and physical activity as a strategy to reduce or control Type 2 Diabetes is still “Recommended.”

The recommendation is unchanged from before because there have not been additional studies done to change the strength of the recommendation. The studies included in the table are related to diet and exercise and Type 2 Diabetes, but do not support or negate this particular strategy. For example, one study compared whether choosing or being assigned the particular diet made a difference in diabetes risk factors. While there was no difference between the “Choice” and “No Choice” groups, the study still supported that diet reduced risk factors of diabetes. The other two studies neither negated or supported this strategy because they dealt with methods of delivering counseling about diet and exercise, not specifically testing the effects of these.

Based on searches done in the PubMed and UGA Library databases as well as Google Scholar, I could not find any new research published since the Community Guide recommendation in 2014 that specifically measured the effect of diet and exercise on the prevention or management of Type 2 Diabetes. The previous evidence was strong enough to support this recommendation without the immediate need for future research. Previous studies used in the Community Guide provided diet goals, weight loss goals, and physical activity goals for subjects and included various forms of counseling sessions. All of the previous studies showed a decrease in the proportion of people who developed Type 2 Diabetes, an increase in the proportion of people who showed normal blood glucose levels, and a decrease in body weight.  For these reasons, the recommendation holds as “Recommended.”

Part II. Theoretical Framework/Model

Diet and exercise are often misconstrued as purely personal achievements. However, these changes occur in a variety of environmental frameworks which must be considered when designing interventions. Interventions that consider various segments of society that individuals interact with are generally more successful, especially in dealing with diet and exercise. The Social Ecological Model describes these segments or levels of the environment and can be used to develop multi-level interventions. This is especially helpful for health problems that are extremely prevalent, such as diabetes.

The Social Ecological Model acknowledges that there are many different factors at many different levels that can influence a behavior. In order to change a behavior, one can make changes at the individual level, interpersonal level, institutional level, community level, and policy level. Interventions can even occur at a combination of these levels in order to be most effective.

The individual level describes any characteristics or factors of an individual that can influence behavior, such as race, gender, socioeconomic status, etc. It can also include biological factors such as body mass index, blood pressure, genetics, etc. Some important factors to consider for increasing physical activity and healthy eating habits for people with or at risk for diabetes include their race, socioeconomic status, current blood glucose levels, BMI, and their ability or interest to self-educate.

The interpersonal level describes close relationships to the individual such as family, friends, and colleagues. These “social support systems” can provide positive influence on the individual’s behavior – such as if the family encourages the individual to eat healthy – but can also provide negative influence – such as if friends encourage regular eating out and colleagues often bring sugary treats to work.

The institutional level mostly describes factors that occur in the individual’s institutional interactions, such as churches, schools, and the workplace. Unlike interpersonal factors that deal with the social relationships, the institutional factors deal with the rules in place at those institutions. This is an important level for reducing and preventing diabetes because there is much being done at the elementary school level to increase physical activity, reduce sugary beverage consumption, and incorporate healthier meals into the cafeteria.

The community level is the next bubble in this model because it incorporates the relationships between institutions, groups, and personal relationships in a community. It is the social network beyond just the individual’s friends and families. Traditionally, this level only included the social factors associated with community, but for health problems such as diabetes, it can also be beneficial to include aspects of the built community. For example, a community can support a healthy lifestyle and host events that promote physical activity or cooking classes, but if the built environment is not conducive to these activities, there is a major hindrance to the individual’s behavior change. For diet and physical activity, changes in the built environment of the community could include access to walking trails and parks, as well as access to grocery stores and fresh farmers markets.

The policy level is the final bubble and includes any laws, decisions, policies, etc. that occur through government. For example, in Athens, GA, individuals are able to double their food stamps to use at the Farmers Market based on a local policy initiative. At the national level, government subsidies of corn in the U.S. make corn syrup sweeteners a very cheap commodity, and thus, unhealthy, sugary foods become very affordable and would potentially decrease healthy eating at the individual level.

Part III. Logic Model, Causal and Intervention Hypotheses, and Intervention Strategies

The target population will be adolescents enrolled in Athens-Clarke County Middle Schools, grades 6-8. This intervention focuses on adolescents for two main reasons. 1) Healthy diet and physical activity must be established as a habit, and youth is a very formative time to incorporate fruits and vegetables, exercise, and other healthy habits into your daily life. These lesson plans will be introduced now with the hopes that healthy habits will continue on throughout their adult life. 2) This intervention will focus on adolescents communicating with their families and disseminating information they learn through lesson plans. Not only does this hope to strengthen the interpersonal connections between students and families and address environmental factors that could be barriers to healthy diet and physical activity, but also it is an efficient way to transfer information to parents who are busy working and do not have time to attend weekly information sessions or workshops.  

The intervention will take place within the schools, during the regular school day, as part of a weekly hands-on educational session. Athens-Clarke County public schools have high rates of poverty and a large minority population. 79% of those enrolled are “economically disadvantaged,” 53.9% are black, and 18.6% are Hispanic. In 2013, the County Health Ratings reported 21% of Athens-Clarke County residents as having “limited access to healthy foods,” a community level risk factor for diabetes, and 19% report physical inactivity. Diabetes mellitus is the 8th leading cause of death in Athens-Clarke County (2006-2010). For these reasons, public schools are an appropriate intervention setting. Not only will children be reached in these at-risk populations, but also families of similar demographics. 

Logic Model 

Intervention Hypothesis:

Lesson plans that include cooking classes and reading nutrition labels will increase students’ knowledge and self-efficacy to make good food choices.

Lesson plans that include engaging their families at home will increase families’ knowledge of healthier diet and exercise habits.

Lessons plans that include education on how to engage with families at home will increase students’ self-efficacy to educate their families.

Journaling and reflecting on barriers to healthy habits will increase students’ motivation to engage in those behaviors.

Causal hypothesis

An increase in students’ knowledge and self-efficacy regarding healthy diet and physical activity will increase healthy eating and physical activity behaviors.

An increase in families’ knowledge of healthier diet and exercise habits will increase healthy diet and physical activity in students’ families.

The pilot study will be a one group pre-test/post-test design. Pre-test will occur immediately before the intervention and post-test will occur immediately after the intervention with a 6-month follow up test. Further interventions will be quasi-experiemental with matched control groups with pre- and post-tests of the same schedule.

Pilot:

O1     X     O2       O3

Quasi-experimental:

Group 1A:

O1  X  O2  O3

Group 2B: [control]

O1     O2  O3

Group 2A:

O1 X  O2  O3

Group 2B: [control]

O1     O2  O3

Threats to validity:

Selection:

The pilot group experiences some threats to internal validity because of the lack of randomization. This group was chosen based on school and teacher interest in launching the pilot program so there is no comparison group and no matched control. This will be addressed in the further interventions as the pilot study is primarily used to fix any major problems with implementation.

Hopefully by using matched control groups, we can eliminate or at least be aware of some threats to internal validity. The groups will be as similar as possible – coming from the same age range, school system, and we will attempt to balance various demographic factors. Conducting a pre-test will provide information regarding similarity to be used for analysis.

Attrition:

Including pre- and post-tests will allow us to measure attrition so that we can determine if drop outs occurred because of a specific reason. If individuals who dropped out have similar pre-test results that are unique from the rest, then that can indicate a reason fro dropping out. Drop out is generally limited when tests are conducted within a school setting, especially because weekly activities will occur during the school day.

History:

Some students could receive information regarding diet and physical activity or could change their behaviors due to other activities, experiences, or influences outside of this intervention. This can be addressed with the use of multiple groups in different schools to test so that we collect a varied group of students who hopefully have experienced different histories.

Maturation:

Because we are testing middle school aged children, it will be expected that many physical and psychological factors will be different over the course of the school year and in the 6-month post-test simply due to students growing and maturing. To accommodate these changes, physical measures will be a secondary measure and other surveys and scales based on knowledge and behavior will be favored instead.

Testing effects:

Conducting the same or similar surveys and tests may change or improve students’ results of those tests; similarly, students may become more aware of the behaviors because of the tests and may participate in the intervention differently than without pre-test.

Part V. Process Evaluation and Data Collection Forms

School enrollment form:

Student Test Tracking Form:

Student Activity Completion Form:

Teacher Questionnaire: 

Please answer each question fully. 

Completion of Activities 

Were you able to deliver all 16 lesson plans? 

If not, which ones were you unable to complete and why?

Were you able to send all 16 pamphlets home with the students? 

If not, which ones were you unable to send home and why? 

Were you able to assign the weekly assignments for all 16 lesson plans? 

If  not, which ones were you unable to assign and why? 

Integrity of Activities

Please rate the following components on a scale from 1 – 7, 1 being low to 7 being high. Please distribute your scores so that 5% are 1s, 10% are 2s, 20% are 3s, 30% are 4s, 20% are 5s, 10% are 6s, and 5% are 7s (Hansen, 1991). 

1) Your enthusiasm towards the material in the classroom  1 2 3 4 5 6 7

2) The degree to which your delivery met the goals of the program 1 2 3 4 5 6 7

3) The degree to which you engaged all students 1 2 3 4 5 6 7 

4) Your control of the classroom during delivery of activities 1 2 3 4 5 6 7

5) The students’ enthusiasm towards the material in the classroom 1 2 3 4 5 6 7

6) The students’ responsiveness to the material 1 2 3 4 5 6 7

7) The students’ degree of participation in the activities  1 2 3 4 5 6 7

8) The overall smoothness of the lessons  1 2 3 4 5 6 7

Evaluation of Barriers 

Please answer the following questions after reviewing students’ journals. Keep journals on hand in order to reference them for the following questions. 

What were the most commonly listed barriers to completing the activities (e.g. family could not afford, no access to food or space, family unsupportive, etc.) You may answer this questions with a tally for repeated barriers. 

Week 1:

Week 2:

Week 3:

Week 4:

Week 5:

Week 6:

Week 7:

Week 8:

Week 9:

Week 10:

Week 11:

Week 12:

Week 13:

Week 14:

Week 15:

Week 16: 

Were there any barriers that were specific to your school or community, or that dealt with particular community partners? 

References: