Translation efforts based upon the successful Diabetes Prevention Program (DPP) have shown that this behavioral lifestyle intervention model is effective in a variety of diverse community settings. Despite the fact that physical activity isa key part of the DPP lifestyle intervention as one of the two intervention goals, activity change in the DPP, and/or the resulting translation studies modeled after it, has never been verified with an accurate objective measure. In addition, previous research has shown that, in many subgroups of the general population, moderate/vigorous (moderate+) physical activity is non-existent. These same individuals may have a difficult time increasing their levels of moderate+ intensity physical activity due to either limited function or lack of motivation. For these individuals, interventions attempting to increase planned bouts of moderate+ intensity activity may not be as effective or as beneficial as trying to decrease time spent sitting. The goal of this proposal is to understand the impact of movement, specifically physical activity and sitting time, in community lifestyle intervention efforts.
Aim #1 addresses an important remaining gap in the prevention literature; does objectively measured activity improve as a result of the existing intervention that is being used in DPP-based translation efforts and does this change in activity have an impact on weight change? Aim #2 examines the impact of replacing the conventional physical activity goal of increasing planned and relatively brief bouts of moderate+ physical activity with one focusing on decreasing sedentary time within the framework of a successful translation lifestyle intervention adapted from the DPP, the Group Lifestyle Balance (GLB) program. The study design is a prospective, six month delayed-control intervention in which 321 subjects (age 50 and older with a BMI of e24 kg/m2 and with prediabetes and/or metabolic syndrome) will be recruited from community centers and randomly assigned to one of three groups: the standard GLB program which includes the conventional moderate+ activity goal (GLB-MOD), the GLB program with a focus on decreasing sedentary behavior (GLB-SED), or delayed intervention. Subjects assigned to GLB-MOD and GLB-SED will each be compared at 6 months to the delayed-control group after which time, the delayed group will be randomly assigned to either GLB-MOD or GLB-SED. Participants will complete baseline, 6, and 12 month assessment visits. Change in weight, objectively measured activity, and time spent sedentary are the primary outcomes with secondary outcomes including change in self-reported physical activity, HbA1c, fasting glucose, lipids, blood pressure, waist circumference, quality of life and physical function. It is hypothesized that physical activity assessed by accelerometry in GLB-MOD will significantly increase (mostly moderate intense activity) and that there will be a significant decrease in weight, which will partly be related to change in activity levels. The 2nd hypothesis is that the GLB-SED intervention will significantly decrease time spent sitting as measured by accelerometry and that this change will also be related to a significant decrease in weight. The information that will be gained from this entire effort is important, innovative, and wll allow us to obtain a complete and accurate understanding of both ends of the physical activity/inactivity spectrum and their impact in community prevention intervention programs. If shown to be effective, the innovative, modified sedentary-focused translation intervention program would provide a valuable future translation option.
DPP translational efforts, such as our Group Lifestyle Balance Program (GLB), have been shown to be effective in reducing weight and modifying diabetes and CVD risk factors in a variety of diverse community settings. However, although one of the two primary goals of these DPP translation programs focuses on increasing physical activity levels, less than half of all published DPP translation studies reported results on change in physical activity and all of the published activity results based on self-report data. In order to completel understand the role that physical activity plays in making healthy lifestyle change, it is critical that we validate the impact of activity using an objective measure. In addition, current studies suggest that decreasing prolonged sitting bouts may be as important as or even more important than participating in planned bouts of moderate intensity activity. Therefore, we propose to examine the impact of a modified version of the GLB program, which will focus on decreasing sedentary behavior. The results of this project will provide information regarding best options for physical activity within lifestyle intervention programs, focusing first on verifying the current rle of physical activity in lifestyle intervention using an objective measure, and second on examining an alternative intervention option for translation efforts.
