Engagement indicators predict health changes in a lifestyle intervention

Authors: Thomson, Jessica; TUSSING-HUMPHREYS, LISA - University Of Illinois; Goodman, Melissa; ZOELLNER, JAMIE - Virginia Tech

Submitted to: American Journal of Health Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2015
Publication Date: 1/26/2015
Publication URL: http://handle.nal.usda.gov/10113/62027
Citation: Thomson, J.L., Tussing-Humphreys, L.M., Goodman, M.H., Zoellner, J.M. 2015. Engagement indicators predict health changes in a lifestyle intervention. American Journal of Health Behavior. 2015;39(3):409-420. https://doi.org/10.5993/AJHB.39.3.13.
DOI: https://doi.org/10.5993/AJHB.39.3.13

Interpretive Summary: Lack of participant adherence to intervention components can adversely affect the success of behavioral lifestyle interventions for achieving positive health outcomes. Adherence determines the dose of the intervention received by participants and can help in understanding relationships between program elements and participant outcomes. Because multicomponent lifestyle interventions are designed to affect changes in several aspects of an individual’s daily habits, notably diet and physical activity, diverse measures are needed to track participant engagement in all components of an intervention. However, most lifestyle intervention studies only report participant adherence to a single component, most commonly frequency of class attendance. In the present study, several participant adherence measures were used, separately and in combination, to predict changes in dietary, physical activity, and clinical outcomes in a church-based lifestyle intervention conducted in rural, Southern, African American adults. Results from these analyses indicated that the observed positive changes in dietary, physical activity, and blood lipid outcomes were largely driven by level of participant adherence to components of the intervention. Because no adherence measure emerged as the “best” overall predictor of health outcome changes, the use of single adherence measures specific to each component of a behavioral lifestyle intervention for predicting relevant outcome changes is proposed (e.g., attendance at nutrition education sessions for predicting changes in dietary outcomes). Further, the use of multifactorial measures for predicting more “downstream” outcomes that may be directly or indirectly affected by all intervention components is suggested as well (e.g., attendance at nutrition education sessions and participation in physical activity classes for predicting changes in body composition, blood pressure, and blood lipids).

Technical Abstract: This secondary analysis evaluated the utility of several participant adherence indicators for predicting health outcome changes in a 6-month, church-based, controlled, lifestyle intervention previously proven effective for improving diet quality, physical activity, and blood lipids. Descriptive indicators were constructed using 3 participant adherence measures – education session attendance (ESA), participation in physical activity classes (PPA), and motivational interviewing telephone calls – separately and combined. Analyses, based on data from 409 Southern, primarily African American adult participants, included bivariate tests and generalized linear mixed models to test for relationships between 7 adherence indicators and health outcome changes, including 13 dietary, 3 physical activity, and 8 clinical measures. ESA was significantly correlated with 6 dietary outcomes, and PPA with 1 physical activity and 1 clinical outcome. The combined continuous indicator was significantly correlated with the same 8 outcomes. Single continuous adherence indicators were as good as the combined indicator for predicting health outcome changes.