Advisor(s)
Wendy Demark-Wahnefried
Committee Member(s)
Dorothy Pekmezi
Drew Sayer
Gregory Pavela
Holly Wyatt
School
School of Health Professions
Document Type
Dissertation
Department (new version)
Nutrition Sciences
Date of Award
9-9-2024
Abstract
Cancer survivors are a high-risk population with poor lifestyle behaviors and a higher prevalence of obesity, necessitating effective lifestyle interventions to promote weight management, consumption of a healthy diet, and increased physical activity. Recently, lifestyle interventions have evolved to web-based platforms that are easily accessible. However, there is a need to understand how web-based lifestyle interventions work, and who they work best for to maximize impact. Thus, the objective of this dissertation was to evaluate social cognitive theory (SCT) mechanisms (i.e., self-efficacy, social support, and perceived barriers) through which two web-based lifestyle interventions, DUET and AMPLIFY, mediate changes in diet, moderate-to-vigorous physical activity (MVPA), and/or adiposity, and determine the potential moderating role of cohabitation on SCT constructs. To address aims 1 and 2, simple and moderated-mediation analyses were performed on data from 112 cancer survivors and their partners (56 dyads) enrolled in the DUET trial. For aim 3, parallel mediation analyses were performed using data from 349 cancer survivors enrolled in the AMPLIFY diet trial. The key findings from this dissertation revealed that (1) the effect of the DUET intervention on weight loss was mediated through reductions in perceived dietary barriers (ab: -1.60, 95% CI [-3.84 to -0.47]); (2) cancer survivors and partners who did not cohabitate reported significantly higher dietary social support (path a1: 0.36, [0.083, 0.659]) and lower perceived barriers to dietary and exercise changes (path a1: -10.57, [-19.109, -3.091]), (path a1: -11.29, [-22.098, -3.500]), respectively, and mediating effects were also stronger among non-cohabitating pairs (ab: -2.21, [-4.794, -0.548]); (3) the effect of the AMPLIFY intervention on weight loss was mediated through reductions in perceived dietary barriers (ab: -0.47, [-0.981, -0.094]); and (4) self-efficacy and social support did not emerge as significant mediators in explaining the positive effects of either the DUET and AMPLIFY interventions. These findings suggest that the DUET and AMPLIFY web-based interventions successfully achieved weight loss through reductions in perceived dietary barriers. This research also informs future dyadic interventions to enroll support networks outside the home to maximize impact. Further work is needed to elucidate the effects of self-efficacy and social support within web-based platforms.
ProQuest ID
Recommended Citation
Kaur, Harleen, "Investigating Theoretical Constructs Of Social Cognitive Theory As Working Mechanisms Of Web-Based Diet And Physical Activity Interventions Among Cancer Survivors" (2024). All ETDs from UAB. 7582.
https://digitalcommons.library.uab.edu/etd-collection/7582
