Moderators and mediators of behaviour change in a lifestyle program for treated hypertensives: a randomized controlled trial (ADAPT)

Abstract

We aimed to examine moderators and mediators of behaviour change in a cognitive lifestyle program for drug-treated overweight hypertensives in Perth, Australia. We collected data at baseline, 4 months (post-intervention) and 1-year follow-up in a randomized controlled trial of a program that focused on weight loss, diet, and exercise. Mediation analysis used regression models that estimate indirect effects with bootstrapped confidence limits. Outcomes examined were saturated fat intake (% energy) and physical activity (hours per week). In total, 90/118 individuals randomized to usual care and 102/123 to the program-completed follow-up. Sex was a moderator of response post-intervention for diet and physical activity, with a greater response among women with usual care and among men with the program. Change in self-efficacy was a mediator of dietary change post-intervention [effect size (ES) -0.055, 95% confidence interval (CI) -0.125, -0.005] and at follow-up (ES 0.054, 95% CI -0.127, -0.005), and in physical activity post-intervention (ES 0.059, 95% CI 0.003, 0.147). These findings highlight different responses of men and women to the program, and the importance of self-efficacy as a mediator. Mediators for physical activity in the longer term should be investigated in other models, with appropriate cognitive measurements, in future trials.

Association between Self-Efficacy and Health Behaviour in Disease Control: A Systematic Review

“…From the total 13 included studies, eight were found a direct association between self-efficacy and specific health behaviours (Berendes & Rimal, 2011;V. Burke et al, 2007;Chariyeva et al, 2013;Ievers-Landis et al, 2003;Luszczynska, 2004;Morisky et al, 2001;Piaseu et al, 2002;Strathdee et al, 2009).…”

“…Another randomized controlled trial of a cognitive lifestyle program for drug-treated overweight hypertensive patients in Perth, Australia reported that change in self-efficacy mediated change in saturated fat consumption (effect size (ES) -0.055, 95% CI (-0.125, -.005) at post intervention and (ES -0.054, 95%CI ;0.127, -0.005) at the follow up (V. Burke, Beilin, Cutt, Mansour, & Mori, 2007). Self-efficacy also explained change in time spent in exercise at least moderate intensity at post intervention (ES 0.059, 95% CI; 0.003, 0.147).…”

Factors influencing dietary fat intake among black emerging adults

“…In this study neither perceived family social support nor friend social support moderated the effect of gender, BMI, income adequacy, and religious commitment on DFI. Similarly, Burke et al (2008) did not find a significant interaction of social support for dietary fat intake; but the sample consisted of adults ranging from 40 to 70 years old. It may be possible that a statistically significant interaction between perceived family social support and perceived friend social support with BMI, income adequacy, and religious commitment was not found because the sample in this current study was homogeneous, which "may weaken detection of a moderator effect" (Bennett, 2000, p. 418).…”

“…No studies were found for religious commitment. As for the moderating effects of social support, with dietary fat intake as the dependent variable, only one study, with a sample of adults ages 40-70, has been conducted by Burke et al (2008). This is the first study, to date, to examine the potential moderating effects of religious commitment and social support in regards to dietary fat intake among Black emerging adults.…”

Moderator and Mediator Effects of Personal Factors in Patients with Stroke

“…Burke et al 8) describe the gender-related variances of the effect of diet control and exercises on saturated fat intake and physical Activities of overweight and hypertensive patients treated with drugs and point out that the involvement of diet control and exercises increases the self-efficacy and affect the saturated fat intake and physical Activities. In this case, gender is a moderator, and self-efficacy is a mediator.…”