Mechanisms of Strong Hearts, Healthy Communities-2.0 Effects on Weight: A Mediation Analysis

OBJECTIVE: To evaluate potential mediators of weight loss in the Strong Hearts, Health Communities-2.0 (SHHC-2.0) trial. DESIGN: Community-randomized trial (intervention vs delayed intervention). Outcomes were evaluated at baseline and postintervention. SETTING: Eleven rural, medically-underserved communities PARTICIPANTS: Women (n = 182), mean age 57.2 years, 97.6% White, non-Hispanic. INTERVENTION: Classes delivered 2 times/wk for 24 weeks, targeting diet and physical activity behaviors. MAIN OUTCOMES MEASURES: Dependent variable: weight; mediators: diet and physical activity behaviors, and related psychosocial factors. ANALYSIS: Mixed linear regressions evaluated the effect of mediators on weight loss. RESULTS: Significant mediators included dietary behaviors (Rapid Eating Assessment for Participants-Short; 31.8%; P = 0.03), healthy eating attitudes (23.0%; P = 0.03), and dietary cognitive restraint (29.8%; P = 0.01). Physical activity did not mediate weight loss; however, a worsening in attitudes toward exercise was a mediator of weight loss (22.6%; P = 0.01). Social support for diet and physical activity was unchanged in the intervention group and did not mediate weight loss effects. CONCLUSIONS AND IMPLICATIONS: Healthy eating attitudes and dietary cognitive restraint represent important targets for future behavioral interventions for weight loss. Hypothesized mediators found to be nonsignificant (i.e., social support) represent opportunities for future intervention optimization.