Assessing Mediation and Moderation of an Efficacious Physical Activity Intervention for African American Men Living with HIV: The Influence of Self-Efficacy in Behavior Change

This research evaluates the mediation and moderation of an efficacious physical activity (PA) intervention designed for African American men living with human immunodeficiency virus (HIV). Physical activity is a crucial element in managing the health of individuals with HIV, but African American men represent a population that is disproportionately affected by HIV and often faces barriers to engaging in regular PA. We analyzed data obtained from a randomized controlled trial (N = 302) that recruited African American men living with HIV who are 40 years or older and randomly assigned them to a PA intervention group or a health-awareness control group. We collected data at baseline, immediate post-intervention, and 3-, 6-, and 12-month post-intervention. We examined whether the intervention’s effect on adherence to PA guidelines was mediated through the Reasoned Action Approach and the Social Cognitive Theory constructs, including attitudes, social norms, self-efficacy, and intention. We explored whether individual characteristics, including Body Mass Index (BMI), Waist-Hip Ratio (WHR), age, education level, and marital status, influenced the intervention’s effect. We found that self-efficacy mediated the intervention’s effect (α×β×γ product = 0.125, 95% ACI [0.053, 0.229]) by influencing intentions. Statistical analyses did not identify significant moderations of the intervention effect by age, marital status, education level, BMI, or WHR. These findings suggest that interventions to enhance PA among African American men living with HIV should particularly focus on boosting self-efficacy to exercise. Future research should explore additional psychological mechanisms and potential moderators to further refine and tailor PA interventions for this population.