Mediators of behavior change resulting from a sexual risk reduction intervention for STI patients, Cape Town, South Africa

Theory-based sexual risk reduction interventions are often demonstrated effective, but few studies have examined the mechanisms that mediate their behavior changes. In addition, critical contextual factors, such as alcohol use, are often not accounted for by social cognitive theories and may add to the explanatory value of intervention effects. The purpose of this study is to examine the underlying mechanisms driving condom use following a brief sexual risk reduction intervention grounded in the information, motivation, behavioral skills (IMB) model of behavior change. We examined IMB theoretical constructs and alcohol-related contextual factors as potential mediators in separate models. Patients (n = 617) from an STI clinic in Cape Town, South Africa were randomly assigned to either a brief risk reduction intervention or an education-only control condition. We assessed IMB, and alcohol-related variables at baseline, 3, 6, 9, and 12 months and modeled IMB constructs and alcohol-related factors as mediators of behavior change. Results of growth-curve mediational modeling showed that 1 year after counseling, the intervention indirectly affected sexual risk behavior through alcohol-related constructs, but not IMB constructs. Alcohol use and related factors play critical roles in explaining HIV and STI risk reduction intervention effects. Interventions that directly address alcohol use as a factor in sexual risk behavior and behavior change should be the focus of future research.