ABSTRACT
The current study examined mediators of an efficacious physical activity intervention. Women with a mean age of 42.6 (range 23–61) years and a family history of breast cancer were randomized to either an Internet-based physical activity intervention (n = 28) or an active control condition (n = 27) for three months. Data were collected between November 2010 and August 2011. Hypothesized mediators were examined using a product of coefficients model with bootstrapped standard errors. Significant mediation was observed for both self-efficacy and behavioral processes. Specifically, the regression coefficients of the indirect effects (“ab path”: unstandardized effect of the intervention on physical activity that occurred through the mediator) were ab = 38.58 (95% confidence interval [CI]: 8.66–92.76) for self-efficacy, and ab = 42.02 (95% CI: 6.76–104.84) for behavioral processes. Other factors examined in this study, including cognitive processes, decisional balance, and perceived risk of breast cancer, were not statistically significant mediators. Findings suggest that self-efficacy and behavioral processes may be key constructs to use in targeting future physical activity interventions among women with a family history of breast cancer.
Funding
Research support was provided by funding from the National Cancer Institute (R25CA087972). Dr. Marinac was supported by the National Cancer Institute of the National Institutes of Health under Award Number F31CA183125; Dr. Hartman was supported under Award Number K07CA181323. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.