Physical activity and quality of life in breast cancer survivors: The role of self-efficacy and health status

Objective Mechanisms underlying the relationship between physical activity and quality of life (QOL) in breast cancer survivors are not well understood. The purpose of the present study was to longitudinally test a model examining self-efficacy and health status as potential mediators of this relationship. Methods At baseline and 6 months, breast cancer survivors (n = 1527) completed physical activity, self-efficacy, health status, and QOL measures, and a subsample (n = 370) wore an accelerometer. Panel analysis within a covariance modeling framework was used to test the hypothesis that physical activity indirectly influences QOL across time. Results The hypothesized model provided a good fit in the full sample (χ² = 409.06; d.f. = 91, p < 0.001; comparative fit index (CFI) = 0.98; standardized root mean residual (SRMR) = 0.04) and the accelerometer subsample (χ² = 320.96, d.f. = 134, p < 0.001; CFI = 0.95; SRMR = 0.05), indicating that physical activity indirectly, via self-efficacy and health status indicators, influences QOL across time. Conclusions Physical activity may influence QOL in breast cancer survivors through more proximal, modifiable factors.