Pain, movement, and mind: does physical activity mediate the relationship between pain and mental health among survivors of breast cancer?

OBJECTIVES: This study examined the relationship between pain and mental health outcomes of depression and affect among survivors of breast cancer. The mediating role of physical activity was also tested.
METHODS: Survivors of breast cancer (N=145) completed self-report measures of pain symptoms at baseline, wore an accelerometer for 7 days, and reported levels of depression symptoms and negative and positive affect 3 months later. Hierarchical linear regression analyses, controlling for personal and cancer-related demographics, were used to test the association between pain symptoms and each mental health outcome, as well as the mediation effect of physical activity.
RESULTS: Pain positively predicted depression symptoms [F(6,139)=4.31, P<0.01, R=0.15] and negative affect [F(5,140)=4.17, P<0.01, R=0.13], and negatively predicted positive affect [F(6,139)=2.12, P=0.03, R=0.08]. Physical activity was a significant (P<0.01) partial mediator of the relationship between pain and depression and between pain and positive affect. DISCUSSION: Participation in physical activity is one pathway through which pain influences mental health. Efforts are needed to help survivors of breast cancer manage pain symptoms and increase their level of physical activity to help improve mental health.