Mediating and Moderating Factors of Adherence to Nutrition and Physical Activity Guidelines, Breastfeeding Experience, and Spousal Support on the Relationship between Stress and Quality of Life in Breast Cancer Survivors

Spousal support may attenuate stress in breast cancer survivors and improve their health-related quality of life (HRQoL). However, there is limited evidence of a relationship between spousal support, stress, and HRQoL in Asian populations. The current study examined whether spousal support, adherence to the American Cancer Society (ACS) Guidelines on Nutrition and Physical Activity for Cancer Survivors, and breastfeeding experience mediated or moderated the relationship between stress and HRQoL in Korean breast-cancer survivors. Between June 2016 and May 2018, 144 Korean women who survived breast cancer were recruited for the current cross-sectional study. Structured questionnaires and medical records were used to collect data. Structural equation modeling was used to examine mediating and moderating factors. Spousal support buffered the adverse effect of stress on HRQoL (β = −0.22 for stress→spousal support; β = 0.27 for spousal support→physical HRQoL; β = 0.40 for spousal support→mental HRQoL). We found that adherence to ACS guidelines moderated the association between stress and HRQoL (β = −0.14 for stress→mental HRQoL in high ACS adherence; β = −0.79 for stress→mental HRQoL in low ACS adherence). Moreover, beta coefficients were −0.22 for stress→mental HRQoL in women with breastfeeding experience, and −0.71 in those without breastfeeding experience. In conclusion, spousal support mediated the association between stress and HRQoL and this association was moderated by both adherence to ACS guidelines and breastfeeding experience.