Self-Reported Physical Activity: Its Correlates and Relationship with Health-Related Quality of Life in a Large Cohort of Colorectal Cancer Survivors

BACKGROUND Physical activity (PA) is suggested to be an important non-pharmacologic means to improve health-related outcomes among cancer survivors. We aimed to describe the PA level, its correlates, and association with health-related quality of life (HRQoL) in colorectal cancer (CRC) survivors. METHODS CRC survivors identified from the Eindhoven Cancer Registry treated between 1998 and 2007 were included. Survivors completed validated questionnaires on PA, distress, fatigue, and HRQoL. Moderate-to-vigorous physical activity (MVPA) levels were calculated by summing the time spent on walking, bicycling, gardening and sports (≥3 MET). Multiple linear regression analyses were conducted to study which socio-demographic and clinical factors were associated with MVPA. Furthermore, we examined associations between MVPA and physical and mental HRQoL, and whether these associations were mediated by fatigue and distress. RESULTS Cross-sectional data of 1371 survivors (response: 82%) were analysed. Participants were 69.5 (SD 9.7) years old, 56% were male, and survival duration was 3.9 (SD 2.5) years. Participants self-reported on average 95.5 (SD 80.3) min on MVPA per day. Younger age, male sex, being employed, non-smoking, lower BMI, colon cancer (vs. rectal cancer), chemotherapy treatment and having no co-morbidities were associated with higher MVPA (p<0.05). MVPA was positively associated with physical HRQoL (regression coefficient of total association (c) = 0.030; se = 0.004) after adjusting for socio-demographic and clinical factors. Fatigue mediated this association between MVPA and physical HRQoL (44% mediated). The association between MVPA and mental HRQoL was not statistically significant after adjusting for socio-demographic and cancer-related factors (c = 0.005; se = 0.004). CONCLUSION In CRC survivors, clinical factors including the absence of co-morbidity, tumour site and chemotherapy treatment were associated with higher MVPA, in addition to several socio-demographic factors. Higher MVPA was associated with higher physical HRQoL but not with mental HRQoL. Fatigue and distress mediated the association between MVPA and HRQoL.