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.