Association of physical activity with stroke among long-term colorectal cancer survivors

Purpose Cancer survivors are currently considered high-risk populations for cardiovascular disease. However, no studies have directly evaluated risks and benefits of physical activity for stroke among long-term colorectal cancer survivors. Methods This large-scale observational cohort study used data from the Korean National Health Insurance Service database. Newly diagnosed colorectal cancer patients diagnosed between 2006 and 2013 who survived at least 5 years were studied. The primary outcome was stroke, including ischemic stroke and hemorrhage stroke. All patients were followed up to the date of stroke, death, or December 2018, whichever occurred earliest. Results Of 20,674 colorectal cancer survivors with a median age of 64 years, stroke occurred in 601 patients (2.9%). Moderate-to-vigorous physical activity lowered stroke risk in 5-9 time/week group (adjusted hazard ratio [aHR], 0.72; 95% confidence interval [CI], 0.57-0.93; P=0.010), but not in ≥10 time/week group (aHR, 0.85; 95% CI, 0.62-1.17; P=0.327). Walking also lowered stroke risk in 4-5 time/week group (aHR, 0.75; 95% CI, 0.58-0.97; P=0.028), but not in ≥6 time/week group (aHR, 0.96; 95% CI, 0.78-1.18; P=0.707). In addition, benefits of physical activity were maximized when carried out both moderate-to-vigorous physical activity and walking with moderate frequency (aHR, 0.77; 95% CI, 0.60-0.97; P=0.027). Conclusions Moderate frequency of moderate-to-vigorous physical activity (5-9 time/week) and walking (4-5 time/week) significantly lowers the risk of stroke, whereas high-frequency physical activity reduces the benefits of physical activity. Implications for cancer survivors Physical activity with moderate frequency is important in the prevention of stroke for long-term colorectal cancer survivors.