Postdiagnosis dietary and lifestyle factors and mortality outcomes among colorectal cancer patients: a meta-analysis

Background: Dietary and lifestyle factors are well-studied for colorectal cancer (CRC) prevention. However, less evidence exists on their impact on CRC survival. Methods: PubMed and Embase were searched from inception to September 2024. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated using the DerSimonian–Laird random effects model. Results: Lower all-cause mortality was observed with unprocessed red meat (summary RR = 0.74, 95% CI = 0.57 to 0.94), whole grains (summary RR = 0.77, 95% CI = 0.66 to 0.90), coffee (summary RR = 0.65, 95% CI = 0.55 to 0.77), milk (summary RR = 0.82, 95% CI = 0.71 to 0.93), low-fat dairy (summary RR = 0.77, 95% CI = 0.64 to 0.94), total calcium (summary RR = 0.76, 95% CI = 0.61 to 0.94), alcohol intake under 45 g/day (J-shaped association), and physical activity (summary RR = 0.55, 95% CI = 0.44 to 0.69). Higher all-cause mortality was observed with refined grains (summary RR = 1.55, 95% CI = 1.03 to 2.33), high-fat dairy (summary RR = 1.34, 95% CI = 1.05 to 1.71), smoking (current: summary RR = 1.49, 95% CI = 1.24 to 1.78; former: summary RR = 1.18, 95% CI = 1.04 to 1.34), and television watching (summary RR = 1.28, 95% CI = 1.06 to 1.55). Risk increased linearly with body mass index greater than 27kg/m² but also increased toward lower body mass index. For CRC-specific mortality, most of the results were largely consistent, with calcium supplement showing an inverse association (summary RR = 0.66, 95% CI = 0.47 to 0.94). Conclusions: Factors related to CRC survival share differences as well as similarities with established factors related to CRC prevention. To optimize CRC survival, CRC patients may be recommended to adopt a diet rich in whole grains, coffee, milk, and dietary calcium; to avoid excessive alcohol, refined grains, high-fat dairy, sugar-sweetened beverages, smoking, and sedentary lifestyle; and to engage in regular physical activity while maintaining a healthy weight.