Dietary Intake in Association with All-Cause Mortality and Colorectal Cancer Mortality among Colorectal Cancer Survivors: A Systematic Review and Meta-Analysis of Prospective Studies

Abstract

We carried out a systematic review and meta-analysis to determine the effects of both prediagnostic and postdiagnostic dietary intake on all-cause mortality and CRC-specific mortality among CRC survivors. An extensive search of PubMed and Embase was conducted to identify eligible studies. We applied a random-effects model to estimate the pooled relative risks (RRs)/hazard ratios (HRs) and their 95% confidence intervals (CIs). As a result, a total of 45 studies were included in the final analysis. Pooled effect sizes from at least three study populations showed that whole grains and calcium were inversely associated with all-cause mortality, with RRs/HRs (95% CIs) of 0.83 (0.69–0.99) and 0.84 (0.73–0.97), respectively. In contrast, a positive association between an unhealthy dietary pattern and both all-cause mortality (RR/HR = 1.47, 95% CI = 1.05–2.05) and CRC-specific mortality (RR/HR = 1.52, 95% CI = 1.13–2.06) was observed among CRC survivors. In the subgroup analysis by CRC diagnosis, prediagnostic and postdiagnostic dietary intake such as carbohydrates, proteins, lipids, and fiber were observed to have different effects on all-cause mortality. Overall, an unhealthy dietary pattern increased the risks of both all-cause mortality and CRC-specific mortality. The role of prediagnostic and postdiagnostic intake of dietary elements such as macronutrients and fatty acids could be different in the risk of all-cause mortality.

Association between Dietary Fiber Intake and Mortality among Colorectal Cancer Survivors: Results from the Newfoundland Familial Colorectal Cancer Cohort Study and a Meta-Analysis of Prospective Studies

“…The observed threshold effect is biologically plausible because dietary fiber, particularly soluble fiber, has limits in transport, metabolism, or storage, and their beneficial effects may be mediated by intestinal bacteria through fermentation that can be saturated. In a meta-analysis of dietary intake and CRC survival published in 2020, Hoang et al [ 16 ] reported that fiber consumption was not related to either all-cause (HR: 0.84, 95% CI: 0.58–1.22) or CRC-specific mortality (HR: 0.72, 95% CI: 0.44–1.18). Hoang’s findings are apparently inconsistent with ours.…”

“…Moreover, immortal time bias may influence the results, but this is minimized by using family proxies to enroll deceased cancer patients. Last, as a limitation shared by all meta-analyses on published articles, the cut-off level of dietary intake quantiles was generally inconsistent across studies; we may, therefore, have overestimated or underestimated the effects of fiber on CRC survival [ 16 ]. The between-study heterogeneity in our study may be attributed to the methodological or actual differences across studies.…”

“…Nevertheless, these published reports were mainly performed in the United States, France, and Western Europe, but none were in Canada. A recent meta-analysis demonstrated that post-diagnostic rather than pre-diagnostic intake of fiber was significantly associated with CRC-specific mortality (HR: 0.54, 95% CIs: 0.35–0.84) [ 16 ]. However, the evidence from the current body of original research and meta-analyses is insufficient to draw a consistent conclusion.…”

The Link between Food Environment and Colorectal Cancer: A Systematic Review

“…The rapid rise in CRC incidence was associated with urbanisation and lifestyle westernisation, which caused a change in eating behaviour [ 2 ] that increased obesity prevalence [ 3 , 4 , 5 ]. Furthermore, dietary factors significantly contributed to CRC mortality risk [ 6 ]. Nevertheless, CRC is highly preventable [ 7 ]; therefore, an important CRC prevention measure is to improve the modifiable CRC risk factors in diet and nutrition.…”

The Association Between Different Types of Dietary Carbohydrates and Colorectal Cancer: A Case-Control Study

“…Recent studies reported that a high intake of dietary carbohydrates may be associated with the increased risk of many health outcomes, such as all-cause mortality rate and many cancers such as CRC (13,14). A high glycemic load (GL) diet such as the western diet which includes high amounts of refined carbohydrates (for example white rice and noodles) may promote CRC risk through its hyperinsulinemia effects (14)(15)(16)(17)(18).…”