AUTHOR=Zhao Yujie , Zhan Junyi , Wang Yongsen , Wang Dongli 

TITLE=The Relationship Between Plant-Based Diet and Risk of Digestive System Cancers: A Meta-Analysis Based on 3,059,009 Subjects

JOURNAL=Frontiers in Public Health

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2022.892153

DOI=10.3389/fpubh.2022.892153

ISSN=2296-2565

ABSTRACT=<sec><title>Background and Objectives</title><p>Diets containing red or processed meat are associated with a growing risk of digestive system cancers. Whether a plant-based diet is protective against cancer needs a high level of statistical evidence.</p></sec><sec><title>Methods</title><p>We performed a meta-analysis of five English databases, including PubMed, Medline, Embase, Web of Science databases, and Scopus, on October 24, 2021 to identify published papers. Cohort studies or case-control studies that reported a relationship between plant-based diets and cancers of the digestive system were included. Summary effect-size estimates are expressed as Risk ratios (RRs) or Odds ratios (ORs) with 95% confidence intervals and were evaluated using random-effect models. The inconsistency index (I<sup>2</sup>) and τ<sup>2</sup> (Tau<sup>2</sup>) index were used to quantify the magnitude of heterogeneity derived from the random-effects Mantel-Haenszel model.</p></sec><sec><title>Results</title><p>The same results were found in cohort (adjusted RR = 0.82, 95% CI: 0.78–0.86, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 46.4%, Tau<sup>2</sup> = 0.017) and case-control (adjusted OR = 0.70, 95% CI: 0.64–0.77, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 83.8%, Tau<sup>2</sup> = 0.160) studies. The overall analysis concluded that plant-based diets played a protective role in the risk of digestive system neoplasms. Subgroup analyses demonstrated that the plant-based diets reduced the risk of cancers, especially pancreatic (adjusted RR = 0.71, 95% CI: 0.59–0.86, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 55.1%, Tau<sup>2</sup> = 0.028), colorectal (adjusted RR = 0.76, 95% CI: 0.69–0.83, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 53.4%, Tau<sup>2</sup> = 0.023), rectal (adjusted RR = 0.84, 95% CI: 0.78–0.91, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 1.6%, Tau<sup>2</sup> = 0.005) and colon (adjusted RR = 0.88, 95% CI: 0.82–0.95, <italic>P</italic> &lt; 0.001, <italic>I</italic><sup>2</sup> = 0.0%, Tau<sup>2</sup> = 0.000) cancers, in cohort studies. The correlation between vegan and other plant-based diets was compared using Z-tests, and the results showed no difference.</p></sec><sec><title>Conclusions</title><p>Plant-based diets were protective against cancers of the digestive system, with no significant differences between different types of cancer.</p></sec><sec><title>Systematic Review Registration</title><p><ext-link ext-link-type="uri" xlink:href="https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322276" xmlns:xlink="http://www.w3.org/1999/xlink">https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322276</ext-link>, Identifier: CRD42022322276.</p></sec>