Abstract
[{"label":"BACKGROUND AND OBJECTIVES","text":"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."},{"label":"METHODS","text":"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) and \u03c4 (Tau) index were used to quantify the magnitude of heterogeneity derived from the random-effects Mantel-Haenszel model."},{"label":"RESULTS","text":"The same results were found in cohort (adjusted RR = 0.82, 95% CI: 0.78-0.86, < 0.001, = 46.4%, Tau = 0.017) and case-control (adjusted OR = 0.70, 95% CI: 0.64-0.77, < 0.001, = 83.8%, Tau = 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, < 0.001, = 55.1%, Tau = 0.028), colorectal (adjusted RR = 0.76, 95% CI: 0.69-0.83, < 0.001, = 53.4%, Tau = 0.023), rectal (adjusted RR = 0.84, 95% CI: 0.78-0.91, < 0.001, = 1.6%, Tau = 0.005) and colon (adjusted RR = 0.88, 95% CI: 0.82-0.95, < 0.001, = 0.0%, Tau = 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."},{"label":"CONCLUSIONS","text":"Plant-based diets were protective against cancers of the digestive system, with no significant differences between different types of cancer."},{"label":"SYSTEMATIC REVIEW REGISTRATION","text":"https:\/\/www.crd.york.ac.uk\/prospero\/display_record.php?ID=CRD42022322276, Identifier: CRD42022322276."},{"copyright":"Copyright \u00a9 2022 Zhao, Zhan, Wang and Wang."}]
