Cruciferous vegetables intake and risk of colon cancer: a dose-response meta-analysis

Colon cancer (CC) is the third most diagnosed malignancy and second leading cause of cancer mortality globally, with ~ 1.9 million new cases and 903,859 deaths annually (Bray et al. in CA Cancer J Clin 68(6):394-424, 2018). Diet represents a key modifiable risk factor for CC pathogenesis (Herr and Buchler in Cancer Treat Rev 36:377-383, 2010). Cruciferous vegetables (CV)-rich in glucosinolates that hydrolyze into bioactive isothiocyanates (Willett in Cancer Epidem Biomar 10:3-8, 2001; Murillo and Mehta in Nutr Cancer. 41(1-2):17-28, 2001; Higdon et al. in Pharmacol Res 55:224-36, 2007)-exhibit chemopreventive properties through carcinogen detoxification, apoptosis induction, and cell cycle arrest (Zhang et al. in Proc Nutr Soc 65:68-75, 2006). While prior meta-analyses report an inverse association between CV intake and CC risk (Tse and Eslick in Nutr Cancer 66(1):128-39, 2014), the quantitative dose-response relationship remains uncharacterized, limiting translational insights for dietary guidance.

A thorough search of the literature was conducted in Embase, Scopus,Web of Science, PubMed, and Cochrane Library from inception to June 28, 2025, using a predetermined strategy encompassing both cohort and case-control studies. Two independent reviewers selected studies based on predefined inclusion criteria, with discrepancies resolved by consensus or senior investigator adjudication. Statistical analyses were performed using Stata (version 14.2). Subgroup analyses accounted for study design, geographic location, and potential confounders. Publication bias was assessed using Egger's test, the LFK index, and the trim-and-fill method. Sensitivity analyses employed the leave-one-out approach. The dose-response relationship was evaluated using restricted cubic spline models.

Data from 17 research-including 7 cohort studies and 10 case-control studies-with 97,595 patients were methodically combined in this investigation.Consumption of CV was found to be inversely correlated with CC risk (odds ratios [OR] = 0.8; 95% confidence interval [CI] 0.72-0.90) in the pooled analysis using a random-effects model. Furthermore, a progressive decrease in risk was shown by the non-linear dose-response analysis as consumption levels increased.

This meta-analysis suggests a potential inverse association between higher CV intake and CC incidence. However, these findings should be interpreted cautiously due to methodological limitations, including heterogeneity in study designs, dietary assessment methods and potential residual confounding.