Effect of laxative use and laxative type on colorectal cancer risk: A pooling up analysis and evidence synthesis

Colorectal cancer (CRC) is the third most common cancer worldwide and there is a controversy regarding the influence of laxative use on the incidence of CRC. Therefore, the present study aimed to investigate the effects of laxative use and different subtypes of laxatives on the incidence of CRC. To this aim, a comprehensive search of three databases (PubMed, Embase and the Cochrane Library) was conducted on April 12, 2022, using key words that included 'laxative' and 'CRC', which initially retrieved 305 records. Ultimately, 12 studies involving 415,313 patients met all eligibility criteria and were included in a meta-analysis. Subsequently, patients were categorized into the laxative use and non-laxative use groups. Stata 16.0 software was used for all data analyses. The results indicated that laxative use was not significantly associated with CRC risk [odds ratio (OR), 0.95; 95% confidence interval (CI), 0.75-1.20; P=0.65; I2=94.63%]. In the subgroup analyses, the effects of different laxative types were further examined. Notably, all types of laxatives except for fiber laxatives showed no significant influence on CRC risk (P>0.1). By contrast, fiber laxatives were associated with a reduced risk of CRC (OR, 0.74; 95% CI, 0.59-0.93; P=0.01; I2=32.15%), suggesting a potential protective effect of this medication. In conclusion, the findings of the present study suggest that the use of laxatives does not increase the risk of CRC. Moreover, the use of fiber laxatives may have a protective effect by reducing CRC incidence.