Retrospective study on laxative use and melanosis coli as risk factors for colorectal neoplasma.

In a retrospective study a cohort of 2,277 patients was defined by colonoscopy. Among other factors it was tested whether in these patients laxative use or the endoscopically diagnosed presence of melanosis coli were risk factors related to colorectal neoplasma. In comparison to patients taking no laxatives there was no significant increase in colorectal cancer rate either in laxative users or in patients with melanosis coli. However, there was a statistically significant association between the occurrence of colorectal adenomas and laxative use (relative risk of all patients exposed to laxatives = 1.72; of patients exposed to laxatives without melanosis coli = 1.47). The relative risk of adenoma development in patients with melanosis coli was 2.19. Taking into account that polyps can be diagnosed in the dark mucosa of melanosis coli patients more easily, even this relative risk of 2.19 seems to be related to a generally enhanced risk of laxative intake rather than to a special group of (anthranoid containing) laxatives.