There was an error in the third sentence, of the third paragraph, under the subheading 'Data analysis' of the Materials and Methods. The correct sentence is: Covariates were considered as confounders if they correlated with any use of dietary supplements and colorectal adenoma risk, and if they changed the hazard ratio by ≥10% using forward selection. There is an error in reference 18. The correct reference is: Winkels RM, Botma A, Van Duijnhoven FJ, Nagengast FM, Kleibeuker JH, et al. (2012) Smoking Increases the Risk for Colorectal Adenomas in Patients With Lynch Syndrome. Gastroenterology. 142: 241-247 There is an error in reference 28. The correct reference is: Carroll C, Booth A, Cooper K (2011) A worked example of "best fit" framework synthesis: A systematic review of views concerning the taking of some potential chemopreventive agents. Bmc Medical Research Methodology 11: 29