Association of NAT2 polymorphisms with risk of colorectal adenomas: Evidence from 3,197 cases and 4,681 controls

Previous studies have implicated NAT2 polymorphisms as risk factors for various types of cancer. Colorectal adenomas are recognized as a pre-neoplastic lesion. A growing body of research documenting the association of NAT2 polymorphisms with the risk of colorectal adenomas has yielded conflicting results. The aim of the present study was to derive a more precise estimation of this association. Meta-analyses assessing the association of NAT2 variants with colorectal adenomas were conducted and subgroup analyses on smoking status and the source of the controls were also performed. Eligible studies were identified for the period before March 2012. A total of seven case-control studies, including 3,197 cases and 4,681 controls, were selected following extensive searching and screening. In the overall data, no associations between NAT2 polymorphisms and colorectal adenomas were observed [odds ratio (OR), 1.04; 95% confidence interval (CI), 0.90-1.21]. However, in the subgroup analysis concerning smoking status, slow acetylator variants were revealed to be correlated with increased colorectal adenoma risk in individuals who have smoked (OR, 1.31; 95% CI, 1.04-1.64). In conclusion, the data of the present study suggested that NAT2 polymorphisms may be a risk factor for colorectal adenomas in individuals who have a history of smoking.