Arsenic methylation and bladder cancer risk in case-control studies in Argentina and the United States.

Abstract

We sought to assess whether the metabolism of arsenic impacts a person's susceptibility to bladder cancer. Urinary methylation products were measured in subjects from Argentina (114 cases and 114 controls) and the United States (23 cases and 49 controls). In Argentina, the adjusted odds ratio (OR) for subjects with a high proportion of ingested arsenic excreted as monomethylarsonate (%MMA) was 2.17 (95% confidence interval [CI] = 1.02-4.63) in smokers and 0.48 (95% CI = 0.17-1.33) in nonsmokers. In the United States, the adjusted ORs for high %MMA in subjects with arsenic intakes less than and greater than 100 microg/d were 1.20 (95% CI = 0.27-5.38) and 2.70 (95% CI = 0.39-18.6). Overall, these results are consistent with data from Taiwan suggesting that some individuals who excrete a higher proportion of ingested arsenic as MMA are more susceptible to arsenic-related cancer.