Assessing the Causal Relationship between Waterpipe Smoking and Bladder Cancer.

Rates of waterpipe use increase with very little data reporting any potential health consequences. The current study, a large case-control study, of 4,194 patients from Iran denotes an elevated risk of bladder cancer in exclusive waterpipe smokers compared with non-users. Additional studies are needed to further understand the risk waterpipe smoking has on bladder cancer. See related article by Hadji et al., p. 509.