Waterpipe tobacco smoking: an emerging health crisis in the United States.

To examine the prevalence and potential health risks of waterpipe tobacco smoking. A literature review was performed to compile information relating to waterpipe tobacco smoking. Waterpipe tobacco smoking is increasing in prevalence worldwide; in the United States, 10-20% of some young adult populations are current waterpipe users. Depending on the toxicant measured, a single waterpipe session produces the equivalent of at least 1 and as many as 50 cigarettes. Misconceptions about waterpipe smoke content may lead users to underestimate health risks. Inclusion of waterpipe tobacco smoking in tobacco control activities may help reduce its spread.