Exhaled Carbon Monoxide With Waterpipe Use in US Students

To the Editor: Waterpipe smoking (hookah, arghile, shisha) is an increasing trend within the global tobacco epidemic.¹ A study of freshmen at a US university estimated a 15% current use and a 13% past use of waterpipe.² Toxic constituents including nicotine, carbon monoxide (CO), tar, and heavy metals remain after the smoke passes through water before inhalation by the smoker, with potentially increased risk of malignancy, impaired lung function, and cardiovascular disease.¹ The use of charcoal as a heat source and the large volumes of smoke produced during waterpipe use also raise health concerns. The World Health Organization has called for studying the health effects of waterpipe smoking.³ We therefore investigated concentrations of exhaled CO among a group of US university students who are waterpipe smokers.