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Background

Benzene is a human hematotoxicant and a leukemogen that causes lymphohematopoietic cancers, especially acute myelogenous leukemia. We investigated uptake of benzene in hookah smokers and non-smokers attending hookah social events in naturalistic settings where hookah tobacco was smoked exclusively.

Methods

We quantified S-phenylmercapturic acid (SPMA), a metabolite of benzene, in the urine of 105 hookah smokers and 103 non-smokers. Participants provided spot urine samples the morning of and the morning after attending an indoor hookah-only smoking social event at a hookah lounge or in a private home.

Results

Urinary SPMA levels in hookah smokers increased significantly following a hookah social event (P < 0.001). This increase was 4.2 times higher after hookah lounge events (P < 0.001) and 1.9 times higher after home events (P = 0.003). In non-smokers, urinary SPMA levels increased 2.6 times after hookah lounge events (P = 0.055); however, similar urinary SPMA levels were detected before and after home events, possibly indicating chronic exposure to benzene (P = 0.933).

Conclusions

Our data provide the first evidence for uptake of benzene in hookah smokers and non-smokers exposed to hookah tobacco secondhand smoke at social events in private homes compared with their counterparts in hookah lounges. Hookah tobacco smoke is a source of benzene exposure, a risk factor for leukemia.

Impact

Because there is no safe level of exposure to benzene, our results call for interventions to reduce or prevent hookah tobacco use, regulatory actions to limit hookah-related exposure to toxicants including benzene, initiate labeling of hookah-related products, and include hookah smoking in clean indoor air legislation.