INTRODUCTION: Waterpipe @entity286 smoking is a global health concern. Laboratory research has focused on individual waterpipe users while group use is common. This study examined user toxicant exposure and smoke toxicant yield associated with individual and group waterpipe smoking. METHODS: Twenty-two pairs of waterpipe smokers used a waterpipe individually and as a dyad. Before and after smoking, blood was sampled and expired @entity1223 (CO) measured; puff topography was recorded throughout. One @entity1 from each pair was selected randomly and their plasma @entity1239 and expired air CO concentrations were compared when smoking alone to when smoking as part of a dyad. Recorded puff topography was used to machine-produce smoke that was analyzed for toxicant content. RESULTS: There was no difference in mean plasma @entity1239 concentration when an individual smoked as part of a dyad (mean = 14.9ng/ml; standard error of the mean [SEM] = 3.0) compared to when smoking alone (mean = 10.0ng/ml; @entity8448 .5). An individual smoking as part of as a dyad had, on average, lower CO (mean = 15.8 ppm; SEM = 2.0) compared to when smoking alone (mean= 21.3 ppm; SEM = 2.7). When two @entity1 smoked as a dyad they took, on average, more puffs (mean = 109.8; SEM = 7.6) than a singleton smoker (mean = 77.7; SEM = 8.1) and a shorter interpuff interval (IPI; dyad mean = 23.8 seconds; @entity8448 .9; singleton mean = 40.8 seconds; SEM = 4.8). Higher concentrations of several toxicants were observed in dyad-produced smoke. DISCUSSION: Dyad smoking may increase smoke toxicant content, likely due to the dyad's shorter IPIs and greater puff number. More work is needed to understand if group waterpipe smoking alters the health risks of waterpipe @entity286 smoking. IMPLICATIONS: This study is the first to measure toxicants in smoke generated from a waterpipe when used by a dyad. Relative to smoke generated by a singleton, dyad smoke had higher concentration of some toxicants. These differences may be attributed to differences in puffing behavior, specifically the shorter IPI and greater puff number observed in the @entity558 . Relative to singleton smokers, dyad smokers were exposed to less CO, but @entity1239 exposure did not differ. More work is needed to assess the health effects of inhalation of more toxicant-laden smoke during group waterpipe use.

Group Waterpipe XXXX Smoking Increases Smoke Toxicant Concentration.

@entity1 :: ('9606', 'Species') :: ['participants', 'participant'] @entity286 :: ('4097', 'Species') :: ['tobacco'] @entity8448 :: ('7979', 'Gene') :: ['SEM = 1'] @entity558 :: ('MESH:C536528', 'Disease') :: ['dyad condition'] @entity1223 :: ('MESH:D002248', 'Chemical') :: ['carbon monoxide'] @entity1239 :: ('MESH:D009538', 'Chemical') :: ['nicotine']
@entity286 :: (4097,Species) :: ['Tobacco']
