They have been identified in cigarette tobacco (Ashley et al., 2003; Brunnemann, Cox, & Hoffmann, 1992; Song & Ashley, 1999), environmental tobacco smoke (ETS; Brunnemann et al., 1992), smokeless tobacco (Hoffmann, Adams, Lisk, Fisenne, & Brunnemann, 1987), and other tobacco products such as cigars, selleck chem Abiraterone toombak, and bidi cigarettes (Idris, Prokopczyk, & Hoffmann, 1994; McNeill, Bedi, Islam, Alkhatib, & West, 2006; Murphy, Carmella, Idris, & Hoffmann, 1994; Nair, Pakhale, & Bhide, 1989). Furthermore, TSNA yields in tobacco smoke vary significantly in tested cigarettes from different parts of the world as the formation of TSNAs is influenced by the tobacco blend and the curing processes (Ashley et al., 2003; Ding et al., 2006).

The most carcinogenic of the commonly occurring tobacco-specific nitrosamines is 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK; Hecht, 1998). NNK and its metabolite NNAL are metabolically activated to reactive intermediates that are carcinogenic. NNAL is detoxified by glucuronidation, and urinary metabolites of NNAL and its glucuronides (NNAL-Glucuronide) are useful biomarkers of NNK uptake in humans (Kavvadias et al., 2009; Xia, Bernert, Jain, Ashley, & Pirkle, 2011). Advantages of the NNAL and NNAL-Glucuronide (NNAL-Gluc) biomarkers include tobacco specificity, direct relevance to carcinogen uptake, and consistent detection in exposed individuals (Carmella, Han, Fristad, Yang, & Hecht, 2003; Hecht, 1998, 2002). NNAL (free NNAL plus NNAL-Gluc), has been measured in studies of NNK uptake in cigarette smokers (Anderson et al.

, 2001; Carmella, Akerkar, & Hecht, 1993; Carmella, Akerkar, Richie, & Hecht, 1995; Carmella, Le Ka, Upadhyaya, & Hecht, 2002; Richie et al., 1997; Murphy et al., 2004; Muscat, Djordjevic, Colosimo, Stellman, & Richie, 2005), smokeless tobacco users (Hecht, 2002; Murphy et al., 1994; Stepanov, Jensen, Hatsukami, & Hecht, 2008), and nonsmokers exposed to ETS (Anderson et al., 2001; Hecht et al., 1993). Little or no reported research has assessed NNK carcinogenic uptake in waterpipe smokers. In this study, we quantified two of its metabolites, NNAL and NNAL-Gluc, in the urine of Egyptian males who were either current cigarette or waterpipe smokers, as compared with nonsmoking females exposed to ETS from cigarettes or waterpipe, respectively.

Methods Study Participants We previously conducted a baseline smoking prevalence survey in nine villages in the Qalyubia governorate in Delta Egypt (Auf et al., 2012; Boulos et al., 2009; Radwan et al., 2007). In each village, 300 households were selected using a systematic random sample, and adults (aged �� 18 years) were Drug_discovery interviewed for their demographics, smoking and quitting behaviors, exposure to ETS, and their knowledge, attitudes, and practices toward a variety of smoking-related variables.