Completing enrollment on schedule provides additional evidence that homeless smokers are interested in engaging in a clinical study to help them quit. Outcome results at 6 months will provide relevant information regarding adherence to study protocol, retention rates over 6 months, verified quit rates, as well as moderating effects of substance abuse and psychiatric Enzalutamide order comorbidities on cessation outcomes. Given the high prevalence of smoking and high interest in quitting despite unique socioeconomic challenges within homeless populations, the public health community ought to redouble its efforts to extend evidence-based smoking cessation interventions to homeless populations. Such efforts are critical for reducing tobacco-related health disparities within vulnerable groups.

Funding This work was supported by a grant from the National Heart Lung and Blood Institute (R01HL081522). Declaration of Interests Authors have no conflict of interest to disclose. Acknowledgments The authors thank Jennifer Warren, Ph.D., and project staff Sharae Walker, Bonnie Houg, R��Gina Sellers, Casey Tuck, Abimbola Olayinka, Carolyn Borja, Carolyn Bramante, Julia Davis, Pravesh Napaul, and Brandi White for their assistance with implementation of the project. The authors further acknowledge the directors and staff of participating shelters, Dorothy Day Center, Our Savior��s Shelter, Listening House, Union Gospel Mission, Naomi Family Center, and People Serving People. Finally, we express gratitude to the members of the Community Advisory Board and the study participants.

Transdermal nicotine is a popular and effective treatment for smoking cessation (Stead et al., 2008; West et al., 2001). However, two clinical trials have indicated that smokers who are fast metabolizers of nicotine, estimated by the ratio of 3��-hydroxycotinine (3-HC) to its precursor cotinine, show significantly lower rates of cessation when treated with the standard, 21 mg dose of transdermal nicotine, compared with slower metabolizers (Lerman et al., 2006; Schnoll et al., 2009). Bupropion and varenicline may be plausible treatment alternatives for these smokers; however, faster metabolizers of nicotine (i.e., those with 3-HC/cotinine values which fall in the top three quartiles of 3-HC/cotinine distribution) also show significantly lower levels of plasma nicotine during 21 mg nicotine patch treatment versus slow metabolizers (i.

e., GSK-3 those with 3-HC/cotinine values which fall within the first quartile of the 3-HC/cotinine distribution; Lerman et al., 2006; Schnoll et al., 2009). These findings suggest that fast metabolizers of nicotine may require a higher dose of nicotine patch in order to achieve successful abstinence when using transdermal nicotine. Previous clinical trials have examined doses of transdermal nicotine substantially higher than the standard 21-mg dose.