Both studies assessed age, sex, menthol use, baseline CPD, baseline plasma cotinine, Fagerstrom Test for Nicotine Dependence (FTND). Study 2 also assessed urinary total nicotine equivalents, which is the total urinary level of nicotine and 8 of its metabolites. The analytical procedures were described previously (33). Together, the 9 analytes account for about 90% of nicotine dose (34), and creatinine adjusted spot urinary TNE correlates with daily tobacco consumption (35).
