Table 1.

Inclusion and exclusion criteria assessed in eligibility screener

Inclusion	Exclusion
All participants
AI with at least two biological grandparents of AI descent 18 to 65 years of age	Use of medications for seizures, tuberculosis, or cancer Involvement in a tobacco cessation program or use of NRT Pregnant or breastfeeding Use of illicit drugs in the 30 days prior to the study Use of alcohol or marijuana on the day of the study
Cigarette smokers
≥5 cigarettes per day in the past 3 months At least 1 cigarette in prior 24-hours No other tobacco product use in the past 3 months
E-cigarette users
Use of e-cigarettes every day in the past 3 months Use of e-cigarette in the prior 24-hours No other tobacco product use in the past 3 months
Dual users
≥5 cigarettes per day in the past 3 months Use of e-cigarettes every day in the past 3 months At least 1 cigarette in prior 24-hours Use of e-cigarette in the prior 24-hours No other tobacco product use in the past 3 months