Table 1.

Measurement of Study Variables

Variable	Measurement	Categories
Predictor Variables
Serious psychological distress (SPD)*	Kessler’s scale of 6 questions assessing frequency of symptoms on a 0 to 4 scale. Score of 13 or greater indicated SPD. Example: About how often during the past 30 days did you feel nervous-would you say all of the time, most of the time, some of the time, a little of the time, or none of the time?	0= no 1= yes
Binge drinking	In the past 12 months, about how many times did you have 5 (male)/4 (female) or more alcoholic drinks in a single day?	0= no days binge drinking 1= 1–10 days/year 2= more than 10 days/year
Self-rated health	Would you say your health in general is excellent, very good, good, fair, or poor?	1= excellent 2= very good 3= good 4= fair 5= poor
Dependent Variable
Tobacco/Nicotine Use	Combination of the variables current cigarette smoking pattern (i.e., Do you now smoke cigarettes every day, some days, or not at all?) and electronic cigarette smoking pattern (i.e., Do you now use e-cigarettes every day, some days, or not at all?)	0= non-users 1= only tobacco cigarettes 2= only e-cigarettes 3= dual users
Moderators
Age	[Variable created from multiple survey questions]	1= 18–24 2= 25–69 3= 60 and over
Sex	May I confirm your gender?	1= male 2= female
Covariates
Education		1= Less than High school 2= High school/some college 3= College and beyond