Introduction
Current measures of nicotine dependence (ND) were developed and validated for cigarette smokers only, limiting their utility for other combustible tobacco users. This study evaluates the psychometric properties of a pool of new and adapted items to measure ND among cigarillo and multiple tobacco product users.
Methods
Items were drawn from the PROMIS Nicotine Dependence Item Bank which were adapted to be product neutral and new items were developed from a qualitative study of 60 adolescent and young adult cigarillo smokers. A total of 42 ND items were included in a web-based survey. Eligible participants were 14 to 28 year olds who smoked a minimum of 2 cigarillos per week. Analyses included confirmatory factor analysis, item response theory analysis, analysis of differential item functioning (DIF) and reliability. Ordinary least square regression was used to test the association of ND score with deciles of nicotine consumption.
Results
Among the 1089 participants, the median number of cigarillos smoked per week was 20; 54% of participants also smoked cigarettes. All PROMIS items and 8 of 10 new items met the IRT fit criteria. Two PROMIS items had non-ignorable DIF. The pool of 40 items had good score reliability for a range of 2 standard deviations. Twenty-, eight-, and four-item short forms showed similarly good measurement properties; each was positively associated with decile of nicotine consumption, p<.001; R 2 = 0.33.
Conclusions
This adapted bank of ND items is psychometrically sound and includes items that are product neutral, making it suitable for assessing ND among cigarillo and polytobacco users.
Implications
This study rigorously evaluates adapted items to measure ND among cigarillo and polytobacco users and reports the reliability initial evidence of validity of short form scores.