Via this systematic review and meta-analysis the researchers examined associations between self-reported frequency of cigarette and e-cigarette use, and nicotine levels in the hair samples of participants, at two assessments 1 year apart.
Given that intermittent, dual use of cigarettes and e-cigarettes is a common pattern among youth and young adults and tends to be harder to measure, the Participants selected (n = 90) 65% of which were female, were 19- to 25-year-old intermittent cigarette smokers.
Dual users consume more nicotine
Besides self reporting on their use patterns, the participants were required to submit hair samples via mail, 1 and 2 years after enrollment in the parent study. The compiled data indicated that self-reporting measures are valid methods of assessing intermittent use of both cigarettes and e-cigarettes. Additionally, in line with previous findings, this study indicated that dual users tend to consume more nicotine and thus be at greater risk for dependence than single product users.
“Findings indicated that days of use of both cigarettes and e-cigarettes in the past 30 days independently predicted hair nicotine in the full sample, and when examining only time points at which any cigarette use was reported. Time points when any e-cigarette use was reported, hair nicotine was positively associated with e-cigarette but not cigarette frequency,” read the study abstract.