Studying the interactive effects of menthol and nicotine among youth: An examination using e-cigarettes

Abstract

Background Tobacco products containing menthol are widely used by youth. We used ecigarettes to conduct an experimental evaluation of the independent and interactive effects of menthol and nicotine among youth. Procedures Pilot chemosensory experiments with fourteen e-cigarette users identified low (barely perceptible, 0.5%) and high (similar to commercial e-liquid, 3.5%) menthol concentrations. Sixty e-cigarette users were randomized to a nicotine concentration (0 mg/ml, 6 mg/ml, 12 mg/ml) and participated in 3 laboratory sessions. During each session, they received their assigned nicotine concentration, along with one of three menthol concentrations in random counterbalanced order across sessions (0, 0.5%, 3.5%), and participated in three fixed-dose, and an ad-lib, puffing period. Urinary menthol glucuronide and salivary nicotine levels validated menthol and nicotine exposure. We examined changes in e-cigarette liking/wanting and taste, coolness, stimulant effects, nicotine withdrawal and ad-lib use. Results Overall, the high concentration of menthol (3.5%) significantly increased e-cigarette liking/wanting relative to no menthol (p<0.001); there was marginal evidence of nicotine* menthol interactions (p=0.06), with an increase in liking/wanting when 3.5% menthol was combined with 12 mg/ml nicotine, but not 6 mg/ml nicotine. Importantly, both 0.5% and 3.5% menthol concentrations significantly improved taste and increased coolness. We did not observe nicotine or menthol-related changes in stimulant effects, nicotine withdrawal symptoms or ad-lib use. Conclusions Menthol, even at very low doses, alters the appeal of e-cigarettes among youth. Further, menthol enhances positive rewarding effects of high nicotine-containing e-cigarettes among youth.

Sensory attributes of e-cigarette flavours and nicotine as mediators of interproduct differences in appeal among young adults

“…To guide such policies, evidence of mechanisms mediating differences in e-cigarette appeal across products varying in flavour and nicotine is needed, particularly among young adults who more likely vape non-tobacco flavours (eg, fruit, menthol) 6. Past evidence suggests sensory attributes of e-cigarette flavours and nicotine are germane to their appeal 7–13. E-cigarettes in non-tobacco (vs tobacco) flavours typically elicit more desired taste perceptions (eg, greater sweetness, lower bitterness) and product appeal 8–13.…”

“…Past evidence suggests sensory attributes of e-cigarette flavours and nicotine are germane to their appeal 7–13. E-cigarettes in non-tobacco (vs tobacco) flavours typically elicit more desired taste perceptions (eg, greater sweetness, lower bitterness) and product appeal 8–13. Nicotine, which has central nervous system-mediated reinforcing effects,14 produces instantaneous unpleasant sensory perceptions on exposure (ie, bitterness and harshness/irritation) and reduces appeal of users’ puffing experiences 8 9 11 12.…”

“…E-cigarettes in non-tobacco (vs tobacco) flavours typically elicit more desired taste perceptions (eg, greater sweetness, lower bitterness) and product appeal 8–13. Nicotine, which has central nervous system-mediated reinforcing effects,14 produces instantaneous unpleasant sensory perceptions on exposure (ie, bitterness and harshness/irritation) and reduces appeal of users’ puffing experiences 8 9 11 12. Menthol and nicotine may have interactive effects, whereby menthol attenuates the harshness or aversive taste of nicotine 8 9 12…”

“…It is possible perceived smoothness provides information about product appeal not captured by other sensory ratings and may be a useful component of e-cigarette product appeal testing. Second, extant studies of whether flavourings interact with nicotine to alter nicotine’s sensory attributes solely compare fruit and menthol flavours to flavourless solutions or to each other,9 11 12 15 without testing head-to-head comparisons to tobacco-flavoured products. Tobacco flavours have bitter properties10 16 and could interact with nicotine’s bitter qualities to alter the taste of nicotine–tobacco flavour combinations.…”

See you in court: obstacles to enforcing the ban on electronic cigarette flavours and marketing in Finland

“…In 2014, on English language websites there were almost 8000 named flavours for e-cigarettes. 15 There is increasing evidence that flavours attract youngsters to use e-cigarettes, [16][17][18][19][20][21][22] making them nicotine dependent and exposing them to the other ingredients of e-cigarettes. The safety of flavours, in most cases, has been tested only for use as food additives but not when heated and vaped into the lungs.…”