Puffing Topography, Mouth Level Exposure, Average Daily Consumption and Machine Emissions of Three Variants of glo™ Heated Tobacco Products Among UK Smokers

Heated tobacco products (HTPs) typically expose consumers to significantly reduced toxicant emissions relative to conventional cigarettes, when measured under machine-generated conditions. As HTPs evolve in design and new consumables are introduced, it is essential to assess whether these changes affect how consumers use HTPs and thus their potential exposure to toxicants in the aerosol. The objective of this study was to assess whether changes in tobacco flavour or nicotine content of HTP consumables influenced consumers' use behaviour and exposure. Here, puffing topography, average daily consumption (ADC) and mouth-level exposure (MLE) to nicotine and nicotine-free dry particulate matter (NFDPM) were measured among 72 healthy adult cigarette smokers in the UK. Participants used a Type 1 HTP device (glo™) with three consumables: a base consumable (Bright Tobacco flavour, 0.85% nicotine) previously indicated with the glo™ device to support a reduced risk profile relative to conventional cigarettes; Variant 1 (Rich Tobacco flavour, 0.85% nicotine); and Variant 2 (Rich Tobacco flavour, 1.5% nicotine). The respective machine-generated aerosols were also analysed for nine toxicants. In a two-week randomised crossover study, participants used each study product for five days at home, while recording daily product use. Their puffing topography and MLE were then measured using a desktop-based puffing analyser device (SA7) at a central location testing facility. Differences in puffing behaviour and ADC for both variant consumables were either smaller than predefined analytical thresholds, or were within predefined equivalence margins (0.80–1.25 and 90% confidence intervals of mean ratio), with the exception of effort for Variant 2, and therefore puffing behaviour and ADC were considered equivalent to the base consumable. Differences in MLE for Variant 1 were either smaller than the predefined analytical thresholds, or within the predefined equivalence margins. For Variant 2, differences in MLE to NFDPM were smaller than the predefined analytical thresholds, however MLE to nicotine was higher relative to the base consumable (0.40 vs. 0.29 mg/stick), and did not fall within the equivalence margins, consistent with the higher nicotine content in this variant. Under the conditions of this study, variations in flavour and nicotine concentration did not lead to significant changes in measures of user behaviour or NFDPM exposure.