BACKGROUND: Heated tobacco products (HTPs) deliver nicotine with significantly lower toxicant exposure relative to combustible cigarettes. HTPs may serve as viable tobacco harm reduction options for adults who smoke but are not able or interested in stopping consuming nicotine-containing products. There is limited information on the degree to which adults in the United States who smoke will switch away from or reduce combusted cigarette consumption when provided with HTPs, and none assessing differences due to menthol cigarette preference or menthol HTP use. METHODS: In a six-week actual use study of an HTP (IQOS®), adults in the United States, ages 21-64 (n = 615), who smoke combustible cigarettes and were not planning to quit were offered free choice of HTPs (one non-menthol and two menthol varieties) to use ad libitum. Preference for smoking menthol or non-menthol cigarettes was assessed upon study entry (374 menthol
241 non-menthol). The number of HTP sticks and combusted cigarettes consumed were assessed via daily diary administered through smartphone application. Complete switching was defined on a seven-day point prevalence basis-reporting consuming zero combusted cigarettes while continuing to use the HTP research product in Week 6. RESULTS: Overall, 247 participants completely switched to HTP, corresponding to 21.1% of all those enrolled at baseline (n = 1173) or 40.2% of those included in primary analyses (n = 615). Among individuals included in primary analyses, we observed greater switching among those who preferred menthol versus non-menthol cigarettes (46.8% vs 29.9%). Probability of switching increased with greater proportional use of menthol versus non-menthol HTPs. Non-menthol cigarette-preferring participants had greater increases in switching when using proportionally more menthol than non-menthol HTPs
switching remained consistently high among menthol-preferring participants. Among participants who did not switch and continued smoking at Week 6, preference for menthol cigarettes and use of proportionally greater menthol versus non-menthol HTPs were each associated with greater reductions in cigarette consumption. CONCLUSION: HTP use facilitated switching away from or reducing consumption of combusted cigarettes among adults who smoke, especially when using menthol HTPs. Most participants used menthol HTPs, regardless of their incoming preference for smoking menthol or non-menthol cigarettes. Availability of HTPs in menthol and non-menthol varieties offers an increased tobacco harm reduction opportunity over solely non-menthol by providing adults who smoke with smoke-free alternatives that they find appealing.