Background: The perceived reduced formation of harmful chemicals (RF) or perceived reduced risk of harm (RH) of a smoke-free tobacco product relative to combustible tobacco products may influence its acceptance and use patterns among adult smokers and therefore impact public health. We analyzed whether and how the RF and/or RH of the heated tobacco product (HTP) IQOSTM impacted “exclusive” (100%) IQOSTM use in Japan, Italy, Germany, and Russia.
Methods: Between 2016 and 2020, adult participants from longitudinal IQOSTM user cohorts in Japan (N = 6257), Italy (N = 8137), Germany (N = 8474), and Russia (N = 7231) repeatedly indicated the reasons for using IQOSTM, including reasons referring to RF and RH, during their first 48 weeks in the cohort. Logistic and Cox regression were used to analyze the relationships between RF and/or RH indications for using IQOSTM and exclusive or stable exclusive IQOSTM use.
Results: At week 48, exclusive IQOSTM use in Japan (odds ratio [OR] = 1.89), Italy (OR = 3.35), Germany (OR = 3.48), and Russia (OR = 3.05) was more likely among participants who more frequently (highest vs. lowest category of number of RF and/or RH indications) indicated RF and/or RH as a reason for using IQOSTM. In Japan, where other HTPs were also marketed, this was also true for the overall HTP category. Also, in Japan where RF and RH could be indicated separately as reasons for using IQOSTM, indicating RH (OR = 2.92) compared to RF (OR = 1.81) resulted in a greater likelihood of exclusive IQOSTM use within the highest category of RF or RH indications. In Japan (hazard ratio [HR] = 0.74), Italy (HR = 0.80), Germany (HR = 0.72), and Russia (HR = 0.85), IQOSTM users who indicated RF and/or RH as a reason for using IQOSTM had a lower risk of becoming a stable nonexclusive than stable exclusive IQOSTM user as well as a 10–25% lower number of weeks until reaching stable exclusive IQOSTM use.
Conclusions: Perceived reduced formation of harmful chemicals (RF) or perceived reduced risk of harm (RH) of IQOSTM have a significant impact on IQOSTM users’ switching to exclusive IQOSTM use and the acceleration of stable exclusive IQOSTM use. This may also be true for the overall HTP category. Moreover, perceived RH of IQOSTM seems to be a stronger driver for exclusive IQOSTM use than perceived RF.