Adverse events associated with dual and poly use of conventional cigarettes, electronic cigarettes, and heated tobacco: A cross-sectional study of Italian adults

INTRODUCTION Electronic cigarettes (ECs) and heated tobacco products (HTPs) face growing skepticism regarding their safety and effectiveness in promoting conventional cigarettes (CCs) cessation. Understanding patterns of use of these products and their health effects is essential on a public health perspective. METHODS Between October 2023 and March 2024, a cross-sectional sample of 22428 Italian adults was recruited through an online panel. Participants completed a structured self-reported questionnaire on their use of CCs, ECs, and HTPs and any adverse events including dry cough, sore throat and dry mouth experienced during or after each product use. We used multivariable logistic regression models to assess adjusted odds ratios (AORs) of reporting at least one CC-related adverse event in dual/poly users (CC plus EC and/or HTP) versus CC-only smokers. RESULTS CC use was reported by 75.6% of EC users and 80.3% of HTP users. At least one product-specific adverse events was reported by 68.2%, 44.7% and 44.5% of CC, EC and HTP users, respectively. Compared to CC-only smokers, CC smokers also using ECs (AOR=1.32; 95% CI: 1.17-1.50), also using HTPs (AOR=1.14; 95% CI: 1.01-1.30) and also using ECs and HTPs (AOR=1.50; 95% CI: 1.29-1.75) had a higher likelihood of experiencing at least one CC-related adverse event. CONCLUSIONS The combination of CCs with ECs and/or HTPs increases the likelihood of adverse events related to CC smoking. To these figures we must add the far from negligible number of adverse events due to EC or HTP use. Our findings are consistent with the growing evidence of a higher harm for dual users compared to CC-only smokers, suggesting that EC and HTP may undermine rather than support tobacco control efforts.