Presentation (CTI)

OBJECTIVES: To develop a modelling framework to quantify the population health impact of Electronic Vapour Products (EVP), focusing on the balance between substitution among current smokers and initiation among non-smokers.
METHODS: A modelling framework was developed to simulate EVP initiation, adoption, and transitions across population groups. A weighting parameter 𝑘;∈[0,1]k∈[0,1] was introduced to represent how EVP initiation among non-smokers is distributed, ranging from individuals who would otherwise remain non-smokers (𝑘;=1k=1) to those who would have initiated cigarette smoking in the absence of Next Generation Products (𝑘;=0k=0).By varying initiation and adoption probabilities while maintaining probabilistic consistency of transitions from the initial state, the model estimated the net population health impact of EVP introduction across a range of plausible scenarios and different values of 𝑘;k, incorporating assumptions on Excess Relative Risk (ERR).
RESULTS: Assuming a low ERR for EVP, positive population health outcomes were primarily driven by adoption among current smokers, with EVP initiation among non-smokers playing a limited role. As the assumed ERR increased, outcomes became more sensitive to the parameter 𝑘;k, reflecting whether EVP use corresponds to full substitution from smoking or includes initiation among individuals who would otherwise have remained non-users.
CONCLUSIONS: The net public health impact of EVP is determined by the balance between harm reduction through substitution in smokers and uptake among non-smokers. Under assumptions of low EVP risk, the overall impact is largely driven by smoker adoption, consistent with current evidence suggesting substantially lower toxicant exposure compared to cigarettes.