Estimating the reduction in US mortality if cigarettes were largely replaced by e-cigarettes.

Introduction:
This text summarizes a study that aimed to estimate the reduction in US mortality if cigarettes were largely replaced by e-cigarettes. The study used a modeling approach based on a shorter period (1991-2040), four main smoking-associated diseases, deaths aged 30-79 years, and a full product history. The study considered variations in several parameters, including the assumed effective dose of e-cigarettes versus cigarettes, their relative quitting rate, proportions smoking after 10 years, and initiation rate of vaping relative to smoking.

Key Points:

* The study used the Population health Impact Model (PhIM) to estimate the reduction in mortality associated with the use of e-cigarettes.
* The study compared a Null Scenario, where the new product (e-cigarettes) is never introduced, to alternative Scenarios, where the new product is introduced and individuals can switch between five groups (never users, current exclusive smokers, current exclusive vapers, current dual users, and former users).
* The study considered four major smoking-related diseases: lung cancer, chronic obstructive pulmonary disease, ischaemic heart disease, and stroke.
* The study estimated the relative risk of each disease for current and former smokers and vapers, compared to never users, using a negative exponential model.
* The study used sex- and age-specific distributions for annual current and former smoking prevalence from 1986 to 2018 and for five-year periods from 1986-1990 to 2016-2020.
* The study used data on age of quitting from the National health Interview Survey (NhIS) for 2006.
* The study estimated the number of deaths and years of life lost (YLL) for each Scenario and compared them to determine the effect of introducing the new product.

Main Message:
The study found that substantially replacing cigarettes with e-cigarettes could result in significant reductions in deaths and YLL, even under pessimistic assumptions. The findings support literature indicating that e-cigarettes can have an important effect on the health challenges created by smoking. however, the study also notes that the estimates varied most for the proportion of the population still smoking after 10 years and the assumed effective dose of e-cigarettes versus cigarettes. Therefore, it is essential to consider these factors when evaluating the potential health benefits of e-cigarettes.

Lee PN, Fry JS, Gilliland S, Campbell P, Joyce aR. Estimating the reduction in US mortality if cigarettes were largely replaced by e-cigarettes. archives of toxicology. 2022;96(1):167-176. doi:10.1007/s00204-021-03180-3