A dynamic modelling analysis of the impact of tobacco control programs on population-level nicotine dependence

Adam Skinner,Jo-An Occhipinti,Nathaniel D Osgood

doi:10.1038/s41598-021-81460-9

Adam Skinner, Jo-An Occhipinti + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-81460-9

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Abstract

According to the ‘hardening hypothesis’, average nicotine dependence will increase as less dependent smokers quit relatively easily in response to effective public health interventions, so that sustained progress in reducing smoking prevalence will depend on shifting the emphasis of tobacco control programs towards intensive treatment of heavily dependent smokers (who comprise an increasing fraction of continuing smokers). We used a system dynamics model of smoking behaviour to explore the potential for hardening in a population of smokers exposed to effective tobacco control measures over an extended period. Policy-induced increases in the per capita cessation rate are shown to lead inevitably to a decline in the proportion of smokers who are heavily dependent, contrary to the hardening hypothesis. Changes in smoking behaviour in Australia over the period 2001‒2016 resulted in substantial decreases in current smoking prevalence (from 23.1% in 2001 to 14.6% in 2016) and the proportion of heavily dependent smokers in the smoking population (from 52.1% to 36.9%). Public health interventions that have proved particularly effective in reducing smoking prevalence (tobacco tax increases, smoke-free environment legislation, antismoking mass media campaigns) are expected to also contribute to a decline in population-level nicotine dependence.

Highlights

According to the ‘hardening hypothesis’, average nicotine dependence will increase as less dependent smokers quit relatively in response to effective public health interventions, so that sustained progress in reducing smoking prevalence will depend on shifting the emphasis of tobacco control programs towards intensive treatment of heavily dependent smokers
Dramatic declines in smoking prevalence have been achieved in countries where effective public health measures have been in place for an extended period, leading some researchers to propose that the smoking populations of these countries may become increasingly less responsive to such measures as prevalence continues to decline, since many smokers who could be prompted to quit will have already done so[2,3,4]
Assuming the per capita initiation rate is positive, the equilibrium value of q is equal to v/(v + c + ζ μ), so increases in the per capita cessation rate for less dependent smokers, c, lead to a decrease in the equilibrium proportion of smokers who are heavily dependent

Summary

Introduction

According to the ‘hardening hypothesis’, average nicotine dependence will increase as less dependent smokers quit relatively in response to effective public health interventions, so that sustained progress in reducing smoking prevalence will depend on shifting the emphasis of tobacco control programs towards intensive treatment of heavily dependent smokers (who comprise an increasing fraction of continuing smokers). Dramatic declines in smoking prevalence have been achieved in countries where effective public health measures (e.g., taxation, mass media campaigns, smoke-free legislation) have been in place for an extended period, leading some researchers to propose that the smoking populations of these countries may become increasingly less responsive to such measures as prevalence continues to decline, since many smokers who could be prompted to quit will have already done so[2,3,4] According to this ‘hardening hypothesis’, sustained progress in reducing smoking prevalence will depend upon shifting the emphasis of tobacco control programs towards intensive treatment of individual s mokers[3]. Using a simple system dynamics model of smoking behaviour, we demonstrate via a series of simulation experiments and a detailed case study that hardening (defined here as an increase in the proportion of smokers who are heavily dependent) would be expected only under a restricted set of conditions that will rarely apply in mature tobacco control policy environments

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