Impact of the WHO Framework Convention on Tobacco Control on global cigarette consumption: quasi-experimental evaluations using interrupted time series analysis and in-sample forecast event modelling

Abstract

Objective: To evaluate the impact of the WHO Framework Convention on Tobacco Control (FCTC) on global cigarette consumption.

Design: Two quasi-experimental impact evaluations, using interrupted time series analysis (ITS) and in-sample forecast event modelling.

Setting and population: 71 countries for which verified national estimates of cigarette consumption from 1970 to 2015 were available, representing over 95% of the world's cigarette consumption and 85% of the world's population.

Main outcome measures: The FCTC is an international treaty adopted in 2003 that aims to reduce harmful tobacco consumption and is legally binding on the 181 countries that have ratified it. Main outcomes were annual national estimates of cigarette consumption per adult from 71 countries since 1970, allowing global, regional, and country comparisons of consumption levels and trends before and after 2003, with counterfactual control groups modelled using pre-intervention linear time trends (for ITS) and in-sample forecasts (for event modelling).

Results: No significant change was found in the rate at which global cigarette consumption had been decreasing after the FCTC's adoption in 2003, using either ITS or event modelling. Results were robust after realigning data to the year FCTC negotiations commenced (1999), or to the year when the FCTC first became legally binding in each country. By contrast to global consumption, high income and European countries showed a decrease in annual consumption by over 1000 cigarettes per adult after 2003, whereas low and middle income and Asian countries showed an increased annual consumption by over 500 cigarettes per adult when compared with a counterfactual event model.

Conclusions: This study finds no evidence to indicate that global progress in reducing cigarette consumption has been accelerated by the FCTC treaty mechanism. This null finding, combined with regional differences, should caution against complacency in the global tobacco control community, motivate greater implementation of proven tobacco control policies, encourage assertive responses to tobacco industry activities, and inform the design of more effective health treaties.

Fig 1

Timeline of major events in the creation, negotiation, adoption, and ratification of the WHO Framework Convention on Tobacco Control (FCTC)

Fig 2

Logic model for conceptualising the impact of the WHO Framework Convention on Tobacco Control (FCTC) on tobacco consumption

Fig 3

Annual population weighted data on cigarette consumption per capita, by country income level, UN region, and OECD membership status. Consumption based on number of cigarettes consumed per adult aged 15 years or older per year. FCTC=WHO Framework Convention on Tobacco Control, adopted in May 2003

Fig 4

Interrupted time series plot of annual change in cigarette consumption per capita, with 95% confidence intervals, before and after 2003 adoption of the WHO Framework Convention on Tobacco Control (FCTC). Cigarette consumption data are based on first differencing (that is, use of year-over-year change in tobacco consumption as the unit of analysis rather than consumption itself) and weighted by global population. Consumption based on units of cigarettes consumed per adult aged 15 years or older per year

Fig 5

Population weighted, global event model predictions of cigarette consumption per capita, including 80%, 90%, and 95% prediction intervals, compared with actual consumption. In-sample forecast cutoff values begin in 2003 (adoption of the WHO Framework Convention on Tobacco Control (FCTC)), after which predictions are based on coefficients for the economy, political system, tobacco industry, and human development. Data are number of cigarettes consumed per adult aged 15 years or older per year

Fig 6

Population weighted, global event model predictions of cigarette consumption per capita for 29 high income countries (top panel) and 41 low and middle income countries (bottom panel), including 80%, 90%, and 95% prediction intervals, compared with actual consumption. In-sample forecast cutoff values begin in 2003 (adoption of the WHO Framework Convention on Tobacco Control (FCTC)), after which predictions are based on coefficients for the economy, political system, tobacco industry, and human development. Data are number of cigarettes consumed per adult aged 15 years or older per year

Fig 7

Population weighted, global event model predictions of cigarette consumption per capita for the Americas (top panel), Europe (middle panel), and Asia (bottom panel) with actual consumption. In-sample forecast cutoff values begin in 2003 (adoption of the WHO Framework Convention on Tobacco Control (FCTC)), after which predictions are based on coefficients for the economy, political system, tobacco industry, and human development. Data are number of cigarettes consumed per adult aged 15 years or older per year