The FCTC promotes evidence based tobacco control policies in nearly every country worldwide.16202146 However, the empirical gap that we found between the FCTCs efficacy and effectiveness accords with realities widely discussed in international legal scholarship, including cases of countries ignoring treaties after ratifying them, treaty provisions creating non-binding recommendations rather than binding obligations, insufficient governmental capacity to act on treaties, countries formally adopting treaty provisions into national policy without actual implementation, and multinational companies and illicit traders moving their activities to countries that have implemented fewer restrictions.232425262728 Indeed, these limitations of international law apply specifically to the FCTC, and could explain two apparent contradictions in this studys findings. Although no study can definitively claim to causally attribute a global discontinuity in cigarette consumption to the FCTC, these study designs are the best possible for establishing strong evidence of association in this context. Funding: This research was supported by the Canadian Institutes of Health Research (project 312902) and the International Collaboration for Capitalizing on Cost-Effective and Life-Saving Commodities (i4C) that is funded through the Research Council of Norways Global Health and Vaccination Programme (project 234608). Finally, we are unable to state with certainty that the associations observed are causal, owing to the exploratory nature of the study that purposefully included multiple testing under various models, assumptions, and scenarios. Each countrys data were appraised by two researchers to evaluate intersource consistency and data confidence. This conflict could be explained by European Union accession rules requiring stringent tobacco control measures among new members,49 and rapidly rising incomes resulting in greater affordability and demand for cigarettes in low and middle income countries.4750. Conversely, European countries had been on an upward trend in consumption until a sudden reversal coinciding with the FCTCs adoption, and Asian countries reversed a moderate downward trend in consumption at the same point in time. Adopted under the auspices of WHO, this international treaty aims to reduce harmful tobacco consumption; lower smoking rates among children; and counteract the tobacco industrys lobbying, advertising, and promotion activities. Patients were not involved in this study. Data are number of cigarettes consumed per adult aged 15 years or older per year. If you are unable to import citations, please contact 
The divergence in cigarette consumption patterns between high income countries and low and middle income countries, and between European and Asian countries, should be studied in more detail. One could also expect market equilibrium effects, whereby action in one country will affect market dynamics in other countries. Each year, tobacco is responsible for about seven million deaths1 and for nearly US$500bn (396bn; 449bn) worth of economic damage owing to excess healthcare system costs and lost productivity.2 It causes over 12% of premature deaths globally3 and incurs substantial social cost for smokers and non-smokers alike.4 Yet the global tobacco epidemic shows no signs of relenting. Consumption based on number of cigarettes consumed per adult aged 15 years or older per year. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. Therefore, we cannot rule out the possibility that there was no difference, or that cigarette consumption had decreased compared with the counterfactual. The data did not include consumption of water tobacco, chewing tobacco, or loose leaf tobacco. African consumption estimates were less certain, owing to a lack of verified data in most countries, but the available results also indicated actual consumption that was higher than the modelled counterfactual (figure A9). The quantities and trends of consumption according to different country groupings were highly variable, however, with high income countries and OECD member countries showing a particularly rapid decline in consumption. Geneva, Switzerland: WHO; 2017 [cited 2018 Aug 29]. Ethical approval: This study was approved by McMaster Universitys Hamilton integrated research ethics board (14-378). In other words, many tobacco control policies have been proven to be both efficacious and effective at the national level and some studies have shown the FCTCs efficacy under ideal circumstances (that is, when the policies it promotes are fully implemented).161822 However, no study so far has quasi-experimentally evaluated the effectiveness of the decision to adopt a tobacco control treaty as a strategy for reducing global cigarette consumption. This statistical test used the annual estimates of cigarette consumption per adult directly and did not require first differencing. Our systematic effort to detect any potential FCTC effects included two quasi-experimental approaches at the global level, for subgroups by region, country income, OECD membership, and top cigarette-consuming country. We thank G Emmanuel Guindon for contributing to the conception, analysis, and interpretation of this study; Jessica Cohen, Julio Frenk, Gary King, Margaret McConnell, John-Arne Rttingen, and Stephen Soumerai for their feedback on the initial design of this study; and our colleagues who provided advice at different stages of its implementation. Stata software codes used to implement all analyses are available in appendix 2. However, upper middle income countries, low and middle income countries, Oceania, the Americas, Asia, and China showed slower rates of decline after 2003, while India had a one-time increase in consumption rate but an accelerated decrease in consumption over time. Not only are there known capacity constraints in the ability of countries to implement international laws,30 there are also many routes in addition to direct legal obligations through which the intended outcomes of these international laws might take effect. Consumption based on units of cigarettes consumed per adult aged 15 years or older per year, Results from interrupted time series analysis, with 2003 cutoff date for various subgroups. Despite their limitations, large scale quantitative approaches allow for the incorporation of data from many more countries and time periods than would be practical with in-depth qualitative approaches. Data are number of cigarettes consumed per adult aged 15 years or older per year. A framework convention on obesity control? World Health Organization. Owing to the use of first differencing in the interrupted time series analysis, level change coefficients represent a one-time decrease (negative coefficients) or increase (positive coefficients) of consumption per adult, and slope change coefficients represent the average rate of change of that acceleration or deceleration per year. Geneva, Switzerland: WHO; 2013 [cited 2018 Aug 29]. Furthermore, cessation of tobacco use has a stronger protective effect on health than reduction in use, so aggregate consumption might not have fully captured the FCTCs effects. 
After numerous statistical analyses, we could not find evidence that the rate at which global cigarette consumption per adult had been decreasing over the past three decades was accelerated by the adoption of the FCTC in 2003, whether through socialisation, normative, or legal pathways. Given the exploratory nature of this study, considerable efforts were undertaken to identify any potential impacts using different models, assumptions, and scenarios. According to the event model (fig 5), the gap between predicted and actual consumption increased from five cigarettes per adult per year in 2003 to 150 cigarettes per adult per year in 2008. Annual population weighted data on cigarette consumption per capita, by country income level, UN region, and OECD membership status. 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. Boston, MA: Houghton, Mifflin, and Co; 2002. xxi, 623. Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: support from the Canadian Institutes of Health Research (project 312902) and the Research Council of Norway; SJH was previously employed by WHO; no other relationships or activities that could appear to have influenced the submitted work. This study was limited by the number of countries for which data were available, including limited availability of supply side data. For example, international laws can change global norms, empower transnational advocacy networks, and alter the expectations that countries have of each other, irrespective of whether they are legally binding on any one particular country.
Data from low and middle income countries showed the opposite trend, with the average adult smoking over 500 cigarettes more per year than the modelled counterfactual predicted by 2013, rising above of the 95% prediction interval by 2010. We also segmented the overall global event model by UN region and country income level. First differencing refers to the use of year-over-year change in tobacco consumption as the unit of analysis rather than consumption itself, meaning that we are testing whether there has been a discontinuity in the rate of change of consumption (that is, an acceleration). WHO global report: mortality attributable to tobacco. 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. Design Two quasi-experimental impact evaluations, using interrupted time series analysis (ITS) and in-sample forecast event modelling. Only a few attempts have been made so far to empirically evaluate the impact of this international treaty. Setting and population 71 countries for which verified national estimates of cigarette consumption from 1970 to 2015 were available, representing over 95% of the worlds cigarette consumption and 85% of the worlds population. The World Health Organizations Framework Convention on Tobacco Control (FCTC) has received nearly universal approval in academic literature, news media, and political speeches, The FCTC aims to reduce harmful tobacco consumption; lower smoking rates among children; and counteract the tobacco industrys lobbying, advertising, and promotion activities, So far no studies have used a more rigorous quasi-experimental approach to evaluate the global impact of the FCTC to account for the fact that cigarette consumption had already been falling for at least 10 years before the international treaty was adopted in 2003, Using quasi-experimental approaches to evaluate the FCTCs impact on global cigarette consumption per capita, this study showed no evidence of an acceleration in the global consumption rate (which had been decreasing over the past three decades) after adoption of the FCTC in 2003, High income and European countries showed accelerated decreases in consumption, whereas low and middle income and Asian countries showed increased consumption above what would have been anticipated without adoption of the FCTC, These results should motivate accelerated implementation of proven tobacco control policies in countries with uneven implementation and more assertive responses to transnational activities of the tobacco industry.
Varied implementation of tobacco control policies and shifting trends in cigarette affordability across countries may have generated market equilibrium effects incentivising the tobacco industry to move its lobbying, marketing, and promotion activities away from high income countries (where they faced increasingly stringent regulations) and towards low and middle income countries and Asian countries (with far less stringent measures).1622303132 If this is the case, the FCTC might even have unintentionally resulted in tobacco companies targeting people in low and middle income countries and Asian countries who would have fewer governmental protections against these companies efforts. 