Project overview
TB and Tobacco – Two colliding epidemics
Tobacco consumption and tuberculosis (TB) are two ‘colliding epidemics’ in many low- and middle- income countries of the world. The two epidemics tend to interact and amplify each other’s negative impacts on the health of the population.
Objectives
The overall objective of the TB and Tobacco project is to reduce the burden of lung diseases in low- and middle-income countries. We aim to do this by helping people with TB to stop smoking, using inexpensive strategies that have already been shown to work. The strategies will be aimed at patients who have been newly diagnosed with TB, and will be integrated into TB control programmes in countries where the burden of TB and tobacco is high. We will conduct our research in three such countries in South Asia: Bangladesh, Nepal and Pakistan.
We plan to assess the effectiveness and cost-effectiveness of tobacco cessation strategies in helping TB patients who use tobacco to quit and to improve their clinical outcomes – the effectiveness goal. We will then explore how best to implement these strategies, scale them up and sustain them over the long term – the implementation goal.
Our studies will evaluate the use of cytisine, when combined with behavioural support for tobacco cessation, compared with behavioural support alone. Cytisine is a low-cost alkaloid, derived from the Golden Rain tree (Laburnum anagyroides). It mimics nicotine by stimulating the receptors in the brain that are also stimulated by nicotine. Cytisine has been shown to be effective as a tobacco cessation medication in Eastern Europe and New Zealand, but no clinical trials have yet been conducted with it in low- and middle-income countries.
An important part of the project will be to gather information about how the strategies could be implemented in TB control programmes and how best to adapt them to suit the different requirements of the health systems and cultures in the three different countries. This knowledge will be essential for the success of any scale-up of the strategies in the future.
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The tobacco epidemic
Globally, 1.1 billion people currently smoke tobacco, and 70% of these live in low- and middle- income countries1. Worldwide, the number of men and women who smoke daily rose from 721 million to 967 million between 1980 and 20121. Tobacco consumption is predicted to rise by 60% in middle-income countries and by 100% in low-income countries, over the next 25 years2.
On its own, tobacco smoking causes more deaths than any other preventable risk factor. One in two long-term smokers dies as a result of their habit, and the global burden of tobacco-related disease rises still further when second-hand (passive) smoking is taken into account3,4. Given current consumption patterns, deaths caused by smoking are expected to rise to 8.3 million per year by 2030; 80% of these will be in low- and middle-income countries5. Half of these deaths will occur among people of working age, leading to a significant reduction in national economic productivity2.
The TB epidemic
TB is a widespread, often fatal, infectious disease caused by a bacterium (Mycobacterium tuberculosis). Pulmonary TB attacks the lungs and is the most infectious and transmissible form of the disease. Almost 4 million new cases of pulmonary TB are diagnosed worldwide every year; the vast majority in low- and middle-income countries. This leads to approximately 1.7 million deaths from TB per year6.
Effective treatment of TB is difficult and often requires prolonged use of different antibiotics. The recent resurgence of TB in Eastern Europe, and the emergence of multi-drug resistant TB are contributing to the on-going challenge of global TB control. TB remains an important target for international agencies trying to combat preventable diseases, not just because of the human misery and suffering it causes, but also because victims of TB tend to be people from economically-productive age-groups.
The colliding epidemics
A growing body of evidence has shown that tobacco smoking increases the risk of acquiring TB infection, as well as increasing the risk of its progression to TB disease. TB patients who continue to smoke have much worse disease outcomes that those who manage to quit; their continued smoking leads to the disease becoming more serious more quickly, and results in a greater likelihood of them dying from TB7.
It is estimated that 15% of the global disease burden of pulmonary TB could be attributed to tobacco use8. Clearly, then, considerable public health benefits could be achieved if TB patients could be persuaded to stop smoking.
The benefits of targeting TB patients
Many studies have shown that tobacco cessation strategies delivered by healthcare professionals can be very effective in helping people to stop smoking. Such strategies might include pharmacological interventions (medicines) and/or behavioural support methods. However, there is practically no evidence concerning the effectiveness and cost-effectiveness of offering such interventions to TB patients.
Despite limited resources, low- and middle-income countries with high TB incidence often have well-developed TB control programmes, with established clinics and highly-trained staff. As mentioned above, these countries also tend to have high tobacco use. There is therefore a unique opportunity to deliver low-cost tobacco cessation strategies as part of routine TB care, and to study the effects of integrating these strategies into the healthcare system.
Not only does targeting TB patients with tobacco cessation assistance have the potential advantage of achieving greater health benefits than targeting the general population, it also offers the opportunity to exploit ‘teachable moments,’ when newly diagnosed TB patients may be particularly amenable to advice about stopping smoking, and particularly motivated to succeed9.
References
- Ng M, Freeman MK, Fleming TD et al (2014). Smoking prevalence and cigarette consumption in 187 countries, 1980-2012. Jama 311(2):183-92.
- Esson M & Leeder R (2004) The millennium development goals and tobacco control: an opportunity for global partnership. World Health Organization 2004.
- Institute for Health Metrics and Evaluation. Global Burden of Disease (GBD) Visualizations (2010).
- Lim SS, Vos T, Flaxman AD et al (2013). A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990 – 2010. Lancet 380(9859):2224-60.
- Mathers CD & Loncar D. (2006) Projections of global mortality and burden of disease from 2002 to 2030. PLoS medicine 3:e442.
- Dye C. (2006) Global epidemiology of tuberculosis. Lancet 367(9514):938-40.
- Bates MN, Khalakdina A, Pai M, Chang L, Lessa F & Smith KR. (2007) Risk of tuberculosis from exposure to tobacco smoke: a systematic review and meta-analysis. Archives of Internal Medicine 167(4):335.
- Pai M, Mohan A, Dheda K et al (2007) Lethal interaction: the colliding epidemics of tobacco and tuberculosis. Expert Review of Anti-infective Therapy 5(3):385-91.
- McBride CM, Emmons KM & Lipkus IM (2003) Understanding the potential of teachable moments: the case of smoking cessation. Health Educ. Res. 18(2):156-70.
