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Projected effects of tobacco smoking on worldwide tuberculosis control: mathematical modelling analysis

BMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d5506 (Published 04 October 2011) Cite this as: BMJ 2011;343:d5506
  1. Sanjay Basu, physician123,
  2. David Stuckler, university lecturer in sociology34,
  3. Asaf Bitton, instructor in medicine56,
  4. Stanton A Glantz, professor of medicine1
  1. 1Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
  2. 2Division of General Internal Medicine, San Francisco General Hospital, San Francisco
  3. 3Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
  4. 4Department of Sociology, Cambridge University, Cambridge, UK
  5. 5Department of Health Care Policy, Harvard Medical School, Boston, MA, USA
  6. 6Division of General Medicine, Brigham and Women’s Hospital, Boston
  1. Correspondence to: S Basu, Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA sanjay.basu{at}ucsf.edu
  • Accepted 28 July 2011

Abstract

Objectives Almost 20% of people smoke tobacco worldwide—a percentage projected to rise in many poor countries. Smoking has been linked to increased individual risk of tuberculosis infection and mortality, but it remains unclear how these risks affect population-wide tuberculosis rates.

Design We constructed a state transition, compartmental, mathematical model of tuberculosis epidemics to estimate the impact of alternative future smoking trends on tuberculosis control. We projected tuberculosis incidence, prevalence, and mortality in each World Health Organization region from 2010 to 2050, and incorporated changing trends in smoking, case detection, treatment success, and HIV prevalence.

Results The model predicted that smoking would produce an excess of 18 million tuberculosis cases (standard error 16-20) and 40 million deaths from tuberculosis (39-41) between 2010 and 2050, if smoking trends continued along current trajectories. The effect of smoking was anticipated to increase the number of tuberculosis cases by 7% (274 million v 256 million) and deaths by 66% (101 million v 61 million), compared with model predictions that did not account for smoking. Smoking was also expected to delay the millennium development goal target to reduce tuberculosis mortality by half from 1990 to 2015. The model estimated that aggressive tobacco control (achieving a 1% decrease in smoking prevalence per year down to eradication) would avert 27 million smoking attributable deaths from tuberculosis by 2050. However, if the prevalence of smoking increased to 50% of adults (as observed in countries with high tobacco use), the model estimated that 34 million additional deaths from tuberculosis would occur by 2050.

Conclusions Tobacco smoking could substantially increase tuberculosis cases and deaths worldwide in coming years, undermining progress towards tuberculosis mortality targets. Aggressive tobacco control could avert millions of deaths from tuberculosis.

Footnotes

  • This article was prepared with the use of limited access data from the World Health Organization and United Nations Programme on HIV/AIDS, and does not necessarily reflect the opinions or views of these organisations. We thank Douglas Bettcher for his insights and assistance.

  • Contributors: SB and SAG prepared the model and analysed the results; DS and AB participated in the presentation and interpretation of results. All authors contributed to the drafting of the manuscript. SB is guarantor of the article.

  • Funding: SB is supported partly by the US Centers for Disease Control and Prevention (R36-CI000607-01) and the National Institutes of Health (T32-GM07205-32). The sponsors had no role in study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding author had full access to all the data in the study, and all authors had final responsibility for the decision to submit for publication.

  • Conflicts of interest: All authors have completed the Unified Competing Interest form at http://www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: SB is supported partly by the US Centers for Disease Control and Prevention (R36-CI000607-01) and the National Institutes of Health (T32-GM07205-32); no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Ethical approval was not required for this work.

  • Data sharing: No additional data available.

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