The 13th World Conference on Tobacco OR Health

Objective: In India, tuberculosis was found to kill more smokers than all types of cancer combined. There is substantial evidence – including a strong dose-response relationship – linking smoking and tuberculosis. This means that in countries where tuberculosis is highly prevalent (like India), smokers are more susceptible to and are spreading an infectious disease. The objectives of my research are to: investigate the causal mechanisms by which smoking affects tuberculosis risks, estimate the true impact of smoking on population-level tuberculosis outcomes, and to determine whether smoking is a factor that should be considered in the development of tuberculosis-control policy.

Methods: A dynamic systems model was developed to represent the key aspects of tuberculosis transmission and disease development. The model is specified by tuberculosis data published in the literature. The introduction of smoking into the model is based on a review of the impact of smoking on lung function and immune response. The size of the impact of smoking was constrained by meta-analysis of the literature on the association between smoking and tuberculosis.

Results: In populations with 29% smoking prevalence (the average in developing countries), nearly half of all incident tuberculosis is attributable to smoking. Aside from the effect of environmental tobacco smoke exposure, the impact of smoking extends to never-smokers because, unlike lung cancer or heart disease, tuberculosis is an infectious disease. In addition to a slew of other health benefits, policies that address smoking behavior (both initiation and cessation) would have a significant impact on tuberculosis incidence.