Smoking is a risk factor for tuberculosis

Reported by Susan Aldridge, PhD, medical journalist

Smoking appears to increase the risk of contracting tuberculosis and developing active disease.
Around one third of the world's population is infected with the bacterium that causes tuberculosis (TB). But it is usually rendered inactive by the immune system, so most people don't actually get TB. However, the disease still kills nearly two million people every year. It has long been suspected that smoking increases the risk of developing TB. This link is now confirmed by a new analysis from a team at the School of Public Health at the University of California, Berkeley.

They looked at 24 previously published studies and learned that those who smoke run a 73 per cent increased risk of becoming infected with TB and have double the risk of developing active TB compared to non-smokers. However, smoking did not seem to increase the risk of death from TB. It may be that smoking damages the immune system, so that the TB bacteria can get a hold in the body. Or it may damage the fine hairs, known as cilia, lining the airways and make the respiratory system more vulnerable to infection. The findings suggest that tobacco control ought to be factored into TB control policies around the world.

Source
Archives of Internal Medicine 26th February 2007 Volume 167 pages 335-342

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