In a recent study published in the medical journal Thorax a study concludes that smoking may increase the risk of tuberculosis infection. The study looked at 2,401 adults from two urban communities in Cape Town, South Africa. The participants were surveyed about their smoking habits and underwent a tuberculin skin test. Factors such as age, sex, education level, body mass index, and income were taken into account.
Of 1,309 current smokers or ex-smokers, 1,070 (82%) had a positive skin tuberculin test. This was significantly higher than for those who had never smoked. It was also noted that those smoking more than 15 pack-years had a highest risk. Smoking for the study was defined as having never smoked for at least one year.
The reason for this increased risk to tuberculosis is unclear however it may be due to the fact that smoking makes lungs more prone to infections. The evidence is very strong to also suggest that the likelihood of developing active tuberculosis is greater in those who have smoked for a long time, says Dr Graham Bothamley.
Source: Association between smoking and tuberculosis infection: a population survey,
Thorax 2005; 60: 555-7