Tuberculosis patients who smoke respond to treatment much slower than patients who don’t smoke, new research has found.

The study, which appeared in the International Journal of Tuberculosis and Lung Disease, found that the more cigarettes a patient smoked, the more likely they were to have delayed culture conversion than those who smoked fewer cigarettes.

This prompted researchers to call for patients to quit smoking during treatment in an effort to improve outcomes in TB control programmes.

Culture conversion, otherwise known as intensive phase of treatment, is a widely used gauge to measure response to anti-TB treatment and is associated with long-term cure.

Overall the study, which was conducted in Brazil and analysed more than 300 TB cases, found that patients who smoked had a three-fold greater chance of remaining sputum positive after two months of treatment, than non-smokers.

Delayed sputum conversion prolongs the time during which patients remain infectious and increases the risk of TB transmission.

Researchers warned that such overwhelming evidence needed to be used to encourage and assist patients living with TB.

Meanwhile, in another study, researchers established that misuse of prescribed medication such as antibiotics and other self-medication often delayed diagnosis, increasing the risk of transmission of TB.

In a study of about 250 TB patients, most continued taking over-the-counter drugs and prescribed medication despite having classical symptoms of TB such as chronic cough, weight loss and fever.

An average patient delay was almost 25 days, but patients who had been prescribed medication by medical practitioners were more than twice as likely to delay their diagnosis by almost 60 days on average.

Those patients who self-medicated, often with antibiotics, had longer patient delays.

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