Lung damage caused by smoking could cause an additional 18 million cases of tuberculosis and 40 million extra deaths from TB by 2050, according to a study published on Tuesday in the British Medical Journal (BMJ).

The estimates derive from a mathematic model of smoking trends and smoking's impact on TB risk.

Africa, the eastern Mediterranean and Southeast Asia will see the biggest rise in smoking-linked TB, the study says.

"Aggressively lowering the prevalence of tobacco smoking could reduce smoking-attributable deaths from tuberculosis by 27 million by 2050," according to the paper, headed by Sanjay Basu of the University of California at San Francisco.