Diabetes increases risk of tuberculosis

Diabetes makes a person about three times as likely to develop tuberculosis (TB), and it may be to blame for more than ten per cent of TB cases in India and China, researchers said on Monday.

To clarify the link between the diseases, researchers at the Harvard School of Public Health in Boston examined data on 1.7 million people from 13 studies done in Canada, Mexico, the United States, Britain, Russia, Taiwan, India and South Korea.

Having diabetes raised a person's chances of getting active TB disease regardless of geographic region, the researchers found, with the risk rising roughly three-fold compared to people without diabetes, the researchers wrote in the Public Library of Science journal PLoS Medicine.

Predisposition

"With an estimated 171 million people afflicted with diabetes, a figure which is expected to double by year 2030, it is clear that diabetes constitutes a substantial contributor to the current and future burdens of TB globally," epidemiologist Megan Murray, who conducted the research with Harvard colleague Christie Jeon, said.

There is evidence that diabetes predisposes people to TB infection and impairs their ability to respond to infection, Murray said. TB is spread from one person to another when someone with active TB disease coughs or sneezes.

The role of diabetes may complicate efforts to drive down rates of TB, which trails only Aids on the list of the leading killers among infectious diseases, the researchers said.

Attack on lungs

An estimated one-third of the world's population is infected with the bacterium that causes TB a disease that typically attacks the lungs.

To better control TB, scientists are eager to better understand what factors may make a person who is infected with TB bacteria but is not sick - known as latent infection - go on to develop active TB disease.

Aids has been helping drive the onslaught of TB, and this research suggests that diabetes also is producing a deadly interaction with TB.