January 27, 2009

Study Links TB, Substance Abuse

Government researchers said on Monday that nearly a fifth of people with tuberculosis in the United States report abusing drugs or alcohol, and the figures are even higher when only U.S.-born patients are included.

Researchers from the U.S. Centers for Disease Control and Prevention said the substance abusers were more contagious than others with the disease and remained contagious longer.

The bacterium that causes TB infects around a third of people worldwide, yet only a small percentage of people ever develop the disease.

But the researchers said the effect of substance abuse on the body may raise the chances that the latent infection turns into active disease, and substance abusers may be less likely to be screened for TB.

For the study 153,268 people with TB in the United States were tracked from 1997 to 2006. The researchers accounted for nearly everyone over the age 15 who had the disease during that time.

The study, reported in the journal Archives of Internal Medicine, found that overall, 19 percent of TB carriers said they abused drugs and/or alcohol. Among the 76,816 U.S.-born people with TB, 29 percent reported substance abuse.

Compared to other parts of the world, the U.S. has a very low TB rate, and more than half of those infected were born in other countries.

CDC epidemiologist Eric Pevzner, one of the researchers in the study, told Reuters that the most commonly reported risk factor for TB was substance abuse.

The researchers reported it was greater than other leading risk factors like HIV infection or homelessness.

Tuberculosis is an infectious bacterial disease typically attacking the lungs. It can be spread by breathing in droplets from a cough or sneeze of an infected person.

The findings had important public health implications as the U.S. attempts to lower its TB rates even further, Pevzner said.

Pevzner said TB couldn't be treated in isolation.
"We have to bring in people who are experts in substance abuse and also treat the life circumstances that people are facing so that we can help cure this disease and help end a chain of transmission."

The study said substance abusers are less likely to complete TB treatment and since they often have less access to medical care, it tends to be diagnosed later in life.


Image Caption: Mantoux tuberculin skin test. (CDC)


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