MONDAY, Jan. 10 (HealthDay News) -- People over age 65 are at increased risk for serious side effects while undergoing latent tuberculosis therapy, a new study finds.

Latent tuberculosis occurs when TB bacteria lurk in the body without making the person sick. The host has no symptoms of TB and is not contagious. However, there is still a chance the bacteria could multiply and cause tuberculosis, which can be fatal if it goes untreated.

Latent TB therapy reduces the chances of developing active TB and is used in Canada and the United States as a way to control the disease. The decision to treat a patient with latent TB therapy depends on his or her risk of developing active disease and of experiencing harmful side effects, explained Dr. Dick Menzies, of the Montreal Chest Institute, and colleagues.

In a six-year study of a large population of more than 9,000 latent TB patients who were treated for tuberculosis and a matching control group that was not treated, Menzies and his colleagues found that a higher percentage of patients undergoing latent TB therapy required hospitalization for serious liver problems that those who went untreated. The excess risk was contributed largely by people over 65, he and his colleagues reported, adding that the risk remained significant even after adjusting for co-existing diseases and other factors.

"Our data suggest that the risks of therapy for latent tuberculosis infection are considerable among the elderly and should be considered very carefully before therapy is given," he and his colleagues concluded in the study.

The study was published in the Jan. 10 issue of the Canadian Medical Association Journal.

More information

The U.S. Centers for Disease Control and Prevention has more about tuberculosis.