The annual rate of new tuberculosis cases in the U.S. is among the lowest in the world, according to the article. However, certain groups remain at higher risk. “The epidemiology of TB in the United States has been best summarised by Iseman: ‘As the epidemic tide of tuberculosis recedes from the shores of America, small tide pools of disease remain behind: pools populated by immigrants, the elderly and the immune compromised’,” the authors write. “A less frequently discussed tide pool that complicates U.S. TB control efforts is the illicit drug–using and alcohol-abusing population.”
Researchers analysed data from 153,268 patients who were reported to have TB between 1997 and 2006. Of these, 28,650 (18.7 percent) reported substance abuse - a larger percentage than those who reported any other established risk factors for TB, including recent immigration to the United States (12.9 percent), infection with HIV (9.5 percent), living in a group setting (6.6 percent), homelessness (6.3 percent) or working in a high-risk occupation (4.3 percent).
“The relation between substance abuse and increased transmission of Mycobacterium tuberculosis can be explained in several ways, some of which are indirect and revolve around delayed diagnosis and difficulties identifying at-risk contacts, screening them for TB and treating patients with positive findings,” the authors write. “Persons who abuse substances may have less access to routine medical care, potentially leading to delayed diagnoses. As the disease progresses, patients tend to become more contagious.”
Patients who abuse substances are less likely to be screened or to begin and complete treatment for latent infection or active disease, the authors note - problems compounded by the compromised immune systems of individuals who abuse substances. In addition, anti tuberculosis medications are usually metabolised by the liver, which is often damaged by substance abuse.
“Our results suggest that substance abuse is the most commonly reported modifiable behaviour impeding TB elimination efforts in the United States. Tuberculosis control and substance abuse programmes need to work together to simultaneously treat the diseases of addiction and TB,” the authors conclude.
MEDICA.de; Source: American Medical Association (AMA)