Tuberculosis: Risk Factors

You are at risk of TB infection if you are around people with active TB disease who are coughing, which releases bacteria into the air. The risk of infection increases for intravenous drug users, healthcare workers, and people who live or work in a homeless shelter, migrant farm camp, prison or jail, or nursing home.

Most people who are infected with the bacteria that cause TB do not develop active disease. The following factors increase the risk that latent disease will develop into active disease:

• Infection with HIV, the virus that causes AIDS and weakens the immune system
• Diabetes mellitus
• Low body weight
• Head or neck cancer, leukemia, or Hodgkin's disease
• Some medical treatments, including corticosteroids or certain medications used for autoimmune or vasculitic diseases such as rheumatoid arthritis or lupus, which suppress the immune system.
• Silicosis, a respiratory condition caused by inhaling silica dust.

People at Risk

Anyone can become infected with M. tuberculosis simply by breathing in the germs, but in the United States today, TB disproportionately involves immigrants and minorities. Those who originated in Asia, the Indian sub-continent, Africa, Latin America or Russia/the former Soviet Republics have a much greater likelihood of harboring TB infection than U.S. citizens. The risk for active TB is highest in the first few years after immigration but persists for a lifetime.

Within the indigenous U.S. population, the risk is greater among Hispanic, African-American or Asian-American individuals. Other factors, which increase the risk for latent TB infection are time in prison, health care employment or extended travel in high risk areas. HIV infections or AIDS dramatically increases the risk of TB reactivation.

Most TB is seen in adult populations, the risk is increasing with age. However, children in households with an active-TB case may be at high risk.