Risk factors

Anyone can get tuberculosis, but certain factors increase your risk of the disease. These factors include:

• Lowered immunity. A healthy immune system can often successfully fight TB bacteria, but your body can't mount an effective defense if your resistance is low. A number of factors can weaken your immune system. Having a disease that suppresses immunity, such as HIV/AIDS, diabetes, end-stage kidney disease, certain cancers or the lung disease silicosis, can reduce your body's ability to protect itself. Your risk is also higher if you take corticosteroids, certain arthritis medications, chemotherapy drugs or other drugs that suppress the immune system.
• Close contact with someone with infectious TB. In general, you must spend an extended period of time with someone with untreated, active TB to become infected yourself. You're more likely to catch the disease from a family member, roommate, friend or close co-worker.
• Country of origin. People from regions with high rates of TB — especially sub-Saharan Africa, India, China, the islands of Southeast Asia and Micronesia, and parts of the former Soviet Union — are more likely to develop TB. In the United States, more than half the people with TB were born in a different country. Among these, the most common countries of origin were Mexico, the Philippines, India and Vietnam.
• Age. Older adults are at greater risk of TB because normal aging or illness may weaken their immune systems. They're also more likely to live in nursing homes, where outbreaks of TB can occur.
• Substance abuse. Long-term drug or alcohol use weakens your immune system and makes you more vulnerable to TB.
• Malnutrition. A poor diet or one too low in calories puts you at greater risk of TB.
• Lack of medical care. If you are on a low or fixed income, live in a remote area, have recently immigrated to the United States or are homeless, you may lack access to the medical care needed to diagnose and treat TB.
• Living or working in a residential care facility. People who live or work in prisons, immigration centers or nursing homes are all at risk of TB. That's because the risk of the disease is higher anywhere there is overcrowding and poor ventilation.
• Living in a refugee camp or shelter. Weakened by poor nutrition and ill health and living in crowded, unsanitary conditions, refugees are at especially high risk of TB infection.
• Health care work. Regular contact with people who are ill increases your chances of exposure to TB bacteria. Wearing a mask and frequent hand washing greatly reduce your risk.
• International travel. As people migrate and travel widely, they may expose others or be exposed to TB bacteria.