What is the strongest risk factor for tuberculosis infection?

What is the strongest risk factor for tuberculosis infection?

• A. HIV/AIDS
• B. Diabetes mellitus
• C. Malnutrition
• D. Smoking

Answer: (A)

HIV/AIDS is the strongest risk factor because it causes profound impairment of cell-mediated immunity, the arm of the immune system that controls TB. CD4+ T cells are essential for activating macrophages to contain Mycobacterium tuberculosis and for forming granulomas that keep the bacteria in check. When HIV reduces CD4+ T cells, exposure to TB is far more likely to result in infection and to progress from latent infection to active disease, including disseminated TB. The other factors—malnutrition, diabetes, and smoking—raise risk by compromising defenses, but they don’t blunt the specific anti-TB immune response as dramatically as advanced HIV.

HIV/AIDS is the strongest risk factor because it causes profound impairment of cell-mediated immunity, the arm of the immune system that controls TB. CD4+ T cells are essential for activating macrophages to contain Mycobacterium tuberculosis and for forming granulomas that keep the bacteria in check. When HIV reduces CD4+ T cells, exposure to TB is far more likely to result in infection and to progress from latent infection to active disease, including disseminated TB. The other factors—malnutrition, diabetes, and smoking—raise risk by compromising defenses, but they don’t blunt the specific anti-TB immune response as dramatically as advanced HIV.