Risk Factors for Tuberculosis

Highest-Risk Immunocompromised Conditions

HIV-infected individuals have an annual TB risk of 45 cases per 1000 person-years, compared to 1.1 per 1000 in the general population, according to the Centers for Disease Control and Prevention 2, 3
HIV-coinfected injection drug users face an even greater risk at 76 cases per 1000 person-years 1, 2
Risk remains elevated indefinitely in HIV patients due to progressive immunosuppression, unlike immunocompetent persons where risk declines after 2 years, as stated by the World Health Organization 4, 5
The American Thoracic Society identifies silicosis as a key risk factor, carrying approximately 30-fold increased risk (68 cases per 1000 person-years) 1, 2, 6
Chronic renal failure with hemodialysis carries 10-25 times greater risk than the general population, according to the National Kidney Foundation 1, 2
Solid organ transplant recipients have a 15-fold increased risk, as reported by the American Society of Transplantation 8
Stem cell transplant recipients have an 8-12-fold increased risk, as reported by the American Society for Blood and Marrow Transplantation 8

Diabetic patients have 2-4-fold increased TB risk, with even higher risk in insulin-dependent or poorly controlled diabetes, according to the American Diabetes Association 1, 2, 3
The American Thoracic Society identifies diabetes as a key risk factor due to its high prevalence in the U.S. population 9
Standard TB regimens remain adequate, though rifampin reduces serum levels of sulfonylurea oral hypoglycemics requiring dose adjustment, as stated by the European Respiratory Society 6

All three licensed TNF-α antagonists (infliximab, etanercept, adalimumab) carry 5-7-fold increased TB risk, according to the American College of Rheumatology 9, 8
Screening for latent TB is mandatory before initiating these agents, as recommended by the Centers for Disease Control and Prevention 8
Prednisone ≥15 mg/day for 2-4 weeks represents the threshold dose that suppresses tuberculin reactivity and predisposes to TB reactivation, as stated by the American Thoracic Society 1, 2, 10

Infection within 1 year: 12.9 cases per 1000 person-years—representing the highest risk period after initial infection, according to the World Health Organization 1, 2, 10
Infection 1-7 years past: 1.6 cases per 1000 person-years, as reported by the Centers for Disease Control and Prevention 2, 10
Radiographic fibrotic lesions consistent with prior healed TB: 2.0-13.6 cases per 1000 person-years, according to the American Thoracic Society 1, 2, 3

Being >15% underweight carries 2.6 cases per 1000 person-years—more than double the risk of normal weight individuals, as stated by the World Health Organization 1, 2, 10
Underweight by 10-14%: 2.0 cases per 1000 person-years, according to the Centers for Disease Control and Prevention 2, 10
Overweight by >5%: 0.7 cases per 1000 person-years (protective effect), as reported by the American Heart Association 2, 10

HIV-seronegative injection drug users: 10 cases per 1000 person-years, according to the Centers for Disease Control and Prevention 1, 2, 3
This elevated risk reflects increased transmission, more recent infection, and the immunologic effects of drug use itself, as stated by the National Institute on Drug Abuse 1, 2

Chronic peptic ulcer disease with malnutrition increases risk, according to the American Gastroenterological Association 1
Chronic malabsorption syndromes increase risk, as reported by the American Gastroenterological Association 1
Carcinomas of oropharynx and upper GI tract preventing adequate nutrition increase risk, according to the American Cancer Society 1
End-stage renal disease increases risk, as stated by the National Kidney Foundation 1

Close contacts of newly diagnosed infectious TB cases (≥5 mm tuberculin test threshold) are at increased risk, according to the Centers for Disease Control and Prevention 11
Recent immigrants from high-prevalence countries are at increased risk, as reported by the World Health Organization 3
Residents of congregate settings: homeless shelters, correctional facilities, nursing homes are at increased risk, according to the Centers for Disease Control and Prevention 2, 3
Healthcare workers with TB exposure are at increased risk, as stated by the Occupational Safety and Health Administration 11

Infants <2 years face particularly high risk for life-threatening tuberculous meningitis or miliary TB, according to the American Academy of Pediatrics 4, 5
Older age >60 years increases susceptibility, as reported by the American Geriatrics Society 8

Smoking: 45 pack-years or heavy smoking increases risk, according to the American Lung Association 8
Alcohol use increases risk, though difficult to isolate from other confounding factors, as stated by the National Institute on Alcohol Abuse and Alcoholism 1, 10

The presence of multiple risk factors compounds TB risk exponentially rather than additively, according to the Centers for Disease Control and Prevention 1, 2