Risk Factors for Latent Tuberculosis Identified Using Epidemiological Investigation in Congregate Settings of Gyeongsan City, Republic of Korea (2014-2023).

Latent tuberculosis infection (LTBI) remains an important public health issue, as individuals can harbor without symptoms and later develop active disease. This study aimed to assess the prevalence and risk factors associated with LTBI positivity among tuberculosis (TB) contacts in congregate settings in Gyeongsan City, the Republic of Korea (ROK), from 2014 to 2023. A total of 213 index cases and 3666 contacts were analyzed using data from the Korea Tuberculosis Infection Control System (KTB-NET). Overall, 20.7% of contacts tested positive for LTBI, with the highest rates observed among contacts aged ≥65 years (50.4%) and in healthcare facilities (34.8%). Binary logistic regression analyses revealed that age ≥65 years (OR: 2.93; 95% CI: 1.95-4.39; < 0.001), social welfare facilities (OR: 2.75; 95% CI: 2.10-3.58; < 0.001), workplaces (OR: 2.42; 95% CI: 1.88-3.10; < 0.001), and healthcare facilities (OR: 3.42; 95% CI: 2.63-4.43; < 0.001) were significantly associated with increased LTBI risk. These findings highlight the importance of targeted interventions and prevention strategies focused on older adults and high-risk groups to prevent future TB outbreaks by reducing the burden of LTBI.