Prevalence and risk factors of latent tuberculosis infection among household contacts of tuberculosis patients: a cross-sectional study.

BACKGROUND

Household contacts (HHCs) of tuberculosis patients are at higher risk for latent tuberculosis infection (LTBI). However, current knowledge regarding LTBI prevalence and risk factors among HHCs in Shandong Province, China remains limited.

OBJECTIVE

This study aims to determine the prevalence of LTBI among HHCs of tuberculosis patients and identify associated risk factors.

METHODS

We conducted a cross-sectional survey among HHCs of tuberculosis patients in Shandong Province, China. LTBI prevalence was assessed using the tuberculin skin test (TST) and tuberculosis antigen-based skin test (TBST). Univariate and multivariable logistic regression analyses were performed to identify risk factors associated with infection.

RESULTS

A total of 5,772 HHCs of 1,657 tuberculosis patients were enrolled. The prevalence of LTBI among HHCs was 10.2% (95% CI: 9.424-10.985). In the multivariable logistic regression analysis, the infection rate increased in older age groups compared to the 0-14 age group. The highest adjusted odds ratio (aOR) was observed in the 45-59 age group (aOR = 3.761; 95% CI: 2.160-6.546). Living in multi-story buildings (aOR = 1.301; 95% CI: 1.024-1.651) and exposure to bacteriologically positive patients (aOR = 1.424; 95% CI: 1.066-1.903) were identified as potential risk factors for LTBI. In contrast, residing in a separate room within the same household was associated with a lower risk of infection compared to sharing the same room with the index patient (aOR = 0.608; 95% CI: 0.453-0.816).

CONCLUSION

Households are high-risk settings for tuberculosis transmission. Therefore, it is necessary to intensify active contact screening at the household level to shorten the interval between tuberculosis diagnosis and contact tracing, thereby interrupting potential transmission chains within the community.