Objective To understand the current status and influencing factors of latent tuberculosis infection (LTBI) among close contacts of pulmonary tuberculosis patients, and to provide a basis for formulating intervention measures for LTBI.

Methods Close contacts of pulmonary tuberculosis patients from 18 counties and districts in Shandong Province were selected as the research subjects. Demographic information was collected through questionnaires, and the infection status of Mycobacterium tuberculosis was detected by skin tests.

Results A total of 6456 close contacts were included, including 3221 males and 3235 females, with an average age of (45.83±20.34) years. 693 cases of LTBI were detected, with a latent tuberculosis infection rate of 10.73%. Logistic regression analysis showed that a positive pathogen in the index case was a risk factor for LTBI (OR=1.685, 95%CI: 1.338−2.121); BMI was a risk factor for LTBI, and the LTBI infection rate increased with the increase of BMI (OR=1.122, 95%CI: 1.013−1.244); living in an urban area was a risk factor for LTBI (OR=1.225, 95%CI: 1.152−1.303); having a smoking history was a risk factor for LTBI (OR=1.441, 95%CI: 1.160−1.790); average nightly sleep time≤5 hours was a risk factor for LTBI (OR=1.152, 95%CI: 1.041−1.276). Living in a different courtyard from the index case was a protective factor for LTBI (OR=0.771, 95%CI: 0.693−0.857); exercising more than 4 times a week was a protective factor for LTBI (OR=0.854, 95%CI: 0.765−0.953); rarely getting angry in the past few months was a protective factor for LTBI (OR=0.847, 95%CI: 0.739−0.972).

Conclusion The key population for LTBI among close contacts of pulmonary tuberculosis patients is those who have contact with index cases with positive pathogens, high BMI values, live in urban areas, have a smoking history, and average nightly sleep time ≤5 hours. These groups should be given special attention. At the same time, it is recommended that all close contacts of pulmonary tuberculosis patients be included in screening.