Journal List > Korean J Healthc Assoc Infect Control Prev > v.24(2) > 1140852

Lee, Lee, Kim, Kim, Heo, and Choi: Prevalence and Risk Factors of Latent Tuberculosis Infection among Healthcare Workers



Due to occupational exposure, healthcare workers (HCW) face an increased risk of tuberculosis (TB) infection. This study was conducted to assess the prevalence and risk factors of latent tuberculosis infection (LTBI), and to estimate the cumulative risk of active TB among HCWs.


We conducted a cross-sectional study among HCWs in Ajou university medical center. A standard questionnaire was used for data collection, and LTBI was detected using the Interferon gamma-release assay (IGRA). The biographical information was collected from the electronic database. A computerized algorithm was used to evaluate the predicted cumulative risk of active TB in HCWs with LTBI.


Of a total of 1,407 HCWs, a positive IGRA result was detected in 138 HCWs. The prevalence of LTBI in HCWs was found to be 9.8% [95% confidence interval (CI) 8.2-11.4]. It was observed that the prevalence of LTBI increased with age (P value<0.001). However, it was also observed that duration of the working periods in a TB-related department was not associated with LTBI (P value=0.369). According to the multivariate analysis, an increased risk of LTBI was observed among participants aged ≥ 50 years [odds ratio (OR) 7.522, 95% CI 3.56-15.89] and nursing assistants (OR 2.912, 95% CI 1.283-6.608). The median cumulative risk of active TB with LTBI was estimated to be 4.31% [interquartile range (IQR) 3.43-5.29], and 4.41% (IQR 3.14-5.29) in HCWs with and without work experience in TB-related department, respectively. No significant difference was observed between two groups (P value=0.715).


The prevalence of LTBI among HCWs may not be higher than that of individuals in other group facilities. It may be necessary to revise the treatment recommendations, which are classified based on the risk for LTBI associated with departments and locations of work.

Figures and Tables

Fig. 1

Flow chart of the study.

Abbreviations: See Table 1.
Fig. 2

Distribution of people by group.

Fig. 3

IGRA positive rate by work period in each risk group.

Fig. 4

IGRA positive rate according to age group.

Fig. 5

IGRA positive rate by occupation.

Fig. 6

Age, total work period and work period in TB related department according to occupation.

Fig. 7

Cumulative risk of active tuberculosis in healthcare workers with latent tuberculosis infection by age group.

Fig. 8

Treatment status by risk group.

Table 1

Comparison of studies for latent tuberculosis infection prevalence among healthcare workers and other groups in South Korea


Abbreviations: LTBI, latent tuberculosis infection; IGRA, interferon gamma release assay; TST, tuberculin skin test.

Table 2

Demographical characteristics and IGRA results of participants


Abbreviations: IGRA, interferon gamma release assay; BMI, body mass index; DM, diabetes mellitus; CKD, chronic kidney disease.

Table 3

Occupational risk factors of latent tuberculosis IGRA by univariate analysis

Table 4

Risk factors of LTBI using IGRA among HCWs by multivariate analysis



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Young Hwa Choi

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