Introduction: The incidence of active tuberculosis rises with age. The present study examined whether this results in an increased prevalence of latent tuberculosis infection (LTBI) in healthcare workers (HCW) in geriatric care, using other HCW as comparison group.
Methods: Data collection was performed by occupational physicians in three hospitals. The LTBI was diagnosed using the QuantiFERON-TB Gold in Tube (QFT-IT), an Interferon-gamma Release Assay (IGRA). The odds ratios adjusted for age, gender and migration were calculated.
Results: A total of 454 HCW were examined, 58 (12.8 %) of whom worked at geriatric care units. The prevalence of LTBI was 19.0 % in geriatric care and 10.5 % in other HCW. The age, gender, and migration adjusted odds ratio for a positive QFT-IT was 2.4 (5 % CI 1.1 - 5.2) in health care workers working at geriatric care units. A strong positive association between age and LTBI was observed. The prevalence of LTBI increased from 4.6 % in HCW younger than 30 years to 69.2 % in HCW older than 60 years (p < 0.0005).
Discussion: The data suggest an elevated prevalence of LTBI and therefore an elevated infection risk for HCW engaged in geriatric care. The increase of the LTBI prevalence with age might be explained by longer exposure time at work but also by a cohort effect.