Open Access Highly Accessed Research article

Latent tuberculosis infection and associated risk factors among undergraduate healthcare students in Italy: a cross-sectional study

Paolo Durando1*, Giovanni Sotgiu2, Fabio Spigno3, Mauro Piccinini4, Giovanni Mazzarello5, Claudio Viscoli6, Francesco Copello7, Alessandro Poli7, Filippo Ansaldi1 and Giancarlo Icardi8

Author Affiliations

1 Department of Health Sciences, Associate Professor of Hygiene, Preventive Medicine and Public Health, Hygiene Unit, IRCCS AOU San Martino-IST teaching Hospital, University of Genoa, Via Antonio Pastore 1, 16132, Genoa, Italy

2 Department of Biomedical Sciences, Associate Professor of Medical Statistics, Research, Medical Education and Professional Development Unit, AOU Sassari, University of Sassari, Via Padre Manzella 4, 07100, Sassari, Italy

3 Department of Health Sciences, Associate Professor of Occupational Health, Chief of the Occupational Health Unit, IRCCS AOU San Martino-IST teaching Hospital, University of Genoa, Largo Rosanna Benzi 10, 16132, Genoa, Italy

4 Prevention and Protection Service of the University of Genoa, Via Balbi 5, 16126, Genoa, Italy

5 Department of Health Sciences, Infectious Diseases Unit, IRCCS AOU San Martino-IST teaching Hospital, University of Genoa, Largo Rosanna Benzi 10, 16132, Genoa, Italy

6 Department of Health Sciences, Full Professor of Infectious Diseases, Chief of the Infectious Diseases Unit, IRCCS AOU San Martino-IST teaching Hospital, University of Genoa, Largo Rosanna Benzi 10, 16132, Genoa, Italy

7 Occupational and Preventive Medicine Unit, IRCCS AOU San Martino-IST teaching Hospital, Largo Rosanna Benzi 10, 16132, Genoa, Italy

8 Department of Health Sciences, Full Professor of Hygiene, Preventive Medicine and Public Health, Chief of the Hygiene Unit, IRCCS AOU San Martino-IST teaching Hospital, University of Genoa, Via Antonio Pastore 1, 16132, Genoa, Italy

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BMC Infectious Diseases 2013, 13:443  doi:10.1186/1471-2334-13-443

Published: 23 September 2013

Abstract

Background

The screening of both healthcare workers and students attending teaching hospitals for latent tuberculosis infection (LTBI) is recommended in hospitals of many countries with a low-incidence of TB, including Italy, as a fundamental tool of tuberculosis (TB) control programs. The aim of the study was to estimate the prevalence of LTBI and evaluate the main risk-factors associated with this condition in a cohort of healthcare Italian students.

Methods

In a cross-sectional study, performed between January and May 2012, 881 undergraduate students attending the Medical, Nursing, Pediatric Nursing and Midwifery Schools of the University of Genoa, trained at the IRCCS San Martino-IST Teaching Hospital of Genoa, were actively called to undergo the Tuberculin Skin Test (TST). All the TST positive cases were also tested with an Interferon-Gamma Release Assay (IGRA) to confirm the diagnosis of LTBI. A standardized questionnaire was collected for risk-assessment analysis.

Results

Seven hundred and thirty-three (83.2%) subjects underwent TST testing. The prevalence of TST positives was 1.4%, and in 4 (0.5%) out of 10 TST positive cases LTBI diagnosis was confirmed by IGRA. No difference in the prevalence of subjects who tested positive to TST emerged between pre-clinical (n = 138) and clinical (n = 595) students. No statistically significant association between TST positivity and age, gender, and BCG vaccination was observed. The main independent variable associated with TST positivity was to be born in a country with a high TB incidence (i.e., ≥20 cases per 100,000 population) (adjusted OR 102.80, 95% CI 18.09-584.04, p < 0.001).

Conclusions

The prevalence of LTBI among healthcare students resulted very low. The only significant association between TST positivity and potential risk factors was to be born in high TB incidence areas. In countries with a low incidence of TB, the screening programs of healthcare students before clinical training can be useful for the early identification and treatment of the sporadic cases of LTBI.

Keywords:
Tuberculosis; Latent tuberculosis infection; Tuberculin skin test; Interferon-gamma release assay; Healthcare students; Risk-factors