title: Risk of tuberculin conversion among healthcare workers and the adoption of preventive measures.
abstract: BACKGROUND
  In industrialised countries, occupational tuberculosis among healthcare workers (HCWs) is re-emerging as an important public health issue. To prevent and control tuberculosis transmission, several institutions have issued and implemented recommendations and practice guidelines.
  
  
  OBJECTIVE
  To estimate the annual rate of tuberculosis infection (ARTI; per 100 person-years) among HCWs in Turin, the capital of the Piedmont region of Italy, to identify factors associated with variations in the ARTI and to evaluate the efficacy of the regional guidelines to prevent and control tuberculosis.
  
  
  METHODS
  The study was conducted between 1997 and 2004 on a cohort of HCWs. The tuberculosis infection was diagnosed through tuberculin skin testing (TST) conversion and defined as an induration increase of at least 10 mm from a previous negative TST. The ARTI and the hazard ratio for each at-risk subgroup, categorised according to working activities and settings, was estimated using exponential survival models. The efficacy of the regional guidelines was estimated by stratifying the analysis according to the moment of the implementation of the guidelines (before/after).
  
  
  RESULTS
  The 2182 study participants were drawn from the dynamic cohort. The overall adjusted ARTI was 1.6 (95% CI: 1.3 to 1.9)/100 person-years. Different workplaces (eg, administrative and infectious diseases inpatient services) and occupations (eg, clerical and medical workers) were associated with significantly different ARTIs, ranging between 0.62 and 2.62 and between 0.61 and 1.71, respectively, whereas the TST conversion risk differed by about 16-68% and 30-60%, respectively. The implementation of the guidelines coincided with overall ARTI reductions of 1.3/100 person-years, and concurrently the variations between ARTIs of different occupations and workplaces disappeared.
  
  
  CONCLUSIONS
  The occupational risk categories for targeting the surveillance and prevention of tuberculosis transmission among HCWs were identified, and the introduction of preventive measures was observed to be effective in decreasing the overall risk of tuberculosis infection among HCWs.
authors.affiliation: Cancer Epidemiology Unit, CPO Piemonte, CeRMS, University of Turin, Turin, Italy. iacopo.baussano@cpo.it
authors.forename: Iacopo
authors.initials: I
authors.lastname: Baussano
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bugiani
authors.forename: Aurelia
authors.initials: A
authors.lastname: Carosso
authors.forename: Dario
authors.initials: D
authors.lastname: Mairano
authors.forename: Anna
authors.initials: A
authors.lastname: Pia Barocelli
authors.forename: Marina
authors.initials: M
authors.lastname: Tagna
authors.forename: Vincenza
authors.initials: V
authors.lastname: Cascio
authors.forename: Pavilio
authors.initials: P
authors.lastname: Piccioni
authors.forename: Walter
authors.initials: W
authors.lastname: Arossa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D005260:Female; D006282:Health Personnel / Q000706:statistics & numerical data*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D017410:Practice Guidelines as Topic; D012306:Risk; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control