title: Risk factors for positive tuberculin skin tests among migrant and resident children in Lausanne, Switzerland.
abstract: METHODS
  Ambulatory paediatric clinic in Lausanne, Switzerland, a country with a significant proportion of tuberculosis (TB) among immigrants.
  
  
  OBJECTIVE
  To assess the factors associated with positive tuberculin skin tests (TST) among children examined during a health check-up or during TB contact tracing, notably the influence of BCG vaccination (Bacille Calmette Guérin) and history of TB contact.
  
  
  METHODS
  A descriptive study of children who had a TST (2 Units RT23) between November 2002 and April 2004. Age, sex, history of TB contact, BCG vaccination status, country of origin and birth outside Switzerland were recorded.
  
  
  RESULTS
  Of 234 children, 176 (75%) had a reaction equal to zero and 31 (13%) tested positive (>10 mm). In a linear regression model, the size of the TST varied significantly according to the history of TB contact, age, TB incidence in the country of origin and BCG vaccination status but not according to sex or birth in or outside Switzerland. In a logistic regression model including all the recorded variables, age (Odds Ratio = 1.21, 95% CI 1.08; 1.35), a history of TB contact (OR = 7.31, 95% CI 2.23; 24) and the incidence of TB in the country of origin (OR = 1.01, 95% CI 1.00; 1.02) were significantly associated with a positive TST but sex (OR = 1.18, 95% CI 0.50; 2.78) and BCG vaccination status (OR = 2.97, 95% CI 0.91; 9.72) were not associated.
  
  
  CONCLUSIONS
  TB incidence in the country of origin, BCG vaccination and age influence the TSTreaction (size or proportion of TST > or = 10 mm). However the most obvious risk factor for a positive TST is a history of contact with TB.
authors.affiliation: University Children's Hospital, Ch. de Montétan 16, CH-1000 Lausanne 7, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Collet
authors.forename: J D
authors.initials: JD
authors.lastname: Krahenbuhl
authors.forename: Mario
authors.initials: M
authors.lastname: Gehri
authors.forename: A
authors.initials: A
authors.lastname: Bissery
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Zellweger
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D001500:BCG Vaccine; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012044:Regression Analysis; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013557:Switzerland / Q000453:epidemiology; D014171:Transients and Migrants / Q000706:statistics & numerical data*; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000208:ethnology*
chemical_list: D001500:BCG Vaccine