title: Risk factors for Mycobacterium tuberculosis infection in 2-4 year olds in a rural HIV-prevalent setting.
abstract: BACKGROUND
  Mycobacterium tuberculosis infection in children acts as a sentinel for infectious tuberculosis.
  
  
  OBJECTIVE
  To assess risk factors associated with tuberculous infection in pre-school children.
  
  
  METHODS
  We conducted a population-wide tuberculin skin test (TST) survey from January to December 2012 in Malawi. All children aged 2-4 years residing in a demographic surveillance area were eligible. Detailed demographic data, including adult human immunodeficiency virus (HIV) status, and clinical and sociodemographic data on all diagnosed tuberculosis (TB) patients were available.
  
  
  RESULTS
  The prevalence of M. tuberculosis infection was 1.1% using a TST induration cut-off of 15 mm (estimated annual risk of infection of 0.3%). The main identifiable risk factors were maternal HIV infection at birth (adjusted OR [aOR] 3.6, 95%CI 1.1-12.2), having three or more adult members in the household over a lifetime (aOR 2.4, 95%CI 1.2-4.8) and living in close proximity to a known case of infectious TB (aOR 1.6, 95%CI 1.1-2.4), modelled as a linear variable across categories (>200 m, 100-200 m, <100 m, within household). Less than 20% of the infected children lived within 200 m of a known diagnosed case.
  
  
  CONCLUSIONS
  Household and community risk factors identified do not explain the majority of M. tuberculosis infections in children in our setting.
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London WD1E 7HT, UK; Karonga Prevention Study, Chilumba, Malawi. palwasha.khan@lshtm.ac.uk.
authors.forename: P Y
authors.initials: PY
authors.lastname: Khan
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Glynn
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: K L
authors.initials: KL
authors.lastname: Fielding
authors.affiliation: Karonga Prevention Study, Chilumba, Malawi.
authors.forename: T
authors.initials: T
authors.lastname: Mzembe
authors.affiliation: Karonga Prevention Study, Chilumba, Malawi.
authors.forename: D
authors.initials: D
authors.lastname: Mulawa
authors.affiliation: Karonga Prevention Study, Chilumba, Malawi.
authors.forename: R
authors.initials: R
authors.lastname: Chiumya
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: P E M
authors.initials: PE
authors.lastname: Fine
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Karonga Prevention Study, Chilumba, Malawi.
authors.forename: O
authors.initials: O
authors.lastname: Koole
authors.affiliation: National and Supranational Mycobacterium Reference Laboratory, Forschungszentrum Borstel, Borstel, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kranzer
authors.affiliation: Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Karonga Prevention Study, Chilumba, Malawi.
authors.forename: A C
authors.initials: AC
authors.lastname: Crampin
mesh_terms: D002675:Child, Preschool; D005191:Family Characteristics; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008295:Malawi / Q000453:epidemiology; D008297:Male; D015999:Multivariate Analysis; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012424:Rural Population; D012959:Socioeconomic Factors; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*