title: High prevalence of latent tuberculosis infection among injection drug users in Tijuana, Mexico.
abstract: BACKGROUND
  We studied prevalence and correlates of latent tuberculosis infection (LTBI) among injection drug users (IDUs) in Tijuana, Mexico, where tuberculosis (TB) is endemic.
  
  
  METHODS
  IDUs aged > or =18 years were recruited via respondent-driven sampling (RDS) and underwent standardized interviews, human immunodeficiency virus (HIV) antibody testing and LTBI screening using Quanti-FERON((R))-TB Gold In-Tube, a whole-blood interferon-gamma release assay (IGRA). LTBI prevalence was estimated and correlates were identified using RDS-weighted logistic regression.
  
  
  RESULTS
  Of 1020 IDUs, 681 (67%) tested IGRA-positive and 44 (4%) tested HIV-positive. Mean age was 37 years, 88% were male and 98% were Mexican-born. IGRA positivity was associated with recruitment nearest the US border (aOR 1.64, 95%CI 1.09-2.48), increasing years of injection (aOR 1.20/5 years, 95%CI 1.07-1.34), and years lived in Tijuana (aOR 1.10/5 years, 95%CI 1.03-1.18). Speaking some English (aOR 0.38, 95%CI 0.25-0.57) and injecting most often at home in the past 6 months (aOR 0.68, 95%CI 0.45-0.99) were inversely associated with IGRA positivity.
  
  
  CONCLUSIONS
  Increased LTBI prevalence among IDUs in Tijuana appears to be associated with greater drug involvement. Given the high risk for HIV infection among Tijuana's IDUs, interventions are urgently needed to prevent HIV infection and treat LTBI among IDUs before these epidemics collide.
authors.affiliation: University of California San Diego, School of Medicine, San Diego, California, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Garfein
authors.forename: R
authors.initials: R
authors.lastname: Lozada
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Laniado-Laborin
authors.forename: T C
authors.initials: TC
authors.lastname: Rodwell
authors.forename: R
authors.initials: R
authors.lastname: Deiss
authors.forename: J
authors.initials: J
authors.lastname: Alvelais
authors.forename: A
authors.initials: A
authors.lastname: Catanzaro
authors.forename: P G
authors.initials: PG
authors.lastname: Chiles
authors.forename: S A
authors.initials: SA
authors.lastname: Strathdee
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D014376:Tuberculosis / Q000097:blood / Q000150:complications / Q000453:epidemiology*
chemical_list: D015415:Biomarkers; D007371:Interferon-gamma