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This Article Full Text (PDF) Free All Versions of this Article: chest.06-2601v1 131/6/1811    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Patel, S. Articles by Horsburgh, C. R. Search for Related Content PubMed PubMed Citation Articles by Patel, S. Articles by Horsburgh, C. R., Jr.

Risk of progression to active tuberculosis among foreign-born persons with latent tuberculosis.

¹Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, Boston MA ²Department of Haematology, University of Cambridge, Cambridge, UK ³Boston Public Health Commission, Boston MA ⁴Department of Epidemiology, Boston University School of Public Health, Boston MA ⁵Division of Tuberculosis Prevention and Control, Massachusetts Department of Public Health, Boston MA

rhorsbu{at}bu.edu

Abstract

BackgroundIncreased risk for tuberculosis (TB) disease has been identified in foreign-born persons in the United States, particularly during the first 5 years after arrival in the U.S. This could be explained by undetected TB disease at entry, increased prevalence of latent tuberculosis infection (LTBI), increased progression from LTBI to disease, or a combination of these factors.

MethodsWe performed a cluster analysis of tuberculosis cases in Boston and a case-control study of risk factors for tuberculosis with a non-clustered isolate among Boston residents with LTBI to determine if such persons have an increased risk of reactivation.

ResultsOf 321 cases of tuberculosis seen between 1996 and 2000, 133 isolates were clustered and 188 were not. In multivariate analysis, foreign birth was associated with an unclustered isolate (OR 2.2, 95% CI 1.2-3.8, p<0.01), while being a close contact of a TB case was negatively associated (OR 0.22, 95% CI 0.07-0.73, p=0.02). When 188 TB patients with unclustered isolates were compared to 188 age-matched controls with LTBI, there was no association between TB disease and foreign birth (OR 0.71, 95% CI 0.42-1.3) and, among foreign-born persons, there was no association between TB disease and being in the U.S. 5 years or less (OR 0.90, 95% CI 0.56-1.44).

ConclusionsWe conclude that the increased risk for tuberculosis among foreign-born persons in the U.S. may be attributable to increased prevalence of LTBI among foreign-born persons or increased prevalence of active disease at arrival, but not to an increased rate of reactivation among persons with LTBI.

Key Words: tuberculosis • latent tuberculosis infection • foreign birth • HIV infection • recent immigration