July 2009

Document Type


Degree Name



Dept. of Public Health and Preventive Medicine


Oregon Health & Science University


The goal of the project was to evaluate Multnomah County Health Department’s Tuberculosis (TB) Control and Prevention Program’s homeless screening outreach activities, focusing on a comparison of foreign-born and United States (US)-born clients in initiation of treatment for latent tuberculosis infection (LTBI). Although TB incidence in Oregon was 2.2 cases per 100,000 in 2007, foreign-born and homeless persons are at higher risk than the general population. While research about foreign-born persons as well as homeless persons with LTBI are common, studies of the overlapping at-risk population of the foreign-born homeless are rare. The study employed a retrospective cohort design using data collected from 2002 through 2008 during screening for TB and a follow up evaluation at Multnomah County Health Department’s TB Clinic. We hypothesized that the foreign-born homeless clients would start treatment for LTBI at a higher proportion than US-born homeless clients. Descriptive statistics included characteristics of the 916 clients for whom treatment was recommended, a comparison of characteristics between foreign-born and US-born clients and separately between clients who began treatment and clients who did not begin. We stratified the foreign-born and treatment initiation association by potential confounders and effect modifiers which included age, sex, race/ethnicity, shelter, and substance abuse. Chi-square tests were performed to compare the primary association of interest between foreign-born versus US-born and treatment initiation, as well as the association between potential confounders and the exposure and the outcome. Interaction by age was statistically assessed using an interaction term in logistic regression. Finally, multiple logistic regression was employed to build a model that would account for confounders. After adjusting for race/ethnicity, we found that foreign-born clients had significantly higher odds of initiating treatment than US-born clients in the sheltered homeless population for the 30-49 [OR 2.13, 95% CI 1.29, 3.52] and 50 and above [OR 6.03, 95% CI: 2.69, 13.52] age groups, but we did not find evidence of a difference in the 18-29 age group [OR 1.29, 95% CI 0.60, 2.79]. There are multiple approaches that can be taken to improve treatment initiation, including but not limited to increased focus on encouraging treatment initiation in all clients given that the percentage starting treatment was low overall. Older foreign-born clients could be encouraged to begin treatment more strongly since they tend to start at higher percentages than US-born clients and may need less encouragement to begin treatment, which would increase the percentage of clients starting treatment even more. Another strategy could be to focus on the US-born clients in all age groups since the percentage starting treatment is low across all age groups.




School of Medicine



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.