The problem with defining foreign birth as a risk factor in tuberculosis epidemiology studies

Tuberculosis and/or HIV Infection and Associated Socio-Behavioural Factors in Immigrants, in Portugal: A Cross-Sectional, Community-Based Descriptive Study

Introduction

Portugal is one of the countries in Western Europe with the highest prevalence of tuberculosis (TB) and human immunodeficiency virus (HIV). The prevalence among migrants is estimated to be higher than among non-migrants, which suggests a greater vulnerability of this population.

Aim

To describe the distribution of TB, HIV and HIV-TB co-infection and socio-behavioural factors associated with immigrants that lived in the metropolitan area of Lisbon and used the services of a Non-Governmental Organization (NGO).

Methods

Quantitative, cross-sectional and descriptive pilot study. An anonymous and structured questionnaire developed specifically for the study was applied by NGO employees duly trained for this purpose to a purposeful sample of 100 immigrants attending health services in an NGO in the metropolitan area of Lisbon, Portugal.

Results

The prevalence of HIV-TB extrapulmonary coinfection and HIV infection was 1% (n = 1) and 17% (n = 17), respectively. Only 1 immigrant had 4 out of the 5 symptoms suggestive of TB. No cases of pulmonary TB were identified, although 3 of the immigrants reported having been treated for pulmonary TB in the past. The participants were young, mainly female and some were male-to-female transsexuals. Most were from the community of Portuguese-speaking countries, especially from Brazil, and almost half of them had not regularized their immigration status. Additionally, almost one-fifth of immigrants were unemployed (17%), and one-sixth performed sex work (14%). Most of the participants (71%) sometimes used or never used a condom during sexual intercourse. Additionally, 40% revealed using illicit drugs and 1% said that they had shared injection material in the last 12 months.

Discussion

Being non-employed, with a low income and a lower level of education, consumption of illicit drugs and regular tobacco consumption were common characteristics in the immigrants studied, which points out social and economic disadvantages that could influence the risk of acquiring HIV and TB. Policies on latent TB infection and TB diagnosis are urgently needed, mainly aimed at vulnerable groups and culturally diverse populations.

US Tuberculosis Rates among Persons Born Outside the United States Compared with Rates in Their Countries of Birth, 2012-20161

The US Centers for Disease Control and Prevention recommends screening populations at increased risk for tuberculosis (TB), including persons born in countries with high TB rates. This approach assumes that TB risk for expatriates living in the United States is representative of TB risk in their countries of birth. We compared US TB rates by country of birth with corresponding country rates by calculating incidence rate ratios (IRRs) (World Health Organization rate/US rate). The median IRR was 5.4. The median IRR was 0.5 for persons who received a TB diagnosis <1 year after US entry, 4.9 at 1 to <10 years, and 10.0 at >10 years. Our analysis suggests that World Health Organization TB rates are not representative of TB risk among expatriates in the United States and that TB testing prioritization in the United States might better be based on US rates by country of birth and years in the United States.