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Abstract
BACKGROUND: The proportion of active tuberculosis (TB) cases occurring in foreign-born persons has been increasing since 1993 in the United States (U.S.). Foreign born persons have accounted for the majority of TB cases in the U.S. every year since 2001. In 2010, 60% of TB cases occurred in foreign born persons. This study measured the annual incidence rate for TB disease among the immigrant population in Georgia and identified risk factors for latent TB infection.
METHODS: Georgia Department of Public Health (GDPH) data from 2004 to 2016 and National Health and Nutrition Examination Survey (NHANES) data from 1999-2000 and 2011-2012 were analysed. The Kaplan-Meier (KM) method was utilized to assess time to diagnosis rates and the median time. The effect of Bacille Calmette Guerin (BCG) vaccination on latent tuberculosis infection (LTBI) diagnosis was assessed. Kappa statistics and mixture method analysis were used to analyze the data for tuberculin skin tests (TST) results.
RESULTS: GDPH data included 5,315 TB cases from 2004 to 2016. There were 2,240 (42.2%) immigrants in the dataset. Immigrants were more likely to be diagnosed with TB disease compared to non-immigrants (IRR= 6.9; 95%CI: 6.8 - 6.9) in Georgia for the years 2004 to 2016. Median time in years for immigrants from date of entry in to the U.S. to diagnosis was 8.4 years (n=1,652; 95% CI: 7.7 - 9.2). There was no significant risk reduction for long term to be diagnosed with TB infection by receiving BCG vaccination (RR=2.78, 95%CI: 2.21 – 3.50). There was moderate overall agreement beyond that expected by chance alone between Quantiferon and TST test when used in diagnosis of LTBI (Kappa statistic= 0.447; 95%CI: 0.395 - 0.498).
CONCLUSION: The results showed that immigrant status/location of origin is associated with an increased risk of TB/LTBI in the U.S. population. This was confirmed from three different datasets for different time periods. Results revealed the urgency for better control methods to eradicate this global epidemic.
METHODS: Georgia Department of Public Health (GDPH) data from 2004 to 2016 and National Health and Nutrition Examination Survey (NHANES) data from 1999-2000 and 2011-2012 were analysed. The Kaplan-Meier (KM) method was utilized to assess time to diagnosis rates and the median time. The effect of Bacille Calmette Guerin (BCG) vaccination on latent tuberculosis infection (LTBI) diagnosis was assessed. Kappa statistics and mixture method analysis were used to analyze the data for tuberculin skin tests (TST) results.
RESULTS: GDPH data included 5,315 TB cases from 2004 to 2016. There were 2,240 (42.2%) immigrants in the dataset. Immigrants were more likely to be diagnosed with TB disease compared to non-immigrants (IRR= 6.9; 95%CI: 6.8 - 6.9) in Georgia for the years 2004 to 2016. Median time in years for immigrants from date of entry in to the U.S. to diagnosis was 8.4 years (n=1,652; 95% CI: 7.7 - 9.2). There was no significant risk reduction for long term to be diagnosed with TB infection by receiving BCG vaccination (RR=2.78, 95%CI: 2.21 – 3.50). There was moderate overall agreement beyond that expected by chance alone between Quantiferon and TST test when used in diagnosis of LTBI (Kappa statistic= 0.447; 95%CI: 0.395 - 0.498).
CONCLUSION: The results showed that immigrant status/location of origin is associated with an increased risk of TB/LTBI in the U.S. population. This was confirmed from three different datasets for different time periods. Results revealed the urgency for better control methods to eradicate this global epidemic.