Risk Of Tuberculosis Infection Research Articles

Risk of Tuberculosis Infection and Disease for Health Care Workers: An Updated Meta-Analysis.

BackgroundTuberculosis (TB) remains a major challenge to global health. Healthcare workers (HCWs) appear to be at increased risk of TB compared with the general population, despite efforts to scale up infection control and reduce nosocomial TB transmission. This review aims to provide an updated estimate of the occupational risk of latent TB infection (LTBI) and active TB among HCWs compared with the general population.MethodsA systematic review was performed to identify studies published over the last 10 years reporting TB prevalence or incidence among HCWs and a control group. Pooled effect estimates were calculated to determine the risk of infection.ResultsTwenty-one studies met the inclusion criteria, providing data on 30961 HCWs across 16 countries. Prevalence of LTBI among HCWs was 37%, and mean incidence rate of active TB was 97/100000 per year. Compared with the general population, the risk of LTBI was greater for HCWs (odds ratio [OR], 2.27; 95% confidence interval [CI], 1.61–3.20), and the incidence rate ratio for active TB was 2.94 (95% CI, 1.67–5.19). Comparing tuberculin skin test and interferon-gamma release assay, OR for LTBI was found to be 1.72 and 5.61, respectively.ConclusionsThe overall risk of both LTBI and TB to HCWs continues to be significantly higher than that of the general population, consistent with previous findings. This study highlights the continuing need for improvements in infection control and HCW screening programs.

Racial inequality in the annual risk of Tuberculosis infection in the United States, 1910-1933.

Tuberculosis (TB) mortality rates in the USA fell rapidly from 1910 to 1933. However, during this period, racial disparities in TB mortality in the nation's expanding cities grew. Because of long delays between infection and disease, TB mortality is a poor indicator of short-term changes in transmission. We estimated the annual risk of TB infection (ARTI) in 11 large US cities to understand whether rising inequality in mortality reflected rising inequality in ARTI using city-level TB mortality data compiled by the US Department of Commerce from 1910 to 1933. We estimated ARTI for African-Americans and whites using pediatric extrapulmonary TB mortality data for African-Americans and whites in our panel of cities. We also estimated age-adjusted pulmonary TB mortality rates for these cities. We find that the ratio of ARTI for African-Americans vs. whites increased from 2·1 (95% CI = 1·7, 2·4) in 1910 to 4·2 (95% CI = 3·4, 5·2) in 1933. This change mirrored the increasing inequality in age-adjusted pulmonary TB mortality during this period. These findings may reflect the combined effects of migration, inequality in access to care, increasing population density, and racial residential segregation in northern cities during this period.

Association of vitamin D deficiency, season of the year, and latent tuberculosis infection among household contacts.

ObjectivesVitamin D (VD) enhances the immune response against Mycobacterium tuberculosis in vitro, and VD deficiency has been described in patients with active tuberculosis (TB). However, the role of hypovitaminosis D in the pathogenesis of early TB infection acquisition is unclear. We aimed to evaluate the association of VD deficiency, season of the year, and latent TB infection in household contacts (HHC), given that this is a potentially modifiable condition often related to nutritional deficiencies and lack of sun exposure.MethodsWe prospectively enrolled new pulmonary TB cases (n = 107) and their HHC (n = 144) over a 2-year period in Santiago, Chile. We compared plasma 25-hydroxycholecalciferol (25OHD) levels and examined the influence of season, ethnic background, living conditions, and country of origin.ResultsOver 77% of TB cases and 62.6% of HHC had VD deficiency (<20 ng/ml). Median 25OHD concentration was significantly lower in TB cases than in HHC (11.7 vs. 18.2 ng/ml, p<0.0001). Migrants HHC had lower 25OHD levels than non-migrants (14.6 vs. 19.0 ng/ml, p = 0.026), and a trend towards a higher burden of latent TB infection (52.9% vs. 35.2%, p = 0.066). Multivariate analysis found VD deficiency in HHC was strongly associated with being sampled in winter/spring (adOR 25.68, 95%CI 7.35–89.7), corresponding to the seasons with lowest solar radiation exposure. Spring enrollment–compared with other seasons–was the chief risk factor for latent TB infection in HHC (adOR 3.14, 95%CI 1.28–7.69).ConclusionsHypovitaminosis D was highly prevalent in TB cases and also in HHC. A marked seasonality was found for both VD levels and latent TB in HHC, with winter being the season with lowest VD levels and spring the season with the highest risk of latent TB infection.

Prevalence of Latent Mycobacterium Tuberculosis Infection (LTBI) in Saudi Arabia; Population based survey

BackgroundThe annual risk of tuberculosis infection (ARTI) data in Saudi Arabia has not been updated since 1993. ObjectivesTo estimate the prevalence of latent TB infection (LTBI) and ARTI in a population-based sample in Saudi Arabia using Tuberculin skin test (TST) and QuantiFERON TB Gold in tube (QFT-GIT) test. MethodsA population-based cross sectional study was conducted between July 2010 and March 2013. Participants were randomly selected from the population served by the primary healthcare centers of the Ministry of National Guard Health Affairs in Riyadh, Jeddah, Alhassa and Dammam, Saudi Arabia. ResultsA total of 1369 participants were included. The overall prevalence of LTBI was similar using TST and QFT-GIT (9.3% and 9.1% respectively, p=0.872) but stratified prevalence rates were variable in all sociodemographic groups except marital status. Additionally, the prevalence rates of LTBI using either test alone showed significant differences by several sociodemographic and behavioral characteristics. The overall ARTI was 0.36% using TST and 0.35% using QFT-GIT. ConclusionsWe are reporting much lower estimates for the prevalence of LTBI and the ARTI in a population-based sample in Saudi Arabia relative to the data that have been used for more than two decades.

Risk of tuberculosis among air passengers estimated by interferon gamma release assay: survey of contact investigations, Japan, 2012 to 2015.

Although the World Health Organization recommends contact investigations around air travel-associated sputum smear-positive tuberculosis (TB) patients, evidence suggests that the information thus obtained may have overestimated the risk of TB infection because it involved some contacts born in countries with high TB burden who were likely to have been infected with TB in the past, or because tuberculin skin tests were used, which are less specific than the interferon gamma release assay (IGRA) particularly in areas where Bacillus Calmette-Guérin (BCG) vaccination coverage is high. We conducted a questionnaire survey on air travel-associated TB contact investigations in local health offices of Japan from 2012 to 2015, focusing on IGRA positivity. Among 651 air travel-associated TB contacts, average positivity was 3.8% (95% confidence interval (CI): 2.5–5.6) with a statistically significant increasing trend with older age (p < 0.0094). Positivity among 0–34 year-old contacts was 1.0% (95% CI: 0.12–3.5%), suggesting their risk of TB infection is as small as among Japanese young adults with low risk of TB infection (positivity: 0.85–0.90%). Limiting the contact investigation to fewer passengers (within two seats surrounding the index case, rather than two rows) seems reasonable in the case of aircraft with many seats per row.

Quiz: Acute Kidney Injury in a Patient on a TNF-α Blocking Agent

Quiz: Acute Kidney Injury in a Patient on a TNF-α Blocking Agent

The prevalence of latent tuberculosis infection in rural Jiangsu, China

ObjectivesDiagnosis and interventional treatment of latent tuberculosis (TB) infection (LTBI) are important components in tuberculosis control. But systematic studies regarding the epidemic of LTBI are still rare in China. The objective of this study was to assess the prevalence and risk factors associated with LTBI based on the results of a domestic TB-specific gamma interferon (IFN-γ) release assay (TB-IGRA) in rural Jiangsu, China. Study designCross-sectional study of subjects registered in eight villages in Jiangsu, China. MethodsThis study was conducted in 2012 in eight villages. After recruitment, individuals with active TB or a history of TB were excluded. The TB-IGRA was performed for diagnosis of LTBI. Results2169 of 2185 subjects met the requirement and were analysed in this study. 524 (24.3%) had a positive result, and positive rate gradually increased with age (P for trend <0.001). Multivariate analyses showed that increasing age, male gender and a history of TB exposure were risk factors associated with LTBI. Bacillus Calmette-Guérin (BCG) vaccination did not reduce the risk of TB infection in participants (aged ≥20 years). ConclusionsThe findings of this study demonstrate that the prevalence of LTBI in China might be overestimated by tuberculin skin test compared with IFN-γ release assay (IGRA). The degree of TB exposure is related to Mycobacterium tubercuium (MTB) infection, and BCG vaccination offers little protection against MTB infection in adults. The early and effective detection and treatment of active TB patients, and screening and intervention for LTBI patients with a high risk of developing active TB could be cost-effective methods for TB control in China.

Diagnostic dilemma of pulmonary tuberculosis among adults with severe mental illness in Beijing, China

BackgroundAlthough the prevalence of tuberculosis has decreased significantly over the past decades, the certain populations with mental illness are at increased risk for tuberculosis infection and transmission. However, no studies have examined the performance of different laboratory examination methods among people with severe mental illness in China.MethodsIn this study, we firstly performed a retrospective study to evaluate the feasibility of three routine laboratory methods, including sputum microscopy, solid culture and GeneXpert, to diagnose tuberculosis patients with mental illness.ResultsDuring August 2010 and March 2013, a total of 251 TB patients based on clinical and radiographic criteria with severe mental illness were enrolled in this study. The majority of patients was homeless (97/251, 38.6%), and the other 62 (24.7%) and 92 (36.7%) were from urban and rural region, respectively. The most frequently diagnosed mental illness was schizophrenia, accounting for 84.1% (211/251) of patients available for analysis. In addition, the laboratory received 753 sputum samples collected from these 251 TB patients, of which 76.0% (572/753) of samples were classified as salivary sputum, which were unqualified for microscopy and culture. When the test results were analyzed by patients, the positive numbers of TB patients detected by sputum microscopy, solid culture and GeneXpert were 3 (1.2%), 5 (2.0%) and 5 (2.0%), respectively.ConclusionsIn conclusion, our findings reveal that the current laboratory examinations based on sputum samples seem not to be suitable for the diagnosis of active TB in the persons with severe mental illness. The products using a non-invasive specimen such as urine deserve further evaluation, which may generate benefit for the early diagnosis of TB in this special population.

Screening of health-care workers for latent tuberculosis infection in a Tertiary Care Hospital.

Health-care workers (HCWs) are at increased risk of acquiring tuberculosis (TB) than the general population. While national-level data on the burden of TB in general population is available from reliable sources, nationally representative data on latent tuberculosis infection (LTBI) burden in HCWs in the high burden countries is lacking. A prospective study was carried out to assess the risk of TB infection among HCWs who directly engage in medical duties. HCWs were recruited between January 2014 and December 2015. A structured questionnaire was used for risk assessment of TB infection among HCWs, including sociodemographic characteristics (e.g., age, gender, period of professional work, and employed position), knowledge of TB prevention and control, and history of professional work. A single-step tuberculin skin test (TST) using 5 international units (IU; 0.1 ml) of tuberculin (purified protein derivative from Mycobacterium bovis Bacillus Calmette-Guérin [BCG]). TB infection was determined using a TST induration ≥10 mm as a cutoff point for TST positivity. TST-positive participants were further subjected to detailed clinical evaluation and chest radiography to rule out active TB. The associations between TB infection and the sociodemographic characteristics, duration of possible exposure to TB while on medical duties, BCG vaccination, and knowledge about TB were estimated using Chi-square test. A two-sided P < 0.05 indicated statistical significance. A total of 206 eligible HCWs signed the informed consent and completed the questionnaires between January 2014 and December 2015. The age of the participants ranged from 18 to 71 years, with a mean age of 27.13 years. TST induration size (mean 6.37 mm) the TST results suggested that 36.8% (76/206) were infected with TB using a TST induration ≥10 mm as a cut-off point. All 76 TST-positive HCWs showed no evidence of active TB in clinical evaluation and chest radiography. However, during the study, two HCWs developed pulmonary TB (both TST baseline test negative). Statistical analysis suggested that age, duration of employment as a health-care professional, literacy status, and working in medical wards/OP/Intensive Care Unit were significantly associated with TB infection. Many studies propose serial tests of LTBI as effective occupational protection strategies. However, practically, it is not feasible because it has to be done at frequent intervals, but how frequently to be done is not clear. Another concern is even if found to have LTBI, there are no clear consensus guidelines about the treatment in high prevalence settings. The prevalence of LTBI is so high in countries like India that affected HCWs could not be exempted from working in high-risk areas. The depth of knowledge of TB prevention and control among HCWs should be improved by regular infection control training.

P1.06-016 Pulmonary Tuberculosis among Newly Diagnosed-Therapy Naive Advanced NSCLC in Persahabatan Hospital Jakarta Indonesia

The prevalence of lung cancer increased in the recent years in Indonesia, meanwhile pulmonary tuberculosis (TB) is still a major public health problem in this community. Malignancy such as lung cancer increase the risk of tuberculosis infection and reactivation, therefore evaluation of tuberculosis among lung cancer patients is needed. Newly diagnosed, therapy-naive advanced NSCLC subjects were enrolled from a referral respiratory hospital Persahabatan Hospital Jakarta Indonesia between 2014 and 2015. Active pulmonary tuberculosis were diagnosed by Xpert MTB/ RIF from induced sputum and LPA M. TB culture. Latent Tuberculosis Infection (LTBI) was determined by Quantiferon-TB Gold-In-Tube (QFT-GIT). Demographic and clinical characteristics were evaluated. Of 50 lung cancer subjects enrolled, 30 (60%) men with mean of age 55 years old (31- 74 years old). Eighty five percents were adenocarcinoma (42 subjects) and 15% squamous cell lung cancer. Most of them were at end stage (87% stage IV and 13%stage IIIB) with WHO performance status (PS) 1 to 3 (20 % PS 1, 70% PS 2 and 10% PS 3). Comorbidities among this group were COPD (3 subjects), diabetes mellitus (2 subjects), hypertension (4 subjects), congestive heart failure (1 subjects). Active tuberculosis were diagnosed in 2 % (1 subject). Based on Quantiferon results, 14 % were positive (7 subjects) and classified as latent tuberculosis infection (LTBI); 60% (30 subjects) classified as non-LTBI (negative Quantiferon result) but 12 (24%) indeterminate cases. The characteristics of LTBI patients were 67% men, two third were adenocarcinomas, 80% stage IV of lung cancer, 80% having WHO PS 2 and 3, 50% were underweight (body mass index (BMI) < 17.5. Active pulmonary tuberculosis and latent tuberculosis infection is common among newly diagnosed therapy naive advanced NSCLC in this population. Most of them are men, adenocarcinoma, PS 2-3, and half of them were underweight.

SPATIAL DISTRIBUTION OF PULMONARY TUBERCULOSIS IN URBAN AREAS: A CASE FROM BELÉM, BRAZIL

&lt;p&gt;The precise location of areas with high incidence of pulmonary tuberculosis (TB) is important to improve public health actions. Official data records of the addresses and neighborhoods where the infected people live allow the mapping of the disease on this spatial scale. However, great socioeconomic diversity often exists inside neighborhoods, wherein high- and low-income families reside. This situation hampers the location of those areas that require close attention. Objective: This study aimed to estimate the risk of pulmonary TB infections in census tracts in Belém City (Brazil) from data on neighborhoods. Methods: A partial least-squares regression model was constructed in the scale of neighborhoods based on the record of addresses of TB-infected people and socioeconomic data from official sources. The model was then slightly modified and used to estimate the risk of TB prevalence in urban census tracts. The results were mapped using a geographical information system. Results: The percentages of explained variance of the set of independent variables and dependent variable were 86.4% and 30.2%, respectively. These values indicated that the model was acceptable for its purpose. Conclusion: The model’s results were consistent with the spatial distribution of socioeconomic and environmental characteristics of Belém City.&lt;/p&gt;

Diabetes incidence and projections from prevalence surveys in Fiji.

BackgroundType 2 diabetes mellitus (T2DM) incidence is traditionally derived from cohort studies that are not always feasible, representative, or available. The present study estimates T2DM incidence in Fijian adults from T2DM prevalence estimates assembled from surveys of 25–64 year old adults conducted over 30 years (n = 14,288).MethodsT2DM prevalence by five-year age group from five population-based risk factor surveys conducted over 1980–2011 were variously adjusted for urban-rural residency, ethnicity, and sex to previous censuses (1976, 1986, 1996, 2009) to improve representativeness. Prevalence estimates were then used to calculate T2DM incidence based on birth cohorts from the age-period (Lexis) matrix following the Styblo technique, first used to estimate annual risk of tuberculosis infection (incidence) from sequential Mantoux population surveys. Poisson regression of year, age, sex, and ethnicity strata (n = 160) was used to develop projections of T2DM prevalence and incidence to 2020 based on various scenarios of population weight measured by body mass index (BMI) change.ResultsT2DM prevalence and annual incidence increased in Fiji over 1980–2011. Prevalence was higher in Indians and men than i-Taukei and women. Incidence was higher in Indians and women. From regression analyses, absolute reductions of 2.6 to 5.1% in T2DM prevalence (13–26% lower), and 0.5–0.9 per 1000 person-years in incidence (8–14% lower), could be expected in 2020 in adults if mean population weight could be reduced by 1–4 kg, compared to the current period trend in weight gain.ConclusionsThis is the first application of the Styblo technique to calculate T2DM incidence from population-based prevalence surveys over time. Reductions in population BMI are predicted to reduce T2DM incidence and prevalence in Fiji among adults aged 25–64 years.Electronic supplementary materialThe online version of this article (doi:10.1186/s12963-016-0114-0) contains supplementary material, which is available to authorized users.

Knowledge and perception about tuberculosis among public transport workers in Lima, Peru

To describe the level of knowledge and perception of tuberculosis among public transport workers attending Road Safety Education courses in Lima, Peru. An observational, cross-sectional, analytic study was conducted between July and August 2014 in public transport workers attending the courses of Road Safety education. In Lima, such courses are mandatory for workers in the public transport area. An anonymous and voluntary survey was applied to obtain the following variables: sociodemographic characteristics, history of tuberculosis, tuberculosis knowledge and attitudes towards the disease. The factors associated to the risk perception of Tuberculosis infection were analysed using Poisson regression. From 309 attendees, 216 surveys were analysed (69.9%). Of these, 88.4% were males, 3.2% had a history of tuberculosis. The most widely known symptom was cough with phlegm (44.4%), the most popular source of information was television (39.8%), and only 9.7% had any training about tuberculosis. A 41.2% of respondents believed that working in the public transport sector was an occupation with a high risk of tuberculosis infection. No significant association between risk perception of tuberculosis and sociodemographic characteristics was found. A considerable lack of knowledge about tuberculosis symptoms and a low perception of risk for tuberculosis exists among public transport workers in Lima. Education strategies directed to this population need to be implemented.

Perceived risk of tuberculosis infection among healthcare workers in Swaziland.

BackgroundThe incidence of tuberculosis (TB) in the Kingdom of Swaziland is extremely high. How healthcare workers (HCWs) in Swaziland perceive infection control (IC) measures for preventing TB transmission is unclear. This study aimed to determine perceived risk of TB infection in relation to IC measures among HCWs in three institutions of Swaziland.MethodsA cross-sectional questionnaire survey was conducted in 2014. Demographic data and IC measures were collected from main and allied HCWs.ResultsIn total, 186 HCWs (19 doctors, 99 nurses, and 68 allied HCWs) were enrolled. The multivariate logistic regression analyses revealed that nurses (OR = 39.87, 95% CI = 2.721–584.3) and other HCWs (OR =99.34, 95% CI = 7.469–1321) perceived a higher TB infection risk than did doctors. Moreover, HCWs working for <4 years at the TB department perceived a lower TB infection risk (OR = 0.099, 95% CI = 0.022–0.453). Availability of N95 respirator masks (OR = 0.055, 95% CI = 0.005–0.586) and a designated sputum collection area (OR = 0.142, 95% CI = 0.037–0.545) also carried lower TB infection risks.ConclusionThis study depicts the current status of IC measures for TB infection in a high prevalence country. The results suggest that HCWs perceived a greater TB infection risk at inadequate environmental IC measures.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2029-6) contains supplementary material, which is available to authorized users.

Nutritional Status and Tuberculosis Risk in Adult and Pediatric Household Contacts

BackgroundStudies show obesity decreases risk of tuberculosis (TB) disease. There is limited evidence on whether high body mass index also protects against TB infection; how very high body mass indices influence TB risk; or whether nutritional status predicts this risk in children. We assessed the impact of body mass index on incident TB infection and disease among adults and children.Methods and FindingsWe conducted a prospective cohort study among household contacts of pulmonary TB cases in Lima, Peru. We determined body mass index at baseline and followed participants for one year for TB infection and disease. We used Cox proportional regression analyses to estimate hazard ratios for incident TB infection and disease. We enrolled 14,044 household contacts, and among 6853 negative for TB infection and disease at baseline, 1787 (26.1%) became infected. A total of 406 contacts developed secondary TB disease during follow-up. Body mass index did not predict risk of TB infection but overweight household contacts had significantly decreased risk of TB disease (HR 0.48; 95% CI 0.37–0.64; p <0.001) compared to those with normal weight. Among adults, body mass index ≥ 35 kg/m2 continued to predict a lower risk of TB disease (HR 0.30; 95% CI 0.12–0.74; p 0.009). We found no association between high body mass index and TB infection or disease among children under 12 years of age.ConclusionsHigh body mass index protects adults against TB disease even at levels ≥ 35 kg/m2. This protective effect does not extend to TB infection and is not seen in children.

Vitamin D Deficiency and Latent Tuberculosis Infection Risk Among Tuberculosis Household Contacts

Vitamin D Deficiency and Latent Tuberculosis Infection Risk Among Tuberculosis Household Contacts

Predictors of low prevalence of latent tuberculosis infection among Egyptian health care workers at intensive care and bronchoscopy units.

Aim: Latent tuberculosis infections (LTBI) contain a significant reservoir for future epidemics. Screening of health care workers (HCWs) in a high-risk tuberculosis (TB) environment is an important strategy in TB control. The study aimed to assess the prevalence of LTBI among high risk Egyptian HCWs and to assess infection associated risk factors.Methods: Fifty-two HCWs who work at intensive care unit (ICU), bronchoscopy unit, and chest diseases department were tested for LTBI using both tuberculin skin test (TST) and Quantiferon TB Gold in-tube test (QFT). Risk factors for infection, knowledge of HCWs towards different aspects of TB infection and agreement between TST and QFT were also evaluated.Results: Prevalence of LTBI in this study was 13.5% by QFT and TST. It was 13.6% by TST alone and 10.3% by QFT alone. There was good concordance between both tests (Kappa=0.713). There was a statistically significant association between prevalence of LTBI and age of staff ≥30 yr (p=0.002), period of working experience (p=0.006) and working at the Bronchoscopy Unit (p=0.001). The total knowledge of HCWs towards different aspects of TB infection was generally good. Conclusion: Although the participants in the current study were among high risk HCWs, the prevalence of LTBI was low. Bacille Calmette-Guerin (BCG) vaccination, young age, short employment duration, good knowledge and a good infection control were the predictors of low risk of contracting TB at our hospitals. The risk of TB infection in resource-limited countries can be reduced with simple continuous educational and administrative infection control programmes.

A Data-Driven Evaluation of the Stop TB Global Partnership Strategy of Targeting Key Populations at Greater Risk for Tuberculosis.

ObjectiveIdentifying those infected with tuberculosis (TB) is an important component of any strategy for reducing TB transmission and population prevalence. The Stop TB Global Partnership recently launched an initiative with a focus on key populations at greater risk for TB infection or poor clinical outcomes, due to housing and working conditions, incarceration, low household income, malnutrition, co-morbidities, exposure to tobacco and silica dust, or barriers to accessing medical care. To achieve operational targets, the global health community needs effective, low cost, and large-scale strategies for identifying key populations. Using South Africa as a test case, we assess the feasibility and effectiveness of targeting active case finding to populations with TB risk factors identified from regularly collected sources of data. Our approach is applicable to all countries with TB testing and census data. It allows countries to tailor their outreach activities to the particular risk factors of greatest significance in their national context.MethodsWe use a national database of TB test results to estimate municipality-level TB infection prevalence, and link it to Census data to measure population risk factors for TB including rates of urban households, informal settlements, household income, unemployment, and mobile phone ownership. To examine the relationship between TB prevalence and risk factors, we perform linear regression analysis and plot the set of population characteristics against TB prevalence and TB testing rate by municipality. We overlay lines of best fit and smoothed curves of best fit from locally weighted scatter plot smoothing.FindingsHigher TB prevalence is statistically significantly associated with more urban municipalities (slope coefficient β1 = 0.129, p < 0.0001, R2 = 0.133), lower mobile phone access (β1 = -0.053, p < 0.001, R2 = 0.089), lower unemployment rates (β1 = -0.020, p = 0.003, R2 = 0.048), and a lower proportion of low-income households (β1 = -0.048, p < 0.0001, R2 = 0.084). Municipalities with more low-income households also have marginally higher TB testing rates, however, this association is not statistically significant (β1 = -0.025, p = 0.676, R2 = 0.001). There is no relationship between TB prevalence and the proportion of informal settlement households (β1 = 0.021, p = 0.136, R2 = 0.014).ConclusionsThese analyses reveal that the set of characteristics identified by the Global Plan as defining key populations do not adequately predict populations with high TB burden. For example, we find that higher TB prevalence is correlated with more urbanized municipalities but not with informal settlements. We highlight several factors that are counter-intuitively those most associated with high TB burdens and which should therefore play a large role in any effective targeting strategy. Targeting active case finding to key populations at higher risk of infection or poor clinical outcomes may prove more cost effective than broad efforts. However, these results should increase caution in current targeting of active case finding interventions.

Identification of populations at high risk of tuberculosis infection in rural China: a population-based, multicentre, prospective study

BackgroundAcquisition and persistence of tuberculosis infection are important epidemiological measurements for evaluation of tuberculosis transmission in a community. However, prospective population data on the incidence of tuberculosis infection have been sparely reported in the global literature. MethodsWe conducted a population-based, multicentre, prospective study to investigate the annual risk of tuberculosis infection and its persistence in rural populations in China from July 2013 to June 2015, using yearly tests with tuberculin skin test (TST) and an interferon-γ release assay (IGRA). Findings15 907 eligible participants from four rural sites (Xiangtan, Hunan province; Zhongmu, Henan Province; Longxi, Gansu Province; Danyang, Jiangsu Province) who were identified as TST-negative (<10 mm) or IGRA-negative in a baseline survey were included in the first year's follow-up examination. 13 580 (85·4%) with completed questionnaires and tests results were included in this study. Annual seroconversion rates among the study sites ranged from 2·1% to 4·9% (average 3·1%) when assessed by IGRA and between 6·0% and 31·1% (14·5%) when assessed by TST. Infection persistence was successfully followed-up in 330 participants who underwent IGRA conversion during the second year of follow-up, 49·7% (164) were found to be consistently IGRA-positive. Both conversion and persistence of IGRA-positivity were increased significantly in association with increasing age (p<0·001 for trend). History of close contact with patients with active tuberculosis and smoking were positively associated with risk of IGRA conversion (adjusted OR 1·54, 95% CI 1·04–2·27, and 1·53, 1·13–2·05, respectively). InterpretationConsistent with published cross-sectional data, the prospective results provide stronger evidence that close contacts, older people, and smokers are high-risk populations for tuberculosis infection in rural China. These groups should be prioritised for tuberculosis control in China and areas with a similar epidemiological profile. The unexpectedly high annual infection rates based on TST could not be explained by local epidemiology and were probably overestimated because of the boosting effect of serial TST testing, BCG vaccination, or environmental mycobacteria. FundingNational Science and Technology Major Project of China (2013ZX10003004-002, 2014ZX10003001-001), and Program for Changjiang Scholars and Innovative Research Team in University of China (IRT13007).

Prognostic effect of tuberculosis on patients with occupational lung diseases: A 13-year observational study in a nationwide cohort.

Occupational lung diseases are well recognized risk factors for tuberculosis (TB). However, little research investigated the effect of TB on the clinical course and outcome of occupational lung diseases.We conducted a 13-year observational study of a nationwide cohort to evaluate the risk and prognosis of TB among patients with occupational lung diseases in Taiwan.By using the Taiwan National Health Insurance database, occupational lung diseases cohort was identified according to diagnosis codes from 1998 to 2008 and prospectively monitored until the end of 2010, loss to follow-up, or death. Newly diagnosed TB, comorbidities, and demographic characteristics were evaluated as prognostic variables in the survival analysis of patients with occupational lung diseases using Cox proportional hazard regression models.A total of 12,787 study participants were enrolled with an average of 9.69 years of follow-up. Among them, 586 (4.58%) had newly diagnosed TB and 3180 (24.87%) died during follow-up. The incidence of TB was 473 per 100,000 person-years, and the risk of TB infection significantly increased over time. The independent risk factors for mortality included male gender (hazard ratio [HR]: 2.23, 95% confidence interval [CI]: 1.91–2.60), age (HR: 1.05, 95% CI: 1.05–1.06), TB (HR: 1.17, 95% CI: 1.01–1.37), congestive heart failure (HR: 1.44, 95% CI: 1.17–1.79), cerebrovascular disease (HR: 1.34, 95% CI: 1.15–1.57), chronic obstructive pulmonary disease (HR: 1.44, 95% CI: 1.33–1.56), and asthma (HR: 1.27, 95% CI: 1.15–1.40). In addition, patients with TB infections had worse outcomes in the survival analysis than those without TB (log-rank test P = 0.02).Despite the low prevalence of occupational lung diseases in Taiwan, patients with those diseases had a higher TB incidence than the general population did (473 vs 55 per 100,000 person-years). Furthermore, even with effective antimicrobial chemotherapy, TB infection was a prognostic factor leading to poor outcomes in the patients with occupational lung diseases. We recommend intensive medical surveillance of TB in these high-risk patients for better control of TB and improvement of occupational health in Taiwan.