Smoking and Tuberculosis among the Elderly in Hong Kong

Construction and Validation of a Nomogram to Identify the Risk of Cavitation in Pulmonary Tuberculosis

Background

The present study aimed to construct and validate a nomogram based on clinical metrics to identify CPTB.

Patients and Methods

The present study retrospectively recruited pulmonary tuberculosis (PTB) patients admitted to Jiashan County First People's Hospital in China from November 2018 to September 2023. PTB patients were classified into the CPTB group and the non-CPTB group based on chest computed tomography findings, and were randomly allocated to the training set (70%) and the validation cohort (30%). The training set and validation set were used to establish and validate nomogram, respectively. Multivariate logistic regression analysis (MLSA) was used to identify the independent risk factors for CPTB in patients with PTB. Statistically significant variables in the MLSA were then used to construct a nomogram predicting CPTB in patients with PTB. The receiver operating characteristic (ROC) curve, calibration curve analysis (CCA), and decision curve analysis (DCA) were used for the evaluation of the nomogram.

Results

A total of 293 PTB patients, including 208 in the training set (85 CPTB) and 85 in the validation set (33 CPTB\), were included in this study. Stepwise MLSA showed that sputum smear (≥2+), smoking(yes), glycosylated hemoglobin A1c(HbA1c), hemoglobin (HB), and systemic inflammatory response index (SIRI) were independent risk factors for the development of cavitation in patients with PTB. The nomogram identifying the high-risk CPTB patients was successfully established and showed a strong predictive capacity, with area under the curves (AUCs) of 0.875 (95% CI:0.806-0.909) and 0.848 (95% CI:0.751-0.946) in the training set and validation set respectively. In addition, the CCA and DCA corroborated the nomogram's high level of accuracy and clinical applicability within both the training and validation sets.

Conclusion

The constructed nomogram, consisting of sputum smear positivity, smoking, HbA1C, HB, and SIRI, serves as a practical and effective tool for early identification and personalized management of CPTB.

Cigarette Smoking as a Risk Factor for Tuberculosis in Adults: Epidemiology and Aspects of Disease Pathogenesis

It has been noted by the World Health Organisation that cases of tuberculosis in 2022 globally numbered 10.6 million, resulting in 1.3 million deaths, such that TB is one of the infectious diseases causing the greatest morbidity and mortality worldwide. Since as early as 1918, there has been an ongoing debate as to the relationship between cigarette smoking and TB. However, numerous epidemiological studies, as well as meta-analyses, have indicated that both active and passive smoking are independent risk factors for TB infection, development of reactivation TB, progression of primary TB, increased severity of cavitary disease, and death from TB, among several other considerations. With this considerable body of evidence confirming the association between smoking and TB, it is not surprising that TB control programmes represent a key potential preventative intervention. In addition to coverage of the epidemiology of TB and its compelling causative link with smoking, the current review is also focused on evidence derived from clinical- and laboratory-based studies of disease pathogenesis, most prominently the protective anti-mycobacterial mechanisms of the alveolar macrophage, the primary intracellular refuge of M. tuberculosis. This section of the review is followed by an overview of the major strategies utilised by the pathogen to subvert these antimicrobial mechanisms in the airway, which are intensified by the suppressive effects of smoke inhalation on alveolar macrophage function. Finally, consideration is given to a somewhat under-explored, pro-infective activity of cigarette smoking, namely augmentation of antibiotic resistance due to direct effects of smoke per se on the pathogen. These include biofilm formation, induction of cellular efflux pumps, which eliminate both smoke-derived toxicants and antibiotics, as well as gene modifications that underpin antibiotic resistance.

[Tobacco and tuberculosis: the nature of the links and the consequences of this association]

Tuberculosis and smoking are responsible for significant mortality worldwide. Smoking is spreading in emerging countries, and its prevalence is high in developed countries among socially disadvantaged populations; it could be the source of a resurgence of tuberculosis in future years. The aim of this review is to clarify the consequences of the association between smoking and tuberculosis, and the benefits of smoking cessation for smokers with tuberculosis.

Predictors of tuberculosis disease in smokers: a case-control study in northeastern Malaysia

Objective

Tuberculosis (TB) is a leading infectious disease. However, many TB cases remain undetected and only present symptoms at a late stage of the infection. Therefore, targeted TB screening in high-risk populations, including smokers, is crucial. This study aimed to determine the predictors of TB disease among the smoker population in northeast Malaysia from 2019 to 2020.

Methods

A case-control study was conducted involving smokers aged 18 years and older from health clinics in Bachok Kelantan, Malaysia. Data were collected via face-to-face interviews or telephone calls from 159 participants, randomly selected from outpatient TB records. Simple and multiple logistic regression, using R software, were used to identify the determinants of TB.

Results

Most participants were male (59.1%) and had a secondary education (56.0%). Active smokers constituted 35.2% of the group, and the mean (SD) duration of exposure to smoking was 23.9 (16.47) and 18.4 (12.84) years for the case and control groups, respectively. Being an ex-smoker (adjusted odds ratio (AOR) 6.17; 95% CI [1.55-28.32]; p = 0.013), weight loss (AOR 13.45; 95% CI [4.58-44.46]; p < 0.005), night sweats (AOR 63.84; 95% CI [8.99-1392.75]; p < 0.005) and duration of symptoms (AOR 1.02; 95% CI [1.01-1.04]; p = 0.022) were shown to be significant predictors for TB disease.

Conclusion

Four predictors of TB disease in the population of smokers were recognised in this study and should be prioritised for early TB screening and diagnosis. This may help increase TB detection, initiate prompt treatment and reduce complications among the group at risk for TB.

No smoke without fire: the impact of cigarette smoking on the immune control of tuberculosis

Cigarette smoke (CS) exposure is a key risk factor for both active and latent tuberculosis (TB). It is associated with delayed diagnosis, more severe disease progression, unfavourable treatment outcomes and relapse after treatment. Critically, CS exposure is common in heavily populated areas with a high burden of TB, such as China, India and the Russian Federation. It is therefore prudent to evaluate interventions for TB while taking into account the immunological impacts of CS exposure. This review is a mechanistic examination of how CS exposure impairs innate barrier defences, as well as alveolar macrophage, neutrophil, dendritic cell and T-cell functions, in the context of TB infection and disease.

Development and Validation of the Tuberculosis Risk Score for Smokers (TBRSS)

Tuberculosis (TB) remains a significant public health issue worldwide. However, the effectiveness of TB screening programmes among smokers is still questionable. There is a need for a simple, reliable, and validated screening system for this risk population. This study aimed to develop and validate the tuberculosis risk score for smokers (TBRSS) in Kelantan, Malaysia. A case–control study was conducted on 159 patients (smokers with and without TB) between January and July 2020. Simple and multiple logistic regressions were applied to determine the variables to be included in the risk score. The cut-off points to determine a score indicating low or high risk for TB disease were obtained based on the receiver operating characteristics curve. Content validation was carried out through interviews with eight experts to measure each variable′s relevancy. The face validation was conducted among 20 health clinic staff. Seven variables were selected for inclusion in the risk score. The chosen cut-off point was 16 (out of 43), with 91% and 78% sensitivity and specificity, respectively. The scale-level content validity index was 0.83, while the face validity index scores for each element ranged between 0.85 and 1.00. The TBRSS can be considered a validated screening tool for use in screening TB disease risk among smokers, which potentially may lead to an increased detection of TB disease in the community.

Association of weight change following smoking cessation with the risk of tuberculosis development: A nationwide population-based cohort study

Background

Smoking or weight loss is a risk of tuberculosis (TB) development. However, the impact of weight change after smoking cessation on the occurrence of TB remains elusive. We aimed to determine the relationship between weight change after smoking cessation and the risk of TB development.

Methods

We conducted a population-based cohort study using the national database in Republic of Korea. Of the 10,490,491 subjects who underwent health check-up in 2009, we enrolled 9,953,124 subjects without a previous TB history and followed them until 2017. We divided all study participants into the following three groups: never, former, and current smokers. The primary endpoint was newly developed TB.

Results

Among 9,953,124 subjects analyzed, 5,922,845 (59.5%) were never smokers, 1,428,209 (14.4%) were former smokers, and 2,602,080 (26.1%) were current smokers. The risk of TB development was significantly higher in current smokers than in never smokers (adjusted hazard ratio (aHR) 1.158; 95% confidence interval [CI] 1.131–1.186). Among current smokers, individuals who stopped smoking and maintained weight after baseline evaluation had a significantly lower risk of TB development compared with those who continued to smoke (aHR 0.771; 95% CI 0.741–0.892). However, even after smoking cessation, individuals who lost weight were at a significantly higher risk of TB development compared with those who continued to smoke (aHR 1.327; 95% CI 1.119–1.715).

Conclusions

Our findings suggest that smoking is a risk factor for TB and weight maintenance (neither gaining or losing) after quitting smoking might reduce the risk of TB development.

Lifestyle Risk Factors Associated with Tuberculosis Patients in Asir Region of Saudi Arabia

Background:

Tuberculosis remains to be a major public health problem. Lifestyle factors that have indirectly influence to the burden of tuberculosis. The aim of this study is to determine the lifestyle risk factors associated with tuberculosis patients in Asir region of KSA.

Methods:

We conducted a case-control study at the military hospital of Asir region of KSA. A total of 135 sample which is divided into 67 cases and 67 controls. Cases were included from hospital database between 2017 and 2018. Control were selected from patient attending the same hospital with respiratory disease other than tuberculosis. Data collection done through interview using a structured questionnaire. Lifestyle factors and socio-demographic factors associated with tuberculosis were analyzed using logistic regression.

Results:

Mean age of study participants (cases and control) are 38.04 ± 9.66 and 40.16 ± 7.72 respectively. Most important factors associated with tuberculosis patients are overweight and obese [OR = 4.40, 95% CI 1.27-15.25 and 2.38 (1.61-9.22)], Smoker [OR = 1.34, 95% CI 0.52-3.43], abnormal sleep at night (<8 hours) [OR = 5.03, 95% CI 1.57-16.10], blue color job worker [OR = 2.69, 95% CI 1.02-7.28], physical exercise <3 days/week [OR = 1.41, 95% CI 1.21-3.47].

Conclusions:

In Saudi Arabia, a person's lifestyle and socioeconomic condition are associated with tuberculosis. Interventions focused on improving the quality of life through a reduction of risky lifestyle which prevent the spread of Tuberculosis in Saudi society and improve the efficiency of Saudi national tuberculosis control programme.

Clinico-radiological particularities of common pulmonary tuberculosis among smokers in Tunisia

INRODUCTION

Smoking and tuberculosis are two major public health issues worldwide, particularly in emerging countries. Currently, the relationship between these two scourges is well established.

AIM

Describe the clinical, radiological and progressive features of common pulmonary tuberculosis in smokers.

METHODS

Comparative study, carried out at the Pneumology department of the Hédi Chaker in Sfax, Tunisia, including 120 patients hospitalized for common pulmonary tuberculosis  from January 2014 to December 2016 and who completed their follow-ups for a minimum period of 2 years . The patients were divided into 2 groups: Group1 (G1) consisting of 60 smoking patients and Group 2 (G2) consisting of 60 non-smoking patients. To assess the severity of radiological lesions, we used the International Labour Organization classification for simple pneumoconiosis and the Brouet classification.

RESULTS

The mean age of the patients was comparable in the two groups with a predominance of male for G1 (91%) and female for G2 (70%). The smokers consulted later (113 days versus 60 days (p=0.023). Dyspnea, hemoptysis and chest pain were significantly more frequent in the smokers. The radiological lesions were more serious in smoking group. Bilateral lesions were more observed in smokers (58% vs 25% p = 0.004). A positive association was noted between the extent of radiological lesions, stage 3 and 4 according to the Brouet classification, and smoking status (p <0.001). Similarly for the International Labour Organization classification for simple pneumoconiosis , the radiological lesions were more severe (scores 6 - 15) in the smokers (p <0.001).Smoking was associated with poor adherence (p <0.008), prolonged anti-tuberculosis treatment (p <0.001), delayed RBK negativation in sputum (p <0.001), and more frequent reactivation of tuberculosis (p=0.001). After the diagnosis of CPT, 83% of patients continued to smoke at the same rate and only 7% of patients had quit smoking.

CONCLUSION

Smoking worsens CPT by making the clinical picture noisier, radiological lesions more aggressive, negativation of BK in sputum later, and reactivation of CPT more frequent.

Incidence of tuberculosis in advanced lung cancer patients treated with immune checkpoint inhibitors - A nationwide population-based cohort study

OBJECTIVES

The aim of this study was to investigate the risk of TB in advanced non-small cell lung cancer (NSCLC) patients treated with Immune checkpoint inhibitors (ICI) after a platinum-based chemotherapy.

MATERIALS AND METHODS

A nationwide population-based retrospective cohort study using National health insurance dataset was designed. Patients who were diagnosed as lung cancer between September 1st, 2017 and August 31st, 2018 in South Korea were selected. Among them, those with NSCLC who initiated a platinum-based chemotherapy within 3 months were finally included and followed up until December 31st, 2018. Patients who received nivolumab, pembrolizumab, and atezolizumab within study period were classified as the ICI group. Cox proportional hazard model with time-varying covariates was used to determine effects of the duration of conventional chemotherapy, ICI, and consecutive use of systemic steroid on TB.

RESULTS

A total of 6335 patients were enrolled with 3568.7 years of total follow-up period. Among them, 899 patients underwent ICI treatment. Within the follow-up period, 15 TB cases were identified in the ICI group (incidence: 2582.5 per 100,000 person-years) and 63 TB cases were found in the conventional chemotherapy group (incidence: 2108.5 per 100,000 person-years). In a multivariable Cox proportional hazard model, treatment with ICI was not a significant risk factor for TB development (hazard ratio (HR): 1.21, 95 % confidence interval (CI): 0.45-3.26,p =  0.700). Instead, prolonged use of steroid was associated with an increased TB risk (HR: 1.91, 95 %CI: 0.89-4.08, p =  0.095), although its statistical significance was dependent on the operational definition of the effect duration. Previous TB history and older age were independent risk factors for TB disease.

CONCLUSION

In this real-world study, additional treatment with ICI did not increase the risk of TB in advanced NSCLC patients who underwent a cytotoxic chemotherapy. However, TB incidence in these patients was high regardless of ICI treatment.

CLASSIFICATIONS

Systemic Treatments.

The possible impact of socioeconomic, income, and educational status on adverse effects of drug and their therapeutic episodes in patients targeted with a combination of tuberculosis interventions

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Socio-economic status is very important in patient receiving DOT therapy.

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Income influences disease occurrence as well as adverse events.

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Occupation increases the risk of diseases and results increase risk of adverse events.

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Low income results mal nutrition and increased risk of drug intolerance or adverse events.

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DOTS is an effective treatment strategy for MTB patients.

First-line antituberculosis (anti-TB) compounds have been considered as proven components of the Directly Observed Treatment-Short course (DOTS). Drug therapy against tuberculosis has been categorized as I, II, or III following the Revised National Tuberculosis Control Program guidelines. Anti-TB are drugs are quite common and show limited adverse effects. However, first-line anti-TB compounds mediated DOTS therapy and were found with several complications. Thus, those drugs have been discontinued. Therefore, the present study was designed to find out the possible impact of socioeconomic, income, and educational status on the adverse effects of drugs and their therapeutic episodes in patients targeted with a combination of tuberculosis intervention. This study found that an increased incidence of tuberculosis was found in patients who have finished high school, contributing to a high percentage of adverse effects. Notably, adverse events were shown maximally in poor patients compared with rich- or high-income patients. On the contrary, a high prevalence of adverse events was shown to be increased in partially skilled workers compared with full-skilled workers. Consequently, adversely considerable events were implicated to be raised in patients associated with minimal socioeconomic class. Such interesting factors would help in monitoring such events in experimental patients.

Survival analysis of patients with tuberculosis and risk factors for multidrug-resistant tuberculosis in Monrovia, Liberia

We reviewed the records of 337 confirmed cases of tuberculosis patients in Monrovia, the capital of Liberia, 2015. The risk factors affecting the survival and multidrug-resistance of tuberculosis patients were examined. Kaplan-Meier analysis and the log-rank test were used to assess the differences in survival among the patients, while Cox regression model was used for multivariate analysis. The qualitative data was tested with chi-square test in the single factor analysis of multidrug-resistant TB. Multivariate analysis was performed using binary logistic regression analysis. The significance level for all the tests were set at 0.05. The mean period of the follow-up of patients was 10 months. In the 337 patients, 33 (9.8%) died, the 21-month survival rate was 90.2%. The results of multivariate Cox regression analysis show that overcrowding (HR = 7.942, 95% CI 3.258-19.356), former smoking (HR = 3.773, 95% CI 1.601-8.889), current smoking (HR = 3.546, 95% CI 1.195-10.521), multidrug-resistance tuberculosis (HR = 4.632, 95% CI 1.913-11.217) were risk factors for death during anti-tuberculosis treatment in TB patients in Liberia. The results of binary logistic regression analysis show that extra-pulmonary (OR = 2.032, 95% CI 1.133-3.644), family history of TB (OR = 2.387, 95% CI 1.186-4.807) and current smoking (OR = 3.436, 95% CI 1.681-7.027) were risk factors for multidrug-resistant tuberculosis. These results can provide insights on local tuberculosis early intervention, increase public health awareness, and strengthen the control of factors that may affect the survival and multidrug-resistance of tuberculosis patients.

The association between chronic kidney disease and tuberculosis; a comparative cohort study in England

BACKGROUND

People with end-stage kidney disease have an increased risk of active tuberculosis (TB). Previous systematic reviews have demonstrated that patients with chronic kidney disease (CKD) have increased risk of severe community-acquired infections. We investigated the association between CKD (prior to renal replacement therapy) and incidence of TB in UK General Practice.

METHODS

Using the UK Clinical Practice Research Datalink, 242,349 patients with CKD (stages 3-5) (estimated glomerular filtration rate < 60 mL/min/1.73 m2 for ≥3 months) between April 2004 and March 2014 were identified and individually matched (by age, gender, general practice and calendar time) to a control from the general population without known CKD. The association between CKD (overall and by stage) and incident TB was investigated using a Poisson regression analysis adjusted for age, gender, ethnicity, socio-economic status, chronic obstructive pulmonary disease (COPD) and diabetes.

RESULTS

The incidence of TB was higher amongst patients with CKD compared to those without CKD: 14.63 and 9.89 cases per 100,000 person-years. After adjusting for age, gender, ethnicity, socio-economic status, diabetes and COPD, the association between CKD and TB remained (adjusted rate ratio [RR] 1.42, 95% confidence interval [CI] 1.01-1.85). The association may be stronger amongst those from non-white ethnic minorities (adjusted RR 2.83, 95%CI 1.32-6.03, p-value for interaction with ethnicity = 0.061). Amongst those with CKD stages 3-5, there was no evidence of a trend with CKD severity.

CONCLUSIONS

CKD is associated with an increased risk of TB diagnosis in a UK General Practice cohort. This group of patients should be considered for testing and treating for latent TB.

Smoking increases the risk of infectious diseases: A narrative review

Smoking is relevant to infectious diseases resulting in increased prevalence and mortality. In this article, we aim to provide an overview of the effects of smoking in various infections and to explain the potential mechanisms. We searched PubMed and other relevant databases for scientific studies that explored the relationship between smoking and infection. The mechanisms of susceptibility to infection in smokers may include alteration of the structural, functional and immunologic host defences. Smoking is one of the main risk factors for infections in the respiratory tract, digestive tract, reproductive tract, and other systems in humans, increasing the prevalence of HIV, tuberculosis, SARS-CoV, and the current SARS-CoV-2. Smoking cessation can reduce the risk of infection. Smoking increases the incidence of infections and aggravates the progress and prognosis of infectious diseases in a dose-dependent manner. Smoking cessation promotion and education are the most practical and economical preventive measures to reduce aggravation of disease infection owing to tobacco use.

Effect of smoking on treatment outcome among tuberculosis patients in Malaysia; a multicenter study

BACKGROUND

Smoking plays a key role in the development of tuberculosis (TB) infection and is also a predictor of poor TB treatment prognosis and outcomes. The current study was conducted to determine the prevalence of smoking and to assess the effects of smoking on treatment outcomes among TB patients.

METHODS

A multi-center retrospective study design was used to collect data from TB patients in four different states of Malaysia, namely Penang, Sabah, Sarawak, and Selangor. The study included medical records of TB patients admitted to the selected hospitals in the period from January 2006 to March 2009. Medical records with incomplete data were not included. Patient demographics and clinical data were collected using a validated data collection form.

RESULTS

Of all patients with TB (9337), the prevalence of smokers was 4313 (46.2%). Among smokers, 3584 (83.1%) were associated with pulmonary TB, while 729 (16.9%) were associated with extrapulmonary TB. Male gender (OR = 1.43, 95% CI 1.30-1.58), Chinese ethnicity (OR = 1.23, 95% CI 1.02-1.49), Sarawak indigenous ethnicity (OR = 0.74, 95% CI 0.58-0.95), urban residents (OR = 1.46, 95% CI 1.33-1.61), employed individuals (OR = 1.21, 95% CI 1.09-1.34), alcoholics (OR = 4.91, 95% CI 4.04-5.96), drug abusers (OR = 7.43, 95% CI 5.70-9.60) and presence of co-morbid condition (OR = 1.27, 95% CI 1.16-1.40) all showed significant association with smoking habits. This study found that 3236 (75.0%) patients were successfully treated in the smokers' group, while 4004 (79.7%) patients were non-smokers. The proportion of deaths (6.6%, n = 283), defaulters (6.6%, n = 284) and treatment interruptions (4.7%, n = 204) was higher in the smokers' group.

CONCLUSIONS

Smoking has a strong influence on TB and is a major barrier towards treatment success (OR = 0.76, 95% CI 0.69-0.84, p < 0.001). Therefore, the findings indicate that smoking cessations are an effective way to decrease treatment failure and drug resistance.

Undiagnosed diabetes mellitus and tuberculosis infection: A population-based, observational study from eastern China

BACKGROUND

China has the largest dual diabetes and tuberculosis epidemic globally. No studies from mainland China have assessed the relationship between tuberculosis infection and diabetes. We conducted a population-based, observational study in eastern China to further explore this relationship.

METHODS

A blood glucose, Quantiferon, and tuberculin skin test were administered at baseline. We compared tuberculosis infection in nondiabetics and diabetics. The cohort was additionally screened for tuberculosis progression over 5 years.

RESULTS

Among 5405 participants, diabetics had elevated levels of Quantiferon and tuberculin positivity, largely driven by undiagnosed diabetics (compared with nondiabetics, adjusted odds ratios of 1.53; 95% confidence interval [CI], 1.05-2.23 and 1.58; 95% CI, 1.07-2.35 for tuberculin and Quantiferon positivity). During follow-up, the annual tuberculosis incidence was three times higher for diabetics compared with the entire cohort.

CONCLUSIONS

These results suggest improving diabetic control through rapidly identifying undiagnosed diabetes may have indirect benefits to tuberculosis control. Targeting of preventive therapy to newly diagnosed diabetics at high-risk for progressive tuberculosis in China should be considered.

Adverse drug reaction prevalence and mechanisms of action of first-line anti-tubercular drugs

PURPOSE

Understanding the appearance of anti-tubercular drug-related adverse drug reactions (ADRs) in patients receiving tuberculosis (TB) treatment is important, and may be related to morbidity and mortality if not recognized early. Here, we aimed to characterize the mechanisms underlying adverse drug reactions due to combination anti-tuberculosis therapy of the Revised National Tuberculosis Control Program (RNTCP).

METHODS

This was a prospective observational study conducted in 9 DOTS centers of New Delhi, India. All enrolled TB patients receiving first-line tuberculosis treatment as per RNTCP guidelines were monitored for ADRs. All ADRs that appeared during the treatment were recorded and analyzed.

RESULTS

The study included 1011 TB patients on anti-TB treatment under DOTS. According to Naranjo's probability scale, of a total 351 (34.72%) reported adverse events, 102 (10.09%) were definite, 59 (5.83%) probable, 123 (12.17%) possible, and 67 (6.63%) doubtful. On the Hartwig severity scale, of the 351 adverse drug events, 225 (22.26%) were mild, 105 (10.38%) were moderate, and 21 (2.08%) were severe. Out of 102 reported adverse drug reactions, 81 (79.41%) were moderate and 21 (20.59%), while 65.28% did not experience any ADRs.

CONCLUSIONS

Directly Observed Treatment (DOT) is effective and safe compared to daily treatment regimens. Patients receiving DOTS therapy needed close monitoring for adverse events. Therefore, a pharmacovigilance program should be added at the National level to accesses the adverse event incidence.

Incidence and risk factors of tuberculosis among the elderly population in China: a prospective cohort study

Background

China is facing challenges of the shifting presentation of tuberculosis (TB) from younger to elderly due to an ageing population, longer life expectancy and reactivation disease. However, the burden of elderly TB and influence factors are not yet clear. To fill the gap, we generated a cohort study to measure the magnitude of TB incidence and associated factors among the elderly population aged 65 years and above in China.

Methods

In this cohort established in 2013 through a prevalence survey conducted in selected sites, a total of 34 076 elderlies without TB were enrolled into two-year follow-up. We used both active and passive case findings to find out all TB patients among them. The person-year (PY) incidence rates for both bacteriologically positive TB and active TB were calculated. Cox proportional regression model was performed to test effect of risk factors, and the population attributable fraction (PAF) of each risk factor contributing to incident TB among elderlies was calculated.

Results

Over the two-year follow-up period, a total of 215 incident active TB were identified, 62 of which were bacteriologically positive. The incidence rates for active TB and bacteriologically positive TB were 481.8 per 100 000 PY (95% CI: 417.4–546.2 per 100 000 PY) and 138.9 per 100 000 PY (95% CI: 104.4–173.5 per 100 000 PY), respectively. Incident cases detected by active case finding were significantly higher (P < 0.001). Male, non-Han nationality, previously treated TB, ex/current smoker and body mass index (BMI) < 18.5 presented as independent predictors for developing TB disease. For developing bacteriologically positive TB, the biggest contribution was from self-reported ex or current smoker (18.06%). And, for developing active TB, the biggest contribution was from non-Han nationality (35.40%), followed by male (26.80%) and age at 75 years and above (10.85%).

Conclusions

Ageing population in China had a high TB incidence rate and risk to develop TB disease, implying that National TB Program (NTP) needs to prioritize for elderly. Active case finding should be applied capture more active TB cases among this particular population, especially for male, non-Han nationality, and those with identified risk factors.

Pulmonary Tuberculosis is Associated with Elevated Risk of Lung cancer in Korea: The Nationwide Cohort Study

Objective: Although previous studies suggest that previous pulmonary tuberculosis was associated with increased risk of lung cancer. It remains controversial whether pulmonary tuberculosis is a risk factor for lung cancer. Our study was aimed to examine the association between pulmonary tuberculosis and lung cancer risk in Korean.

Methods: The Korean National Health and Nutrition Examination Survey database was linked with the Korean National Cancer Incidence Database to examine the occurrence of pulmonary tuberculosis and lung cancer. The linked databases were also merged with causes of death database of Statistics Korea. The Cox-proportional hazards model was used to estimates the hazard risk of lung cancer for Korean adults aged ≥40 years with pulmonary tuberculosis.

Results: Of 20,252 total participants, 2,640 (13.0%) had old pulmonary tuberculosis (a medical history of pulmonary tuberculosis or radiologically inactive tuberculosis). After adjusting for all covariates, the hazard ratio of lung cancer among patients with old pulmonary tuberculosis was 3.24 (95% CI, 1.87‒5.62) compared to the control group. According to smoking status, the hazard ratios of lung cancer for never smokers, ex-smokers, and current smokers among participants with old pulmonary tuberculosis were 3.52 (95% CI, 1.17‒10.63), 2.16 (95% CI, 0.89‒5.24), and 3.71 (95% CI, 1.49‒9.22) compared to the control group, respectively.

Conclusions: Korean adults with old pulmonary tuberculosis have a higher risk of lung cancer, compared to general population without pulmonary tuberculosis.

Design, development and randomised controlled trial of a smartphone application, 'QinTB', for smoking cessation in tuberculosis patients: study protocol

INTRODUCTION

Providing smoking cessation treatment is an important intervention for tuberculosis (TB) patients. Mobile technologies, such as smartphone applications, have shown promising potential. However, there are few effective applications that could support TB patients in their efforts to quit smoking. To address this problem, we will develop a smartphone application 'QinTB' to help TB patients quit smoking, and we will evaluate the clinical efficacy of this application by using a randomised controlled trial (RCT).

METHODS AND ANALYSIS

This is a two-step study. In the first step, we will develop a smartphone application based on an interactive application of the transtheoretical model and protection motivation theory. Then, we will perform an RCT using a two-arm design; a total of 400 patients will be randomly assigned to the application group or the doctors' advice group; both treatments will be 6 months and follow-up will be 12 months; the primary outcome is the biochemically verified 6 month sustained abstinence rate; data will be analysed on an intention-to-treat basis.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Beijing Research Institute for Tuberculosis Control and Prevention. We will disseminate the findings of this study through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

This study was registered in the Chinese Clinical Trial Registry (ChiCTR1900022008) and the stage is Pre-results.

Primary drug resistance of mycobacterium tuberculosis in Shandong, China, 2004-2018

BACKGROUND

Primary drug-resistant tuberculosis (DR-TB) has contributed to a significant health and economic burden on a global scale, especially in China. we sought to estimate epidemiological characteristics of primary DR-TB in China from 2004 to 2018.

METHODS

Eleven thousand four hundred sixty-seven newly diagnosed and 1981 retreated TB cases with drug susceptibility data were included. Chi-Square test for trends, linear regression, a joinpoint regression model and temporal trend in proportions of the different resistance patterns were carried out.

RESULTS

The proportion of primary DR-TB and mono-resistant TB (MR-TB) in China had reduced by more than 12% since 2004, and were 21.38%, 13.35% in 2018 respectively. Among primary DR-TB cases (2173,18.95%), the percentage of multiresistant TB (MDR-TB, from 5.41 to 17.46%), male (from 77.03 to 84.13%), cavity (from 13.51 to 43.92%), rifampicin(RFP)-resistant TB (from 8.11 to 26.98%), streptomycin(SM)-resistant TB (from 50.00 to 71.43%) increased significantly (P < 0.05). On the contrary, the proportion of female, non-cavity, isoniazide(INH)-resistant TB (from 55.41 to 48.15%) and MR-TB (from 82.43 to 62.43%) decreased significant (P < 0.05). The primary drug resistance rate among female, cavity, smoking, drinking, 15 to 44 year-old TB subgroups increased by 0.16, 6.24, 20.95, 158.85, 31.49%, respectively. The percentage of primary DR-TB, RFP-resistant TB dropped significantly during 2004-2007 in Joinpoint regression model.

CONCLUSION

The total rate of drug resistance among new TB cases showed a downward trend in Shandong, China, from 2004 to 2018. Primary drug resistance patterns were shifting from female, non-cavity, INH-resistant TB, and MR-TB groups to male, cavity, RFP/SM-resistant TB, and MDR-TB groups. Considering the rising drug resistance rate among some special population, future control of primary DR-TB in China may require an increased focus on female, cavity, smoking, drinking, or 15 to 44 year-old TB subgroups.

Non-communicable diseases and tuberculosis: Anticipating the impending global storm

The epidemiological transitions that have occurred in low and middle income countries (LMIC) during the past decades have led to an increased prevalence on non-communicable diseases (NCDs) in these countries, where the burden of infectious diseases (IDs), especially tuberculosis (TB), remains high. Although the true dimensions of this comorbidity have not yet been fully understood, there is a growing amount of data, over the last 10 years, that suggest a clear association between NCDs and TB. In particular, there is a continuously increasing body of evidence that diabetes mellitus, chronic respiratory conditions, tobacco use, mental health illnesses and chronic kidney disease increase TB morbidity and mortality and vice versa. This bidirectional negative association between diseases may jeopardise the achievement of the Sustainable Development Goals (SDGs) specific TB targets, thus underlying the importance of integrated public health responses towards both epidemics. Population as well as individual based approaches are required, along with both strategic and operation integration on a global scale. This year's United Nations High Level Meetings (ΗLMs) presented a rare opportunity for the political foundations of the TB and NCD responses to be dug together, thus creating a potential breakthrough in the global response to both epidemics.

Prevalence of Tuberculosis Risk Factors among Bacteriologically Negative and Bacteriologically Confirmed Tuberculosis Patients from Five Regional Referral Hospitals in Uganda

Understanding risk factors for tuberculosis (TB) and their prevalence helps guide early diagnosis. We determined their prevalence among bacteriologically negative and bacteriologically confirmed TB patients in five regional referral hospitals in Uganda. This cross-sectional study considered 1,862 adult presumptive TB participants. We performed fluorescent microscopy, Xpert MTB/RIF (Xpert), Lowenstein-Jensen culture, human immunodeficiency virus, and random blood sugar testing on recruited patients. Prevalence and prevalence ratios of risk factors were compared among bacteriologically negative and confirmed cases. Odds ratios and 95% confidence interval (CI) were determined for significant risk factors in bacteriologically confirmed patients. Of the 1,862 participants, 978 (55%) were male and the median age of the participants was 36 years (interquartile range: 27-48). Up to 273 (15%) had a positive result on all three TB tests. Most prevalent risk factors (prevalence ratio [PR] > 1.0) among bacteriologically negative and positive TB patients were cigarette smoking (9.3% versus 2.1%; PR = 2.1), biosmoke (24% versus 39.7%; PR = 1.7), contact (4.2% versus 6.5%; PR = 1.6), male gender (51.4% versus 72.5%; PR = 1.4), alcohol use (17.2% versus 24.4%; PR = 1.4), diabetes (0.7% versus 0.9%; PR = 1.3), and family history of TB (12.1% versus 13.7%; PR = 1.1). The risk factors and their adjusted prevalence rate ratios (95% CI) of being bacteriologically positive were male (1.8 [1.4-2.4]), biosmoke exposure (1.5 [1.2-2.0]), and history of cigarette smoking (1.6 [1.1-2.4]). Among bacteriologically confirmed patients in Uganda, cigarette smoking, biosmoke exposure, contact, male gender, alcohol use, diabetes, and family history of TB are important risk factors for TB. Interventions for TB control in people with these risk factors would help in TB control efforts.

Contribution of Smoking to Tuberculosis Incidence and Mortality in High-Tuberculosis-Burden Countries

Globally, 10 million incident cases of tuberculosis (TB) are reported annually, and 95% of TB cases and 80% of tobacco users reside in low- and middle-income countries. Smoking approximately doubles the risk of TB disease and TB mortality. We estimated the proportion of annual incident TB cases and TB mortality attributable to tobacco smoking in 32 high-TB-burden countries. We obtained country-specific estimates of TB incidence, TB mortality, and smoking prevalence from the World Health Organization Global TB Report (2017), tobacco surveillance reports (2015), and the Tobacco Atlas. Risk ratios for the effect of smoking on TB incidence and TB mortality were obtained from published meta-analyses. An estimated 17.6% (95% confidence interval (CI): 8.4, 21.4) of TB cases and 15.2% (95% CI: 1.8, 31.9) of TB mortality were attributable to smoking. Among high-TB-burden countries, Russia had the highest proportion of smoking-attributable TB disease (31.6%, 95% CI: 15.9, 37.6) and deaths (28.1%, 95% CI: 3.8, 51.4). Men had a greater proportion of TB cases attributable to smoking (30.3%, 95% CI: 14.7, 36.6) than did women (4.3, 95% CI: 1.7, 5.7). Our findings highlight the need for tobacco control in high-TB-burden countries to combat TB incidence and TB mortality.

Oxidative Stress and First-Line Antituberculosis Drug-Induced Hepatotoxicity

Hepatotoxicity induced by antituberculosis drugs is a serious adverse reaction with significant morbidity and even, rarely, mortality. This form of toxicity potentially impacts the treatment outcome of tuberculosis in some patients. Covering only first-line antituberculosis drugs, this review addresses whether and how oxidative stress and, more broadly, disturbance in redox homeostasis alongside mitochondrial dysfunction may contribute to the hepatotoxicity induced by them. Risk factors for such toxicity that have been identified, in addition to genetic factors, principally include old age, malnutrition, alcoholism, chronic hepatitis C and chronic hepatitis B infection, HIV infection, and preexisting liver disease. Importantly, these comorbid conditions are associated with oxidative stress. Thus, the shared pathogenetic mechanism(s) for liver injury might be in operation due to disease-drug interaction. Our current ability to predict, prevent, or treat hepatotoxicity (other than removing potentially hepatotoxic drugs) remains limited. More translational research to unravel the pathogenesis, inclusive of the underlying molecular basis, regarding antituberculosis drug-induced hepatotoxicity is needed, and so is clinical research pertaining to the advances in therapy with antioxidants and drugs related to antioxidants, especially those for management of mitochondrial dysfunction. The role of pharmacogenetics in the clinical management of drug-induced hepatotoxicity also likely merits further evaluation.

Epidemiologic Evidence of and Potential Mechanisms by Which Second-Hand Smoke Causes Predisposition to Latent and Active Tuberculosis

Many studies have linked cigarette smoke (CS) exposure and tuberculosis (TB) infection and disease although much fewer have studied second-hand smoke (SHS) exposure. Our goal is to review the epidemiologic link between SHS and TB as well as to summarize the effects SHS and direct CS on various immune cells relevant for TB. PubMed searches were performed using the key words "tuberculosis" with "cigarette," "tobacco," or "second-hand smoke." The bibliography of relevant papers were examined for additional relevant publications. Relatively few studies associate SHS exposure with TB infection and active disease. Both SHS and direct CS can alter various components of host immunity resulting in increased vulnerability to TB. While the epidemiologic link of these 2 health maladies is robust, more definitive, mechanistic studies are required to prove that SHS and direct CS actually cause increased susceptibility to TB.

Epidemiological, clinical and mechanistic perspectives of tuberculosis in older people

With the ageing population globally, tuberculosis (TB) in older people becomes a major clinical and public health challenge. In many Asian countries, especially those located in the eastern and southeastern parts of the continent, geriatric TB is a significant problem. TB in the older patients is more difficult to diagnose in the early course of disease, and has poorer treatment outcomes, largely as increased failure and death. More drug-induced adverse reactions are also experienced by this population during TB therapy. Oxidative stress and mitochondrial dysfunction are now well recognized to be associated with the ageing process, and it is likely that the cellular and molecular perturbations interact inextricably with the immunological dysfunction biophysiologically inherent to ageing. These underlying mechanistic bases putatively contribute to the development of TB in the geriatric population and worsen the disease outcomes, especially when the TB is compounded by co-morbid conditions such as smoking and diabetes mellitus. Unravelling these mechanisms further would yield knowledge that might potentially help to prevent reactivated TB in older people, and also to better manage the established disease with drug regimens and other new therapeutic strategies. In addition, addressing the social elements associated with geriatric TB is also imperative in the relief of individual patient suffering and improvement of overall disease control.

Effects of diabetes mellitus on the clinical presentation and treatment response in tuberculosis

BACKGROUND AND OBJECTIVE

With the colliding global epidemics of diabetes mellitus (DM) and tuberculosis (TB), we studied the effects of DM on the presentation of TB and its response to treatment.

METHODS

Consecutive TB patients from 2006 to 2010 in a territory-wide treatment programme offering 9-month extended treatment for TB patients with DM were examined and followed up prospectively to assess their treatment response. Successful treatment completers were tracked through the TB registry and death registry for relapse, death or till 31 December 2014, whichever was the earliest.

RESULTS

DM was independently associated with more chest symptoms (adjusted OR (AOR): 1.13) and systemic symptoms (AOR: 1.30) but less with other site-specific symptoms (AOR: 0.58) at TB presentation. There was more frequent pulmonary involvement (AOR: 1.69), with more extensive lung lesion (AOR: 1.25), lung cavity (AOR: 2.00) and positive sputum smear (AOR: 1.83) and culture (AOR: 1.38), but no difference in the proportion of retreatment cases or isoniazid and/or rifampicin resistance. After treatment initiation, there was higher overall incidence (AOR: 1.38) of adverse effects (mainly gastrointestinal symptoms, renal impairment and peripheral neuropathy but less fever and skin hypersensitivity reactions), more smear non-conversion (AOR: 1.59) and culture non-conversion (AOR: 1.40) at 2 months, and lower combined cure/treatment completion rate at 12 months (AOR: 0.79), but no difference in the relapse rate after having successfully completed treatment.

CONCLUSION

DM adversely affected the clinical presentation and treatment response of TB, but there was no difference in the drug resistance and relapse rates.

A case control study of risk factors associated with pulmonary tuberculosis in romania: experience at a clinical hospital of pneumology

BACKGROUND AND AIM

Tuberculosis (TB) remains a major public health issue in Romania. The aim of the present study was to evaluate the potential demographic, socioeconomic and behavioral risk factors for TB among hospitalized patients in Romania.

METHODS

This is a case-control study conducted between March 1st 2014 and March 30th 2015 at Leon Daniello Clinical Hospital of Pneumology, Cluj Napoca. A total of 150 TB patients defined as "cases" were matched for age, sex and county of residence to 150 controls selected from patients attending the same hospital with respiratory diseases other than TB. Data collection was obtained through patient interviews using a structured questionnaire. Factors potentially associated with TB infection were analyzed using univariate and multivariate logistic regression.

RESULTS

Factors independently associated with TB were illiteracy (OR=2.42, 95% CI 1.09-5.37), unemployment (OR=2.08, 95% CI 1.23-3.53), low household income (OR=4.12, 95% CI 2.53-6.71), smoking (more than 20 cigarettes per day) (OR=2.12, 95% CI 1.20-3.74), poor knowledge of TB (OR=3.46, 95% CI 1.97-6.07), presence of TB patient in household (OR=4.35, 95% CI 1.42-13.36), prior TB treatment (OR=2.2, 95% CI 1.93-2.5) and diabetes (OR=3.32, 95% CI 1.36-8.08).

CONCLUSION

This study provided useful information that might help to develop and adapt effective policies for TB control in Romania.

Smoked and smokeless tobacco use among pulmonary tuberculosis patients under RNTCP in urban Puducherry, India

BACKGROUND

Smoking is associated with unfavourable treatment outcomes like failures and defaults among the TB patients.

OBJECTIVES

To study the prevalence and pattern of tobacco use among the pulmonary tuberculosis (PTB) patients in urban Pondicherry and study the association of various socio-demographic variables with current smoked and smokeless tobacco users.

METHODS

A cross-sectional study was conducted among 235 PTB patients from 6 randomly selected urban PHCs of Pondicherry from Jan 2013 to March 2014. Fagerstrom Test for Nicotine Dependence was used. Chi-square test and multiple-logistic regression were done.

RESULTS

Prevalence of smoking among the PTB patients at the time of TB diagnosis was 35.3%, whereas the same during the continuation phase (CP) was 23.4%. Among 83 smokers at the time of diagnosis, 52 modified and 31 did not modify their smoking after TB diagnosis. Similarly, prevalence of smokeless tobacco use both at the time of TB diagnosis and during CP was 9.8%. Male and lower education level was associated with current smoking. Similarly, female and lower education level was associated with current smokeless tobacco use.

CONCLUSIONS

One-third of PTB patients used smoked or smokeless tobacco during their CP. Health programme needs to concentrate on PTB patients who continue to use smoked or smokeless tobacco during their treatment; necessary interventions need to be planned.

The risk of pulmonary tuberculosis in underground copper miners in Zambia exposed to respirable silica: a cross-sectional study

Background

Pulmonary tuberculosis (PTB) among underground miners exposed to silica remains a global problem. Although well described in gold and coal mining, risk in other mining entities are not as well documented. This study aims to determine dust-related dose response risk for PTB among underground miners exposed to silica dust in Zambia's copper mines.

Methods

A cross sectional study of in-service miners (n = 357) was conducted at Occupational Health and Safety Institute (OHSI), Zambia. A systematic review of medical data over a 5-year period from assessments conducted by doctors at OHSI and statutory silica exposure data (n = 16678) from the Mine Safety Department (MSD) were analysed. Lifetime cumulative exposure metrics were calculated. Multivariate logistic regression analysis was used to determine the association between PTB and lifetime exposure to silica, while adjusting for various confounders.

Results

The median respirable silica dust level was 0.3 mg/m³ (range 0.1–1.3). The overall prevalence of PTB was 9.5 % (n = 34). High cumulative respirable silica dust category showed a statistically significant association with PTB (OR = 6.4 (95 % CI 1. 8–23)) and a significant trend of increasing disease prevalence with increasing cumulative respirable silica dust categories was observed (p_trend < 0.01). Smoking showed a statistically significant association with PTB with OR = 4.3 (95 % CI 1.9–9.9).

Conclusions

Our results demonstrate the association of increased risk for certified active TB with cumulative respirable dust in a dose related manner among this sample of copper miners. There is need to intensify dust control measures and incorporate anti-smoking interventions into TB prevention and control programmes in the mines.

SmokeHaz: Systematic Reviews and Meta-analyses of the Effects of Smoking on Respiratory Health

BACKGROUND

Smoking tobacco increases the risk of respiratory disease in adults and children, but communicating the magnitude of these effects in a scientific manner that is accessible and usable by the public and policymakers presents a challenge. We have therefore summarized scientific data on the impact of smoking on respiratory diseases to provide the content for a unique resource, SmokeHaz.

METHODS

We conducted systematic reviews and meta-analyses of longitudinal studies (published to 2013) identified from electronic databases, gray literature, and experts. Random effect meta-analyses were used to pool the findings.

RESULTS

We included 216 articles. Among adult smokers, we confirmed substantially increased risks of lung cancer (risk ratio (RR), 10.92; 95% CI, 8.28-14.40; 34 studies), COPD (RR, 4.01; 95% CI, 3.18-5.05; 22 studies), and asthma (RR, 1.61; 95% CI, 1.07-2.42; eight studies). Exposure to passive smoke significantly increased the risk of lung cancer in adult nonsmokers and increased the risks of asthma, wheeze, lower respiratory infections, and reduced lung function in children. Smoking significantly increased the risk of sleep apnea and asthma exacerbations in adult and pregnant populations, and active and passive smoking increased the risk of tuberculosis.

CONCLUSIONS

These findings have been translated into easily digestible content and published on the SmokeHaz website.

Adverse Events in Treating Smear-Positive Tuberculosis Patients in China

This study aimed to estimate the adverse events (AE) rate during anti-tuberculosis treatment and to explore AE-related risk factors. New and previously treated smear-positive tuberculosis (TB) cases were enrolled from eight regions in China between April 2009 and October 2010. The AE rate was estimated, and AE risk factors during anti-TB treatment were assessed using Cox proportional models. Among 2091 Chinese subjects with anti-TB treatment, 462 (22.1%, 95% confidence interval (CI), 20.3–23.9) patients developed AE, with liver injury and gastrointestinal reactions constituting the most common AE. Specifically, 9.8% (95% CI, 8.5–11.1) and 6.3% (95% CI, 5.3–7.4) developed liver injuries and gastrointestinal reactions, respectively. We found that AE rate differed by regions, TB knowledge score, symptoms score and smoking status. Liver injuries were associated with age, sex and smoking status; gastrointestinal reactions were associated with education level and symptom score. Improving patients’ knowledge on TB could reduce AE rate.

Cigarette smoke is a risk factor for severity and treatment outcome in patients with culture-positive tuberculosis

Objective

Smoking has been associated with tuberculosis (TB); however, the effects of smoking on the effectiveness of TB treatment remain unclear.

Materials and methods

Data were retrieved from case notes and interviews of subjects registered in the TB-reporting system from 2010 to 2012. Study cases were defined as subjects with TB-positive sputum cultures, whereas the controls were defined as subjects with non-TB-related pulmonary diseases. Statistical analyses included logistic regression and multivariate Cox proportional hazard regression models.

Results

A total of 245 cases with cultures positive for TB and 114 controls with non-TB-related pulmonary diseases and negative sputum cultures were recruited. Current smokers had the highest failure rate (33%) for TB treatment, and they had the most severe pulmonary lesions based on chest X-ray grading. Current smokers had a 1.36-fold (95% confidence interval 1.03–2.36, P<0.05) higher odds ratio for cultures positive for TB compared with nonsmokers. In subjects with TB-positive cultures, current smoking was associated with an increase in treatment days required for cultures to convert from positive to negative (hazard ratio 1.12, 95% confidence interval 1.03–1.39; P<0.05).

Conclusion

Longer periods of treatment may be required for TB patients who are current smokers.

Impact of HIV infection and smoking on lung immunity and related disorders

HIV-infected persons not only have higher rates of smoking than the general population, but are also unusually vulnerable to the associated adverse health effects, both infective and noninfective in origin. Indeed, in the setting of well-organised care and availability of highly active antiretroviral therapy, HIV-infected smokers lose more life-years to smoking than to HIV infection per se, presenting a major challenge to healthcare providers. Not surprisingly, the respiratory system is particularly susceptible to the damaging interactive chronic inflammatory and immunosuppressive effects of HIV and smoking, intensifying the risk of the development of opportunistic infections, as well as lung cancer and obstructive lung disorders. The impact of smoking on the immunopathogenesis and frequencies of these respiratory conditions in the setting of HIV infection, as well as on the efficacy of antiretroviral therapy, represent the primary focus of this review.

Smoking on treatment outcomes among tuberculosis patients

BACKGROUND

Smoking is a risk factor not only for the development of cancer and coronary heart disease but also for tuberculosis (TB). The aim of this study was to determine the prevalence of smoking in patients with TB, identify demographic and clinical characteristics associated with smoking and to evaluate TB treatment outcomes in the smokers.

METHOD

A retrospective cohort study of patients with TB was conducted at Khyber Teaching Hospital, Peshawar, Pakistan. All patients with pulmonary and extrapulmonary TB and those coinfected with HIV, hepatitis or diabetes mellitus were included in the study. The patients were categorized into smokers and nonsmokers. Treatment outcomes were evaluated by smear testing at the end of the treatment.

RESULTS

Of 472 enrolled subjects, 68 (14.4%) were smokers. The prevalence of smoking among male and female patients with TB was 11.8% and 2.5%, respectively. Univariate analysis indicated that the gender, age group and marital status of patients with TB were associated with smoking. The results indicated that patient gender (P = 0.05), age: 15 to 24 years (P = 0.05) and age >55 years (P = 0.004) were risk factors associated with smoking among TB patients. Of the 68 smokers with TB, the treatment outcomes among 54 patients (79.4%) were unsuccessful. The treatment outcomes was statistically significantly associated with smoking (odds ratio: 2.58, P = 0.004).

CONCLUSIONS

Findings from the current study proved smoking to be one of the main factors associated with the occurrence of TB and significantly reducing the outcomes of TB therapy.

Tobacco smoking and tuberculosis treatment outcomes: a prospective cohort study in Georgia

OBJECTIVE

To assess the effect of tobacco smoking on the outcome of tuberculosis treatment in Tbilisi, Georgia.

METHODS

We conducted a prospective cohort study of adults with laboratory-confirmed tuberculosis from May 2011 to November 2013. History of tobacco smoking was collected using a standardized questionnaire adapted from the global adult tobacco survey. We considered tuberculosis therapy to have a poor outcome if participants defaulted, failed treatment or died. We used multivariable regressions to estimate the risk of a poor treatment outcome.

FINDINGS

Of the 591 tuberculosis patients enrolled, 188 (31.8%) were past smokers and 271 (45.9%) were current smokers. Ninety (33.2%) of the current smokers and 24 (18.2%) of the participants who had never smoked had previously been treated for tuberculosis (P < 0.01). Treatment outcome data were available for 524 of the participants, of whom 128 (24.4%) - including 80 (32.9%) of the 243 current smokers and 21 (17.2%) of the 122 individuals who had never smoked - had a poor treatment outcome. Compared with those who had never smoked, current smokers had an increased risk of poor treatment outcome (adjusted relative risk, aRR: 1.70; 95% confidence interval, CI: 1.00-2.90). Those who had ceased smoking more than two months before enrolment did not have such an increased risk (aRR: 1.01; 95% CI: 0.51-1.99).

CONCLUSION

There is a high prevalence of smoking among patients with tuberculosis in Georgia and smoking increases the risk of a poor treatment outcome.

Epidemiologic link between tuberculosis and cigarette/biomass smoke exposure: Limitations despite the vast literature

The geographic overlap between the prevalence of cigarette smoke (CS) exposure and tuberculosis (TB) in the world is striking. In recent years, relatively large number of studies has linked cigarette or biomass fuel smoke exposure and various aspects of TB. Our goals are to summarize the significance of the known published studies, graphically represent reports that quantified the association and discuss their potential limitations. PubMed searches were performed using the key words 'tuberculosis' with 'cigarette', 'tobacco', 'smoke' or 'biomass fuel smoke.' The references of relevant articles were examined for additional pertinent papers. A large number of mostly case-control and cross-sectional studies significantly associate both direct and second-hand smoke exposure with tuberculous infection, active TB, and/or more severe and lethal TB. Fewer link biomass fuel smoke exposure and TB. While a number of studies interpreted the association with multivariate analysis, other confounders are often not accounted for in these analyses. It is also important to emphasize that these retrospective studies can only show an association and not any causal link. We further explored the possibility that even if CS exposure is a risk factor for TB, several mechanisms may be responsible. Numerous studies associate cigarette and biomass smoke exposure with TB but the mechanism(s) remains largely unknown. While the associative link of these two health maladies is well established, more definitive, mechanistic studies are needed to cement the effect of smoke exposure on TB pathogenesis and to utilize this knowledge in empowering public health policies.

Cohort Profile: Hong Kong Department of Health Elderly Health Service Cohort

The Department of Health Elderly Health Service Cohort in Hong Kong was set up to promote understanding of ageing in a global context, to exploit the role of Hong Kong as a sentinel for populations currently experiencing very rapid economic development, to provide a developed non-Western 'social laboratory' where empirically derived hypotheses can be tested and to leverage the different patterns of common chronic diseases between East and West to generate novel hypotheses about their determinants. The initial cohort enrolled from July 1998 to the end of December 2001 includes 66 820 people aged 65 years or older, forming about 9% of the population of this age. A comprehensive health assessment was made at enrollment and then repeated regularly on an ongoing basis. The health assessment included a comprehensive assessment of lifestyle, social circumstances, physical health and mental health, including an assessment of cognition and depressive symptoms. Health services use and deaths have been obtained by record linkage and confirmed, where necessary, by telephone interview. Currently, the data are not publicly available; we would welcome collaborations and research proposals.

Survival analysis of adult tuberculosis disease

BACKGROUND

We conducted a survival analysis of all the confirmed cases of Adult Tuberculosis (TB) patients treated in Cork-City, Ireland. The aim of this study was to estimate Survival time (ST), including median time of survival and to assess the association and impact of covariates (TB risk factors) to event status and ST. The outcome of the survival analysis is reported in this paper.

METHODS

We used a retrospective cohort study research design to review data of 647 bacteriologically confirmed TB patients from the medical record of two teaching hospitals. Mean age 49 years (Range 18-112). We collected information on potential risk factors of all confirmed cases of TB treated between 2008-2012. For the survival analysis, the outcome of interest was 'treatment failure' or 'death' (whichever came first). A univariate descriptive statistics analysis was conducted using a non- parametric procedure, Kaplan -Meier (KM) method to estimate overall survival (OS), while the Cox proportional hazard model was used for the multivariate analysis to determine possible association of predictor variables and to obtain adjusted hazard ratio. P value was set at <0.05, log likelihood ratio test at >0.10. Data were analysed using SPSS version 15.0.

RESULTS

There was no significant difference in the survival curves of male and female patients. (Log rank statistic  = 0.194, df  = 1, p = 0.66) and among different age group (Log rank statistic  = 1.337, df = 3, p = 0.72). The mean overall survival (OS) was 209 days (95%CI: 92-346) while the median was 51 days (95% CI: 35.7-66). The mean ST for women was 385 days (95%CI: 76.6-694) and for men was 69 days (95%CI: 48.8-88.5). Multivariate Cox regression showed that patient who had history of drug misuse had 2.2 times hazard than those who do not have drug misuse. Smokers and alcohol drinkers had hazard of 1.8 while patients born in country of high endemicity (BICHE) had hazard of 6.3 and HIV co-infection hazard was 1.2.

CONCLUSION

There was no significant difference in survival curves of male and female and among age group. Women had a higher ST compared to men. But men had a higher hazard rate compared to women. Anti-TNF, immunosuppressive medication and diabetes were found to be associated with longer ST, while alcohol, smoking, RICHE, BICHE was associated with shorter ST.

Disease burden due to biomass cooking-fuel-related household air pollution among women in India

Background

Household air pollution (HAP) due to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women.

Methods

We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths due to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI).

Results

The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP due to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease.

Conclusions

HAP due to biomass fuel has diverse and major impacts on women’s health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within the broader framework of rural development will go a long way in reducing disease burden.

Smoking adversely affects treatment response, outcome and relapse in tuberculosis

The impact of smoking on tuberculosis outcome was evaluated in a territory-wide treatment programme. 16,345 consecutive patients undergoing chemotherapy for active tuberculosis in government chest clinics in Hong Kong from 2001 to 2003 were followed up prospectively for 2 years for treatment outcome and subsequently tracked through the territory-wide tuberculosis notification registry for relapse until the end of 2012. Smoking was associated with more extensive lung disease, lung cavitation and positive sputum smear and culture at the baseline. In both current smokers and ex-smokers, sputum smears and cultures were significantly more likely to remain positive after 2 months of treatment. Both categories of smokers were significantly less likely to achieve cure or treatment completion within 2 years. Overall, 16.7% of unsuccessful treatment outcomes were attributable to smoking, with the key contributor being default in current smokers and death in ex-smokers. Among successful treatment completers, there was a clear gradient (hazard ratios of 1.00, 1.33 and 1.63) of relapse risk from never-smokers to ex-smokers and current smokers, with an overall population attributable risk of 19.4% (current smokers: 12.2%; ex-smokers: 7.2%). Smoking adversely affects baseline disease severity, bacteriological response, treatment outcome and relapse in tuberculosis. Smoking cessation likely reduces relapse and secondary transmission.

Joint effects of smoking and silicosis on diseases to the lungs

Smokers are subject to being more susceptible to the long-term effects of silica dust, whilst it remains unclear whether the joint effect of smoking and silicosis differs amongst diseases to the lungs; this study aims to address this knowledge gap. This was a historical cohort study comprised of 3202 silicotics in Hong Kong during 1981-2005 who were followed up till 31/12/2006. We estimated the standardized mortality ratio (SMR) in the smoking and never smoking silicotics using the mortality rates of male general population indiscriminately by smoking status, but these SMRs were regarded as biased. We adjusted these biased SMRs using "smoking adjustment factors (SAF)". We assessed the multiplicative interaction between smoking and silicosis using 'relative silicosis effect (RSE)' that was the ratio of SAF-corrected SMR of smoking silicotics to the never smokers. A RSE differs significantly from one implies the presence of multiplicative interaction. A significant excess SMR was observed for respiratory diseases (lung cancer, chronic obstructive pulmonary diseases [COPD], silicosis) and other diseases to the lungs (pulmonary heart disease, tuberculosis). All the 'biased-SMRs' in smokers were higher than those in never smokers, but the SAF-corrected SMRs became higher in never smokers. The RSE was 0.95 (95%CI: 0.37-3.55), 0.94 (95%CI: 0.42-2.60), and 0.81 (95%CI: 0.60-1.19) for lung cancer, COPD, and silicosis; whilst it was 1.21 (95%CI: 0.32-10.26) for tuberculosis and 1.02 (95%CI: 0.16-42.90) for pulmonary heart disease. This study firstly demonstrated the joint effect of smoking and silicosis may differ amongst diseases to the lungs, but power is limited.

The Association Between Passive Smoking and Type 2 Diabetes

The number of people with diabetes has been exponentially increasing. A number of reports in the literature have suggested that exposure to passive smoke may play a key role in the development of diabetes; however, the association has not been jointly summarized yet. In this meta-analysis, 2 databases were searched to identify studies, and the references of these studies were scanned for further studies. Fourteen studies on the relationship between passive smoking and diabetes were included. After all the studies were pooled, the results showed that passive smoking was significantly associated with an increased risk of type 2 diabetes in a random model. The subgroup analysis results were consistent with overall results regardless of type of study design, age, gender, adjustment of dependent variables, area, or study quality. Sensitivity analysis indicated that the overall results were reliable. There was no publication bias observed in the selected studies.

Risk of tuberculosis in high-rise and high density dwellings: an exploratory spatial analysis

Studies have shown that socioeconomic and environmental factors have direct/indirect influences on TB. This research focuses on TB prevalence of Hong Kong in relation to its compact urban development comprising of high-rise and high-density residential dwellings caused by rapid population growth and limited land resources. It has been postulated that occupants living on higher levels of a building would benefit from better ventilation and direct sunlight and thus less likely to contract infectious respiratory diseases. On the contrary, those on lower floors amid the dense clusters of high-rises are more susceptible to TB infection because of poorer air quality from street-level pollution and lesser exposure to direct sunlight. However, there have not been published studies to support these claims. As TB continues to threaten public health in Hong Kong, this study seeks to understand the effects of housing development on TB occurrences in an urban setting.

Tobacco use patterns in tuberculosis patients with high rates of human immunodeficiency virus co-infection in South Africa

BACKGROUND

Tuberculosis (TB) patients who smoke tobacco are at an increased risk for adverse TB treatment outcomes. This study describes tobacco use patterns among newly diagnosed TB patients, their readiness to quit, and their beliefs about tobacco-related health effects in a high HIV-burden setting in South Africa. Socio-economic and demographic factors associated with smoking were also determined.

METHODS

This was a cross-sectional analysis of baseline data collected for a smoking cessation study at six large tuberculosis clinics in a South African township (N = 1926). We collected information on current and past tobacco use, socio-economic and demographic status, beliefs regarding the harmful effects of smoking and quit behaviour, and motivation, using structured interviewer-administered questionnaires. TB- and HIV-related information was obtained from patient records. Data analysis entailed descriptive statistics, followed by multivariate logistic regression with backward elimination, adjusted for clustering by facility.

RESULTS

Just over one fifth of respondents (21.8%, 420/1924) reported currently smoking tobacco (males 37.6%, females 4.6%). By contrast, only 1.8% (35/1918) of all respondents reported being past smokers. Of the current smokers, about half (51.8%, 211/407) had previously attempted to quit, mainly for health reasons. The majority of respondents (89.3%, 1675/1875) believed tobacco smoking was harmful for their health and smokers were highly motivated to quit (median score 9, interquartile range 7-10). Smoking was less common among female respondents (Odds Ratio [OR] 0.10, 95% Confidence Interval [CI] 0.06-0.19) and respondents who had completed high school (OR 0.57, 95% CI 0.39-0.84), but was more common among respondents who do occasional work (OR 2.82, 95% CI 1.58-5.02), respondents who to bed hungry regularly (OR 4.19, 95% CI 2.42-7.25), those who have an alcohol problem (OR 5.79, 95% CI 3.24-10.34) and those who use illicit substances (OR 10.81, 95% CI 4.62-25.3).

CONCLUSIONS

Despite documented evidence of its harmful effects, smoking is prevalent among male TB patients in this high HIV-prevalence population. Few patients have managed to quit smoking on their own. However, patients are highly motivated to stop smoking. We recommend implementing and evaluating a smoking cessation programme in tandem with TB services.

Long-term dominance of Mycobacterium tuberculosis Uganda family in peri-urban Kampala-Uganda is not associated with cavitary disease

Background

Previous studies have shown that Mycobacterium tuberculosis (MTB) Uganda family, a sub-lineage of the MTB Lineage 4, is the main cause of tuberculosis (TB) in Uganda. Using a well characterized patient population, this study sought to determine whether there are clinical and patient characteristics associated with the success of the MTB Uganda family in Kampala.

Methods

A total of 1,746 MTB clinical isolates collected from1992-2009 in a household contact study were genotyped. Genotyping was performed using Single Nucleotide Polymorphic (SNP) markers specific for the MTB Uganda family, other Lineage 4 strains, and Lineage 3, respectively. Out of 1,746 isolates, 1,213 were from patients with detailed clinical data. These data were used to seek associations between MTB lineage/sub-lineage and patient phenotypes.

Results

Three MTB lineages were found to dominate the MTB population in Kampala during the last two decades. Overall, MTB Uganda accounted for 63% (1,092/1,746) of all cases, followed by other Lineage 4 strains accounting for 22% (394/1,746), and Lineage 3 for 11% (187/1,746) of cases, respectively. Seventy-three (4 %) strains remained unclassified. Our longitudinal data showed that MTB Uganda family occurred at the highest frequency during the whole study period, followed by other Lineage 4 strains and Lineage 3. To explore whether the long-term success of MTB Uganda family was due to increased virulence, we used cavitary disease as a proxy, as this form of TB is the most transmissible. Multivariate analysis revealed that even though cavitary disease was associated with known risk factors such as smoking (adjusted odds ratio (aOR) 4.8, 95% confidence interval (CI) 3.33-6.84) and low income (aOR 2.1, 95% CI 1.47-3.01), no association was found between MTB lineage and cavitary TB.

Conclusion

The MTB Uganda family has been dominating in Kampala for the last 18 years, but this long-term success is not due to increased virulence as defined by cavitary disease.