Quantifying the potential effects of air pollution reduction on population health and health expenditure in Taiwan.

Air pollution, particularly ambient fine particulate matter (PM2.5) pollution, poses a significant risk to public health, underscoring the importance of comprehending the long-term impact on health burden and expenditure at national and subnational levels. Therefore, this study aims to quantify the disease burden and healthcare expenditure associated with PM2.5 exposure in Taiwan and assess the potential benefits of reducing pollution levels. Using a comparative risk assessment framework that integrates an auto-aggressive integrated moving average model, we evaluated the avoidable burden of cardiopulmonary diseases (including ischemic heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and diabetes mellitus) and related healthcare expenditure under different air quality target scenarios, including status quo and target scenarios of 15, 10, and 5 µg/m3 reduction in PM2.5 concentration. Our findings indicate that reducing PM2.5 exposure has the potential to significantly alleviate the burden of multiple diseases. Comparing the estimated attributable disease burden and healthcare expenditure between reference and target scenarios from 2022 to 2050, the avoidable disability-adjusted life years were 0.61, 1.83, and 3.19 million for the 15, 10, and 5 µg/m3 target scenarios, respectively. Correspondingly, avoidable healthcare expenditure ranged from US$ 0.63 to 3.67 billion. We also highlighted the unequal allocation of resources and the need for policy interventions to address health disparities due to air pollution. Notably, in the 5 µg/m3 target scenario, Kaohsiung City stands to benefit the most, with 527,368 disability-adjusted life years avoided and US$ 0.53 billion saved from 2022 to 2050. Our findings suggest that adopting stricter emission targets can effectively reduce the health burden and associated healthcare expenditure in Taiwan. Overall, this study provides policymakers in Taiwan with valuable insights for mitigating the negative effects of air pollution by establishing a comprehensive framework for evaluating the co-benefits of air pollution reduction on healthcare expenditure and disease burden.

Long-term exposure to ambient fine particulate matter (PM2.5) and associations with cardiopulmonary diseases and lung cancer in Taiwan: a nationwide longitudinal cohort study.

BACKGROUND: Although a number of studies have reported on the health effects of fine particulate matter (PM2.5) exposure, particularly in North American and European countries as well as China, the evidence about intermediate to high levels of PM2.5 exposures is still limited. We aimed to investigate the associations between long-term exposure to PM2.5 and risk of cardiopulmonary disease incidence in Taiwan with intermediate levels of PM2.5 exposure. METHODS: A cohort of Taiwanese adults, who participated in the 2001, 2005, 2009 and 2013 National Health Interview Surveys, was followed through 2016 to identify cardiopulmonary disease onset. Exposure to PM2.5 was estimated by incorporating a widespread monitoring network of air quality monitoring stations and microsensors. We used time-dependent Cox regression models to examine the associations between the PM2.5 exposures and health outcomes, adjusting for individual characteristics and ecological covariates. The natural cubic spline functions were used to explore the non-linear effects of the PM2.5 exposure. RESULTS: A total of 62 694 adults from 353 towns were enrolled. Each 10-µg/m3 increase in 5-year average exposure to PM2.5 was associated with a 4.8% increased risk of incident ischaemic heart disease (95% CI: -3.3, 13.6), 3.9% increased risk of incident stroke (95% CI: -2.9, 11.1), 6.7% increased risk of incident diabetes (95% CI: 1.1, 12.7), 15.7% increased risk of incident lung cancer (95% CI: -0.9, 35.1) and 11.5% increased risk of incident chronic obstructive pulmonary disease (95% CI: -0.8, 25.2). The concentration-response curve showed that there was no statistical evidence of non-linearity for most of the disease outcomes except for ischaemic heart disease (P for non-linearity = 0.014). CONCLUSIONS: Long-term exposure to intermediate levels of ambient PM2.5 was associated with cardiopulmonary health outcomes. Our study adds value to future application and national burden of disease estimation in evaluating the health co-benefits from ambient air pollution reduction policy in Asian countries.

Global burden of tuberculosis attributable to cancer in 2019: Global, regional, and national estimates.

BACKGROUND: Cancer is an independent risk factor for tuberculosis (TB). The global burden of incident TB attributable to cancer has never been explored. We aimed to evaluate the cancer-attributable burden of TB. METHODS: We estimated the population attributable fraction (PAF) by Levin's formula. The cancer prevalence rates were derived from the Institute for Health Metrics and Evaluation. The relative risk of TB in cancer patients was estimated by using the National Health Insurance Research Database in Taiwan. The global burden of incidence TB attributable to cancer was the weighted sum of PAFs multiplied by the incidence of TB retrieved from the World Health Organization. RESULTS: Worldwide, the total of incident TB cases attributable to cancer was 115,478 cases with a 95% confidence interval (CI), 110,482-123,007, in 2019. The global PAF of TB due to cancer was 1.85% (95% CI, 1.77-1.97%). The three countries with the highest PAFs were Greenland (7.77%), Canada (7.75%), and the United States of America (6.79%), while the three countries with the highest attributable TB cases due to cancer were China (25,240), India (21,629), and Indonesia (13,917). Cancer of respiratory system contributed to 60,257 of TB cases. CONCLUSIONS: This study comprehensively explored the impact of cancer on the global burden of TB. Efforts to reduce cancer risk, delay the occurrence of cancer, or treat latent TB infection in the cancer population could potentially reduce the burden of TB and rely on formulating integrated strategies.

Time-dependent association between cancer and risk of tuberculosis: A population-based cohort study.

BACKGROUND: We aimed to investigate the time-dependent association between cancer and the risk of tuberculosis (TB) before and after cancer diagnosis. METHODS: This population-based cohort study incorporated the National Health Insurance Research Database and the National Health Interview Survey in Taiwan to estimate TB risk in cancer and noncancer populations. We estimated the period-specific incidence rate ratio (IRR) between cancer and risk of TB and used Cox proportional hazards models to estimate the average hazard ratio between cancer and TB during the peridiagnostic period. RESULTS: From 2001 to 2015, 457 673 cancer and 3 738 122 noncancer individuals were enrolled. After stratifying the IRR of TB by year relative to the date of cancer diagnosis, the peak IRRs clustered in the year before and after the index date. In the peridiagnostic period of cancer, the adjusted hazard ratio was 2.29 (95% CI, 2.22-2.35) using the Cox model and 2.20 (95% CI, 2.09-2.32) after adjustment for missing confounders. Patients with cancers in the respiratory tract, upper digestive tract, and hematologic system were at the highest risk for TB. CONCLUSIONS: Cancer is an independent risk factor for TB, with the highest risk observed around the time of cancer diagnosis.

Patient pathways of tuberculosis care-seeking and treatment: an individual-level analysis of National Health Insurance data in Taiwan.

INTRODUCTION: Patients with tuberculosis (TB) often experience difficulties in accessing diagnosis and treatment. Patient pathway analysis identifies mismatches between TB patient care-seeking patterns and service coverage, but to date, studies have only employed cross-sectional aggregate data. METHODS: We developed an algorithmic approach to analyse and interpret patient-level routine data on healthcare use and to construct patients' pathways from initial care-seeking to treatment outcome. We applied this to patients with TB in a simple random sample of one million patients' records in the Taiwan National Health Insurance database. We analysed heterogeneity in pathway patterns, delays, service coverage and patient flows between different health system levels. RESULTS: We constructed 7255 pathways for 6258 patients. Patients most commonly initially sought care at the primary clinic level, where the capacity for diagnosing TB patients was 12%, before eventually initiating treatment at higher levels. Patient pathways are extremely heterogeneous prior to diagnosis, with the 10% most complex pathways accounting for 48% of all clinical encounters, and 55% of those pathways yet to initiate treatment after a year. Extended consideration of alternative diagnoses was more common for patients aged 65 years or older and for patients with chronic lung disease. CONCLUSION: Our study demonstrates that longitudinal analysis of routine individual-level healthcare data can be used to generate a detailed picture of TB care-seeking pathways. This allows an understanding of several temporal aspects of care pathways, including lead times to care and the variability in patient pathways.

Health impact assessment of PM2.5 from a planned coal-fired power plant in Taiwan.

PURPOSE: To investigate the impact of a planned coal-fired power plant (CFPPT) in Shenao on air quality and health at subnational levels in Taiwan. METHODS: We applied the Gaussian trajectory transfer-coefficient (GTx) model to estimate annual average PM2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) increments in 19 Taiwanese cities and counties caused by CFPPT operation. A population health risk assessment was performed by incorporating evidence of the health effects of PM2.5 provided by prospective studies and estimating long-term PM2.5 exposure. Additionally, we considered ischemic heart disease, stroke, lung cancer, and chronic obstruct pulmonary disease as the primary outcomes. The population-attributable fraction was used to estimate the county-level mortality burden attributable to CFPPT-generated PM2.5 in 2025. RESULTS: The estimated annual PM2.5 increments ranged from 0.004 µg/m3 (Taitung County) to 0.28 µg/m3 (Hsinchu County) due to the Shenao CFPPT. The total and premature deaths attributable to PM2.5 from Shenao CFPPT operation in Taiwan during 2025-2040 would be 576 (95% confidence interval [CI]: 537-619) and 145 (95% CI: 136-155), respectively. Notably, we estimated 198 (95% CI: 169-234) deaths and 58 (95% CI: 51-66) premature deaths, respectively, in New Taipei City, which accounted for over a quarter of the total deaths. Overall, the mortality rate attributable to the Shenao CFPPT in Taiwan was 6 per 10,000. CONCLUSION: A scientific approach should be adopted for assessing the impacts of CFPPT operation on population health, which can serve as a valuable policymaking reference for the government.

Development and validation of a prediction model for active tuberculosis case finding among HIV-negative/unknown populations.

A prediction model of prevalent pulmonary tuberculosis (TB) in HIV negative/unknown individuals was developed to assist systematic screening. Data from a large TB screening trial were used. A multivariable logistic regression model was developed in the South African (SA) training dataset, using TB symptoms and risk factors as predictors. The model was converted into a scoring system for risk stratification and was evaluated in separate SA and Zambian validation datasets. The number of TB cases were 355, 176, and 107 in the SA training, SA validation, and Zambian validation datasets respectively. The area under curve (AUC) of the scoring system was 0·68 (95% CI 0·64-0·72) in the SA validation set, compared to prolonged cough (0·58, 95% CI 0·54-0·62) and any TB symptoms (0·6, 95% CI 0·56-0·64). In the Zambian dataset the AUC of the scoring system was 0·66 (95% CI 0·60-0·72). In the cost-effectiveness analysis, the scoring system dominated the conventional strategies. The cost per TB case detected ranged from 429 to 1,848 USD in the SA validation set and from 171 to 10,518 USD in the Zambian dataset. The scoring system may help targeted TB case finding under budget constraints.

Adult mortality of diseases and injuries attributable to selected metabolic, lifestyle, environmental, and infectious risk factors in Taiwan: a comparative risk assessment.

BACKGROUND: To facilitate priority-setting in health policymaking, we compiled the best available information to estimate the adult mortality (>30 years) burden attributable to 13 metabolic, lifestyle, infectious, and environmental risk factors in Taiwan. METHODS: We obtained data on risk factor exposure from nationally representative health surveys, cause-specific mortality from the National Death Registry, and relative risks from epidemiological studies and meta-analyses. We applied the comparative risk assessment framework to estimate mortality burden attributable to individual risk factors or risk factor clusters. RESULTS: In 2009, high blood glucose accounted for 14,900 deaths (95% UI: 11,850-17,960), or 10.4% of all deaths in that year. It was followed by tobacco smoking (13,340 deaths, 95% UI: 10,330-16,450), high blood pressure (11,190 deaths, 95% UI: 8,190-14,190), ambient particulate matter pollution (8,600 deaths, 95% UI: 7,370-9,840), and dietary risks (high sodium intake and low intake of fruits and vegetables, 7,890 deaths, 95% UI: 5,970-9,810). Overweight-obesity and physical inactivity accounted for 7,620 deaths (95% UI: 6,040-9,190), and 7,400 deaths (95% UI: 6,670-8,130), respectively. The cardiometabolic risk factors of high blood pressure, high blood glucose, high cholesterol, and overweight-obesity jointly accounted for 12,120 deaths (95% UI: 11,220-13,020) from cardiovascular diseases. For domestic risk factors, infections from hepatitis B virus (HBV) and hepatitis C virus (HCV) were responsible for 6,300 deaths (95% UI: 5,610-6,980) and 3,170 deaths (95% UI: 1,860-4,490), respectively, and betel nut use was associated with 1,780 deaths from oral, laryngeal, and esophageal cancer (95% UI: 1,190-2,360). The leading risk factors for years of life lost were similar, but the impact of tobacco smoking and alcohol use became larger because the attributable deaths from these risk factors occurred among young adults aged less than 60 years. CONCLUSIONS: High blood glucose, tobacco smoking, and high blood pressure are the major risk factors for deaths from diseases and injuries among Taiwanese adults. A large number of years of life would be gained if the 13 modifiable risk factors could be removed or reduced to the optimal level.

Burden of disease attributable to ambient fine particulate matter exposure in Taiwan.

BACKGROUND/PURPOSE: There is compelling epidemiological evidence that links air pollution to increased risk of mortality from cardiopulmonary disease and lung cancer. We quantified the burden of mortality attributable to ambient fine particulate matter (PM2.5) among the Taiwanese population in 2014 at the national and subnational levels. METHODS: Subnational PM2.5 exposure levels were obtained from Taiwan Air Quality Monitoring Network. Relative risks were derived from a previously developed exposure-response model. Population attributable fraction for cause-specific mortality was estimated at the county level using the estimated ambient PM2.5 concentrations and the relative risk functions. RESULTS: In 2014, PM2.5 accounted for 6282 deaths [95% confidence interval (CI), 5716-6847], from ischemic heart disease (2244 deaths; 95% CI, 2015-2473), stroke (2140 deaths; 95% CI, 1760-2520), lung cancer (1252 deaths; 95% CI, 995-1509), and chronic obstructive pulmonary disease (645 deaths; 95% CI, 418-872). Nationally, the population attributable mortality fraction of PM2.5 for the four disease causes was 18.6% (95% CI, 16.9-20.3%). Substantial geographic variation in PM2.5 attributable mortality fraction was found; the percentage of deaths attributable to PM2.5 ranged from 8.7% in Hualian County to 21.8% in Yunlin County. In terms of absolute number of deaths, New Taipei and Kaohsiung cities had the largest number of deaths associated with PM2.5 (874 and 829 deaths, respectively) among all cities and counties. CONCLUSION: Ambient PM2.5 pollution is a major mortality risk factor in Taiwan. Aggressive and multisectorial intervention strategies are urgently needed to bring down the impact of air pollution on environment and health.

Feasibility of achieving the 2025 WHO global tuberculosis targets in South Africa, China, and India: a combined analysis of 11 mathematical models.

BACKGROUND: The post-2015 End TB Strategy proposes targets of 50% reduction in tuberculosis incidence and 75% reduction in mortality from tuberculosis by 2025. We aimed to assess whether these targets are feasible in three high-burden countries with contrasting epidemiology and previous programmatic achievements. METHODS: 11 independently developed mathematical models of tuberculosis transmission projected the epidemiological impact of currently available tuberculosis interventions for prevention, diagnosis, and treatment in China, India, and South Africa. Models were calibrated with data on tuberculosis incidence and mortality in 2012. Representatives from national tuberculosis programmes and the advocacy community provided distinct country-specific intervention scenarios, which included screening for symptoms, active case finding, and preventive therapy. FINDINGS: Aggressive scale-up of any single intervention scenario could not achieve the post-2015 End TB Strategy targets in any country. However, the models projected that, in the South Africa national tuberculosis programme scenario, a combination of continuous isoniazid preventive therapy for individuals on antiretroviral therapy, expanded facility-based screening for symptoms of tuberculosis at health centres, and improved tuberculosis care could achieve a 55% reduction in incidence (range 31-62%) and a 72% reduction in mortality (range 64-82%) compared with 2015 levels. For India, and particularly for China, full scale-up of all interventions in tuberculosis-programme performance fell short of the 2025 targets, despite preventing a cumulative 3·4 million cases. The advocacy scenarios illustrated the high impact of detecting and treating latent tuberculosis. INTERPRETATION: Major reductions in tuberculosis burden seem possible with current interventions. However, additional interventions, adapted to country-specific tuberculosis epidemiology and health systems, are needed to reach the post-2015 End TB Strategy targets at country level. FUNDING: Bill and Melinda Gates Foundation.

Ambient air pollution and risk of tuberculosis: a cohort study.

OBJECTIVES: Several respirable hazards, including smoking and indoor air pollution from biomass, were suggested to increase the risk of tuberculosis. Few studies have been conducted on ambient air pollution and tuberculosis. We investigated the association between exposure to ambient air pollution and incidence of active tuberculosis. METHODS: We conducted a cohort study using 106,678 participants of a community-based screening service in Taiwan, 2005-2012. We estimated individual exposure to air pollution using data from the nearest air quality monitoring station and the road intensity within a 500 m buffer zone. The incidence of tuberculosis was ascertained from the national tuberculosis registry. RESULTS: After a median follow-up of 6.7 years, 418 cases of tuberculosis occurred. Exposure to fine particulate matter (PM2.5) was associated with increased risk of active tuberculosis (adjusted HR: 1.39/10 µg/m3 (95% CI 0.95 to 2.03)). In addition, traffic-related air pollution including nitrogen dioxide (adjusted HR: 1.33/10 ppb; 95% CI 1.04 to 1.70), nitrogen oxides (adjusted HR: 1.21/10 ppb; 95% CI 1.04 to 1.41) and carbon monoxide (adjusted HR: 1.89/ppm; 95% CI 0.78 to 4.58) was associated with tuberculosis risk. There was a non-significant trend between the length of major roads in the neighbourhood and culture-confirmed tuberculosis (adjusted HR: 1.04/km; 95% CI 0.995 to 1.09). CONCLUSIONS: Our study revealed a possible link between ambient air pollution and risk of active tuberculosis. Since people from developing countries continue to be exposed to high levels of ambient air pollution and to experience high rates of tuberculosis, the impact of worsening air pollution on global tuberculosis control warrants further investigation.

The influence of diabetes, glycemic control, and diabetes-related comorbidities on pulmonary tuberculosis.

BACKGROUND: To assess the influence of diabetes mellitus (DM), glycemic control, and diabetes-related comorbidities on manifestations and outcome of treatment of pulmonary tuberculosis (TB). METHODOLOGY/PRINCIPAL FINDINGS: Culture positive pulmonary TB patients notified to health authorities in three hospitals in Taiwan from 2005-2010 were investigated. Glycemic control was assessed by glycated haemoglobin A1C (HbA1C) and diabetic patients were categorized into 3 groups: HbA1C<7%, HbA1C 7-9%, HbA1C>9%. 1,473 (705 with DM and 768 without DM) patients were enrolled. Of the 705 diabetic patients, 82 (11.6%) had pretreatment HbA1C<7%, 152 (21.6%) 7%-9%, 276 (39.2%) >9%, and 195 (27.7%) had no information of HbA1C. The proportions of patients with any symptom, cough, hemoptysis, tiredness and weight loss were all highest in diabetic patients with HbA1C>9%. In multivariate analysis adjusted for age, sex, smoking, and drug resistance, diabetic patients with HbA1C>9% (adjOR 3.55, 95% CI 2.40-5.25) and HbA1C 7-9% (adjOR 1.62, 95% CI 1.07-2.44) were significantly more likely to be smear positive as compared with non-diabetic patients, but not those with HbA1C<7% (adjOR 1.16, 95% CI 0.70-1.92). The influence of DM on outcome of TB treatment was not proportionately related to HbA1C, but mainly mediated through diabetes-related comorbidities. Patients with diabetes-related comorbidities had an increased risk of unfavorable outcome (adjOR 3.38, 95% CI 2.19-5.22, p<0.001) and one year mortality (adjOR 2.80, 95% CI 1.89-4.16). However, diabetes was not associated with amplification of resistance to isoniazid (p = 0.363) or to rifampicin (p = 0.344). CONCLUSIONS/SIGNIFICANCE: Poor glycemic control is associated with poor TB treatment outcome and improved glycemic control may reduce the influence of diabetes on TB.

Smoking, drinking, and pancreatitis: a population-based cohort study in Taiwan.

OBJECTIVES: In Western population, smoking is a dose-dependent risk factor for pancreatitis, whereas a threshold of 5 drinks per day may exist for alcohol to increase pancreatitis risk. Given ethnic differences in tobacco and alcohol metabolism, we examined the associations between smoking, alcohol, and pancreatitis in Asians. METHODS: A population-based cohort was assembled using participants of the National Health Interview Survey in Taiwan. Information on drinking and smoking was collected by in-person interview at baseline. Incident cases of pancreatitis were identified through data linkage with National Health Insurance claims database. RESULTS: During 94,601 person-years of follow-up, 66 incident cases of pancreatitis occurred. Neither current nor ever smoking was associated with the incidence of pancreatitis (adjusted hazard ratio [aHR] 1.13; 95% confidence interval [CI], 0.62-2.06; and aHR, 1.14; 95% CI, 0.63-2.06, respectively). Dose-response analysis also showed no association between smoking and pancreatitis. By contrast, regular (aHR, 3.09; 95% CI, 1.51-6.30) and heavy alcohol drinking (aHR, 6.46; 95% CI, 3.07-13.60) were associated with an increased incidence of pancreatitis compared with abstinence. CONCLUSIONS: In this Asian population-based cohort, alcohol was associated with pancreatitis in a dose-dependent way, but smoking was not associated with pancreatitis. These results support for ethnic differences in susceptibility to smoking- and alcohol-related pancreatitis.

Exposure to secondhand smoke and risk of tuberculosis: prospective cohort study.

BACKGROUND: Prospective evidence on the association between secondhand-smoke exposure and tuberculosis is limited. METHODS: We included 23,827 never smokers from two rounds (2001 and 2005) of Taiwan National Health Interview Survey. Information on exposure to secondhand smoke at home as well as other sociodemographic and behavioral factors was collected through in-person interview. The participants were prospectively followed for incidence of tuberculosis through cross-matching the survey database to the national tuberculosis registry of Taiwan. RESULTS: A total of 85 cases of active tuberculosis were identified after a median follow-up of 7.0 years. The prevalence of exposure to secondhand smoke at home was 41.8% in the study population. In the multivariable Cox proportional hazards analysis, secondhand smoke was not associated with active tuberculosis (adjusted hazard ratio [HR], 1.03; 95% CI, 0.64 to 1.64). In the subgroup analysis, the association between secondhand smoke and tuberculosis decreased with increasing age; the adjusted HR for those <18, > = 18 and <40, > = 40 and <60, and > = 60 years old was 8.48 (0.77 to 93.56), 2.29 (0.75 to 7.01), 1.33 (0.58 to 3.01), and 0.66 (0.35 to 1.23) respectively. Results from extensive sensitivity analyses suggested that potential misclassification of secondhand-smoke exposure would not substantially affect the observed associations. CONCLUSIONS: The results from this prospective cohort study did not support an overall association between secondhand smoke and tuberculosis. However, the finding that adolescents might be particularly susceptible to secondhand smoke's effect warrants further investigation.

Use of thiazolidinediones and the risk of colorectal cancer in patients with diabetes: a nationwide, population-based, case-control study.

OBJECTIVE: Preclinical data suggest that peroxisome proliferator-activated receptor γ (PPARγ) agonists have antineoplastic effects in colorectal cancer. We aimed to assess the association between the use of synthetic PPARγ agonists, represented by thiazolidinediones (TZDs), and the risk of developing colorectal cancer. RESEARCH DESIGN AND METHODS: We conducted a nationwide, population-based, case-control study using the Taiwan National Health Insurance Research Database. Case subjects were defined as patients who were diagnosed with diabetes at least 365 days prior to a new diagnosis of colorectal cancer between 2000 and 2008. We randomly selected diabetic control subjects for each case subject, which were matched by sex, age, and the duration of diabetes. Among the 24,496 eligible case subjects and control subjects, we used conditional logistic regression to assess the risk of colorectal cancer in association with the use of TZDs. An additional analysis was conducted to assess the effects of concomitant use of TZDs and low-dose aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) on the risk of colorectal cancer. RESULTS: A decreased risk of colorectal cancer was observed in patients who had used TZDs compared with those who had never used TZDs (adjusted odds ratio 0.86 [95% CI 0.79-0.94]). Furthermore, the benefit of a decreased colorectal cancer risk was also found with concomitant use of TZDs and low-dose aspirin or NSAIDs. CONCLUSIONS: The use of TZDs may be associated with a decreased risk of colorectal cancer in patients with diabetes. Further studies are warranted to confirm our findings.

Association between tobacco smoking and active tuberculosis in Taiwan: prospective cohort study.

RATIONALE: Previous case-control studies and a small number of cohort studies in high-risk populations have found an association between tobacco and active tuberculosis, but no cohort studies have been conducted in the general population on this association to date. OBJECTIVES: To investigate the association between tobacco smoking and active tuberculosis in a cohort of a general population. METHODS: 17,699 participants (>or=12 y of age) in Taiwan National Health Interview Survey were followed up from 2001 to 2004. Smoking status and other covariates were measured by an in-person interview at baseline. Incident cases of active tuberculosis were identified from the National Health Insurance database. Multivariate logistic regression was used to estimate the association between smoking status and active tuberculosis, with adjustment for age, sex, alcohol consumption, socioeconomic status, and other covariates. MEASUREMENTS AND MAIN RESULTS: Fifty-seven new cases of active tuberculosis occurred during the 3.3 years of follow-up. Current smoking was associated with an increased risk of active tuberculosis (adjusted odds ratio [OR], 1.94; 95% confidence interval, 1.01-3.73). The association was stronger among those less than 65 years of age (adjusted OR, 3.04) than those greater than 65 years of age (adjusted OR, 0.78; P(interaction) = 0.036). We found significant dose-response relations for cigarettes per day (P(trend) = 0.0036), years of smoking (P(trend) = 0.023), and pack-years (P(trend) = 0.0023). CONCLUSIONS: Tobacco smoking was associated with a twofold increased risk of active tuberculosis in a representative cohort of Taiwan's population.

Effects of smoking and solid-fuel use on COPD, lung cancer, and tuberculosis in China: a time-based, multiple risk factor, modelling study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD), lung cancer, and tuberculosis are three leading causes of death in China, where prevalences of smoking and solid-fuel use are also high. We aimed to predict the effects of risk-factor trends on COPD, lung cancer, and tuberculosis. METHODS: We used representative data sources to estimate past trends in smoking and household solid-fuel use and to construct a range of future scenarios. We obtained the aetiological effects of risk factors on diseases from meta-analyses of epidemiological studies and from large studies in China. We modelled future COPD and lung cancer mortality and tuberculosis incidence, taking into account the accumulation of hazardous effects of risk factors on COPD and lung cancer over time, and dependency of the risk of tuberculosis infection on the prevalence of disease. We quantified the sensitivity of our results to methods and data choices. FINDINGS: If smoking and solid-fuel use remain at current levels between 2003 and 2033, 65 million deaths from COPD and 18 million deaths from lung cancer are predicted in China; 82% of COPD deaths and 75% of lung cancer deaths will be attributable to the combined effects of smoking and solid-fuel use. Complete gradual cessation of smoking and solid-fuel use by 2033 could avoid 26 million deaths from COPD and 6.3 million deaths from lung cancer; interventions of intermediate magnitude would reduce deaths by 6-31% (COPD) and 8-26% (lung cancer). Complete cessation of smoking and solid-fuel use by 2033 would reduce the projected annual tuberculosis incidence in 2033 by 14-52% if 80% DOTS coverage is sustained, 27-62% if 50% coverage is sustained, or 33-71% if 20% coverage is sustained. INTERPRETATION: Reducing smoking and solid-fuel use can substantially lower predictions of COPD and lung cancer burden and would contribute to effective tuberculosis control in China.

Tobacco smoke, indoor air pollution and tuberculosis: a systematic review and meta-analysis.

BACKGROUND: Tobacco smoking, passive smoking, and indoor air pollution from biomass fuels have been implicated as risk factors for tuberculosis (TB) infection, disease, and death. Tobacco smoking and indoor air pollution are persistent or growing exposures in regions where TB poses a major health risk. We undertook a systematic review and meta-analysis to quantitatively assess the association between these exposures and the risk of infection, disease, and death from TB. METHODS AND FINDINGS: We conducted a systematic review and meta-analysis of observational studies reporting effect estimates and 95% confidence intervals on how tobacco smoking, passive smoke exposure, and indoor air pollution are associated with TB. We identified 33 papers on tobacco smoking and TB, five papers on passive smoking and TB, and five on indoor air pollution and TB. We found substantial evidence that tobacco smoking is positively associated with TB, regardless of the specific TB outcomes. Compared with people who do not smoke, smokers have an increased risk of having a positive tuberculin skin test, of having active TB, and of dying from TB. Although we also found evidence that passive smoking and indoor air pollution increased the risk of TB disease, these associations are less strongly supported by the available evidence. CONCLUSIONS: There is consistent evidence that tobacco smoking is associated with an increased risk of TB. The finding that passive smoking and biomass fuel combustion also increase TB risk should be substantiated with larger studies in future. TB control programs might benefit from a focus on interventions aimed at reducing tobacco and indoor air pollution exposures, especially among those at high risk for exposure to TB.