Prevalence and risk factors for LTBI among DM patients in Taiwan [TBN 063]

What

This study examined the prevalence of latent tuberculosis infection (LTBI) among patients with diabetes mellitus (DM) in Taiwan and identified factors associated with LTBI risk in this population. Diabetes is recognized as an important risk factor for tuberculosis progression, yet evidence regarding LTBI burden among diabetic populations in Taiwan remained limited, particularly in the context of widespread Bacillus Calmette–Guérin (BCG) vaccination. Because routine childhood BCG vaccination and booster doses may reduce the accuracy of traditional tuberculin skin testing (TST), this study employed interferon-gamma release assay (IGRA) to provide a more reliable estimate of LTBI prevalence among diabetic patients.

Among 1,120 diabetic patients included in the analysis, 21.5% tested positive for LTBI, indicating a substantial burden of latent infection within this population. Patients with LTBI were significantly older, with a mean age of 58.2 years compared with 55.0 years in LTBI-negative individuals. Furthermore, the age of diabetes onset was also higher among LTBI-positive patients, suggesting that older individuals with diabetes may accumulate TB exposure risk over time. When stratified by age, patients older than 50 years demonstrated a markedly higher LTBI prevalence compared with those younger than 50 years (25.8% vs. 11.6%), highlighting age as a key risk determinant.

In contrast, glycemic control did not appear to influence LTBI prevalence. Neither average nor peak hemoglobin A1c levels over the preceding three years differed significantly between LTBI-positive and LTBI-negative groups. Similarly, diabetes treatment regimens—used as proxies for disease severity—showed no significant association with LTBI status. These findings suggest that while diabetes itself is associated with increased TB risk, the degree of glycemic control may not directly correlate with latent infection prevalence.

Other potential risk factors, including sex, body mass index, smoking status, and TB contact history, were not significantly associated with LTBI after analysis. However, age-stratified patterns showed male predominance across most age groups, particularly among LTBI-positive individuals. Overall, the study concluded that older diabetic patients, particularly those over 50 years, represent a high-risk population for LTBI and may benefit from targeted screening strategies using IGRA in TB-endemic settings.

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How

This study used a cross-sectional design conducted at a regional hospital in northern Taiwan, specifically the Taipei Medical University–Shuang Ho Hospital. Participants included diabetic patients aged 20–70 years who attended a metabolic outpatient clinic between February 2011 and February 2013. Patients with active tuberculosis, suspected TB, HIV infection, autoimmune disease requiring immunomodulators, recent chemotherapy, liver cirrhosis, or hepatitis were excluded to minimize confounding factors that could influence LTBI detection or immune response.

Demographic and clinical information was collected from medical records and structured questionnaires. Variables included age, sex, smoking status, TB contact history, underlying comorbidities, and glycemic control indicators such as hemoglobin A1c. These variables were analyzed to identify potential risk factors associated with LTBI among diabetic patients. This comprehensive data collection enabled assessment of both clinical and behavioral determinants of latent TB infection.

LTBI screening was performed using the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay, an interferon-gamma release assay considered more specific in BCG-vaccinated populations. Blood samples were analyzed using enzyme-linked immunosorbent assay (ELISA), and results were classified as positive or negative based on standard interferon-gamma thresholds. This laboratory-based approach allowed more accurate identification of latent infection compared with traditional skin testing in highly vaccinated populations.

Statistical analyses included comparisons between LTBI-positive and LTBI-negative groups, age-stratified analyses, and multivariate logistic regression to identify independent predictors of LTBI. The researchers further evaluated glycemic control, diabetes duration, and medication use as potential indicators of disease severity. Through this structured analytical approach, the study identified age—particularly over 50 years—as the most consistent predictor of LTBI among diabetic patients in Taiwan.

Source: Chang, A., Wu, C. Z., Lin, J. D., Lee, C. N., Tsai, K. Y., Wu, P. H., & Hsieh, A. T. (2022). Prevalence and risk factors for latent tuberculosis among diabetes patients in Taiwan: A cross-sectional study. The Journal of Infection in Developing Countries, 16(04), 644-649.

Determinants of LTBI and treatment interruption in long-term care facilities [TBN 062]

What

This cohort study examined the burden of latent tuberculosis infection (LTBI) and determinants of treatment interruption among residents and employees in long-term care facilities (LTCFs) in Taipei, Taiwan. Recognizing LTCFs as high-risk congregate settings for tuberculosis transmission, the study aimed to identify populations most vulnerable to LTBI and to determine which preventive therapy regimens best support treatment completion. Understanding these factors is critical for optimizing TB prevention strategies, particularly in aging populations and institutional care environments where outbreaks can spread rapidly and cause significant morbidity.

Among 2,207 participants included in the analysis, the overall LTBI prevalence was 16.8%, with a higher prevalence among residents (19.5%) compared with employees (11.3%). Individuals with LTBI were more likely to be older, male, smokers, and residents of public LTCFs. After adjusting for covariates, residents in public LTCFs had a significantly higher likelihood of LTBI than those in private facilities (adjusted odds ratio [AOR] 1.37; 95% CI: 1.08–1.74). Age also emerged as a strong independent predictor, with individuals aged 50 years and older having more than twice the risk of LTBI compared with younger participants, underscoring the vulnerability of elderly institutional populations.

Of the 371 individuals diagnosed with LTBI, 73.9% initiated preventive therapy, and 72.3% completed treatment. However, treatment interruption occurred in 19.7% of cases, highlighting persistent adherence challenges even within structured prevention programs. The most common causes of treatment interruption included drug-induced liver injury (28.8%), patient refusal (28.8%), and flu-like symptoms (23.1%). These findings emphasize that adverse drug reactions and patient tolerance remain critical barriers to successful LTBI management in long-term care settings.

The study further demonstrated that treatment regimen selection influenced adherence and safety outcomes. Individuals receiving the 3HP regimen were significantly less likely to interrupt treatment than those receiving the traditional 9-month isoniazid regimen (AOR 0.22; 95% CI: 0.07–0.71). Additionally, hepatotoxicity occurred in 5.8% of participants receiving 9H, whereas no hepatotoxicity cases were observed in the 3HP group. These results suggest that shorter, safer regimens may enhance treatment completion and reduce adverse events, particularly among older populations in institutional care.

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How

This research employed a cohort design using LTBI surveillance data from 20 long-term care facilities in Taipei, Taiwan, between May 2017 and September 2020. All participants underwent chest radiography and QuantiFERON-TB Gold In-Tube (QFT) testing for LTBI screening at enrollment. Individuals who tested positive were offered preventive therapy and followed until treatment completion, death, treatment interruption, or the study end date of December 31, 2020. Treatment interruption was defined as missing seven or more consecutive days of medication or failing to complete the required regimen.

Preventive therapy followed national Taiwan LTBI Eradication Program guidelines, which included three regimens: nine months of isoniazid (9H), four months of rifampin (4R), and three months of weekly isoniazid plus rifapentine (3HP). Treatment decisions were made collaboratively among physicians, patients, and families, with the 4R regimen prioritized for individuals exposed to isoniazid-resistant TB. All treatment costs were subsidized by the government, minimizing financial barriers and improving accessibility to preventive therapy.

To improve adherence, the study implemented directly observed preventive therapy (DOPT), a program initiated by Taiwan CDC in 2016. Trained observers monitored medication adherence and adverse events daily, while public health nurses coordinated medical follow-up for participants experiencing side effects. Monthly laboratory monitoring, including blood counts and liver function tests, was conducted to detect hepatotoxicity early and ensure treatment safety. Preventive therapy was discontinued if participants developed significant liver injury or adverse reactions.

Participant characteristics were collected at baseline, including demographic factors, smoking status, BMI, TB contact history, and LTCF characteristics such as facility type (public vs. private). Statistical analyses evaluated predictors of LTBI and treatment interruption, using multivariate models to control for confounding factors. Subgroup analyses further explored differences between residents and employees, allowing the study to identify population-specific risks and inform targeted TB prevention strategies in long-term care environments.

Source: Chiu, T. F., Yen, M. Y., Shie, Y. H., Huang, H. L., Chen, C. C., & Yen, Y. F. (2022). Determinants of latent tuberculosis infection and treatment interruption in long-term care facilities: A retrospective cohort study in Taiwan. Journal of Microbiology, Immunology and Infection, 55(6), 1310-1317.

Demographic Control Measure Implications of TB Infection for Migrant Workers across Taiwan [TBN 061]

What

This study examined migrant-associated tuberculosis (TB) transmission dynamics in highly endemic regions of Taiwan and evaluated the potential impact of multiple control strategies. The investigation focused on three major administrative areas—Taoyuan City, Taichung City, and New Taipei City—where large migrant worker populations overlap with persistent TB burden. Migrant workers, primarily from Vietnam, the Philippines, and Indonesia, increased substantially between 2013 and 2019, with Vietnam and the Philippines accounting for 43% and 28% of migrant workers, respectively, by 2019. Concurrently, TB incidence rates in migrant source countries remained markedly higher than in Taiwan, with the Philippines reporting 554 cases per 100,000 population compared with 37 per 100,000 in Taiwan, highlighting a potential pathway for cross-population transmission.

The study further documented epidemiological trends showing that TB cases among migrant workers rose between 2006 and 2014 and subsequently stabilized at approximately 600–700 confirmed cases annually. Among 6,416 total migrant TB cases reported between 2006 and 2019, Indonesia contributed the largest proportion (47%), followed by the Philippines (25%), Vietnam (18%), and Thailand (9%). These findings underscored the persistent contribution of migrant populations to TB burden in Taiwan and justified modeling efforts that explicitly incorporated migrant-local transmission dynamics. Sensitivity analyses demonstrated that transmission rates within migrant and local populations were key drivers of projected infection trends, with model projections indicating that both migrant and local infectious populations would peak around 2022–2023 in hotspot cities.

Simulation of control strategies revealed that social distancing was the most effective single intervention for reducing the combined population of latently infected and infectious individuals. In five-year projections, high-intensity distancing measures reduced infections by up to approximately 80% in Taoyuan City, 85% in Taichung City, and 97% in New Taipei City. Early screening and directly observed therapy short-course (DOTS) also demonstrated measurable reductions but were consistently less effective when implemented individually. These findings indicated that interventions targeting transmission prevention yielded stronger reductions than those focused solely on detection or treatment.

Combination strategies produced greater reductions in TB burden, particularly when social distancing was paired with early screening or DOTS. Dual strategies achieved reductions of up to approximately 96% in five-year projections, while triple-intervention strategies provided only marginal additional benefit of approximately 1–3%. The authors concluded that dual-intervention approaches offered the optimal balance between effectiveness and resource allocation, suggesting that combined distancing and early screening may provide the most efficient TB control strategy in migrant-dense settings.

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How

This study employed a population-based dynamic modeling approach using an enhanced migrant-based susceptible–latent–infectious–recovered (SLTR) transmission framework. The total population was divided into migrant and local subpopulations, each further categorized into susceptible, latently infected, infectious, and recovered compartments. This structure enabled modeling of bidirectional TB transmission between migrant and local populations, incorporating both within-group and cross-group transmission pathways. The model extended previous frameworks by explicitly including transmission from infectious local individuals to migrant populations, thereby capturing more realistic interaction dynamics in high-density urban regions.

Model parameterization relied on a large-scale meta-analysis combined with national surveillance data. Demographic data for migrant workers between 2013 and 2019 were obtained from Taiwan’s Workforce Development Agency, while TB incidence data for Taiwan and migrant source countries were derived from Taiwan Centers for Disease Control and the World Health Organization. Historical TB case data from 2006 to 2019 were also incorporated to calibrate model assumptions and validate projections. These datasets informed transmission rates, reactivation parameters, and population dynamics within the three selected hotspot cities.

Sensitivity analyses were conducted to evaluate the impact of key transmission parameters and reactivation rates on projected TB dynamics. The modeling results demonstrated that transmission rates within migrant and local populations exerted the strongest influence on infection trajectories, while increases in reactivation rates produced gradual growth in infectious populations without significantly affecting susceptible populations. These analyses strengthened the robustness of the model and identified critical parameters influencing TB spread.

The study then simulated three primary interventions—social distancing, early screening, and DOTS—both individually and in combination. Control intensities were varied across short-term (two-year) and long-term (five-year) projections to assess effectiveness. Dual- and triple-intervention strategies were further modeled to evaluate synergistic effects, using predefined control intensities to simplify comparisons. The modeling framework ultimately allowed estimation of percentage reductions in latently infected and infectious populations under multiple policy scenarios, providing evidence-based insights for optimizing TB control strategies in migrant-dense regions.

Source: Chen, S.C., Wang, T.Y., Tsai, H.C., Chen, C.Y., Lu, T.H., Lin, Y.J., You, S.H., Yang, Y.F. and Liao, C.M., 2022. Demographic Control Measure Implications of Tuberculosis Infection for Migrant Workers across Taiwan Regions. International journal of environmental research and public health, 19(16), p.9899.

Quality of life and social correlates among drug sensitive and MDR-TB patients [TBN 060]

WHAT

This comparative study assessed quality of life (QOL) among patients with multidrug-resistant tuberculosis (MDR-TB) compared with drug-sensitive tuberculosis patients in Chitradurga district, India. The study included 40 MDR-TB patients and 80 age- and gender-matched drug-sensitive TB patients, with a case-to-control ratio of 1:2. MDR-TB cases were defined as patients resistant to isoniazid and rifampicin confirmed using CBNAAT testing, while controls were patients sensitive to first-line anti-TB drugs.

The results showed significant differences in socioeconomic and educational status between the two groups (P < 0.05), suggesting that MDR-TB patients were more likely to have socioeconomic disadvantages. However, no significant differences were found in lifestyle factors such as alcohol consumption or smoking between MDR-TB and drug-sensitive TB patients (P > 0.05).

Overall quality of life and health satisfaction were significantly lower among MDR-TB patients compared with drug-sensitive TB patients. The mean QOL score was 3.33 ± 1.199, and the mean health satisfaction score was 3.28 ± 1.190. Drug-sensitive TB patients reported significantly better QOL and health satisfaction than MDR-TB patients (P < 0.05), indicating a greater burden of disease among MDR-TB patients.

Across all four WHOQOL-BREF domains—physical, psychological, social relationships, and environmental—drug-sensitive TB patients had higher scores than MDR-TB patients. The psychological domain was the most affected domain in both groups. Among MDR-TB patients, the physical domain had the highest scores, while among drug-sensitive TB patients, the environmental domain scored highest.

Comparative analysis demonstrated that psychological wellbeing was significantly poorer among MDR-TB patients compared with drug-sensitive TB patients (P < 0.05). These findings suggest that MDR-TB has a substantial negative impact on mental health and overall quality of life, beyond the physical burden of disease.

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HOW

This study used a comparative cross-sectional design conducted in the Department of Community Medicine at Basaveshwara Medical College and Hospital, Chitradurga, India, from 2018 to 2019. MDR-TB patients resistant to isoniazid and rifampicin, with or without resistance to other drugs, were identified using CBNAAT testing and included as cases.

A total of 40 MDR-TB patients were identified from district records. For the control group, 80 drug-sensitive TB patients were selected using age and gender matching in a 1:2 case-to-control ratio. Controls were randomly selected from TB patients registered at the District Tuberculosis Centre (DTC). Written informed consent was obtained from all participants prior to data collection.

Quality of life was assessed using the WHOQOL-BREF questionnaire, which contains 26 items measuring four domains: physical health, psychological health, social relationships, and environmental wellbeing. Additional sociodemographic information, including education, occupation, marital status, and lifestyle factors, was also collected.

The questionnaire was interviewer-administered to minimize misunderstanding and ensure consistent data collection. Responses were recorded without influence from family members or accompanying health workers to reduce response bias.

Source: Hamsaveni, G., Amrutha, A.M., Sidenur, B., Mangasuli, V. and Vijeth, S.B., 2024. Assessment of quality of life and social correlates among drug sensitive and multidrug-resistant tuberculosis patients. Journal of Association of Pulmonologist of Tamil Nadu, 7(3), pp.100-104.

Second-Line Anti-TB Drugs Susceptibility Pattern in MDR-TB Patients in Bandung, Indonesia [TBN 059]

WHAT

This cross-sectional descriptive study examined resistance patterns to second-line anti-tuberculosis drugs among drug-resistant tuberculosis (DR-TB) patients treated at Dr. Hasan Sadikin General Hospital, Bandung, Indonesia. A total of 134 patient records were retrieved, but after excluding duplicate entries and incomplete data, 82 patients were included in the final analysis. The median age of participants was 42 years (range 27–51 years), and most patients were female (53.7%). Over half of the patients (52.4%) were classified as new or primary MDR-TB cases, followed by relapse cases (29.3%).

Drug susceptibility testing showed that resistance to high-dose isoniazid was the most common, affecting 43.9% of patients. Resistance to fluoroquinolones was also observed, with 14.6% showing resistance to low-dose moxifloxacin and an equal proportion (14.6%) resistant to low-dose levofloxacin. Among patients resistant to low-dose moxifloxacin, a subset also demonstrated cross-resistance to other fluoroquinolones, indicating potential limitations in second-line treatment options.

Testing using the Mycobacteria Growth Indicator Tube (MGIT) further confirmed resistance patterns, showing high-dose isoniazid resistance as the most frequent, followed by low-dose levofloxacin resistance (9.8%). These findings highlight that resistance extended beyond first-line therapy and affected important second-line drugs used in MDR-TB management.

Most patients were of productive working age, suggesting a substantial potential socioeconomic burden of MDR-TB. Additionally, the high proportion of primary MDR-TB cases indicates ongoing transmission of drug-resistant strains rather than resistance developing solely from prior treatment failure.

Overall, the study identified considerable resistance to both high-dose isoniazid and fluoroquinolones among MDR-TB patients. These findings emphasize the importance of drug susceptibility testing to guide individualized treatment regimens and prevent treatment failure.

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HOW

This study used a descriptive cross-sectional design based on secondary data obtained from the Tuberculosis Information System (SITB) at the MDR clinic of Dr. Hasan Sadikin General Hospital in Bandung, West Java, Indonesia. The study period covered patients registered between December 2021 and June 2022. Total sampling was applied to include all eligible patients during the study period.

Inclusion criteria were patients aged 18 years or older diagnosed with drug-resistant tuberculosis and treated at the MDR clinic. Patients with incomplete records or missing data were excluded. From 134 retrieved records, 7 duplicate entries and 45 incomplete records were excluded, resulting in 82 patients included in the final analysis.

Collected variables included demographic characteristics (age and gender), history of previous anti-tuberculosis treatment, and second-line drug susceptibility test results. Previous treatment history included categories such as new cases, relapse, treatment failure, loss to follow-up, TB-HIV co-infection, and exposure to MDR-TB contacts.

Drug resistance patterns were assessed using two laboratory methods: Line Probe Assay (LPA) and Mycobacteria Growth Indicator Tube (MGIT). These tests evaluated resistance to second-line anti-tuberculosis drugs including moxifloxacin (low-dose and high-dose), levofloxacin, and high-dose isoniazid. 

Source: Suwandi, S.N., Kulsum, I.D. and Andriyoko, B., 2024. Second-Line Anti-Tuberculosis Drugs Susceptibility Pattern in Multidrug-resistant Tuberculosis Patients at Dr. Hasan Sadikin General Hospital, Bandung, Indonesia. Althea Medical Journal, 11(2), pp.100-105.

Prospective cohort study on TB incidence and risk factors in the elderly population of eastern China [TBN 058]

WHAT

This large cohort study evaluated the incidence and risk factors for active tuberculosis (TB) among elderly individuals aged ≥65 years in Zhenjiang City, Jiangsu Province, China. A total of 39,122 older adults were included after excluding 10 individuals with existing TB at baseline. Participants underwent annual free public health screening in 2016, which included demographic surveys, lifestyle assessment, laboratory testing, and clinical examinations.

At baseline, 46.1% of participants were male. Nutritional status showed that 3.9% were underweight, 47.6% normal weight, 37.5% overweight, and 10.9% obese. Smoking was reported in 16.2% of participants, with 7.2% former smokers. Alcohol consumption was reported by 15.9%, and 12.2% had diabetes. Approximately one-fifth reported regular exercise, while 0.9% had symptoms suggestive of TB. Notably, 65.2% of participants had abnormal findings during physical examinations.

After more than seven years of follow-up, 246 individuals developed active TB, corresponding to an incidence rate of 92.21 per 100,000 person-years (95% CI 81.2–104.3). Among these cases, 51.2% were bacteriologically confirmed, and 4.1% were diagnosed with tuberculous pleurisy. The incidence was substantially higher among males (140.2 per 100,000 person-years) compared with females (51.4 per 100,000 person-years).

Nutritional status was strongly associated with TB risk. Underweight individuals had the highest incidence rate (390.3 per 100,000 person-years), whereas obese individuals had the lowest incidence (34.1 per 100,000 person-years). Former smokers also showed markedly higher TB risk, with incidence rates nearly four times higher than never-smokers and three times higher than current smokers.

In multivariable analysis, increasing age remained associated with higher TB risk (adjusted hazard ratio [AHR] 1.03 per year increase, 95% CI 1.01–1.04). Male sex was associated with significantly increased risk (HR 2.73, 95% CI 2.08–3.58). Compared with obese individuals, those with normal BMI had nearly three times higher TB risk (AHR 2.87, 95% CI 1.51–5.46), and underweight individuals had nearly ten times higher risk (AHR 9.89, 95% CI 4.92–19.85). Former smoking was also associated with increased risk (AHR 1.35, 95% CI 1.12–1.64).

Population attributable fraction (PAF) analysis showed that normal BMI contributed the largest proportion of TB risk (47.1%), followed by male sex (43.0%), underweight BMI (25.7%), and smoking cessation (1.6%). These findings suggest that demographic and nutritional factors play a major role in TB risk among older adults.

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HOW

This study used a population-based cohort design based on annual public health screening services provided to elderly individuals aged ≥65 years in Zhenjiang City, China, between January and December 2016. These government-sponsored screenings included demographic surveys, lifestyle questionnaires, clinical examinations, and laboratory testing such as blood glucose, lipid profiles, electrocardiogram, complete blood count, urinalysis, and abdominal ultrasound.

Individuals with symptoms suggestive of TB—including persistent cough, hemoptysis, unexplained weight loss, fever, night sweats, chest pain, or lymph node swelling—underwent additional chest X-ray screening. Active TB cases were identified by linking participants to the Tuberculosis Management Information System using identification numbers. Diagnoses were verified through consultation with physicians at designated TB hospitals.

TB cases were classified as bacteriologically confirmed or clinically diagnosed. Bacteriological diagnosis included sputum smear, culture, GeneXpert testing, or pathological confirmation. Clinical diagnosis required negative bacteriological testing but compatible chest X-ray findings and clinical symptoms or supportive immunologic tests such as tuberculin skin test or interferon-gamma release assay.

Baseline variables included BMI, smoking status, alcohol use, diabetes, physical activity, and abnormal physical examination findings. BMI was categorized as underweight, normal, overweight, and obese according to Chinese guidelines. Diabetes control was classified using fasting plasma glucose levels, and abnormal physical examination referred to any abnormal clinical findings during screening.

Participants were followed for more than seven years to identify incident TB cases. Incidence rates were calculated per 100,000 person-years. Risk factors were evaluated using both univariate and multivariable Cox proportional hazards models. Population attributable fractions were calculated to estimate the contribution of key risk factors to TB incidence.

Source: Jiang, H., Chen, X., Lv, J., Dai, B., Liu, Q., Ding, X., Pan, J., Ding, H., Lu, W., Zhu, L. and Lu, P., 2024. Prospective cohort study on tuberculosis incidence and risk factors in the elderly population of eastern China. Heliyon, 10(3).

Association of ambient temperature with tuberculosis incidence in Japan [TBN 057]

WHAT

This ecological study examined the association between ambient temperature and tuberculosis (TB) incidence across Japan from 2007 to 2019 using national surveillance data. A total of 335,060 newly confirmed TB cases were reported across all 47 prefectures during the study period. TB diagnosis was based on clinical symptoms (e.g., cough, sputum, fever, chest pain) combined with laboratory confirmation, including sputum smear, culture, nucleic acid testing, tuberculin skin tests, interferon-gamma release assays, radiography, or clinical judgment.

The analysis found a nonlinear relationship between temperature and TB incidence. The minimum risk temperature (MMT) was identified at 4.45°C, corresponding to the 10th percentile of mean temperature. Compared with this reference, high temperatures were associated with significantly increased TB risk. Specifically, at the 99th percentile (30.1°C), the relative risk (RR) of TB incidence was 1.52 (95% CI 1.04–2.23), indicating a 52% higher risk at extreme heat levels.

Cold temperature effects were smaller and short-term. At −1.2°C (1st percentile), the relative risk was 1.03 (95% CI 1.01–1.06), with the highest effect observed at lag 0 weeks, declining thereafter. In contrast, heat exposure demonstrated delayed effects, with increased TB risk observed at mid-term lag periods ranging from 2 to 26 weeks. These findings suggest that heat exposure may influence TB incidence over longer time frames compared with cold exposure.

Considerable regional variation was observed across prefectures. For example, the minimum risk temperature was 19.4°C (80th percentile) in Hokkaido, while in Okinawa it was 14.8°C (1st percentile), suggesting differences in population adaptation to local climates. These findings indicate that climate-related TB risk may depend on regional environmental conditions and population acclimatization.

Sensitivity analyses demonstrated that the association between temperature and TB incidence remained generally stable across different model specifications, including variations in degrees of freedom, lag periods, and autocorrelation adjustments. Heat-related effects were consistent across sensitivity analyses, whereas cold-related effects were less stable. Overall, results suggest that higher ambient temperatures are associated with increased TB incidence, with delayed and nonlinear effects.

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HOW

This study used an ecological time-series design based on national surveillance data from Japan’s National Epidemiological Surveillance of Infectious Diseases system. Weekly counts of newly confirmed TB cases from 2007 to 2019 were collected for all 47 Japanese prefectures. Meteorological data—including mean temperature, minimum temperature, maximum temperature, and relative humidity—were obtained from monitoring stations located in each prefecture’s capital city. Diurnal temperature range (DTR) was calculated as the difference between daily maximum and minimum temperatures, and weekly averages were computed for analysis.

A two-stage meta-analysis framework was applied. In the first stage, generalized linear models with quasi-Poisson distribution and log link function were used to estimate prefecture-specific associations between temperature and TB incidence. To capture nonlinear and delayed effects, the study used distributed lag nonlinear models (DLNM) with natural cubic B-splines. Lag periods of up to 26 weeks were examined to evaluate delayed temperature effects on TB incidence.

Seasonality and long-term trends were controlled using natural cubic spline functions for week number and year. Additionally, autoregressive terms with 1- and 2-week lags were included to account for transmission dynamics and temporal autocorrelation. The minimum risk temperature (MMT) was identified from cumulative exposure-response curves, and relative risks for extreme cold and heat were calculated using the MMT as the reference.

In the second stage, mixed-effects meta-analysis was performed to pool prefecture-specific estimates and obtain national-level results. Meteorological variables such as mean temperature, diurnal temperature range, and relative humidity were included as meta-predictors to account for between-prefecture heterogeneity. Residual heterogeneity was assessed using Cochran’s Q-test and I-square statistics, and best linear unbiased predictions (BLUPs) were generated for prefecture-specific estimates.

Multiple sensitivity analyses were conducted to test robustness. These included varying degrees of freedom for seasonal adjustment, extending lag periods from 26 to 52 weeks, removing or adding autocorrelation terms, and replacing spline models with Fourier (trigonometric) terms. The findings remained largely consistent across models, supporting the robustness of the observed association between temperature and TB incidence.

Source: Wagatsuma, K., 2024. Association of ambient temperature with tuberculosis incidence in Japan: An ecological study. IJID regions, 12, p.100384.

Health-related quality of life among adults newly diagnosed with pulmonary TB in Lagos, Nigeria [TBN 056]

WHAT

This prospective cohort study examined changes in health-related quality of life (HRQOL) among patients with pulmonary tuberculosis (PTB) during six months of standard treatment in Lagos State, Nigeria. A total of 210 newly diagnosed PTB patients aged 15–70 years were recruited, with 194 (92.4%) completing the six-month follow-up. Most participants were male (63.3%), under 45 years of age (79.1%), and had low income, with 81.9% earning ≤45,000 Naira monthly. Nearly half (44.7%) were unemployed, and 10% reported losing employment due to illness, highlighting the socioeconomic burden associated with TB.

Clinical symptoms at baseline were common and included cough (80.5%), anorexia (68.6%), weight loss, breathlessness, fever, and chest pain. These symptoms progressively improved during treatment, although approximately one in five participants still reported cough at six months. About 80.5% of patients had bacteriologically confirmed PTB, and roughly one-fifth were HIV-positive. Nutritional status also improved over time, with underweight prevalence decreasing from 27.6% at baseline to 12.7% at six months.

Across the six-month treatment period, HRQOL scores improved significantly in all four WHOQOL-BREF domains: physical, psychological, social, and environmental. At baseline, the lowest score was observed in the environmental domain (45.27 ± 14.59), while the social domain had the highest score (50.98 ± 17.37), which remained the highest at treatment completion. Repeated-measures ANOVA demonstrated statistically significant improvements across all domains, with partial eta squared values ranging from 0.178 to 0.295, indicating moderate to large effect sizes.

The most substantial improvements in HRQOL occurred during the first two months of treatment, particularly in overall satisfaction with health, physical health, and psychological domains. Improvements between months two and six were smaller, suggesting that the intensive treatment phase contributed most to quality-of-life gains. Notably, although social domain scores were consistently highest, they showed the smallest magnitude of improvement across the treatment period.

General satisfaction with health improved substantially during treatment, increasing from 13.5% at baseline to 55.7% at six months. Effect size analysis showed large improvements between baseline and six-month measurements across most domains, while changes between the second and sixth months were smaller. A statistically significant linear trend across time points indicated steady improvement in HRQOL during treatment.

Multivariable analysis identified key factors influencing HRQOL improvement. Employment status was positively associated with better HRQOL across all domains. Persistent symptoms were negatively associated with quality of life, while improvement in body mass index (BMI) was linked to better physical, psychological, and social outcomes. Delayed presentation negatively affected social domain scores but showed a positive association with environmental domain changes. Overall, clinical recovery, improved nutrition, and socioeconomic stability were important determinants of HRQOL improvement.

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HOW

This study used a prospective cohort design conducted in publicly owned TB-DOTS centers across Lagos State, Nigeria, to ensure consistent treatment guidelines and facility characteristics. Participants were recruited immediately after diagnosis and followed for six months, with assessments conducted at baseline, after the two-month intensive treatment phase, and within two weeks after completing treatment. The overall study duration was 15 months.

Eligibility criteria included individuals aged 15 years or older who were newly diagnosed with pulmonary tuberculosis and had received less than four weeks of prior TB treatment. Patients with severe illness, pre-existing chronic respiratory diseases such as asthma or COPD, or prior TB treatment were excluded. Facilities were selected based on their capacity to diagnose and treat TB and HIV and at least two years of TB service provision.

A two-stage sampling method was applied. First, one local government area from each of three senatorial districts in Lagos State was selected using simple random sampling. Then, one eligible TB treatment facility was randomly selected within each district. Patients were consecutively recruited at each facility until the required sample size was reached.

Data collection used interviewer-administered questionnaires capturing socio-demographic characteristics, clinical history, employment status, and symptoms. Height and weight were measured, and body mass index (BMI) calculated. All participants were offered HIV counseling and testing. Sputum microscopy results were extracted from patient records during follow-up visits.

Health-related quality of life was assessed using the WHOQOL-BREF instrument, which evaluates four domains: physical, psychological, social relationships, and environmental wellbeing. The instrument includes 26 items scored on a Likert scale from 1 to 5, with higher scores indicating better quality of life. Both English and Yoruba versions were used, with translation and back-translation procedures conducted to ensure accuracy.

The WHOQOL-BREF demonstrated strong reliability and validity in this study. Cronbach’s alpha exceeded 0.80 across all domains, indicating high internal consistency. Convergent validity was assessed using Pearson correlation coefficients between domain scores and global quality-of-life items, with values ranging from 0.433 to 0.801, indicating moderate to strong correlations. Statistical analysis included repeated-measures ANOVA, effect size estimation, and multivariable regression to identify predictors of HRQOL change.

Source: Adebayo, B.I., Adejumo, O.A. and Odusanya, O.O., 2024. Health-related quality of life among adults newly diagnosed with pulmonary tuberculosis in Lagos State, Nigeria: A prospective study. Quality of life research, 33(1), pp.157-168.

Tuberculosis survivors and the risk of cardiovascular disease in Korea [TBN 055]

WHAT

This nationwide population-based study examined the association between prior pulmonary tuberculosis (TB) and 10-year atherosclerotic cardiovascular disease (ASCVD) risk among Korean adults. Using data from the Korea National Health and Nutrition Examination Survey (KNHANES), the analysis included 69,331 participants after excluding individuals with missing weight variables or ASCVD data. Among the final sample, 3,101 participants (approximately 4%) were classified as post-TB survivors, while 66,230 participants (96%) had no history of TB and served as the control group.

Baseline characteristics showed that individuals with prior TB differed substantially from those without TB. The post-TB group was older on average (53.73 vs. 45.35 years), had a higher proportion of men (60.20% vs. 49.53%), and included more underweight individuals (6.58% vs. 4.33%). They were also more likely to be smokers (53.84% vs. 44.60%), less likely to be unmarried (10.01% vs. 23.01%), had lower household income (25.88% vs. 30.55% high income), and had lower educational attainment (P < 0.001 for all comparisons).

Comorbidity burden was also higher among post-TB survivors. Compared with controls, the post-TB group had higher prevalence of asthma (5.75% vs. 2.76%), stroke (2.33% vs. 1.46%), chronic obstructive pulmonary disease (2.41% vs. 0.33%), diabetes mellitus (14.04% vs. 10.32%), hypertension (35.16% vs. 26.48%), cardiovascular disease (5.11% vs. 3.11%), liver cirrhosis (0.64% vs. 0.22%), and cancer history (4.46% vs. 2.96%) (P < 0.001 for all). Depression was also more common in the post-TB group (4.66% vs. 3.65%, P = 0.012), while dyslipidemia was slightly higher but not statistically significant (53.69% vs. 51.89%, P = 0.105).

When comparing cardiovascular risk, post-TB survivors demonstrated significantly higher 10-year ASCVD risk. The proportion of participants classified in the high-risk category was markedly greater in the post-TB group compared with controls (40.46% vs. 24.00%, P < 0.001). Logistic regression analysis further showed that prior TB was associated with increased cardiovascular risk. Compared with controls, post-TB survivors had higher odds of intermediate ASCVD risk (OR 1.14, 95% CI 1.04–1.23) and substantially higher odds of high ASCVD risk (OR 1.69, 95% CI 1.59–1.78).

Among individuals with TB, several factors were independently associated with cardiovascular disease in multivariable analysis. Increasing age (adjusted OR [aOR] 1.10, 95% CI 1.07–1.12), current smoking (aOR 2.63, 95% CI 1.34–5.14), high family income (aOR 2.48, 95% CI 1.33–4.62), diabetes mellitus (aOR 1.97, 95% CI 1.23–3.14), and depression (aOR 2.06, 95% CI 1.03–4.10) were significantly associated with increased cardiovascular disease risk among post-TB survivors. These findings suggest that individuals with prior TB represent a population with elevated cardiovascular risk and multiple contributing risk factors.

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HOW

This study used data from the Korea National Health and Nutrition Examination Survey (KNHANES), a nationwide population-based surveillance system conducted by the Korea Disease Control and Prevention Agency since 1998. The analysis included five survey cycles: KNHANES IV (2007–2009), V (2010–2012), VI (2013–2015), VII (2016–2018), and VIII (2019). Participants were selected using a stratified multistage sampling design to ensure national representativeness.

During the 13-year study period, 105,732 individuals without age restrictions were initially enrolled. Participants with missing weight data or missing 10-year ASCVD risk values (n = 36,401) were excluded, leaving 69,331 participants in the final analytic sample. Participants were categorized into two groups based on prior TB diagnosis. Previous pulmonary TB was defined as either a physician-diagnosed history of pulmonary TB or formal chest radiograph interpretation indicating prior TB.

The primary outcome was 10-year ASCVD risk, calculated using the American Heart Association risk equations. This risk model incorporates multiple variables, including age, sex, race, cholesterol levels, blood pressure, medication use, diabetes status, and smoking history. ASCVD risk was categorized into four groups: low risk (0–4.9%), borderline risk (5.0–7.4%), intermediate risk (7.5–20%), and high risk (>20%).

Demographic, socioeconomic, and clinical variables were obtained from the KNHANES database. These included age, sex, waist circumference, body mass index (BMI), smoking status, alcohol consumption, marital status, income, and educational level. BMI was categorized using Asian-specific criteria: underweight (<18.5 kg/m²), normal (18.5–22.9 kg/m²), overweight (23.0–24.9 kg/m²), and obese (≥25.0–29.9 kg/m²). Heavy alcohol consumption was defined as more than 30 g/day.

Comorbidities were defined primarily using physician-reported diagnoses. Diabetes mellitus was defined as fasting glucose ≥126 mg/dL, use of antidiabetic medications, or physician diagnosis. Hypertension was defined as physician diagnosis, antihypertensive medication use, systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg. Dyslipidemia was defined by physician diagnosis, lipid-lowering medication use, total cholesterol ≥240 mg/dL, or fasting triglycerides ≥200 mg/dL.

Source: Yang, J., Kim, S.H., Sim, J.K., Gu, S., Seok, J.W., Bae, D.H., Cho, J.Y., Lee, K.M., Choe, K.H., Lee, H. and Yang, B., 2024. Tuberculosis survivors and the risk of cardiovascular disease: analysis using a nationwide survey in Korea. Frontiers in Cardiovascular Medicine, 11, p.1364337.

LTBI among Household Contacts of DS Pulmonary TB Patients in Medan, Indonesia [TBN 054]

WHAT

This study examined the prevalence of latent tuberculosis infection (LTBI) among household contacts of pulmonary tuberculosis (TB) patients in Medan, Indonesia. Among 102 household contacts of 62 drug-sensitive pulmonary TB index cases, 30 individuals (29.41%) were diagnosed with LTBI, 60 individuals (58.82%) tested negative, and 12 individuals were diagnosed with active pulmonary TB and excluded from the LTBI analysis. Thus, the final analytic sample included 90 household contacts.

The study also evaluated potential risk factors associated with LTBI, including age, sex, occupation, educational level, nutritional status, comorbidities, smoking behavior, alcohol consumption, and duration of household contact. The majority of participants were female (76.6%), with the most common age group among LTBI cases being 46–55 years, while the non-LTBI group was most commonly aged 26–35 years. Most participants had senior high school education, did not smoke, did not consume alcohol, and reported no comorbidities. Contact duration of ≥5 hours per day was common in both groups.

Bivariate analysis demonstrated that none of the assessed variables were significantly associated with LTBI. Specifically, age, gender, educational level, occupation, nutritional status, comorbidities, smoking, alcohol consumption, and contact duration showed no statistically significant relationship with LTBI occurrence (p > 0.05). These findings suggest that LTBI among household contacts may occur regardless of commonly measured demographic, behavioral, or clinical risk factors.

Overall, the study found a relatively high prevalence of LTBI among household contacts of pulmonary TB patients. The authors concluded that these findings highlight the importance of strengthening contact investigation programs and expanding TB preventive treatment among household contacts, particularly in high-burden urban settings such as Medan.

HOW

This study used a cross-sectional design conducted in Medan, an urban city and the capital of North Sumatra, Indonesia, with a population of approximately 2.47 million people. Pulmonary TB index cases were identified from hospitals, clinics, and community health centers (Puskesmas). Eligible index cases were pulmonary TB patients with sputum positive for Mycobacterium tuberculosis and rifampicin-sensitive results confirmed using the Xpert MTB/RIF test. Verification of index cases was performed using the Indonesian Tuberculosis Information System (SITB).

Household contacts aged 15 years and older who lived in the same household as pulmonary drug-sensitive TB patients and consented to participate were recruited using consecutive sampling between October 1 and December 5, 2023. Family members of extrapulmonary TB patients and individuals diagnosed with active TB during contact investigation were excluded. The minimum sample size calculated using the Lemeshow formula was 99 participants, and 102 household contacts were ultimately enrolled.

Data collection included structured interviews, anthropometric measurements, Interferon-Gamma Release Assay (IGRA) testing, chest X-ray examination, and sputum testing when clinically indicated. Interviews collected demographic information, education, occupation, smoking behavior, alcohol consumption, comorbidities, and duration of contact with the index case. Nutritional status was assessed using body mass index derived from height and weight measurements.

LTBI was defined as a positive QuantiFERON-TB Gold Plus (QFT-Plus) IGRA result with a normal chest X-ray and absence of TB symptoms. Participants with abnormal chest X-ray findings or symptoms suggestive of TB underwent sputum examination using Xpert MTB/RIF testing. Individuals diagnosed with active TB, either microbiologically confirmed or clinically diagnosed, were excluded from the LTBI analysis.

Source: Sinaga, B.Y.M., Siregar, J., Sormin, D.E., Sundari, R. and Samodra, Y.L., 2025. Latent Tuberculosis Infection among Household Contacts of Drug-sensitive Pulmonary Tuberculosis Patients: A Cross-sectional Study from Medan, Indonesia. Acta Medica Philippina, 59(19), p.84-90.