Association between long-term exposure to ambient air pollutants and the risk of tuberculosis: A time-series study in Nantong, China

Predicting Tuberculosis Risk in Cattle, Buffaloes, Sheep, and Goats in China Based on Air Pollutants and Meteorological Factors

Tuberculosis is a zoonotic chronic respiratory infectious disease caused by the Mycobacterium tuberculosis complex. The outbreak and epidemic of tuberculosis can seriously threaten human and veterinary health. To investigate the effects of environmental factors on tuberculosis in domestic ruminants, we collected data regarding the prevalence of tuberculosis in cattle, buffaloes, sheep, and goats in China (1956-2024) from publicly published literature and available databases. We identified the key risk factors among six major air pollutants and 19 bioclimatic variables; simulated the risk distribution of tuberculosis in cattle, buffaloes, sheep, and goats in China using the maximum entropy ecological niche model; and evaluated the effects of environmental factors. The area under the curve of the model was 0.873 (95% confidence interval, 0.851-0.895). The risk factors that most significantly influenced the prevalence of tuberculosis were the nitrogen dioxide (NO2) level, mean temperature of the coldest quarter, cattle distribution density, sheep distribution density, ozone (O3) level, and precipitation of the driest month. The predicted map of tuberculosis risk in cattle, buffaloes, sheep, and goats indicated that the high-risk regions were mainly distributed in South, North, East, and Northwest China. Improved surveillance is needed in these high-risk areas, and early preventive measures must be implemented based on the risk factors identified to reduce the future prevalence of tuberculosis in cattle, buffaloes, sheep, and goats.

Association between ambient particulate matter and latent tuberculosis infection among 198 275 students

Background

Numerous studies have estimated the impact of outdoor particulate matter (PM) on tuberculosis risk. Nevertheless, whether there is an association between ambient PM and latent tuberculosis infection (LTBI) risk remains uncertain.

Methods

We collected the basic information and LTBI test results of students who underwent freshmen enrolment physical examinations in 68 middle schools from six prefecture-level cities located in eastern China between 2018 and 2021. We also extracted data on air pollutant concentrations and meteorological factors in six cities between 2015 and 2021. We applied the generalised additive model (GAM) to assess the effect of PM on LTBI risk.

Results

We included 198 275 students in the final analysis, of whom 11 721 were diagnosed with LTBI. The LTBI group had higher proportions of males (P < 0.001), individuals of Han nationality (P < 0.001), and body mass index compared to the non-LTBI group (P < 0.001). For each 1-μg/m3 increase in PM10 concentration, the LTBI risk increased by 0.82% (95% confidence interval (CI) = 0.65-1.00), 0.90% (95% CI = 0.73-1.08), and 0.86% (95% CI = 0.69-1.03) when lagged at one, two, and three years, respectively. For PM2.5, the LTBI risk increased by 0.91% (95% CI = 0.63-1.20), 1.05% (95% CI = 0.75-1.36), and 1.32% (95% CI = 0.96-1.69) when lagged at one, two, and three years, respectively.

Conclusions

Outdoor PM concentration was positively correlated with LTBI risk. Considering that many developing countries are facing the dual challenges of high LTBI rates and serious ambient air pollution, reducing outdoor PM concentration would contribute to alleviating their tuberculosis burden.

Ambient air pollution contributed to pulmonary tuberculosis in China

Published studies on outdoor air pollution and tuberculosis risk have shown heterogeneous results. Discrepancies in prior studies may be partially explained by the limited geographic scope, diverse exposure times, and heterogeneous statistical methods. Thus, we conducted a multi-province, multi-city time-series study to comprehensively investigate this issue. We selected 67 districts or counties from all geographic regions of China as study sites. We extracted data on newly diagnosed pulmonary tuberculosis (PTB) cases, outdoor air pollutant concentrations, and meteorological factors in 67 sites from January 1, 2014 to December 31, 2019. We utilized a generalized additive model to evaluate the relationship between ambient air pollutants and PTB risk. Between 2014 and 2019, there were 172,160 newly diagnosed PTB cases reported in 67 sites. With every 10-μg/m3 increase in SO2, NO2, PM10, PM2.5, and 1-mg/m3 in CO, the PTB risk increased by 1.97% [lag 0 week, 95% confidence interval (CI): 1.26, 2.68], 1.30% (lag 0 week, 95% CI: 0.43, 2.19), 0.55% (lag 8 weeks, 95% CI: 0.24, 0.85), 0.59% (lag 10 weeks, 95% CI: 0.16, 1.03), and 5.80% (lag 15 weeks, 95% CI: 2.96, 8.72), respectively. Our results indicated that ambient air pollutants were positively correlated with PTB risk, suggesting that decreasing outdoor air pollutant concentrations may help to reduce the burden of tuberculosis in countries with a high burden of tuberculosis and air pollution.

Exploring the short-term effects of extreme temperatures on tuberculosis incidence in Shantou, China: a Coastal City perspective

OBJECTIVE

Coastal cities, due to their proximity to coastlines and unique climatic conditions, face growing challenges from extreme temperature events associated with climate change. Research on the impact of extreme temperatures on tuberculosis (TB) in these cities is limited, and findings from different regions lack consensus. This study focuses on Shantou, a coastal city in China, to investigate the influence of extreme temperatures on TB within this distinctive geographical context.

METHODS

Distributed Lag Non-Linear Models (DLNM) were employed to evaluate the effect of extreme temperatures on TB incidence risk in Shantou, a coastal city in China, spanning from 2014 to 2021. Daily TB case data were provided by the Shantou Tuberculosis Prevention and Control Institute. Daily meteorological information was sourced from the Reliable Prognosis website, while daily air pollutant data were obtained from the China Air Quality Online Monitoring and Analysis Platform.

RESULTS

The study revealed a significant association between extreme temperatures and TB incidence, with the impact peaking at a lag of 27 days after exposure. Notably, extreme cold temperatures led to a temporary decrease in TB incidence with a lag of 1-2 days. Subgroup analysis indicated that males had a notably higher risk of TB under extreme temperature conditions compared to females. Additionally, individuals aged 65 years and above showed a significant cumulative effect in such conditions.

CONCLUSIONS

This research enhances our comprehension of the effects of extreme temperatures on TB in coastal cities and carries substantial public health implications for TB prevention in China.

Spatio-Temporal Pattern of Tuberculosis Distribution in Romania and Particulate Matter Pollution Associated With Risk of Infection

The study proposes a dynamic spatio-temporal profile of the distribution of tuberculosis incidence and air pollution in Romania, where this infectious disease induces more than 8,000 new cases annually. The descriptive analysis for the years 2012-2021 assumes an identification of the structuring patterns of mycobacterium tuberculosis risk in the Romanian population, according to gender and age, exploiting spatial modeling techniques of time series data. Through spatial autocorrelation, the degree of similarity between the analyzed territorial systems was highlighted and the relationships that are built between the analysis units in spatial proximity were investigated. By modeling the geographical distribution of tuberculosis, the spatial correlation with particulate matter (PM2.5) pollution was revealed. The identification of clusters of infected persons is an indispensable step in the construction of efficient tuberculosis management systems. The results highlight the link between the distribution of tuberculosis, air pollution and socio-economic development, which requires a detailed analysis of the epidemiological data obtained in the national tuberculosis surveillance and control program from the perspective of geographical distribution.

Association of ambient PM2.5 concentration with tuberculosis reactivation diseases-an integrated spatio-temporal analysis

Objectives

While the plausible role of ambient particulate matter (PM)2.5 exposure in tuberculosis (TB) reactivation has been inferred from in vitro experiments, epidemiologic evidence is lacking. We examined the relationship between ambient PM2.5 concentration and pulmonary TB (PTB) in an intermediate TB endemicity city dominated by reactivation diseases.

Methods

Spatio-temporal analyses were performed on TB notification data and satellite-based annual mean PM2.5 concentration in Hong Kong. A total of 52,623 PTB cases from 2005-2018 were mapped to over 400 subdistrict units. PTB standardized notification ratio by population subgroups (elderly aged ≥65, middle-aged 50-64, and young adults aged 15-49) was calculated and correlated with ambient PM2.5 concentration.

Results

Significant associations were detected between high ambient PM2.5 concentration and increased PTB among the elderly. Such associations were stable to the adjustment for socio-economic factors and other criteria pollutants. Unstable patterns of association between PM2.5 and PTB risk were observed in the middle-aged population and young adults, for which the observed associations were confounded by other criteria pollutants.

Conclusion

With elderly PTB almost exclusively attributable to reactivation, our findings suggested that increased TB reactivations have occurred in association with high ambient PM2.5 exposure, lending support to preventive measures that minimize PM2.5-related TB reactivation.