Traffic-Related Air Pollution and All-Cause Mortality during Tuberculosis Treatment in California

Abstract

Background:Ambient air pollution and tuberculosis (TB) have an impact on public health worldwide, yet associations between the two remain uncertain.Objective:We determined the impact of residential traffic on mortality during treatment of active TB.Methods:From 2000–2012, we enrolled 32,875 patients in California with active TB and followed them throughout treatment. We obtained patient data from the California Tuberculosis Registry and calculated traffic volumes and traffic densities in 100- to 400-m radius buffers around residential addresses. We used Cox models to determine mortality hazard ratios, controlling for demographic, socioeconomic, and clinical potential confounders. We categorized traffic exposures as quintiles and determined trends using Wald tests.Results:Participants contributed 22,576 person-years at risk. There were 2,305 deaths during treatment for a crude mortality rate of 1,021 deaths per 10,000 person-years. Traffic volumes and traffic densities in all buffers around patient residences were associated with increased mortality during TB treatment, although the findings were not statistically significant in all buffers. As the buffer size decreased, fifth-quintile mortality hazards increased, and trends across quintiles of traffic exposure became more statistically significant. Increasing quintiles of nearest-road traffic volumes in the 100-m buffer were associated with 3%, 14%, 19%, and 28% increased risk of death during TB treatment [first quintile, referent; second quintile hazard ratio (HR)=1.03 [95% confidence interval (CI): 0.86, 1.25]; third quintile HR=1.14 (95% CI: 0.95, 1.37); fourth quintile HR=1.19 (95% CI: 0.99, 1.43); fifth quintile HR=1.28 (95% CI: 1.07, 1.53), respectively; p-trend=0.002].Conclusions:Residential proximity to road traffic volumes and traffic density were associated with increased all-cause mortality in patients undergoing treatment for active tuberculosis even after adjusting for multiple demographic, socioeconomic, and clinical factors, suggesting that TB patients are susceptible to the adverse health effects of traffic-related air pollution. https://doi.org/10.1289/EHP1699

Urban airborne particle exposure impairs human lung and bloodMycobacterium tuberculosisimmunity

“…Taken together, we propose that the PM effects on local lung and systemic cytokine responses to M. tuberculosis , observed in the current study, may represent functional correlates of air pollution effects that in earlier epidemiological studies were found to be correlated with increased incidence rates of TB and M. tuberculosis infection14 as well as adverse TB treatment outcomes 15…”

“…Whether exposure to urban outdoor air PM, similarly, increases the risk of M. tuberculosis infection and TB development is subject of ongoing research 14. A recent study showed increased mortality from TB associated with living near major roadways in the USA 15. Mechanistic studies examining PM effects on antimycobacterial immunity, particularly in human immune cells, are limited16 17 and rare in human primary lung immune cells to date.…”

<p>Secular Seasonality and Trend Forecasting of Tuberculosis Incidence Rate in China Using the Advanced Error-Trend-Seasonal Framework</p>

“…Firstly, growing work has been documenting that ambient air pollutants including PM 2.5 , PM 10 , CO, NO 2 , O 3 , SO 2 and air quality index (AQI) are positively linked with TB seasonality. 35,36 Figure 6 Annual TB incidence projections up to 2035 using the ETS(M,M,M) method based on the entire dataset. As illustrated, albeit the TB incidence continued to display a declined trend at 2.613% per year in China, it showed major challenges ahead to achieve the WHO's milestones and goals.…”

Temporal Cross-Correlations between Ambient Air Pollutants and Seasonality of Tuberculosis: A Time-Series Analysis

“…Tuberculosis showed a highly significant correlation with PM 2.5 in a cross-sectional study in Japan [20]. In addition, exposure to PM 2.5 [25] and residential proximity to road traffic volumes and traffic density [26] were also found to increase the risk of death in tuberculosis patients.…”