Impact of fine particulate matter on latent tuberculosis infection and active tuberculosis in older adults: a population-based multicentre cohort study

ABSTRACT

Evidence showed that air pollution was associated with an increased risk of tuberculosis (TB). This study aimed to study the impact of long-term exposure to ambient particulate matter with an aerodynamic diameter less than 2.5 μm (PM_2.5) on the acquisition of LTBI and on the risk of subsequent active disease development among rural older adults from a multicentre cohort, which have not yet been investigated to date. A total of 4790 older adults were included in a population-based, multicentre, prospective cohort study (LATENTTB-NSTM) from 2013 to 2018. The level of long-term exposure to PM_2.5 for each participant was assessed by aggregating satellite-based estimates. Logistic regression and time-varying Cox proportional hazards models with province-level random intercepts were employed to assess associations of long-term exposures to PM_2.5 with the risk of LTBI and subsequent development of active TB, respectively. Out of 4790 participants, 3284 were LTBI-free at baseline, among whom 2806 completed the one-year follow-up and 127 developed newly identified LTBI. No significant associations were identified between PM_2.5 and the risk of LTBI. And among 1506 participants with LTBI at baseline, 30 active TB cases were recorded during the 5-year follow-up. Particularly, an increment of 5 μg/m³ in 2-year moving averaged PM_2.5 was associated with a 50.6% increased risk of active TB (HR = 1.506, 95% CI: 1.161-1.955). Long-term air pollution might be a neglected risk factor for active TB development from LTBI, especially for those living in developing or less-developed areas where the air quality is poor.

KEYWORDS:

• Latent tuberculosis infection
• tuberculosis
• PM_2.5
• air pollution
• time dependent Cox regression

Acknowledgements

We thank Dr. Chen Chen from China CDC for helping clean the air pollution data, and all the health workers for their contribution to the site work during the baseline survey and follow-up examinations. L Gao, X Gao and Q Jin designed the study. L Gao, SG Pan, ZS Liu, DK Wang, B Zhang coordinated the study implementation and management. HN Xin, XF Cao, BX Feng, YJ He, YP He, JX Yan, LY Shen, YZ Di and YX Chen were responsible for laboratory testing. J Du and L Shen contributed to field investigation and quality control. SF Tian, TL Guo and HN Xin did data management and data analysis. Marianthi-Anna Kioumourtzoglou helped model construction. TL Guo and SF Tian wrote the report. All authors contributed to review and revision and have seen and approved the final version of manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Dr. Xu Gao was supported by grants from the National Key Research and Development Program of China (No. 2022YFC3702704) and the National Natural Science Foundation of China (82304098). Dr. Lei Gao was supported by the CAMS Innovation Fund for Medical Sciences (CIFMS) [2021-I2M-1-037], the Fundamental Research Funds for the Central Universities [3332021092]. They did not involve in trial design, patient recruitment, data collection, analysis, interpretation or any aspect pertinent to the study.