Short-term Exposure to Nitrogen Dioxide and Mortality: a systematic review and meta-analysis Open Access

Abstract

Background: Ambient air pollution has been characterized as a leading cause of mortality worldwide and has been associated with cardiovascular and respiratory diseases. There is increasing evidence that short-term exposure to nitrogen dioxide (NO2), is related to adverse health effects and mortality. 

Methods: We conducted a systematic review of short-term NO2 and daily mortality, which were indexed in PubMed and Embase up to February 2020. We calculated random-effects estimates by different continents and globally, and tested for heterogeneity and publication bias. 

Results: We included 79 articles in our quantitative analysis. NO2 and all-cause as well as cause-specific mortality were positively associated in the main analysis. For all-cause mortality, a 10 ppb increase in NO2 was associated with a 1.49% (95%CI 1.24% to 1.75%, I2 = 90.8%, Eggers’ test p < 0.01, N= 51) increase in the risk of death. For cause-specific mortality, a 10 ppb increase in NO2 was associated with a 1.79% (95%CI 1.45% to 2.12%, I2 = 88.3%, Eggers’ test p < 0.01, N= 38) increase in cardiovascular mortality and a 2.15% (95%CI 1.56% to 2.74%, I2 = 80.1%, Eggers’ test p = 0.013, N= 34) increase in respiratory mortality. In the sensitivity analysis, the meta-estimates for all-cause mortality, cardiovascular and respiratory mortality were nearly identical. The heterogeneity would decline to varying degrees through regional and study-type stratification.

Conclusions: This study provides evidence of an association between short-term exposure to NO2 and all-cause, cardiovascular and respiratory mortality. The results are robust based on sensitivity analysis and we provide a possible explanation for the high heterogeneity observed between the regions.

Table of Contents

1. Introduction ----------------------------------------------------------------------------------------- 1

2. Methods --------------------------------------------------------------------------------------------- 2

 2.1 Studies search and selection ----------------------------------------------------------------------- 2

 2.2 Data extraction ------------------------------------------------------------------------------------ 3

  2.3 Risk of bias ---------------------------------------------------------------------------------------- 3

  2.4 Statistical analysis -------------------------------------------------------------------------------- 4

3. Results ----------------------------------------------------------------------------------------------- 6

  3.1 Characteristic of the eligible studies -------------------------------------------------------------- 6

  3.2 Risk of bias assessment ---------------------------------------------------------------------------- 6

  3.3 Results of the meta-analysis ----------------------------------------------------------------------- 7

    3.3.1 All-cause mortality ----------------------------------------------------------------------------- 8

    3.3.2 Cardiovascular mortality ----------------------------------------------------------------------- 8

    3.3.3 Respiratory mortality --------------------------------------------------------------------------- 9

    3.3.4 Publication bias -------------------------------------------------------------------------------- 10

    3.3.5 Sensitivity analysis ----------------------------------------------------------------------------- 10

4. Discussion ------------------------------------------------------------------------------------------- 11

5. Reference -------------------------------------------------------------------------------------------- 14

6. Figures ----------------------------------------------------------------------------------------------- 18

7. Tables ------------------------------------------------------------------------------------------------ 27

8. Acknowledgement ----------------------------------------------------------------------------------- 32

About this Master's Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Rollins School of Public Health
Department	Environmental Health
Degree	M.P.H.
Submission	Master's Thesis
Language	English
Research Field	Statistics Health Sciences, Epidemiology Environmental Health
Keyword	Mortality Meta-analysis Air pollution Nitrogen dioxide
Committee Chair / Thesis Advisor	Liuhua, Shi, Emory University

Last modified

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	Short-term Exposure to Nitrogen Dioxide and Mortality: a systematic review and meta-analysis ()	2021-05-05 12:42:51 -0400	Press to Select an action Download

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions
	Appendix (Appendix)	2021-05-05 12:42:58 -0400	Press to Select an action Download