Impacts of Air Pollutant Exposure on the Risk of Out-of-Hospital Cardiac Arrest: A Systematic Review and Recommendations for Urban Population

Abstract

Introduction: The relationship between air pollutant exposure and the risk of out of hospital cardiac arrests (OHCAs) has been explored by many studies. Urban populations are particularly susceptible to air pollution whilst OHCAs poses a significant burden on the mortality and morbidity worldwide^[1].

Objective: This review aims to evaluate the impact of air pollution exposure on OHCA risk and offer sustainable recommendations on mitigating OHCA related incidences in urban and rapidly urbanising environments.

Method: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline, we identified 136 articles from 2020 to present from PubMed, Scopus, and Web of Science databases on Covidence. After screening in accordance with a predefined PICO (population, intervention, comparison, outcome) protocol, 24 studies were extracted for analysis. Data extraction identified information on setting, population, pollutant type(s) (based on 6 air pollutants named as concerning by the World Health Organisation^[2]: PM2.5, PM10, NO₂, SO₂, O₃ and CO), lag exposure time, number of OHCAs and statistical analysis (e.g., odd ratio, relative risk). Risk of bias was assessed using the ROBIS tool. Meta-analysis was not possible due to study heterogeneity therefore, a systematic review was conducted.

Results: Comparing the exposures of the 6 air pollutants to the risk of developing OHCA across various urban populations worldwide, a statistical significance was demonstrated in PM2.5, especially in short term exposure. Inconsistent findings were seen in other pollutants which showed context-dependent effects, with some significance in multivariate analysis alongside other factors such as vulnerable subgroups and highly industrialised areas.

Conclusion: Given the findings, we recommend a multidisciplinary approach to address the urgent need for improvement in air quality standards. Suggestions include global health policies and urban planning to reduce ambient pollutant exposure and in return reduce the healthcare burden of OHCAs in urban populations.

Keywords: Out-of-hospital cardiac arrest, air pollution, urban health