Ozone and cardiac arrest: The role of previous hospitalizations

• Published in: Environmental pollution (1987) Vol. 245; pp. 1 - 8
• Main Authors: Raza, Auriba, Dahlquist, Marcus, Jonsson, Martin, Hollenberg, Jacob, Svensson, Leif, Lind, Tomas, Ljungman, Petter L.S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-02-2019
• Subjects: Air pollution; Medicin och hälsovetenskap; Out-of-hospital cardiac arrest; Previous hospitalizations; Susceptibility; Previous hospitalizations; Out-of-hospital cardiac arrest; Air pollution; Susceptibility
• ISSN: 0269-7491; 1873-6424; 1873-6424
• DOI: 10.1016/j.envpol.2018.10.042

Several studies have reported associations between exposure to particulate matter and incidence of out-of-hospital cardiac arrest (OHCA) and some have observed associations with ozone (O3). There are no studies investigating susceptibility based on previous disease history to short-term O3 exposure and the risk of OHCA.
To investigate the role of previous cardiovascular-related hospitalizations in modifying the associations between the risk of OHCA and short-term increase in O3 concentrations.
A time-stratified case-crossover analysis of 11,923 OHCA registered in the Swedish Register for Cardiopulmonary Resuscitation from 2006 to 2014 was performed. Using personal identification numbers, OHCA were linked to all previous hospitalizations in Sweden since 1987 to create susceptible groups based on the principal diagnosis code at discharge. Susceptibility was based on hospitalization for i) acute myocardial infarction; ii) heart failure; iii) arrhythmias; iv) diabetes; v) hypertension; and vi) stroke. Moving 2 and 24-h averages for O3, PM2.5, PM10, and NO2 were constructed from hourly averages.
A 10 μg/m3 higher 2-h average O3 concentration was associated with a 2% higher risk of OHCA (95% CI, 0% 3%). Associations were similar for 24-h average O3 and in individuals with or without hospitalizations for AMI, heart failure, diabetes, hypertension or stroke. Individuals with previous hospitalizations for arrhythmias had a lower risk of OHCA with higher O3. No associations were observed for other pollutants.
Short-term exposure to O3 was associated with an elevated risk of OHCA, however, previous hospitalizations for cardiovascular diseases were not associated with additionally augmented risks.
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•We studied the role of prior hospitalizations on the association between short-term O3 exposure and OHCA.•We used a large sample of a well-defined outcome with etiologic data of OHCA.•We had highly accurate information concerning handling times provided by Swedish Register for Cardiopulmonary Resuscitation.•We observed associations between transient exposure to O3 and OHCA.•Prior hospitalizations for CVD did not confer a higher risk of OHCA following exposure to higher short-term averages of O3.
In a large study with detailed data on previous hospitalizations, we reported higher risks of out-of-hospital cardiac arrest with higher short-term levels of ambient ozone but did not find evidence to support consideration of possible greater risks for this outcome in subgroups based on previous cardiac disease.