Auriba Raza1, Marcus Dahlquist2, Martin Jonsson3, Jacob Hollenberg3, Leif Svensson3, Tomas Lind4, Petter L S Ljungman5. 1. Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, SE-171 77, Stockholm, Sweden. Electronic address: auriba@gmail.com. 2. Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, SE-171 77, Stockholm, Sweden. 3. Center for Resuscitation Science, Department of Medicine Solna, Karolinska Institutet, Sweden, Stockholm, Sweden. 4. Department of Occupational and Environmental Medicine, Stockholm County Council, Torsplan, Solnavägen 4, 113 65, Stockholm, Sweden. 5. Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, SE-171 77, Stockholm, Sweden; Department of Cardiology, Danderyds Sjukhus, Mörbygårdsvägen 88, 182 88, Danderyd, Sweden.
Abstract
BACKGROUND: 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. AIM: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
BACKGROUND: 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. AIM: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.