Marcus Dahlquist1, Auriba Raza2, Getahun Bero-Bedada2, Jacob Hollenberg3, Tomas Lind2, Nicola Orsini4, Bengt Sjögren5, Leif Svensson6, Petter L Ljungman7. 1. Department of Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden; Unit of Environmental Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. Electronic address: marcus.dahlquist@ki.se. 2. Department of Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden; Unit of Environmental Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. 3. Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden; Department of Cardiology, Stockholm South General Hospital, Stockholm, Sweden. 4. Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. 5. Unit of Work Environmental Toxicology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. 6. Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden. 7. Department of Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden; Unit of Environmental Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden; Department of Cardiology, Danderyd Hospital, Stockholm, Sweden.
Abstract
BACKGROUND: Associations have been reported between daily ambient temperature and all-cause and cardiovascular mortality. However, the potential harmful effect of temperature on out-of-hospital cardiac arrest (OHCA) is insufficiently studied. OBJECTIVES: The objective of this study was to investigate the short-term association between ambient temperature and the occurrence of OHCA. METHODS: In 5961 cases of OHCAs treated by Emergency Medical Service occurring in Stockholm County we investigated the association between the preceding 24-h and 1h mean ambient temperature, obtained from a fixed monitoring station, and OHCA using a time-stratified case-crossover design. RESULTS: We observed a V-shaped relationship between preceding mean 24-h and 1-h ambient temperature and the occurrence of OHCAs. For mean 24-h temperature we observed an odds ratio (OR) of 1.05 (1.00-1.11) for each 5°C below the optimum temperature and 1.05 (0.96-1.18) for each 5°C above the optimum. We observed similar results for 1-h mean temperature exposure. Results for temperatures above the optimum temperature showed evidence of confounding by ozone. CONCLUSION: Ambient temperature below an optimum temperature was associated with increased risk of OHCA in Stockholm. Temperature above an optimum temperature was not significantly associated with OHCA.
BACKGROUND: Associations have been reported between daily ambient temperature and all-cause and cardiovascular mortality. However, the potential harmful effect of temperature on out-of-hospital cardiac arrest (OHCA) is insufficiently studied. OBJECTIVES: The objective of this study was to investigate the short-term association between ambient temperature and the occurrence of OHCA. METHODS: In 5961 cases of OHCAs treated by Emergency Medical Service occurring in Stockholm County we investigated the association between the preceding 24-h and 1h mean ambient temperature, obtained from a fixed monitoring station, and OHCA using a time-stratified case-crossover design. RESULTS: We observed a V-shaped relationship between preceding mean 24-h and 1-h ambient temperature and the occurrence of OHCAs. For mean 24-h temperature we observed an odds ratio (OR) of 1.05 (1.00-1.11) for each 5°C below the optimum temperature and 1.05 (0.96-1.18) for each 5°C above the optimum. We observed similar results for 1-h mean temperature exposure. Results for temperatures above the optimum temperature showed evidence of confounding by ozone. CONCLUSION: Ambient temperature below an optimum temperature was associated with increased risk of OHCA in Stockholm. Temperature above an optimum temperature was not significantly associated with OHCA.
Authors: Mare Lõhmus; Tomas Lind; Laura MacLachlan; Agneta Ekebom; Björn Gedda; Pia Östensson; Antonios Georgelis Journal: Int J Environ Res Public Health Date: 2022-05-11 Impact factor: 4.614