title: Effects of extreme temperatures on cardiovascular emergency hospitalizations in a Mediterranean region: a self-controlled case series study.
abstract: Cold spells and heatwaves increase mortality. However little is known about the effect of heatwaves or cold spells on cardiovascular morbidity. This study aims to assess the effect of cold spells and heatwaves on cardiovascular diseases in a Mediterranean region (Catalonia, Southern Europe).
  
  
  
  We conducted a population-based retrospective study. Data were obtained from the System for the Development of Research in Primary Care and from the Catalan Meteorological Service. The outcome was first emergency hospitalizations due to coronary heart disease, stroke, or heart failure. Exposures were: cold spells; cold spells and 3 or 7 subsequent days; and heatwaves. Incidence rate ratios (IRR) and 95% confidence intervals were calculated using the self-controlled case series method. We accounted for age, time trends, and air pollutants; results were shown by age groups, gender or cardiovascular event type.
  
  
  
  There were 22,611 cardiovascular hospitalizations in winter and 17,017 in summer between 2006 and 2013. The overall incidence of cardiovascular hospitalizations significantly increased during cold spells (IRR = 1.120; CI 95%: 1.10-1.30) and the effect was even stronger in the 7 days subsequent to the cold spell (IRR = 1.29; CI 95%: 1.22-1.36). Conversely, cardiovascular hospitalizations did not increase during heatwaves, neither in the overall nor in the stratified analysis.
  
  
  
  Cold spells but not heatwaves, increased the incidence of emergency cardiovascular hospitalizations in Catalonia. The effect of cold spells was greater when including the 7 subsequent days. Such knowledge might be useful to develop strategies to reduce the impact of extreme temperature episodes on human health.
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain. aponjoan@idiapjgol.info.|Girona Biomedical Research Institute (IDIBGi), c/ del Dr. Castany, s/n, Salt, Girona, 17190, Catalonia, Spain. aponjoan@idiapjgol.info.|Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Bellaterra, Spain. aponjoan@idiapjgol.info.
authors.forename: Anna
authors.identifier: 0000-0003-4314-6387
authors.initials: A
authors.lastname: Ponjoan
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Blanch
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.
authors.forename: Lia
authors.initials: L
authors.lastname: Alves-Cabratosa
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.|Girona Biomedical Research Institute (IDIBGi), c/ del Dr. Castany, s/n, Salt, Girona, 17190, Catalonia, Spain.|Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Bellaterra, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Martí-Lluch
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Comas-Cufí
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.|Centre d'Atenció Primària Santa Clara, Gerència d'Àmbit d'Atenció Primària Girona, Institut Català de la Salut, Girona, Spain.
authors.forename: Dídac
authors.initials: D
authors.lastname: Parramon
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Del Mar Garcia-Gil
authors.affiliation: Vascular Health Research Group (ISV-Girona), Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), c/ Maluquer Salvador, 11 baixos, Girona, 17002, Catalonia, Spain.|Department of Medical Sciences, School of Medicine, Campus Salut, University of Girona, Girona, Spain.
authors.forename: Rafel
authors.initials: R
authors.lastname: Ramos
authors.affiliation: Department of Primary Care and Population Health, University College of London, London, UK.|Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark.
authors.forename: Irene
authors.initials: I
authors.lastname: Petersen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003080:Cold Temperature / Q000009:adverse effects*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006358:Hot Temperature; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology
keywords: Climate change; Cold snap; Coronary heart disease; Heart failure; Heat; Hospital admissions; Stroke; Weather