title: Mortality on extreme heat days using official thresholds in Spain: a multi-city time series analysis.
abstract: BACKGROUND
  The 2003 heat wave had a high impact on mortality in Europe, which made necessary to develop heat health watch warning systems. In Spain this was carried-out by the Ministry of Health in 2004, being based on exceeding of city-specific simultaneous thresholds of minimum and maximum daily temperatures. The aim of this study is to assess effectiveness of the official thresholds established by the Ministry of Health for each provincial capital city, by quantifying and comparing the short-term effects of above-threshold days on total daily mortality.
  
  
  METHODS
  Total daily mortality and minimum and maximum temperatures for the 52 capitals of province in Spain were collected during summer months (June to September) for the study period 1995-2004. Data was analysed using GEE for Poisson regression. Relative Risk (RR) of total daily mortality was quantified for the current day of official thresholds exceeded.
  
  
  RESULTS
  The number of days in which the thresholds were exceeded show great inconsistency, with provinces with great number of exceeded days adjacent to provinces that did not exceed or rarely exceeded. The average overall excess risk of dying during an extreme heat day was about 25% (RR = 1.24; 95% confidence interval (CI) = [1.19-1.30]). Relative risks showed a significant heterogeneity between cities (I2 = 54.9%). Western situation and low mean summer temperatures were associated with higher relative risks, suggesting thresholds may have been set too high in these areas.
  
  
  CONCLUSIONS
  This study confirmed that extreme heat days have a considerable impact on total daily mortality in Spain. Official thresholds gave consistent relative risk in the large capital cities. However, in some other cities thresholds.
authors.affiliation: Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Barcelona, Spain. aurelio.tobias@idaea.csic.es
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobias
authors.forename: Ben
authors.initials: B
authors.lastname: Armstrong
authors.forename: Ines
authors.initials: I
authors.lastname: Zuza
authors.forename: Antonio
authors.initials: A
authors.lastname: Gasparrini
authors.forename: Cristina
authors.initials: C
authors.lastname: Linares
authors.forename: Julio
authors.initials: J
authors.lastname: Diaz
mesh_terms: D002947:Cities / Q000453:epidemiology*; D016001:Confidence Intervals; D055874:Extreme Heat / Q000009:adverse effects*; D005260:Female; D018883:Heat Stroke / Q000401:mortality*; D006801:Humans; D008297:Male; D009026:Mortality / Q000639:trends; D016012:Poisson Distribution; D013030:Spain / Q000453:epidemiology; D013996:Time and Motion Studies; D014887:Weather