title: The relation between temperature, ozone, and mortality in nine French cities during the heat wave of 2003.
abstract: BACKGROUND
  During August 2003, record high temperatures were observed across Europe, and France was the country most affected. During this period, elevated ozone concentrations were measured all over the country. Questions were raised concerning the contribution of O3 to the health impact of the summer 2003 heat wave.
  
  
  METHODS
  We used a time-series design to analyze short-term effects of temperature and O3 pollution on mortality. Counts of deaths were regressed on temperatures and O3 levels, controlling for possible confounders: long-term trends, season, influenza outbreaks, day of the week, and bank holiday effects. For comparison with previous results of the nine cities, we calculated pooled excess risk using a random effect approach and an empirical Bayes approach.
  
  
  RESULTS
  For the nine cities, the excess risk of death is significant (1.01% ; 95% confidence interval, 0.58-1.44) for an increase of 10 microg/m3 in O3 level. For the 3-17 August 2003 period, the excess risk of deaths linked to O3 and temperatures together ranged from 10.6% in Le Havre to 174.7% in Paris. When we compared the relative contributions of O3 and temperature to this joint excess risk, the contribution of O3 varied according to the city, ranging from 2.5% in Bordeaux to 85.3% in Toulouse.
  
  
  CONCLUSIONS
  We observed heterogeneity among the nine cities not only for the joint effect of O3 and temperatures, but also for the relative contribution of each factor. These results confirmed that in urban areas O3 levels have a non-negligible impact in terms of public health.
authors.affiliation: Institut de Veille Sanitaire, Bordeaux, France. laurent.filleul@sante.gouv.fr
authors.forename: Laurent
authors.initials: L
authors.lastname: Filleul
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cassadou
authors.forename: Sylvia
authors.initials: S
authors.lastname: Médina
authors.forename: Pascal
authors.initials: P
authors.lastname: Fabres
authors.forename: Agnés
authors.initials: A
authors.lastname: Lefranc
authors.forename: Daniel
authors.initials: D
authors.lastname: Eilstein
authors.forename: Alain
authors.initials: A
authors.lastname: Le Tertre
authors.forename: Laurence
authors.initials: L
authors.lastname: Pascal
authors.forename: Benoit
authors.initials: B
authors.lastname: Chardon
authors.forename: Myriam
authors.initials: M
authors.lastname: Blanchard
authors.forename: Christophe
authors.initials: C
authors.lastname: Declercq
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Jusot
authors.forename: Hélène
authors.initials: H
authors.lastname: Prouvost
authors.forename: Martine
authors.initials: M
authors.lastname: Ledrans
mesh_terms: D002947:Cities; D004781:Environmental Exposure; D005060:Europe / Q000453:epidemiology; D005602:France / Q000453:epidemiology; D018882:Heat Stress Disorders / Q000453:epidemiology / Q000266:history / Q000401:mortality; D049674:History, 21st Century; D006801:Humans; D007259:Infrared Rays / Q000009:adverse effects*; D009026:Mortality / Q000639:trends*; D010126:Ozone / Q000633:toxicity*; D011634:Public Health / Q000706:statistics & numerical data*; D018570:Risk Assessment; D013997:Time Factors
chemical_list: D010126:Ozone