title: Neighbourhood Characteristics and Long-Term Air Pollution Levels Modify the Association between the Short-Term Nitrogen Dioxide Concentrations and All-Cause Mortality in Paris.
abstract: BACKGROUND
  While a great number of papers have been published on the short-term effects of air pollution on mortality, few have tried to assess whether this association varies according to the neighbourhood socioeconomic level and long-term ambient air concentrations measured at the place of residence. We explored the effect modification of 1) socioeconomic status, 2) long-term NO2 ambient air concentrations, and 3) both combined, on the association between short-term exposure to NO2 and all-cause mortality in Paris (France).
  
  
  METHODS
  A time-stratified case-crossover analysis was performed to evaluate the effect of short-term NO2 variations on mortality, based on 79,107 deaths having occurred among subjects aged over 35 years, from 2004 to 2009, in the city of Paris. Simple and double interactions were statistically tested in order to analyse effect modification by neighbourhood characteristics on the association between mortality and short-term NO2 exposure. The data was estimated at the census block scale (n=866).
  
  
  RESULTS
  The mean of the NO2 concentrations during the five days prior to deaths were associated with an increased risk of all-cause mortality: overall Excess Risk (ER) was 0.94% (95%CI=[0.08;1.80]. A higher risk was revealed for subjects living in the most deprived census blocks in comparison with higher socioeconomic level areas (ER=3.14% (95%CI=[1.41-4.90], p<0.001). Among these deprived census blocks, excess risk was even higher where long-term average NO2 concentrations were above 55.8 μg/m3 (the top tercile of distribution): ER=4.84% (95%CI=[1.56;8.24], p for interaction=0.02).
  
  
  CONCLUSIONS
  Our results show that people living in census blocks characterized by low socioeconomic status are more vulnerable to air pollution episodes. There is also an indication that people living in these disadvantaged census blocks might experience even higher risk following short-term air pollution episodes, when they are also chronically exposed to higher NO2 levels.
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Deguen
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Petit
authors.affiliation: EHESP School of Public Health, Rennes, France.
authors.forename: Angélique
authors.initials: A
authors.lastname: Delbarre
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France.
authors.forename: Wahida
authors.initials: W
authors.lastname: Kihal
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France.
authors.forename: Cindy
authors.initials: C
authors.lastname: Padilla
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France.
authors.forename: Tarik
authors.initials: T
authors.lastname: Benmarhnia
authors.affiliation: INSERM U707, Research Group on the Social Determinants of Health and Healthcare, Paris, France.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Lapostolle
authors.affiliation: INSERM U707, Research Group on the Social Determinants of Health and Healthcare, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Chauvin
authors.affiliation: EHESP School of Public Health, Rennes, France; INSERM U1085 (IRSET), Rennes, France; Lorraine University Medical School, Vandœuvre-les-Nancy, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Zmirou-Navier
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D009585:Nitrogen Dioxide / Q000633:toxicity*; D010297:Paris / Q000453:epidemiology; D012307:Risk Factors; D012959:Socioeconomic Factors; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D009585:Nitrogen Dioxide