title: Acute effects of ambient particulate matter on mortality in Europe and North America: results from the APHENA study.
abstract: BACKGROUND
  THE APHENA (AIR POLLUTION AND HEALTH: A Combined European and North American Approach) study is a collaborative analysis of multicity time-series data on the effect of air pollution on population health, bringing together data from the European APHEA (Air Pollution and Health: A European Approach) and U.S. NMMAPS (National Morbidity, Mortality and Air Pollution Study) projects, along with Canadian data.
  
  
  OBJECTIVE
  The main objective of APHENA was to assess the coherence of the findings of the multicity studies carried out in Europe and North America, when analyzed with a common protocol, and to explore sources of possible heterogeneity. We present APHENA results on the effects of particulate matter (PM) < or = 10 microm in aerodynamic diameter (PM(10)) on the daily number of deaths for all ages and for those < 75 and > or = 75 years of age. We explored the impact of potential environmental and socioeconomic factors that may modify this association.
  
  
  METHODS
  In the first stage of a two-stage analysis, we used Poisson regression models, with natural and penalized splines, to adjust for seasonality, with various degrees of freedom. In the second stage, we used meta-regression approaches to combine time-series results across cites and to assess effect modification by selected ecologic covariates.
  
  
  RESULTS
  Air pollution risk estimates were relatively robust to different modeling approaches. Risk estimates from Europe and United States were similar, but those from Canada were substantially higher. The combined effect of PM(10) on all-cause mortality across all ages for cities with daily air pollution data ranged from 0.2% to 0.6% for a 10-microg/m(3) increase in ambient PM(10) concentration. Effect modification by other pollutants and climatic variables differed in Europe and the United States. In both of these regions, a higher proportion of older people and higher unemployment were associated with increased air pollution risk.
  
  
  CONCLUSIONS
  Estimates of the increased mortality associated with PM air pollution based on the APHENA study were generally comparable with results of previous reports. Overall, risk estimates were similar in Europe and in the United States but higher in Canada. However, PM(10) effect modification patterns were somewhat different in Europe and the United States.
authors.affiliation: Department of Hygiene and Epidemiology, University of Athens Medical School, Athens, Greece. esamoli@med.uoa.gr
authors.forename: Evangelia
authors.initials: E
authors.lastname: Samoli
authors.forename: Roger
authors.initials: R
authors.lastname: Peng
authors.forename: Tim
authors.initials: T
authors.lastname: Ramsay
authors.forename: Marina
authors.initials: M
authors.lastname: Pipikou
authors.forename: Giota
authors.initials: G
authors.lastname: Touloumi
authors.forename: Francesca
authors.initials: F
authors.lastname: Dominici
authors.forename: Rick
authors.initials: R
authors.lastname: Burnett
authors.forename: Aaron
authors.initials: A
authors.lastname: Cohen
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: Jon
authors.initials: J
authors.lastname: Samet
authors.forename: Klea
authors.initials: K
authors.lastname: Katsouyanni
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D004781:Environmental Exposure; D005060:Europe / Q000453:epidemiology; D009026:Mortality; D009656:North America / Q000453:epidemiology; D010316:Particle Size; D018570:Risk Assessment
chemical_list: D000393:Air Pollutants