title: Risk of cancer in the vicinity of municipal solid waste incinerators: importance of using a flexible modelling strategy.
abstract: BACKGROUND
  We conducted an ecological study in four French administrative departments and highlighted an excess risk in cancer morbidity for residents around municipal solid waste incinerators. The aim of this paper is to show how important are advanced tools and statistical techniques to better assess weak associations between the risk of cancer and past environmental exposures.
  
  
  METHODS
  The steps to evaluate the association between the risk of cancer and the exposure to incinerators, from the assessment of exposure to the definition of the confounding variables and the statistical analysis carried out are detailed and discussed. Dispersion modelling was used to assess exposure to sixteen incinerators. A geographical information system was developed to define an index of exposure at the IRIS level that is the geographical unit we considered. Population density, rural/urban status, socio-economic deprivation, exposure to air pollution from traffic and from other industries were considered as potential confounding factors and defined at the IRIS level. Generalized additive models and Bayesian hierarchical models were used to estimate the association between the risk of cancer and the index of exposure to incinerators accounting for the confounding factors.
  
  
  RESULTS
  Modelling to assess the exposure to municipal solid waste incinerators allowed accounting for factors known to influence the exposure (meteorological data, point source characteristics, topography). The statistical models defined allowed modelling extra-Poisson variability and also non-linear relationships between the risk of cancer and the exposure to incinerators and the confounders.
  
  
  CONCLUSIONS
  In most epidemiological studies distance is still used as a proxy for exposure. This can lead to significant exposure misclassification. Additionally, in geographical correlation studies the non-linear relationships are usually not accounted for in the statistical analysis. In studies of weak associations it is important to use advanced methods to better assess dose-response relationships with disease risk.
authors.affiliation: Institute of Public Health Surveillance (InVS), Saint-Maurice, France. s.goria@invs.sante.fr
authors.forename: Sarah
authors.initials: S
authors.lastname: Goria
authors.forename: Côme
authors.initials: C
authors.lastname: Daniau
authors.forename: Perrine
authors.initials: P
authors.lastname: de Crouy-Chanel
authors.forename: Pascal
authors.initials: P
authors.lastname: Empereur-Bissonnet
authors.forename: Pascal
authors.initials: P
authors.lastname: Fabre
authors.forename: Marc
authors.initials: M
authors.lastname: Colonna
authors.forename: Cedric
authors.initials: C
authors.lastname: Duboudin
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Viel
authors.forename: Sylvia
authors.initials: S
authors.lastname: Richardson
mesh_terms: D000397:Air Pollution / Q000009:adverse effects; D004781:Environmental Exposure / Q000009:adverse effects; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D017745:Incineration / Q000379:methods; D009111:Local Government; D008297:Male; D008962:Models, Theoretical; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D012037:Refuse Disposal / Q000379:methods; D012307:Risk Factors