title: Building spatial composite indicators to analyze environmental health inequalities on a regional scale.
abstract: BACKGROUND
  Reducing health inequalities involves the identification and characterization of social and exposure factors and the way they accumulate in a given area. The areas of accumulation then allow for prioritization of interventions. The present study aims to build spatial composite indicators based on the aggregation of environmental, social and health indicators and their inter-relationships.
  
  
  METHODS
  Preliminary work was carried out firstly to homogenize spatial coverage, and secondly to study spatial variation of environmental (EI), socioeconomic (SI) and health (HI) indicators. The aggregation of the different indicators was performed using several methodologies for which results and decision-makers' usability were compared.
  
  
  RESULTS
  Four methodologies were tested: 1) A simple summation of normalized HI, EI and SI indicators (IC), 2) the sum of the normalized HI, EI and SI indicators weighted by the first principal component of a Principal Component Analysis (IC PCA), 3) the sum of normalized and weighted indicators of the first principal component of Local Principal Component Analysis (IC LPCA), and 4) the sum of normalized and weighted indicators of the first principal component of a Geographically Weighted Principal Component Analysis (IC GWPCA).
  
  
  CONCLUSIONS
  The GWPCA is particularly adapted to taking into account the spatial heterogeneity and the spatial autocorrelation between SI, EI and HI. This approach invalidates the basic assumptions of many standard statistical analyses. Where socioeconomic indicators present high deprivation and where they are associated with potential modifiable health determinants, decision-makers can prioritize these areas for reducing inequalities by controlling the socioeconomic and health determinants.
authors: French National Institute for Industrial Environment and Risks, Parc Technologique Alata,BP 2, 60550, Verneuil-en-Halatte, France. saib.mahdi.s@gmail.com.
authors: Mahdi-Salim
authors: MS
authors: Saib
authors: French National Institute for Industrial Environment and Risks, Parc Technologique Alata,BP 2, 60550, Verneuil-en-Halatte, France.
authors: Julien
authors: J
authors: Caudeville
authors: French National Institute for Industrial Environment and Risks, Parc Technologique Alata,BP 2, 60550, Verneuil-en-Halatte, France.
authors: Maxime
authors: M
authors: Beauchamp
authors: French National Institute for Industrial Environment and Risks, Parc Technologique Alata,BP 2, 60550, Verneuil-en-Halatte, France.
authors: Florence
authors: F
authors: Carré
authors: Epidemiology and public health department, University hospital of Amiens, Amiens, France.
authors: Olivier
authors: O
authors: Ganry
authors: Regional Observatory of Health and Social Issues in Picardie, Amiens, France.
authors: Alain
authors: A
authors: Trugeon
authors: French National Institute for Industrial Environment and Risks, Parc Technologique Alata,BP 2, 60550, Verneuil-en-Halatte, France.
authors: Andre
authors: A
authors: Cicolella
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004782:Environmental Health / Q000379:methods*; D005260:Female; D005602:France; D005843:Geography; D054625:Healthcare Disparities / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D062206:Spatial Analysis; D055815:Young Adult