Creation of synthetic homogeneous neighbourhoods using zone design algorithms to explore relationships between asthma and deprivation in Strasbourg, France C.E. Sabel a, * , W. Kihal b, c , D. Bard b , C. Weber c a Geography, College of Life & Environmental Sciences, and European Centre for Environment and Human Health, Exeter Medical School, University of Exeter, Amory Building, Rennes Drive, Exeter EX4 4RJ, UK b Ecole des Hautes Etudes en Santé Publique (EHESP), Rennes, France c University of Strasbourg, France article info Article history: Available online 28 November 2012 Keywords: France Zone design Neighbourhood MAUP Asthma Deprivation index abstract The concept of ‘neighbourhood’ as a unit of analysis has received considerable research attention over the last decade. Many of these studies raise the question of the influence of local characteristics on variations in health and more recently, researchers have sought to understand how the neighbourhood can influence individual health through individual behaviour. Relatively few studies discuss the question of the borders and definition of a neighbourhood but we know that the results from health or population datasets are very sensitive to how zones are constructed e part of the Modifiable Areal Unit Problem (MAUP). In reality, we know that neighbourhoods are not constrained by artificial statistical boundaries, but rather exist as complex multi-dimensional living communities. This paper tries to better represent the reality on the ground of these communities to better inform studies of health. In this work, we have developed an experimental approach for the automated design of neighbourhoods using a small tessellated cell as a basic building block. Using the software AZTool, we considered population, shape and homogeneity constraints to develop a highly innovative approach to zone construction. The paper reports the challenges and compromises involved in building these new synthetic neighbourhoods. We provide a fully worked example of how our new synthetic homogeneous zones perform using data from Strasbourg, France. We examine data on Asthma reported through calls to the emergency services, and compare these rates with an index of multiple deprivation (NDI) which we have constructed and reported elsewhere. Higher correlations between Asthma and NDI were found using our newly con- structed synthetic zones than using the existing French census areas of similar size. The significance of our work is that we show that careful construction of neighbourhoods e which we claim are more realistic than census areas e can greatly aid unpacking our understanding of neighbourhood relation- ships between health and the social and physical environments. Ó 2012 Elsevier Ltd. All rights reserved. Introduction The last decade of research in the environment and health field has seen the emergence of the concept of neighbourhood (Diez Roux, 2003; Kawachi, 2003; Pickett & Pearl, 2001) as a unit of analysis. Many of these studies raise the question of the influence of local characteristics on variations in health (Macintyre, Ellaway, & Cummins, 2002; Pickett & Pearl, 2001). For instance, the effects of proximate exposure to environmental stressors such as local ambient air pollution gave rise to a body of literature linking air pollution to several health outcomes, including asthma exacerbation (Samet & Krewski, 2007; Ward & Ayres, 2004). Most studies use average citywide ambient pollutant concentrations in order to esti- mate exposure, although these concentrations often vary spatially and strongly within cities (Jerrett et al., 2005). The social gradient for asthma is also well established; the most deprived being more at risk (Laurent, Bard, Filleul, & Segala, 2007). An effort has then been made to explore the influence of socioeconomic factors on the above associations (Lin, Chen, Burnett, Villeneuve, & Krewski, 2003) again with a low spatial resolution. Our group carried out studies on this topic using a small area design for assessing both exposure to air pollutants and socioeconomic status (Laurent, Filleul, et al., 2008, Laurent et al., 2009). Paralleling work in Anglo-Saxon countries, here has been some early work investigating definitions of neighbourhood in France by * Corresponding author. E-mail address: c.sabel@exeter.ac.uk (C.E. Sabel). Contents lists available at SciVerse ScienceDirect Social Science & Medicine journal homepage: www.elsevier.com/locate/socscimed 0277-9536/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.socscimed.2012.11.018 Social Science & Medicine 91 (2013) 110e121