Effects of changing exposure to neighbourhood greenness on general and mental health: A longitudinal study Hanna Weimann a,n , Lars Rylander a , Maria Albin a , Erik Skärbäck b , Patrik Grahn c , Per-Olof Östergren d , Jonas Björk a a Division of Occupational and Environmental Medicine, Lund University, 22185 Lund, Sweden b Department of Landscape Architecture, Planning and Management, Swedish University of Agricultural Sciences, 23053 Alnarp, Sweden c Department of Work Science, Business Economics and Environmental Psychology, Swedish University of Agricultural Sciences, 23053 Alnarp, Sweden d Division of Social Medicine and Global Health, Lund University, 21428 Malmö, Sweden article info Article history: Received 24 November 2014 Received in revised form 28 January 2015 Accepted 2 February 2015 Keywords: Green quality Neighborhood perceptions General health Mental health Longitudinal data abstract Green neighbourhood environments have been associated with physical and psychological wellbeing in adults. Access to greenness is potentially more important in vulnerable subgroups. In this study based on longitudinal survey data from southern Sweden the cohort was divided into prognostic groups for good self-reported general (n ¼8891) and mental (n ¼9444) health. We used independent survey data to assess perceived neighbourhood greenness in 1 km 2 areas, and estimated effects of changing exposure longitudinally stratified by prognostic group. The overall effect on health was small and statistically uncertain (for general health OR 1.04, 95% CI 0.98–1.10, for mental health OR 1.07, 95% CI 1.00–1.14). A more beneficial effect of increased greenness was indicated among subjects with lowest prognostic of good general health (OR 1.24, 95% CI 1.01–1.52). The study provided only weak evidence for beneficial effects of increased neighbourhood greenness triggered by changing residence. It seems that altered life circumstances, e.g. changed civil or socioeconomic status that often trigger a decision to move, are also the key determinants of the health consequences of changing residence. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction Availability and quality of green areas in neighbourhood environments have been associated with general and mental health (Alcock et al., 2014; Björk et al., 2008; Bowler et al., 2010; de Jong et al., 2012; Maas et al., 2006; Stigsdotter et al., 2010; Sugiyama et al., 2008; van Dillen et al., 2011; White et al., 2013). The Attention Restoration Theory, presented in the mid-1990s, proposed an original rationale for associations between green environments and health by suggesting that restoration from fatigue, caused by an overload of directed attention, can be obtained in natural environments (Kaplan, 1995). The effect of greenness in neighbourhood environments on health may differ across population groups and individual living conditions. Results from the UK suggest a stronger beneficial effect from exposure to green space on disease risk and mortality in low-income groups (Mitchell and Popham, 2007, 2008). Studies from southern Swe- den also suggest a positive influence of nature on the health of particularly vulnerable groups such as elderly people (Ottosson and Grahn, 2006), individuals in rehabilitation for stress-related mental disorders (Pálsdóttir, 2014) and individuals in crisis reha- bilitation (Ottosson and Grahn, 2008). Although there are some recent longitudinal ones (Alcock et al., 2014; Annerstedt et al., 2012; White et al., 2013), previous epidemiological studies on green space and health have mainly used cross-sectional designs and are therefore unable to provide evidence about causality. In particular, cross-sectional designs are prone to self-selection bias, i.e. that individuals with higher well- being choose to live in neighbourhoods that support a healthy lifestyle (Katz, 2009). Moreover, cross-sectional studies are also prone to single source bias, if data on exposure and health status are both based on self-assessments (de Jong et al., 2012). One solution to this latter problem would be to use objective assess- ments of the neighbourhood environment based on landscape data (Björk et al., 2008). However, there are evidence suggesting that perceptions of the neighborhood, e.g. as being green, walkable or noisy, are important for health, also after controlling for objective measures of identical or similar features (Babisch et al., 2013; de Jonget al., 2012; Gebel et al., 2011; Prins et al., 2009; Van Dyck et al., 2014) The problem of single source bias in studies of the perceived environment can be avoided by using neighbour- hood assessments based on an independent sample from the same Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/healthplace Health & Place http://dx.doi.org/10.1016/j.healthplace.2015.02.003 1353-8292/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ46 736 585767. E-mail addresses: hanna.weimann@med.lu.se (H. Weimann), lars.rylander@med.lu.se (L. Rylander), maria.albin@med.lu.se (M. Albin), erik.skarback@slu.se (E. Skärbäck), patrik.grahn@slu.se (P. Grahn), per-olof.ostergren@med.lu.se (P.-O. Östergren), jonas.bjork@med.lu.se (J. Björk). Health & Place 33 (2015) 48–56