The present study revealed several direct and mediating associations between the objective physical environment and different types of walking among Australian women living in socio-economically disadvantaged neighbourhoods. After controlling for socio-demographic covariates, the objective score including measures of density of physical activity/food related destinations and street connectivity, was positively associated with walking for transport. Previous research consistently found a positive relationship between walkability-related environmental characteristics and active transportation in adults [4, 5]. The objective destinations/connectivity score was negatively associated with leisure-time walking. We are unaware of previous studies reporting negative associations between walkability-related features and leisure-time walking in adults. Hitherto, previous findings have been inconsistent with results ranging from positive associations to no significant associations [4, 7, 32, 33]. However, no prior studies have examined these relationships among women living in socio-economically disadvantaged neighbourhoods, so the present findings could be specific for this population subgroup.
The mediating analyses presented in this paper helped to explain the negative association between the objective destinations/connectivity score and leisure-time walking. Living in an environment with high street connectivity and many destinations nearby was related to having positive perceptions of the physical activity environment, but also with perceiving poor aesthetics, low personal safety and low social cohesion of the neighbourhood. In total, 24.4% of the negative association between the objective destinations/connectivity score and leisure-time walking was explained by these negative perceptions. The present findings confirm the hypothesis that high (objective) walkability is not necessarily accompanied by positive perceptions of related environmental attributes . Furthermore, it seems that these negative perceptions might outweigh the importance of walkability-related characteristics to explain specific behaviours like leisure-time walking. Living in a poor-connected neighbourhood with few destinations nearby, but perceiving high safety and favourable aesthetics may be more beneficial for leisure-time walking than living in an objectively well-connected environment with many destinations.
To explain transport-related walking, favourable objective street connectivity and density of destinations, in combination with positive perceptions of the physical activity environment seem to be of overriding importance, even when poor aesthetics and low personal safety were perceived. For transport-related walking, the present findings are in line with the results of McCormack and colleagues , who suggested that walkability characteristics are more important to explain active transportation than other environmental features, like the availability of green spaces.
When considering the mediating effects in more detail, it seems that objective walkability-related characteristics (i.e. density of destinations and connectivity) are directly associated with transport-related walking, while the relationship with leisure-time walking is more complex. A possible explanation for this finding could be that leisure-time walking is a type of physical activity that is consciously practiced, and governed by choice rather than necessity [3, 34, 35]. Probably adults, and more specifically women living in socio-economically disadvantaged neighbourhoods, do not want to walk for recreation in an environment that is aesthetically unappealing, unsafe and has a low level of social cohesion. Because transport-related walking is rather governed by necessity, it is plausible that negative perceptions of neighbourhood social cohesion, personal safety and aesthetics will not prevent women living in socio-economically disadvantaged neighbourhoods from walking for transportation.
Perceived personal safety and aesthetics have been previously related to leisure-time walking, while the perceived physical activity environment has been associated with active transportation [4, 5, 36]. Consequently, although the direction of some of the mediating effects was surprising, the mediating effects of these attributes per se were not unexpected. However, an important novelty of this study is the mediating effect of neighbourhood social cohesion. To our knowledge, the role of neighbourhood social cohesion to explain the relationship between the physical environment and physical activity has not been studied previously. The mediating effect identified here is a key finding for future research because social cohesion has been identified as an important factor positively related to neighbourhood satisfaction and overall physical and mental health [37–39]. Therefore, from a broader health perspective, it is necessary to further clarify these associations and to find out how feelings of social cohesion among women and other residents living in high-walkable environments can be improved.
Acknowledging the cross-sectional study design and the need for confirmation of causal relationships, it seems that to increase both transport-related and leisure-time walking, it is necessary to find an optimal balance between several environmental attributes. Walkability-related characteristics, perceptions of personal safety, favourable aesthetics, high neighbourhood social cohesion and possibly other features that were not included in this study should be optimally balanced in order to support walking. Other physical and social environmental perceptions (e.g. social support, perceived accessibility of facilities) should be included as possible mediators in future studies. This may help to fully understand the indirect nature of the relationship between objective physical environmental characteristics and walking for different purposes in socio-economically disadvantaged women.
A strength of the present study was the large study sample of women living in socio-economically disadvantaged neighbourhoods, a population subgroup being at high risk for overweight and other health problems and difficult to reach in research studies and interventions. Second, women living in both urban and rural regions were included in the study. Third, powerful mediation techniques were used in the analyses, and the large number of participants (n = 4139) gave the power to adjust for a range of covariates in the analyses. Fourth, both objective and perceived measures were used to assess the neighbourhood physical environment. The objective neighbourhood environment was assessed with individualized network buffers, giving a better representation of the actual environment than buffers measured through the car network. Finally, environmental perceptions were assessed using a validated questionnaire and two specific physical activity domains were assessed using a validated questionnaire and examined independently.
Besides these strengths, some limitations need to be acknowledged. The most important study limitation was the cross-sectional design, which ruled out the possibility of determining causality. Second, because the response rate was lower than 50% a selection bias towards more motivated women may have been present. Third, women who had moved from the suburbs included in the study were excluded from the analyses because no GIS data could be linked to their addresses. As these women have a less stable location, it might be that mainly the most socio-economically disadvantaged women were over-represented in this group and potentially excluded from the analyses. Fourth, only women between 18 and 46 years were included, so the present results cannot be generalized to a broader population of adult women living in socio-economically disadvantaged neighbourhoods. Finally, because the IPAQ was used to assess physical activity, it remains unclear if the transport-related and leisure-time walking actually took place in the neighbourhood in which the women lived. To clarify this, future studies should include objective measurement methods like Global Positioning Systems (GPS) .