Based on the results of the present study we might cautiously assume that the relationship between perceived neighborhood built environmental attributes and AT previously found in adults , is not totally comparable to the relationship found in Belgian adolescents. Among Belgian adolescents, the contribution of neighborhood built environmental perceptions to explain the variance in AT seems dependent of the purpose of AT. For AT during leisure time, the importance of the perception of the neighborhood environmental attributes seems rather negligible. After controlling for demographic characteristics and psychosocial factors, only the perception of a higher degree of traffic safety in the neighborhood was found to be associated with more walking for transport during leisure time. For cycling for transport during leisure time, none of the perceived neighborhood environmental attributes was found to be of importance. As to our knowledge this is one of the first studies to investigate the contribution of neighborhood built environmental attributes to active transport during leisure time among adolescents. Further research that focuses on AT during leisure time is therefore recommended. On the other hand, to explain AT to and from school the perception of the neighborhood built environmental attributes is important, even beyond the demographic characteristics and psychosocial factors. A shorter distance to school and perceiving neighborhoods to have connected streets, a lower degree of land use mix diversity, less infrastructure and a lower quality of the infrastructure for walking are found to be associated with more min/day AT to and from school. Furthermore, a higher degree of residential density and more safety for crime were also found to be marginally significantly associated with more AT to and from school. Within the literature focusing on active transport to school, the importance of the distance to school, the connectedness of neighborhood streets and the degree of residential density has been emphasized repeatedly [35–39]. These results highlight the need to build new schools in neighborhoods with a well-connected street network and a high degree of residential density. Furthermore, safety for crime was negatively associated with AT to and from school. Although this finding is somewhat counterintuitive, a lower perception of safety from crime is often associated with a higher residential density, which was positively associated with AT to and from school. Surprisingly, the availability and quality of walking infrastructure were negatively associated with AT to and from school. A possible explanation for this finding can be that adolescents prefer to take a route through parks, recreation domains or backstreets where no pavements or no well-maintained pavements are available instead of through busy city centers, which are usually characterized by paved and well-maintained sidewalks and bikelanes. Furthermore, we also found a negative association with land use mix diversity. A reason for this finding is not apparent. A more thorough examination of this issue is required.
Recently, two papers were published describing the association between neighborhood built environmental attributes and adolescents’ levels of PA in the same Belgian study sample. In the first paper , the same questionnaire was used to measure AT and the perception of the neighborhood built environmental attributes. In contrast to the results of the present study, cul-de-sacs and availability and quality of cycling infrastructure were found to be positively associated with AT. However, as this study did not make a distinction between the different types of AT, comparison needs caution. The second paper described the association of the objectively determined neighborhood walkability with walking and cycling for transport during leisure time and AT to and from school . The results of this paper revealed no associations between objectively determined neighborhood walkability and self-reported AT. However, the difference in results can be attributed to the measurement method of the neighborhood environmental attributes. According to Ball et al. (2008), it is possible that objective assessments of built environmental attributes are indirectly associated with PA, whereas perceptions of environmental attributes have a more direct influence on PA.
A possible explanation for the distinction in the importance of neighborhood built environmental attributes to explain AT to and from school and AT for other purposes, might be that parents of young adolescents still play an important role in determining adolescents’ exposure to factors that are favorable or unfavorable to PA . Young adolescents are often dependent on parental rules governing travel and destination choices. During the week most of the adolescents’ parents are both employed which makes it very difficult to drive their children from home to school and pick their children up after school. Belgian adolescents between 13 and 15 years are not allowed to drive cars nor mopeds and often have few alternative transport modes besides walking and cycling to travel to and from school. The distance to school and the perception of the adolescents of other built environmental attributes can then be of importance to explain AT to and from school in adolescents. In contrast, after school hours and during the weekends, the parents more often have the time and opportunity to transport their children. Therefore, it is possible that adolescents’ AT during their leisure time is more dependent on parental perceptions of neighborhood environmental attributes. Furthermore, during leisure time, the adolescents more often have the choice to be driven by their parents to their destinations or to use AT. It is possible that other factors (e.g. the possibility to be independent) rather than their perception of the environmental attributes are of greater importance in this choice.
Second, the items in the questionnaire concerning the environmental perceptions were related to the adolescents’ own neighborhood. Because a large part of adolescents are involved in sports and other leisure activities, adolescents’ AT during leisure time involve also the route from home to sport or leisure facilities. Consequently, built environmental characteristics of these environments may need to be taken into account. Thus, it would be advisable for future research to also include built environmental characteristics of other routes and destinations where adolescents often travel to during leisure time, such as their friend’s house, sport facilities or parks. Finally, the absence of associations can be attributable to the relatively high activity friendliness of Belgian neighborhoods. In contrast to other continents and countries such as the USA or Australia the built environment in Belgium is quite supportive for walking and cycling . Consequently, this will be reflected in the variability in AT.
When considering the present study results, it should be taken into account that due to the cross-sectional design no inferences on causality can be made. Secondly, as we relied on self-report, our data may suffer from reporting bias. Third, certain neighborhood environmental factors (e.g. quality and attractiveness of parks and neighborhood sport facilities [43, 44]) that were not included in our questionnaire may also be of importance in explaining AT among adolescents. These factors should be investigated more thoroughly in the future. Fourth, comparison of gender distribution, parental employment status and educational level with data from the Belgian National Institute of Statistics showed that the study sample was comparable for gender, but the parents were more likely to be highly educated and employed. This may limit the generalizability of our findings. Strengths of the present study are the large study sample and the use of validated questionnaires to measure built environmental perceptions and AT.
For public health researchers, organizers and providers and policy makers involved in the development of interventions to promote PA, the results of the present study provide evidence that among Belgian adolescents, the perceptions of neighborhood built environmental attributes might be of importance for AT to and from school. Consequently, changing the perception of built environment attributes by awareness-raising initiatives may be effective in the promotion of AT tot and from school but not in the promotion of AT during leisure time. Of course, when considering these results and conclusions, it should be taken into account that they refer to the overall Belgian adolescent population and that they are possibly not applicable for specific subgroups. For example for groups that are most difficult to reach (i.e. adolescents living in socio-economically disadvantaged neighborhoods with less positive scores on psychosocial factors) positive environmental perceptions might help in overcoming personal barriers towards PA. Further research in specific subgroups is therefore needed.