Role of perceived neighbourhood crime in the longitudinal association between perceived built environment and type 2 diabetes mellitus: a moderated mediation analysis

Can good neighbourhood perception magnify the positive effect of favourable built environment on recreational walking in China?

BACKGROUND

It remains unknown whether good neighbourhood perception can enhance the benefits of favourable built environment to physical activity. Moreover, the moderation pattern is less understood in developing countries.

OBJECTIVES

This work aims to examine the moderation effects of perceived neighbourhood safety and aesthetics on the relationship between built environment and time for recreational walking.

METHODS

We performed the examination using a sample of 760 residents in Fuzhou City, China. The Negative Binomial Regression Model was developed to examine the moderation roles of neighbourhood safety and aesthetics on the impact of built environment, adjusting for the effects of location, socioeconomic, personal preferences and social environment factors. Moreover, two sensitivity analyses were performed to test whether the moderators found are robust to the control of residential self-selection, and differential measures of conceptually-comparable aspects of built environment.

RESULTS

We found stronger associations of time for recreational walking with road density and proportion of parks and squares POIs for residents with high perception of neighbourhood safety, compared to those with low perception of neighbourhood safety. There was a greater effect of the proportion of parks and squares POIs, when perceived aesthetics was high than when perceived aesthetics was low. The findings of neighbourhood safety and aesthetics as moderator, were robust in the two sensitivity analyses. No significant moderation effect was found for land use diversity.

CONCLUSIONS

High perceived neighbourhood safety can magnify the positive effects of road connectivity and accessibility to parks and squares. Neighbourhood aesthetics positively moderates the association of time for recreational walking with accessibility to parks and squares. The findings emphasize the need to consider safety- and aesthetics-specific differences in estimates of built environment effects. Improvements in neighbourhood safety and aesthetics are key to effective interventions in built environment to better promote physical activity.

Is prosocial behaviour a missing link between green space quality and child health-related outcomes?

BACKGROUND

This study aimed to investigate prosocial behaviour-those behaviours that benefit others or enhance relationships with others-as a mediator of the associations between green space quality and child health-related outcomes (physical activity, mental health, and health-related quality of life (HRQOL)).

METHODS

This study involved data from 4983 children with 10-year follow-up (2004-2014) retrieved from the Longitudinal Study of Australian Children. Green space quality (the exposure), prosocial behaviour (the candidate mediator), and child health-related outcomes were assessed biennially based on caregiver reports. Causal mediation analysis was used, with four mediation models developed for each outcome.

RESULTS

Mediation by prosocial behaviour appeared in the late childhood mediation model with higher mediation proportions reported compared to models of earlier and middle childhood. Prosocial behaviour had moderate mediation consistency for the association between green space quality and physical activity enjoyment, but no mediation was evident for other physical activity variables. Prosocial behaviour had low mediation consistency for child mental health (internalising and externalising subscales). Similarly, low mediation consistency of prosocial behaviour was also evident for all HRQOL variables, such as physical, emotional, social, school functioning, psychosocial health, and total quality of life (QOL).

CONCLUSION

Prosocial behaviour partially mediated the association between green space quality and child health-related outcomes (physical activity enjoyment, mental health, and HRQOL). Improving the quality of neighbourhood green space that supports the development of prosocial behaviour may result in better child health-related outcomes. Other physical activity variables might not specifically relate to social interactions, and therefore, no mediation by prosocial behaviour was apparent.

Environmental risk factors of type 2 diabetes-an exposome approach

Type 2 diabetes is one of the major chronic diseases accounting for a substantial proportion of disease burden in Western countries. The majority of the burden of type 2 diabetes is attributed to environmental risks and modifiable risk factors such as lifestyle. The environment we live in, and changes to it, can thus contribute substantially to the prevention of type 2 diabetes at a population level. The 'exposome' represents the (measurable) totality of environmental, i.e. nongenetic, drivers of health and disease. The external exposome comprises aspects of the built environment, the social environment, the physico-chemical environment and the lifestyle/food environment. The internal exposome comprises measurements at the epigenetic, transcript, proteome, microbiome or metabolome level to study either the exposures directly, the imprints these exposures leave in the biological system, the potential of the body to combat environmental insults and/or the biology itself. In this review, we describe the evidence for environmental risk factors of type 2 diabetes, focusing on both the general external exposome and imprints of this on the internal exposome. Studies provided established associations of air pollution, residential noise and area-level socioeconomic deprivation with an increased risk of type 2 diabetes, while neighbourhood walkability and green space are consistently associated with a reduced risk of type 2 diabetes. There is little or inconsistent evidence on the contribution of the food environment, other aspects of the social environment and outdoor temperature. These environmental factors are thought to affect type 2 diabetes risk mainly through mechanisms incorporating lifestyle factors such as physical activity or diet, the microbiome, inflammation or chronic stress. To further assess causality of these associations, future studies should focus on investigating the longitudinal effects of our environment (and changes to it) in relation to type 2 diabetes risk and whether these associations are explained by these proposed mechanisms.