Neighborhood environment and children's physical activity and body mass index: evidence from military personnel installation assignments

Heterogeneity in place effects on health: The case of time preferences and adolescent obesity

We leverage a natural experiment in combination with data on adolescents' time preferences to assess whether there is heterogeneity in place effects on adolescent obesity. We exploit the plausibly exogenous assignment of military servicemembers, and consequently their children, to different installations to identify place effects. Adolescents' time preferences are measured by a validated survey scale. Using the obesity rate in the assigned installation county as a summary measure of its obesity-related environments, we show that exposure to counties with higher obesity rates increases the likelihood of obesity among less patient adolescents but not among their more patient counterparts.

Impact of built, social, and economic environments on adolescent obesity and related health behaviors

OBJECTIVE

This study aimed to estimate the effects of the built, social, and economic environments on adolescent obesity and related behaviors.

METHODS

Exploiting quasi-exogenous variation in military families' geographic location, this study estimated intent-to-treat models of the association between the assigned installation's county environments and adolescents' (mean age 13.5 years) self-reported and model-corrected BMI, overweight or obesity status, and self-reported diet and exercise. Three indices for the built, social, and economic environments characterized county-level environments (higher value implies more advantageous environments) based on 19 indicators. Multivariate linear and logistic models were estimated on the full sample (N = 1111) and on subsamples with greater exposure based on time (n = 682) and off-installation residence (n = 604).

RESULTS

Exposure to more advantageous built environments for more than 2 years was associated with lower probabilities of obesity (-0.18; 95% CI: -0.34 to -0.026) and overweight or obesity (-0.34; 95% CI: -0.56 to -0.12) and was associated with lower BMI z scores (-0.76; 95% CI: -1.45 to -0.02). Results for adolescents living off-installation were similar. More advantageous built environments were also associated with lower consumption of unhealthy foods, but not with physical activity. Social and economic environments were not associated with any outcomes.

CONCLUSIONS

The built environment, but not social and economic environments, was a strong predictor of adolescents' BMI, overweight or obesity status, and eating behaviors.

Individual, parental and built environmental features as influencing factors of active travel to school in northeast China: findings from a cross-sectional study

OBJECTIVES

Active travel to school (ATS)-associated factors had been studied in some developed countries but rarely in China. We studied the associated factors of ATS at individual, parental and built environment domains in northeast China.

DESIGN AND PARTICIPANTS

A cross-sectional survey was conducted among 4-6 grade students in 2017. Sociodemographic features and information of parents were collected using questionnaires, and SuperMap (a geographical information system software) was used to catch built environment features. Logistic regression models were used to examine the relationship between multilevel factors and ATS.

RESULTS

Our study sample comprised 3670 primary school students aged from 8 to 15 (boys=51.0%, ATS=48.8%). Perceived to be fat (OR 1.25, 95% CI 1.00 to 1.55, p<0.05), feeling easy to walk for a short distance (OR 1.63, 95% CI 1.21 to 2.20, p<0.05), mother unemployed (OR 1.52, 95% CI 1.13 to 2.06, p<0.05), higher land use mix (OR 1.23, 95% CI 1.11 to 1.37, p<0.001) and higher density of public transport stations (OR 1.22, 95% CI 1.09 to 1.37, p<0.05) were positively associated with increased possibility of ATS, while higher household annual income (OR 0.60, 95% CI 0.44 to 0.83, p<0.05) and possession of private vehicles (OR 0.56, 95% CI 0.45 to 0.69, p<0.001) were negatively associated with possibility of ATS.

CONCLUSIONS

The significant factors associated with ATS were at every examined level, which implies multilevel interventions are needed to encourage ATS. Further interventions could focus on the children's willingness to lead students to opt for healthy behaviours, and children from wealthier families should be encouraged to choose ATS. Also, the government should improve built environment walkability so as to encourage ATS.

Measuring the Built Environment in Studies of Child Health-A Meta-Narrative Review of Associations

Although the built environment (BE) is important for children’s health, there is little consensus about which features are most important due to differences in measurement and outcomes across disciplines. This meta-narrative review was undertaken by a multi-disciplinary team of researchers to summarise ways in which the BE is measured, and how this links to children’s health. A structured search of four databases across the relevant disciplines retrieved 108 relevant references. The most commonly addressed health-related outcomes were active travel, physical activity and play, and obesity. Many studies used objective (GIS and street audits) or standardised subjective (perceived) measurements of the BE. However, there was a wide variety, and sometimes inconsistency, in their definition and use. There were clear associations between the BE and children’s health. Objective physical activity and self-reported active travel, or obesity, were positively associated with higher street connectivity or walkability measures, while self-reported physical activity and play had the strongest association with reduced street connectivity, indicated by quieter, one-way streets. Despite the high heterogeneity found in BE measures and health outcomes, the meta-narrative approach enabled us to identify ten BE categories that are likely to support children’s health and be protective against some non-communicable disease risk factors. Future research should implement consistent BE measures to ensure key features are explored. A systems approach will be particularly relevant for addressing place-based health inequalities, given potential unintended health consequences of making changes to the BE.

State-of-the-art of measures of the obesogenic environment for children

Various measures of the obesogenic environment have been proposed and used in childhood obesity research. The variety of measures poses methodological challenges to designing new research because methodological characteristics integral to developing the measures vary across studies. A systematic review has been conducted to examine the associations between different levels of obesogenic environmental measures (objective or perceived) and childhood obesity. The review includes all articles published in the Cochrane Library, PubMed, Web of Science and Scopus by 31 December 2018. A total of 339 associations in 101 studies have been identified from 18 countries, of which 78 are cross-sectional. Overall, null associations are predominant. Among studies with non-null associations, negative relationships between healthy food outlets in residential neighbourhoods and childhood obesity is found in seven studies; positive associations between unhealthy food outlets and childhood obesity are found in eight studies, whereas negative associations are found in three studies. Measures of recreational or physical activity facilities around the participants' home are also negatively correlated to childhood obesity in nine out of 15 studies. Results differ by the types of measurement, environmental indicators and geographic units used to characterize obesogenic environments in residential and school neighbourhoods. To improve the study quality and compare reported findings, a reporting standard for spatial epidemiological research should be adopted.

Association between neighborhood aesthetics and childhood obesity

The lack of neighbourhood aesthetics (e.g. public art and well-maintained properties) may reduce walkability in the neighbourhood and increase the risk of childhood obesity. In this study, a literature search was conducted in the Cochrane Library, PubMed and Web of Science for articles published before January 1, 2019 to analyse the associations between neighbourhood aesthetics and weight-related behaviours and outcomes among children and adolescents aged <18. One cohort study and 24 cross-sectional studies, conducted in 10 countries with a median sample size of 1124 were identified. Neighbourhood aesthetics was more commonly assessed by self-reported or parent-reported perceptions than objective measurements. Eighteen of the 25 included studies analysed physical activity (PA) as the outcome of interests, eight studies analysed active transport to school (ATS), and eight studies analysed weight status, including body mass index and overweight/obesity status. About two-thirds of studies reported non-significant associations when using PA and weight status as outcomes, and half of studies showed that neighbourhood aesthetics is associated with increased use of ATS. The rest of the studies reported mixed findings with slightly more studies showing neighbourhood aesthetics may promote PA or reduce weight. Better designed studies are necessary to achieve a robust understanding of this epidemiological relationship in the future.

Street connectivity, physical activity, and childhood obesity: A systematic review and meta-analysis

Street connectivity, as a neighbourhood built environmental factor, may affect individual physical activity (PA) and subsequently weight status. However, these associations remain inconclusive. This study aimed to systematically review the association between street connectivity and childhood obesity. A literature search was conducted in the Cochrane Library, PubMed, and Web of Science for articles published before January 1, 2019. All original studies that investigated the association between street connectivity and weight-related behaviours or outcomes among children and adolescents were included. Forty-seven articles were identified, including eight longitudinal and 41 cross-sectional studies conducted in eight countries. The sample size ranged from 88 to 46 813. Street intersection density (SID), measured by Geographic Information Systems in 36 studies and reported in 13 studies, was the main indicator used to represent street connectivity. Forty-four studies examined the association between SID and weight-related behaviours, including overall PA (n = 15), moderate-to-vigorous PA (n = 13), active transport (n = 12), dog walking (n = 1), walking (n = 1), sedentary behaviours (n = 2), and TV viewing (n = 1). Fifteen studies focused on the association between SID and weight-related outcomes. Overall, evidence from this systematic review and meta-analyses suggested a positive association between street connectivity and PA. However, it was difficult to draw a conclusion on the association between street connectivity and BMI. More longitudinal evidence is needed to confirm the causal association between street connectivity and weight status.

School Food and Beverage Availability and Children's Diet, Purchasing, and Obesity: Evidence From a Natural Experiment

PURPOSE

Existing evidence on relationships between school food environments and children's in-school purchases, dietary behaviors, and body composition is based on observational studies that are vulnerable to residential selection bias.

METHODS

This study leveraged exogenous variation in school environments generated by the natural experiment due to military parents' assignment to installations. We analyzed 1,010 child-wave observations from the Military Teenagers Environments, Exercise, and Nutrition Study collected during 2013-2015. Using multiple linear and logistic regression, we examined whether the number of competitive food and beverage (CF&B) items available for purchase in school, overall and by type (unhealthy, healthy, neutral), was associated with in-school food purchases, dietary behaviors, and body mass index (BMI) outcomes. Covariates included child and family characteristics and the healthiness of the home food environment.

RESULTS

Unhealthy item availability was positively associated with purchasing any sweets (adjusted odds ratio [AOR], 1.30; p < .01), snacks (AOR, 1.23; p < .01), and sugar-sweetened beverages (AOR, 1.19; p = .01). However, there were no significant associations with overall food and beverage intake (e.g., sweets, soda) nor BMI outcomes. The home food environment was significantly associated with all outcomes.

CONCLUSIONS

Access to unhealthy CF&B items may influence in-school purchases but does not appear to influence overall dietary behaviors and BMI outcomes. Substitution of caloric intake across locations within versus outside of school may play a role in explaining why purchases were associated with unhealthy CF&B availability but overall diet and downstream BMI were not.

The Effect of State Competitive Food and Beverage Regulations on Childhood Overweight and Obesity

PURPOSE

Policy efforts for combating childhood obesity have sought stronger state policies for regulating competitive foods and beverages (CF&Bs) available in schools. However, the evidence linking state policies to children's overall diet and body weight outcomes is limited and mixed, and experts have called for more rigorous studies that are able to address concerns about selection bias. The present study leverages a rare natural experiment where children in military families are "assigned" to different state policies, due to their military parent's periodic relocation, to examine whether state CF&B policies were associated with children's body mass index (BMI) and overweight or obesity.

METHODS

We analyzed data from 894 children (12-13 years old) in army families attending public schools located near 25 installations across 23 states in 2013. State CF&B policy measures from the Bridging the Gap project were linked to the child data. Primary outcomes included BMI z-scores and indicator for overweight or obesity. For a subsample of children with self-reported food frequency measures, we also examined the link between state CF&B policies and overall diet. All regression analyses adjusted for a rich set of child and family covariates.

RESULTS

Having strong or weak policies was significantly associated with lower BMI z-scores, lower odds of overweight or obesity, and better dietary outcomes, relative to no policy.

CONCLUSIONS

A portfolio of policies that includes multiple strong policies is likely needed to observe any meaningful changes in BMI and obesity.

Neighborhood and home food environment and children's diet and obesity: Evidence from military personnel's installation assignment

Research and policy initiatives are increasingly focused on the role of neighborhood food environment in children's diet and obesity. However, existing evidence relies on observational data that is limited by neighborhood selection bias. The Military Teenagers' Environments, Exercise, and Nutrition Study (M-TEENS) leverages the quasi-random variation in neighborhood environment generated by military personnel's assignment to installations to examine whether neighborhood food environments are associated with children's dietary behaviors and BMI. Our results suggest that neither the actual nor the perceived availability of particular food outlets in the neighborhood is associated with children's diet or BMI. The availability of supermarkets and convenience stores in the neighborhood was not associated with where families shop for food or children's dietary behaviors. Further, the type of store that families shop at was not associated with the healthiness of food available at home. Similarly, availability of fast food and restaurants was unrelated to children's dietary behaviors or how often children eat fast food or restaurant meals. However, the healthiness of food available at home was associated with healthy dietary behaviors while eating at fast food outlets and restaurants were associated with unhealthy dietary behaviors in children. Further, parental supervision, including limits on snack foods and meals eaten as a family, was associated with dietary behaviors. These findings suggest that focusing only on the neighborhood food environment may ignore important factors that influence children's outcomes. Future research should also consider how families make decisions about what foods to purchase, where to shop for foods and eating out, how closely to monitor their children's food intake, and, ultimately how these decisions collectively impact children's outcomes.