Two-Year Changes in Child Weight Status, Diet, and Activity by Neighborhood Nutrition and Physical Activity Environment

A Review of the Role of Built Environment and Temperature in the Development of Childhood Obesity

The burden of obesity is rising globally and is studied widely, yet the evidence for the association of environmental factors (both built and natural) with childhood obesity remains inconsistent. A relation with temperature as a proxy for natural environmental factors for obesity has not been reviewed previously. The purpose of this review was to assimilate updated evidence on environmental factors of childhood obesity. Three databases, MEDLINE (Medical Literature Analysis and Retrieval System Online), Web of Science, and Cochrane, were searched for articles related to the effect of built environment and temperature on childhood obesity in 6-12-year-olds published in the last five years. Twelve studies were identified: four longitudinal and eight cross-sectional. The studies were appraised using the National Institute of Health Quality (NIH) Assessment Tool. A review of included studies showed that built environmental features like higher residential and population density, higher intersection density, more playgrounds, and all park features like the presence or availability of parks, high number of parks, proximity to parks, and an increased park land area, showed a protective association against childhood obesity while land use mix showed a promoting association for the development of childhood obesity. Inconclusive evidence was observed for other built environmental features. The search strategy did not retrieve any literature published in the past five years studying the association between temperature and the development of childhood obesity. Standardization of definitions of exposure and outcome measures is recommended. Further research studying the relationship between environmental temperature and the development of childhood obesity is recommended.

Neighborhood socioeconomic deprivation and individual-level socioeconomic status are associated with dopamine-mediated changes to monocyte subset CCR2 expression via a cAMP-dependent pathway

Social determinants of health (SDoH) include socioeconomic, environmental, and psychological factors that impact health. Neighborhood socioeconomic deprivation (NSD) and low individual-level socioeconomic status (SES) are SDoH that associate with incident heart failure, stroke, and cardiovascular mortality, but the underlying biological mechanisms are not well understood. Previous research has demonstrated an association between NSD, in particular, and key components of the neural-hematopoietic-axis including amygdala activity as a marker of chronic stress, bone marrow activity, and arterial inflammation. Our study further characterizes the role of NSD and SES as potential sources of chronic stress related to downstream immunological factors in this stress-associated biologic pathway. We investigated how NSD, SES, and catecholamine levels (as proxy for sympathetic nervous system activation) may influence monocytes which are known to play a significant role in atherogenesis. First, in an ex vivo approach, we treated healthy donor monocytes with biobanked serum from a community cohort of African Americans at risk for CVD. Subsequently, the treated monocytes were subjected to flow cytometry for characterization of monocyte subsets and receptor expression. We determined that NSD and serum catecholamines (namely dopamine [DA] and norepinephrine [NE]) associated with monocyte C-C chemokine receptor type 2 (CCR2) expression (p < 0.05), a receptor known to facilitate recruitment of monocytes towards arterial plaques. Additionally, NSD associated with catecholamine levels, especially DA in individuals of low SES. To further explore the potential role of NSD and the effects of catecholamines on monocytes, monocytes were treated in vitro with epinephrine [EPI], NE, or DA. Only DA increased CCR2 expression in a dose-dependent manner (p < 0.01), especially on non-classical monocytes (NCM). Furthermore, linear regression analysis between D2-like receptor surface expression and surface CCR2 expression suggested D2-like receptor signaling in NCM. Indicative of D2-signaling, cAMP levels were found to be lower in DA-treated monocytes compared to untreated controls (control 29.78 pmol/ml vs DA 22.97 pmol/ml; p = 0.038) and the impact of DA on NCM CCR2 expression was abrogated by co-treatment with 8-CPT, a cAMP analog. Furthermore, Filamin A (FLNA), a prominent actin-crosslinking protein, that is known to regulate CCR2 recycling, significantly decreased in DA-treated NCM (p < 0.05), indicating a reduction of CCR2 recycling. Overall, we provide a novel immunological mechanism, driven by DA signaling and CCR2, for how NSD may contribute to atherogenesis. Future studies should investigate the importance of DA in CVD development and progression in populations disproportionately experiencing chronic stress due to SDoH.

Associations of home and neighborhood environments with children's physical activity in the U.S.-based Neighborhood Impact on Kids (NIK) longitudinal cohort study

INTRODUCTION

Physical activity is important for children's health and well-being. Supportiveness for physical activity of home and neighborhood environments may affect children's PA, but most studies are cross-sectional. We examined environmental predictors of change in children's physical activity over two years.

METHODS

Data were from the longitudinal, observational cohort study, 'Neighborhood Impact on Kids'. Participants were children (initially aged 6-12 years) and their parent/caregiver (n = 727 dyads) living in neighborhoods throughout San Diego County, California and King County (Seattle area), Washington, USA. Children's moderate-to-vigorous physical activity (MVPA) was measured using accelerometers at T1 (Time 1 or baseline, 2007-2009) and T2, the two-year follow-up. At T1, parents survey-reported on physical activity (PA) equipment at home and demographics. Neighborhood environment was measured using spatial data in Geographic Information Systems (intersection density; park availability) and in-person audits (informal play space near home; park-based PA facilities; land use; support for walking/cycling). Generalized additive mixed models estimated total effects, then direct effects, of environmental attributes on MVPA at T1. Two-way moderating effects of child's sex and age were examined at T1. To examine associations of environmental exposures with changes in MVPA, we estimated interaction effects of environmental attributes on the association between time and MVPA.

RESULTS

On average, children accumulated 146 min/day (standard deviation or SD = 53) of MVPA at T1, and 113 (SD = 58) min/day at T2. There were no significant total or direct effects of environmental attributes on MVPA at T1, and no significant two-way interaction effects of child's age and sex for T1 MVPA. Having informal play spaces proximal to home with more amenities was associated with less MVPA decline from T1 to T2. Higher residential density, higher land use mix, and higher number of PA facilities in nearby parks were unexpectedly associated with greater MVPA decline.

CONCLUSION

Higher quality informal play spaces close to home may help offset declines in MVPA during middle childhood, as they may promote unstructured active play with opportunities for parental or neighbor surveillance. Unexpectedly, environmental factors consistent with higher walkability were associated with greater declines in children's MVPA. As physical activity differs across the lifespan, so may environmental factors that facilitate it.

Food and Physical Activity Environment in the US-Affiliated Pacific Region: The Children's Healthy Living Program

OBJECTIVE

To describe the quality of food and physical activity (PA) environments by World Bank Income level in jurisdictions from the Children's Healthy Living Program.

DESIGN

Baseline cross-sectional community data were analyzed from 11 jurisdictions categorized by World Bank Income levels to describe exposure to different food and PA outlets. The Children's Healthy Living Program was a multilevel, multijurisdictional prevalence study and community intervention trial that reduced child obesity in the US-Affiliated Pacific region.

SETTING

US-Affiliated Pacific region.

PARTICIPANTS

Food (n = 426) and PA (n = 552) Outlets.

MAIN OUTCOME MEASURES

Physical activity and food scores that reflect the quality of the outlets that support being physically active and healthy eating options, respectively.

ANALYSIS

Descriptive statistics are presented as means ± SD or percentages.

RESULTS

High-income-income level jurisdictions had higher food and PA scores than middle-income level jurisdictions.

CONCLUSIONS AND IMPLICATIONS

The US-Affiliated Pacific region has limited quality food and PA outlets in underserved communities at risk for obesity. The findings in this paper can be used to develop tools and design interventions to improve the food and PA environment to increase a healthier, active lifestyle.

Diet Quality of Canadian Preschool Children: Associations with Socio-demographic Characteristics

Purpose: To examine associations between preschoolers' diet quality and parent and child socio-demographic variables.Methods: Cross-sectional analysis with 117 preschoolers. Parents reported socio-demographics and their children's diet using 3-day food records. Diet quality was assessed using the Healthy Eating Index (HEI) 2015. Linear regression models were used to analyze associations between socio-demographics and HEI scores.Results: A total of 86% of children had an HEI-2015 score in the "needs improvement" category (51-80 out of a maximum of 100). Children's overall HEI-2015 score was inversely associated with children's age (β = -0.19, 95% CI -0.37, -0.02). Parental education was positively associated with children's overall HEI score (β = 9.58, 95% CI 3.81, 15.35) and with scores for total fruit (β = 1.00, 95% CI 0.39, 1.76), vegetables (β = 1.11, 95% CI 0.03, 2.18), total protein (β = 1.06, 95% CI 0.28, 1.84), and seafood/plant protein (β = 1.67, 95% CI 0.43, 2.89) components. Children who identified as Caucasian (β = 4.29, 95% CI 2.46, 6.14), had a Caucasian parent (β = 3.01, 95% CI 0.78, 5.25), or parents who were born in Canada (β = 2.32, 95% CI 0.53, 4.11) had higher scores for dairy.Conclusion: Our results suggest that preschoolers' diet quality needs improvement and that children's diet quality varies by children's age and parental education level.

Neighborhood Environment Associates with Trimethylamine-N-Oxide (TMAO) as a Cardiovascular Risk Marker

BACKGROUND

Neighborhoods and the microbiome are linked to cardiovascular disease (CVD), yet investigations to identify microbiome-related factors at neighborhood levels have not been widely investigated. We sought to explore relationships between neighborhood deprivation index (NDI) and the microbial metabolite, trimethylamine-N-oxide. We hypothesized that inflammatory markers and dietary intake would be mediators of the relationship.

METHODS

African-American adults at risk for CVD living in the Washington, DC area were recruited to participate in a cross-sectional community-based study. US census-based neighborhood deprivation index (NDI) measures (at the census-tract level) were determined. Serum samples were analyzed for CVD risk factors, cytokines, and the microbial metabolite, trimethylamine-N-oxide (TMAO). Self-reported dietary intake based on food groups was collected.

RESULTS

Study participants (n = 60) were predominantly female (93.3%), with a mean (SD) age of 60.83 (+/-10.52) years. Mean (SD) NDI was -1.54 (2.94), and mean (SD) TMAO level was 4.99 (9.65) µmol/L. Adjusting for CVD risk factors and BMI, NDI was positively associated with TMAO (β = 0.31, p = 0.02). Using mediation analysis, the relationship between NDI and TMAO was significantly mediated by TNF-α (60.15%) and interleukin)-1 β (IL; 49.96%). When controlling for clustering within neighborhoods, the NDI-TMAO association was no longer significant (β = 5.11, p = 0.11). However, the association between NDI and IL-1 β (β = 0.04, p = 0.004) and TNF-α (β = 0.17, p = 0.003) remained. Neither NDI nor TMAO was significantly associated with daily dietary intake. Conclusion and Relevance: Among a small sample of African-American adults at risk for CVD, there was a significant positive relationship with NDI and TMAO mediated by inflammation. These hypothesis-generating results are initial and need to be confirmed in larger studies.

Investigating associations between physical activity-related neighborhood built environment features and child weight status to inform local practice

Despite evidence of the importance of neighborhood built environment features in relation to physical activity and obesity, research has been limited in informing localized practice due to small sample sizes and limited geographic coverage. This demonstration study integrated data from a local pediatric health system with nationally available neighborhood built environment data to inform local decision making around neighborhood environments and childhood obesity. Height/weight from clinic visits and home neighborhood measures from the U.S. Environmental Protections Agency and WalkScore were obtained for 15,989 6-17 year olds. Multilevel models accounted for the nested data structure and were adjusted for neighborhood income and child sociodemographics. In 9-17 year olds, greater street connectivity and walkability were associated with a 0.01-0.04 lower BMIz (Ps = .009-.017) and greater residential density, street connectivity, and walkability were associated 5-7% lower odds of being overweight/obese (Ps = .004-.044) per standard deviation increase in environment variable. 45.9% of children in the lowest walkability tertile were overweight or obese, whereas 43.1% of children in the highest walkability tertile were overweight or obese. Maps revealed areas with low walkability and a high income-adjusted percent of children overweight/obese. In the Kansas City area, data showed that fewer children were overweight/obese in more walkable neighborhoods. Integrating electronic health records with neighborhood environment data is a replicable process that can inform local practice by highlighting the importance of neighborhood environment features locally and pointing to areas most in need of interventions.

Examining the consumer restaurant environment and dietary intake in children

Within the away-from-home food environment there is a need to account for individual exposure (e.g., frequency of visitation) to that environment. The present study examined the consumer environment in both proximal and visited restaurants and their association with childrens’ diet quality and anthropometrics. A cross-sectional analysis used baseline data from the Neighborhood Impact on Kids (NIK) study (2007–2009). Participants were 6–12-year-olds living in King County, WA and San Diego County, CA. This analysis (conducted 2019–2020) examined relationships between nearby restaurant count, Nutrition Environment Measures Survey in Restaurants (NEMS-R) within the child’s block group, and weighted NEMS-R scores based on the restaurant where the child ate most frequently in relation to child energy intake, Healthy Eating Index (HEI-2010) total score and anthropometrics. Children’s HEI-2010 scores were associated with NEMS-R scores within block groups, with children in the lowest NEMS-R tertile having significantly higher HEI scores than participants in the middle tertile. Weighted NEMS-R scores were significantly associated with waist circumference, with children in the highest NEMS-R tertile having a lower waist circumference than children in the lowest tertile. Nearby restaurant count was not associated with children’s diet quality or anthropometrics. Our findings suggest the relationship between nutrition environment and child diet and anthropometrics varied depending on how nutrition environment was defined. However, findings may be limited by the low frequency of eating out reported in this sample. Food environment measures that account for individual-level behavior are needed to better understand the influence of food environments on diet and anthropometrics

Multilevel prenatal socioeconomic determinants of Mexican American children's weight: Mediation by breastfeeding

Objective: Mexican American (MA) children are more likely to grow up in poverty than their non-Hispanic/Latinx white peers and are at an elevated risk for early onset obesity. The current study evaluated the effects of prenatal family- and neighborhood-level disadvantage on children's weight and weight gain from 12 months through 4.5 years of age. Maternal breastfeeding duration was evaluated as a potential mechanism underlying the relation between multilevel disadvantage and weight. Methods: Data was collected from 322 low-income, MA mother-child dyads. Women reported the degree of family socioeconomic disadvantage and breastfeeding status. Neighborhood disadvantage was evaluated with census-level metrics. Children's weight and height were measured at laboratory visits. Results: Greater prenatal neighborhood disadvantage predicted higher child Body Mass Index (BMI) at 12 months, over and above family-level disadvantage; this effect remained stable through 4.5 years. Breastfeeding duration partially mediated the effect of neighborhood disadvantage on child BMI. Breastfeeding duration predicted child BMI at all timepoints. Conclusions: Maternal prenatal residence in a neighborhood with high concentrated disadvantage may place low-income, MA children at increased risk of elevated weight status during the first few years of life. Breastfeeding duration emerged as potentially modifiable pathway through which the prenatal neighborhood impacts children's early life weight. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Childhood Obesity: Is the Built Environment More Important Than the Food Environment?

Obesity continues to be a health burden to society and new efforts may be needed to combat this epidemic. This study aims to investigate the contribution of parents education and level of income, food environment (grocery stores and fast food restaurants), and built environment (perceived safety, availability/quantity of parks) on childhood obesity. This cross-sectional observational study explored whether parents education and income level, built environment, and food environment can affect children with obesity. Participants were selected from 3 separate elementary schools located in an urban community with higher risk to have children with obesity in Montclair, California. Children living in families with low incomes have 2.31 times greater odds to be affected by obesity than children living in higher income homes. Children whose parents did not feel safe in their neighborhoods had odds of obesity 2.23 times greater than those who reported their neighborhoods as safe. Age also appeared to be a risk factor, and the odds of children affected by obesity among children 8 to 9 years was 0.79, and the odds of being affected by obesity among children 10 to 11 years of age was 0.36, when compared to children 6 to 7 years old. Findings suggest that low family income, perceptions of neighborhoods as unsafe, and young age are associated with higher body mass index (BMI) percentiles among children living in poor neighborhoods in Montclair, California.

Early-Life Environmental Exposures and Childhood Obesity: An Exposome-Wide Approach

BACKGROUND

Chemical and nonchemical environmental exposures are increasingly suspected to influence the development of obesity, especially during early life, but studies mostly consider single exposure groups.

OBJECTIVES

Our study aimed to systematically assess the association between a wide array of early-life environmental exposures and childhood obesity, using an exposome-wide approach.

METHODS

The HELIX (Human Early Life Exposome) study measured child body mass index (BMI), waist circumference, skinfold thickness, and body fat mass in 1,301 children from six European birth cohorts age 6-11 y. We estimated 77 prenatal exposures and 96 childhood exposures (cross-sectionally), including indoor and outdoor air pollutants, built environment, green spaces, tobacco smoking, and biomarkers of chemical pollutants (persistent organic pollutants, metals, phthalates, phenols, and pesticides). We used an exposure-wide association study (ExWAS) to screen all exposure-outcome associations independently and used the deletion-substitution-addition (DSA) variable selection algorithm to build a final multiexposure model.

RESULTS

The prevalence of overweight and obesity combined was 28.8%. Maternal smoking was the only prenatal exposure variable associated with higher child BMI (z-score increase of 0.28, 95% confidence interval: 0.09, 0.48, for active vs. no smoking). For childhood exposures, the multiexposure model identified particulate and nitrogen dioxide air pollution inside the home, urine cotinine levels indicative of secondhand smoke exposure, and residence in more densely populated areas and in areas with fewer facilities to be associated with increased child BMI. Child blood levels of copper and cesium were associated with higher BMI, and levels of organochlorine pollutants, cobalt, and molybdenum were associated with lower BMI. Similar results were found for the other adiposity outcomes.

DISCUSSION

This first comprehensive and systematic analysis of many suspected environmental obesogens strengthens evidence for an association of smoking, air pollution exposure, and characteristics of the built environment with childhood obesity risk. Cross-sectional biomarker results may suffer from reverse causality bias, whereby obesity status influenced the biomarker concentration. https://doi.org/10.1289/EHP5975.

Longitudinal Associations Between Psychosocial, Home, and Neighborhood Factors and Children's Physical Activity

BACKGROUND

Physical activity (PA) provides important health benefits to children, and a large percentage of children's PA occurs at home. The purpose of this study was to examine the associations between psychosocial, home, and neighborhood environmental factors and children's reported PA at home and in the neighborhood, during the transition from elementary to high school.

METHODS

A total of 555 participants (44% boys) were recruited in grade 5 and followed through grades 6, 7, and 9. Children self-reported PA in 3 locations-at home, in the neighborhood, and on the street. Children reported parent support and neighborhood environment, parents reported PA equipment, and a windshield survey assessed incivilities and outside PA equipment. Longitudinal Poisson models evaluated the relationships between environmental variables and 3 self-reported PA variables, adjusting for gender, race/ethnicity, and parent education.

RESULTS

Parent support and PA equipment were significant positive predictors of home PA. Child's perceived environment (positive) and incivilities (negative) were significant predictors of neighborhood PA. Parental support, perceived environment, and outside PA equipment were positive significant predictors of street PA.

CONCLUSIONS

This study supports the need for both family and community/neighborhood PA interventions that encourage parents to support child PA and for communities to reduce incivilities.

Life Events and Longitudinal Effects on Physical Activity: Adolescence to Adulthood

INTRODUCTION

Common life events, such as getting married or gaining employment, may be opportunities to intervene on health behaviors like physical activity. The purpose of this study was to determine the changes in moderate-to-vigorous physical activity (MVPA) associated with several common life events from adolescence to young adulthood.

METHODS

Participants in Project EAT (ages 11 to 18 yr at baseline and 25 to 36 yr at wave 4) were surveyed at four timepoints from 1998 to 2016. Questions included marital status, employment status, postsecondary education completion and enrollment, and living situation between each wave. Linear regression was used to model the effect of each life event on change in self-reported MVPA. Post hoc mediation analysis was conducted to examine whether having a child mediated the effect of getting married on the change in MVPA.

RESULTS

Average MVPA declined from 6.5 h·wk at baseline to 4.3 h·wk at wave 4. Having a child was associated with a significant decrease in MVPA between waves 2 and 3 and between waves 3 and 4. Getting married and leaving parents' home were associated with significant decreases in MVPA between waves 3 and 4. Having a child both mediated and moderated the effect of getting married on MVPA.

CONCLUSIONS

This study provides evidence that MVPA declines both after getting married and after having a child and that these effects are not independent. Interventions to maintain or increase MVPA could profitably target couples planning to get married or have a child.

Prevalence of overweight and obesity and associated risk factors among adult residents of northwest China: a cross-sectional study

OBJECTIVE

Overweight and obesity have been shown to be related to multiple chronic conditions, leading to a heavy economic burden on society throughout the world. This study aims to estimate the prevalence of overweight and obesity and determine potential influencing factors among adults in Xinjiang, northwest China.

DESIGN

A community-based observational study.

SETTING

The First Affiliated Hospital of Xinjiang Medical University.

METHODS

In total, 14 618 adult participants (7799 males; 6819 females) aged over 35 years were recruited from the Cardiovascular Risk Survey conducted in 2010. Data were obtained from face-to-face interviews and physical examinations. The sample was used to estimate the prevalence of overweight (body mass index (BMI) 24-28 kg/m²) and obesity (BMI ≥28 kg/m²) in Xinjiang Province. Influencing factors were analysed based on statistical methods.

RESULTS

In Xinjiang Province, the overall prevalence of overweight was 36.5% (male 40.1%; female 33.4%), and the prevalence of obesity was 26.5% (male 27.2%; female 25.8%). The prevalence of both overweight and obesity were higher in women than in men (p<0.001). The main influencing factors for overweight and obesity were sex, age, race, marital status, education level, occupation, smoking, drinking, hypertension, diabetes and dyslipidaemia (p<0.05).

CONCLUSIONS

This study estimated that the prevalence of overweight and obesity among adult residents of Xinjiang Province, northwest China, was high. These data suggest that efforts related to the prevention and control of overweight and obesity should be a public health priority in northwest China.

Associations of multidimensional socioeconomic and built environment factors with body mass index trajectories among youth in geographically heterogeneous communities

Understanding contextual influences on obesity requires comparison of heterogeneous communities and concurrent assessment of multiple contextual domains. We used a theoretically-based measurement model to assess multidimensional socioeconomic and built environment factors theorized to influence childhood obesity across a diverse geography ranging from rural to urban. Confirmatory factor analysis specified four factors-community socioeconomic deprivation (CSED), food outlet abundance (FOOD), fitness and recreational assets (FIT), and utilitarian physical activity favorability (UTIL)-which were assigned to communities (townships, boroughs, city census tracts) in 37 Pennsylvania counties. Using electronic health records from 2001 to 2012 from 163,820 youth aged 3-18 years from 1288 communities, we conducted multilevel linear regression analyses with factor quartiles and their cross products with age, age2, and age3 to test whether community factors impacted body mass index (BMI) growth trajectories. Models controlled for sex, age, race/ethnicity, and Medical Assistance. Factor scores were lowest in townships, indicating less deprivation, fewer food and physical activity outlets, and lower utilitarian physical activity favorability. BMI at average age was lower in townships versus boroughs (beta [SE]) (0.217 [0.027], P < 0.001) and cities (0.378 [0.036], P < 0.001), as was BMI growth over time. Factor distributions across community types lacked overlap, requiring stratified analyses to avoid extrapolation. In townships, FOOD, UTIL, and FIT were inversely associated with BMI trajectories. Across community types, youth in the lowest (versus higher) CSED quartiles had lower BMI at average age and slower BMI growth, signifying the importance of community deprivation to the obesogenicity of environments.

The Relationships between Adolescents' Obesity and the Built Environment: Are They City Dependent?

There is evidence that the built environment can promote unhealthy habits which may increase the risk for obesity among adolescents. However, the majority of evidence is from North America, Europe and Australia, and less is known about other world regions. The purpose of this study was to examine how the number of overweight and obese adolescents may vary in relation to the built environment, area socioeconomic status (SES), physical activity (PA) and nutritional home environment. We performed a telephone survey of 904 adolescents ages 15-18 from three different cities in Israel. The questionnaire included: reported PA, sedentary behaviors and nutritional home environment. Body Mass Index (BMI) was attained from records of Maccabi Healthcare Services (MHS). The built environment measures were calculated by Geographic Information System (GIS). Multivariable logistic regression analysis was performed to identify variables associated with adolescents' overweight and obesity. The highest level of overweight and obese adolescents was in Beer Sheva (29.2%). The three cities did not differ in built environment characteristics, PA and sedentary behaviors. In Haifa, a more positive nutritional home environment was reported (p = 0.001). Boys, in all three cities presented higher rates of overweight and obesity (29%). After adjusting for covariates, adolescents' overweight and obesity was associated with built environment measures only in a low SES peripheral city (OR = 0.72; 95% CI: 0.56-0.92), and positively associated with higher level of sedentary behavior in the total sample (OR = 1.23; 95% CI:1.03-1.47). This may imply a much more complex causal pathway between the built environment, SES and obesity than suggested in previous literature.