Do Active Communities Support Activity, or Support Active People?: Residential Self-selection in the Estimation of Built Environment Influences on Physical Activity

In a growing body of research, the built environment, composed of neighborhoods, roads, and buildings in which people live, work, and play, has been shown to be related to physical activity. While promising for physical activity promotion, substantial limitations must be addressed before built environment research can adequately inform policy recommendations. To this end, we focused on three methodological challenges of particular concern for built environment research: (1) quantitative characterization of a complex environment, (2) confounding by other inter-related environment characteristics, and (3) residential self-selection bias resulting from systematic sociodemographic and behavioral differences among individuals selecting different types of neighborhoods. We used data from the National Longitudinal Study of Adolescent Health, a nationally representative cohort of over 20,000 adolescents followed over seven years into young adulthood. A large scale geographic information system (GIS) linked community-level built (e.g., recreation facilities, land cover, street connectivity) and socioeconomic (e.g., median household income, crime rate) environment characteristics to individual-level sociodemographic and behavioral data in space and time. Using factor analysis, we identified several built and socioeconomic environment constructs. We found that the socioeconomic environment is a potentially important confounder of built environment and physical activity relationships, but is often omitted in existing studies. We also show that commonly used built environment measures may act as proxies for complex environment constructs; for example, intersection density, typically used to indicate street connectivity, may represent general density of development. Lastly, in longitudinal analysis, we observed an increase in physical activity among males with a greater number of physical activity-related pay facilities and a decrease in physical activity among males and females with higher neighborhood crime rate. Other built environment characteristics were unrelated to physical activity. Additional analysis suggests that residential self-selection can attenuate, as opposed to magnify, environment-physical activity associations. This research revealed complexities in the environment that have implications for analysis and interpretation of this and related research. Findings suggest that built environment characteristics may influence physical activity, yet raises additional questions to be answered by an evolving field

Obesogenic Environments in Youth

To effectively prevent and reduce childhood obesity through healthy community design, it is essential to understand which neighborhood environment features influence weight gain in various age groups. However, most neighborhood environment research is cross-sectional, focuses on adults, and is often carried out in small, nongeneralizable geographic areas. Thus, there is a great need for longitudinal neighborhood environment research in diverse populations across the lifecycle. This paper describes: (1) insights and challenges of longitudinal neighborhood environment research and (2) advancements and remaining gaps in measurement and study design that examine individuals and neighborhoods within the context of the broader community. Literature-based research and findings from the “Obesity and Neighborhood Environment Database” (ONEdata), a unique longitudinal GIS that is spatially and temporally linked to data in the National Longitudinal Study of Adolescent Health (N=20,745), provide examples of current limitations in this area of research. Findings suggest a need for longitudinal methodologic advancements to better control for dynamic sources of bias, investigate and capture appropriate temporal frameworks, and address complex residential location processes within families. Development of improved neighborhood environment measures that capture relevant geographic areas within complex communities and investigation of differences across urbanicity and sociodemographic composition are needed. Further longitudinal research is needed to identify, refine, and evaluate national and local policies to most effectively reduce childhood obesity

Where can they play? Outdoor spaces and physical activity among adolescents in U.S. urbanized areas

Objective—To estimate behavior-specific effects of several objectively-measured outdoor spaces on different types of moderate to vigorous physical activity (MVPA) in a large, diverse sample of U.S. adolescents. Methods—Using data from Wave I (1994–95) of the National Longitudinal Study of Adolescent Health (U.S., n=10,359) and a linked geographic information system, we calculated percent greenspace coverage and distance to the nearest neighborhood and major parks. Using sex-stratified multivariable logistic regression, we modeled reported participation in wheel-based activities, active sports, exercise, and ≥5 MVPA bouts/week as a function of each outdoor space variable, controlling for individual- and neighborhood-level sociodemographics. Results—Availability of major or neighborhood parks was associated with higher participation in active sports and, in females, wheel-based activity and reporting ≥5 MVPA bouts/week [OR (95% CI): up to 1.71 (1.29. 2.27)]. Greater greenspace coverage was associated with reporting ≥5 MVPA bouts/week in males and females [OR (95% CI): up to 1.62 (1.10, 2.39) for 10.1 to 20% versus ≤10% greenspace] and exercise participation in females [OR (95% CI): up to 1.73 (1.21, 2.49)]. Conclusions—Provision of outdoor spaces may promote different types of physical activities, with potentially greater benefits in female adolescents, who have particularly low physical activity levels

Are neighbourhood food resources distributed inequitably by income and race in the USA? Epidemiological findings across the urban spectrum

ObjectiveMany recent policies focus on socioeconomic inequities in availability of healthy food stores and restaurants. Yet understanding of how socioeconomic inequities vary across neighbourhood racial composition and across the range from rural to urban settings is limited, largely due to lack of large, geographically and socio-demographically diverse study populations. Using a national sample, the authors examined differences in neighbourhood food resource availability according to neighbourhood-level poverty and racial/ethnic population in non-urban, low-density urban and high-density urban areas.DesignCross-sectional data from an observational cohort study representative of the US middle and high school-aged population in 1994 followed into young adulthood.ParticipantsUsing neighbourhood characteristics of participants in the National Longitudinal Study of Adolescent Health (Wave III, 2001–2002; n=13 995 young adults aged 18–28 years representing 7588 US block groups), the authors examined associations between neighbourhood poverty and race/ethnicity with neighbourhood food resource availability in urbanicity-stratified multivariable linear regression.Primary and secondary outcome measuresNeighbourhood availability of grocery/supermarkets, convenience stores and fast-food restaurants (measured as number of outlets per 100 km roadway).ResultsNeighbourhood race and income disparities were most pronounced in low-density urban areas, where high-poverty/high-minority areas had lower availability of grocery/supermarkets (β coefficient (β)=–1.91, 95% CI –2.73 to –1.09) and convenience stores (β=–2.38, 95% CI –3.62 to –1.14) and greater availability of fast-food restaurants (β=4.87, 95% CI 2.26 to 7.48) than low-poverty/low-minority areas. However, in high-density urban areas, high-poverty/low-minority neighbourhoods had comparatively greater availability of grocery/supermarkets (β=8.05, 95% CI 2.52 to 13.57), convenience stores (β=2.89, 95% CI 0.64 to 5.14) and fast-food restaurants (β=4.03, 95% CI 1.97 to 6.09), relative to low-poverty/low-minority areas.ConclusionsIn addition to targeting disproportionate fast-food availability in disadvantaged dense urban areas, our findings suggest that policies should also target disparities in grocery/supermarket and fast-food restaurant availability in low-density areas.Article summaryArticle focusUsing national data, we examined whether neighbourhood food resource availability exhibits joint race and socioeconomic inequities across levels of urbanicity.Key messagesSocio-demographic inequities in neighbourhood food resource availability were most pronounced in low-density urban (largely suburban) areas.In high-density urban areas, higher neighbourhood poverty was associated with greater availability of all food resources.Whereas policy has focused on dense urban settings, less urban areas might also benefit from policies addressing food access.Strengths and limitations of this studyWhile business records provide comparable data across the USA, these data may contain error and do not indicate availability of specific foods.National coverage enabled examination of the joint role of neighbourhood race and socioeconomic status across urban strata within a single study

Residential self-selection bias in the estimation of built environment effects on physical activity between adolescence and young adulthood

Abstract Background Built environment research is dominated by cross-sectional designs, which are particularly vulnerable to residential self-selection bias resulting from health-related attitudes, neighborhood preferences, or other unmeasured characteristics related to both neighborhood choice and health-related outcomes. Methods We used cohort data from the National Longitudinal Study of Adolescent Health (United States; Wave I, 1994-95; Wave III, 2001-02; n = 12,701) and a time-varying geographic information system. Longitudinal relationships between moderate to vigorous physical activity (MVPA) bouts and built and socioeconomic environment measures (landcover diversity, pay and public physical activity facilities per 10,000 population, street connectivity, median household income, and crime rate) from adolescence to young adulthood were estimated using random effects models (biased by unmeasured confounders) and fixed effects models (within-person estimator, which adjusts for unmeasured confounders that are stable over time). Results Random effects models yielded null associations except for negative crime-MVPA associations [coefficient (95% CI): -0.056 (-0.083, -0.029) in males, -0.061 (-0.090, -0.033) in females]. After controlling for measured and time invariant unmeasured characteristics using within-person estimators, MVPA was higher with greater physical activity pay facilities in males [coefficient (95% CI): 0.024 (0.006, 0.042)], and lower with higher crime rates in males [coefficient (95% CI): -0.107 (-0.140, -0.075)] and females [coefficient (95% CI): -0.046 (-0.083, -0.009)]. Other associations were null or in the counter-intuitive direction. Conclusions Comparison of within-person estimates to estimates unadjusted for unmeasured characteristics suggest that residential self-selection can bias associations toward the null, as opposed to its typical characterization as a positive confounder. Differential environment-MVPA associations by residential relocation suggest that studies examining changes following residential relocation may be vulnerable to selection bias. The authors discuss complexities of adjusting for residential self-selection and residential relocation, particularly during the adolescent to young adult transition

Walking: the first steps in cardiovascular disease prevention

Health professionals are presented with the challenge of prescribing physical activity that is likely to be sustained by the sedentary majority. Walking is eminently suited to physical activity prescription for inactive individuals as it is accessible to men and women of all age and social groups and poses little risk of injury. This paper reviews recent evidence of the health benefits of walking and promotion of walking behavior

Obesogenic Clusters: Multidimensional Adolescent Obesity-related Behaviors in the U.S.

Diet, physical activity, and psychosocial factors are independent and potentially interactive obesity determinants, but few studies have explored complex behavior patterns

From Fatalism to Mitigation: a Conceptual Framework for Mitigating Fetal Programming of Chronic Disease by Maternal Obesity

Prenatal development is recognized as a critical period in the etiology of obesity and cardiometabolic disease. Potential strategies to reduce maternal obesity-induced risk later in life have been largely overlooked. In this paper, we first propose a conceptual framework for the role of public health and preventive medicine in mitigating the effects of fetal programming. Second, we review a small but growing body of research (through August 2015) that examines interactive effects of maternal obesity and two public health foci – diet and physical activity – in the offspring. Results of the review support the hypothesis that diet and physical activity after early life can attenuate disease susceptibility induced by maternal obesity, but human evidence is scant. Based on the review, we identify major gaps relevant for prevention research, such as characterizing the type and dose response of dietary and physical activity exposures that modify the adverse effects of maternal obesity in the offspring. Third, we discuss potential implications of interactions between maternal obesity and postnatal dietary and physical activity exposures for interventions to mitigate maternal obesity-induced risk among children. Our conceptual framework, evidence review, and future research directions offer a platform to develop, test, and implement fetal programming mitigation strategies for the current and future generations of children

Built and socioeconomic environments: patterning and associations with physical activity in U.S. adolescents

Abstract Background Inter-relationships among built and socioeconomic environmental characteristics may result in confounding of associations between environment exposure measures and health behaviors or outcomes, but traditional multivariate adjustment can be inappropriate due to collinearity. Methods We used principal factor analysis to describe inter-relationships between a large set of Geographic Information System-derived built and socioeconomic environment measures for adolescents in the National Longitudinal Study of Adolescent Health (Wave I, 1995-96, n = 17,294). Using resulting factors in sex-stratified multivariate negative binomial regression models, we tested for confounding of associations between built and socioeconomic environment characteristics and moderate to vigorous physical activity (MVPA). Finally, we used knowledge gained from factor analysis to construct replicable environmental measures that account for inter-relationships and avoid collinearity. Results Using factor analysis, we identified three built environment constructs [(1) homogenous landscape; 2) development intensity with high pay facility count; 3) development intensity with high public facility count] and two socioeconomic environment constructs [1) advantageous economic environment, 2) disadvantageous social environment]. In regression analysis, confounding of built environment-MVPA associations by socioeconomic environment factors was stronger than among built environment factors. In fully adjusted models, MVPA was negatively associated with the highest (versus lowest) quartile of homogenous land cover in males [exp(coeff) (95% CI): 0.91 (0.86, 0.96)] and intensity (pay facilities) [exp(coeff) (95% CI): 0.92 (0.85, 0.99)] in females. Single proxy measures (Simpson's diversity index, count of pay facilities, count of public facilities, median household income, and crime rate) representing each environmental construct replicated associations with MVPA. Conclusions Environmental characteristics are inter-related. Both built and SES environments should be incorporated into analysis in order to minimize confounding. Single environmental measures may be useful proxies for environmental constructs in longitudinal analysis and replication in external populations, but more research is needed to better understand mechanisms of action, and ultimately identify policy-relevant environmental determinants of physical activity

What neighborhood area captures built environment features related to adolescent physical activity?

In research investigating built environment (BE) influences on physical activity (PA), inconsistent neighborhood definitions may contribute to inconsistent findings. Using data from the National Longitudinal Study of Adolescent Health (Wave I; 1994-95), we compared associations between moderate-vigorous PA (MVPA) and PA facility counts and street connectivity measures (intersection density and link:node ratio) within 1, 3, 5, and 8.05 kilometers (km) from each respondent's residence (Euclidean neighborhood buffers). BE-MVPA associations varied by BE characteristic, urbanicity, and sex. PA facilities within 3 km buffers and intersection density within 1k buffers exhibited the most consistent associations with MVPA. Policy recommendations and corresponding research should address potential differences in relevant neighborhood areas across environment feature and population subgroup