Both child and parent obesity were lowest in neighborhoods with environments that were most favorable to both healthy eating, defined as supermarket proximity and/or lower fast-food restaurant density, and physical activity, defined as having built environments more conducive to walking and access to a higher-quality park. Neighborhoods with built environments unfavorable for both healthy eating and physical activity had the highest percentage of childhood and parent obesity. These differences persisted even after accounting for parent weight status (in the analyses regarding child weight status) and various neighborhood-level and individual- and household-level demographic factors. Findings using child and parental overweight as thresholds were in a similar direction, although the associations were not as strong as for obesity.
Current results offer an initial GIS-based definition of “obesogenic neighborhood environments”, a commonly used term to describe a variety of environmental features, but this is among the first studies to test an empirically based definition, and it was shown to be related to child and adult obesity. Both physical activity and nutrition environments were considered and incorporated several environmental indicators that have been widely discussed and studied.16
The physical activity environment definition considered environments that supported both active transportation and active recreation. The nutrition environment definition included access to both healthy and less-healthy food outlets.
Although present criteria for neighborhood types may not currently be easy to replicate because of required use of both archival and newly collected data (e.g., park-quality evaluations), the criteria were quantitative, and data such as these could become more commonly collected if confirmed to be related to obesity and other health outcomes. The specific definitions or thresholds may not be optimal, since they differed by region and had to be adjusted to identify a sufficient number of block groups for recruitment of children aged 6–11 years. Future research can test alternative definitions of physical activity environment and nutrition environment.
Present findings are consistent with emerging evidence about neighborhood environments and child overweight/obesity. In the 2007 National Survey of Children’s Health sample of children aged 10–17 years, parents’ report of less-favorable built environments for physical activity (e.g., no sidewalk access, no access to parks/playgrounds) was related to higher prevalence of child overweight and obesity, with 19.7% of children in the least-favorable neighborhood environments for physical activity being obese versus 14.6% of children in the most-supportive built environments.2
Current findings of lower parent obesity prevalence in neighborhood environments with higher walkability are consistent with prior evidence among adults11, 17,18
and other findings that adult obesity was lower in neighborhoods with supermarket availability.19,20
Results provide empirical support for recommendations from multiple authoritative groups to markedly improve neighborhood built environments and local policies that affect the likelihood of children’s and parent’s healthy eating and physical activity.6, 7
It is notable that the child overweight (31.7%) and obesity (15.9%) estimates in the least-favorable neighborhoods in the present study are comparable to the most-recent NHANES prevalence estimates for overweight (32.6%) and obesity (18.0%) among children aged 6–11 years in the U.S.1
Socioeconomic factors were associated with parent overweight and obesity in mostly expected directions. However, socioeconomic characteristics of the neighborhood and household were not related to child overweight or obesity in this sample. It could be that neighborhood physical activity and nutrition characteristics are more important predictors, particularly among this relatively affluent and well-educated sample. Alternately, spatial sampling methods were used to ensure a mix of neighborhoods that met these built environment characteristics with adequate numbers of respondents per neighborhood. Therefore, study participants and their neighborhoods were not necessarily representative of the population or study area. The present design and analyses can be considered a validation of the spatial sampling approach used in this study, rather than a representative sampling of factors related to child and adult weight status.
Strengths of the present study included measurement of both child and parent BMI, a priori and objective measurement of neighborhood environments using GIS, generalization across two regions of the U.S., and consideration of both neighborhood-level and individual- and household-level demographics. Limitations included the cross-sectional design, relatively low response rate relative to initial contacts, relatively affluent and well-educated sample, and aggregation of environmental characteristics based on overall block group characteristics to individual children and parents.
Different fast-food restaurant density levels were used in King County versus San Diego County areas, in part because of the substantially greater number of restaurants in San Diego. This relative measure makes comparisons to other areas difficult, but it is not clear at this point what level of restaurant quality or quantity differentiates between healthy versus unhealthy dietary quality and weight status. Relative metrics of built environment for walkability were similarly constructed within region.
In addition, neighborhood and the corresponding built environment was defined by block group in which the children lived, rather than their actual activity space or places where they shopped for food and/or ate.21
Replication of present findings is needed, including testing relative versus absolute of built environment (e.g., testing uniform and absolute thresholds of park proximity versus relative park proximity within a region), as are more intervention studies that evaluate effects of change in built environment and policy.
A key contribution was the validation of an initial GIS-based definition of obesogenic and obeso-protective environments. There is some suggestion in the present study that physical activity environment may be more important than nutrition environment for child weight status, at least as operationalized herein, but overall findings suggest the importance of examining the combination of nutrition and physical activity environments. Future research with larger samples and perhaps different designs (e.g., to control for specific characteristics of walkability) is needed to more fully examine the relative contribution of nutrition and physical activity environments.
The magnitude of the difference in obesity rates between the most-obesogenic and least- obesogenic neighborhood types was notable, about 8% for children and 7% for adults. Present findings suggest that environmental changes could have important effects on obesity rates of children and adults. There is concern that many children and their caregivers in the U.S. live in unsupportive environments that fail to provide better access to healthy nutrition and physical activity opportunities.22