Identifying multilevel predictors of behavioral outcomes like park use: A comparison of conditional and marginal modeling approaches.

This study compared marginal and conditional modeling approaches for identifying individual, park and neighborhood park use predictors. Data were derived from the ParkIndex study, which occurred in 128 block groups in Brooklyn (New York), Seattle (Washington), Raleigh (North Carolina), and Greenville (South Carolina). Survey respondents (n = 320) indicated parks within one half-mile of their block group used within the past month. Parks (n = 263) were audited using the Community Park Audit Tool. Measures were collected at the individual (park visitation, physical activity, sociodemographic characteristics), park (distance, quality, size), and block group (park count, population density, age structure, racial composition, walkability) levels. Generalized linear mixed models and generalized estimating equations were used. Ten-fold cross validation compared predictive performance of models. Conditional and marginal models identified common park use predictors: participant race, participant education, distance to parks, park quality, and population >65yrs. Additionally, the conditional mode identified park size as a park use predictor. The conditional model exhibited superior predictive value compared to the marginal model, and they exhibited similar generalizability. Future research should consider conditional and marginal approaches for analyzing health behavior data and employ cross-validation techniques to identify instances where marginal models display superior or comparable performance.

Medical operations in the 21st century: application of TAK among wartime medical assets.

Advances in technology have improved the ability for real-time communication and enhanced awareness of medically related information on the battlefield. A government off-the-shelf platform, Team Awareness Kit (TAK), may enhance the ability for battlefield healthcare delivery, evacuation, telecommunication, and medical command and control. Integration of TAK into existing medical infrastructure provides a global view of resources, patient movement and direct communication, significantly reducing the 'fog of war' as it relates to battlefield injury and evacuation. Rapid integration and adoption are technically feasible with minimal resource investment. This technology can be rapidly scaled for the increasingly interconnected world of healthcare delivery.

Use of a head-mounted patient display in a task driven anaesthesia simulator: a randomised trial.

INTRODUCTION: Head-mounted displays (HMDs) are becoming increasingly investigated in the realm of healthcare. These devices are worn on the user's head and display information directly to the eye. This allows for near-constant delivery of information, regardless of user position. Increasing advances in technology have allowed for miniaturisation, increasing sophistication, wireless capability and prolonged battery life, all of which allow for more opportunities for these devices to be used in a clinical setting. METHODS: A prospective, randomised, controlled, parallel-group study was conducted. Subjects were randomised to either an HMD group or a non-HMD group. All subjects then underwent a standardised intraoperative care simulation experience consisting of multiple procedures that required completion within a set time limit. During this period, subjects concurrently monitored the physiological state of a simulated patient. Multiple standardised physiological derangements were displayed to the subjects via either the worn HMD or standard monitors. The primary outcome was the time to recognition of these physiological derangements. RESULTS: A total of 39 anaesthesia providers were enrolled in this study. There was a significant decrease in the total time it took them to recognise the simulated physiological derangements in the HMD group (difference of 38.2% (95% CI 20.3% to 56.1%); p=0.011) No significant differences in the time that it took to perform the required simulated procedures were observed. Significantly fewer physiological derangements were overlooked by the HMD group than the control group overall (relative risk reduction 0.78 (95% CI 0.31 to 0.94); p=0.003). CONCLUSIONS: Recent advances in HMD technology may be able to produce a functional adjunctive monitoring device that improves the speed with which anaesthesia providers respond to intraoperative events. This benefit comes without increasing distraction from the task. Further studies in true operative environments are needed to validate this technology.

Frequency of Neighborhood Park Use Is Associated With Physical Activity Among Adults in Four US Cities.

BACKGROUND: Neighborhood parks are recognized as important spaces for facilitating physical activity (PA); however, it remains unclear how the frequency of park use is associated with PA. The purpose of this study was to examine associations between minutes of moderate to vigorous PA and multiple park use indicators: (1) use of a neighborhood park, (2) unique number of neighborhood parks used, and (3) frequency of neighborhood park use. METHODS: Adults were surveyed from 4 US cities (Brooklyn, NY; Greenville County, SC; Raleigh, NC; and Seattle, WA). Using a map-based survey platform, participants indicated all neighborhood parks they used and the frequency of use in the past 30 days. Participants self-reported their weekly moderate to vigorous PA. Quantile regression was used to examine associations between PA and park use indicators. RESULTS: Of all respondents (N = 360), 60% indicated visiting a neighborhood park in the past 30 days, with an average of about 13 total neighborhood park visits (SD = 17.5). Significant, positive associations were found between moderate to vigorous PA and both unique neighborhood park visits and total number of neighborhood parks visits. CONCLUSIONS: Frequency of park visitation is associated with PA among US adults. Ensuring equitable and safe access to neighborhood parks has the potential for population-level PA health benefits.

Spatial clustering patterns and regional variations for food and physical activity environments across the United States.

This study examined spatial patterns of obesogenic environments for US counties. We mapped the geographic dispersion of food and physical activity (PA) environments, assessed spatial clustering, and identified food and PA environment differences across U.S. regions and rurality categories. Substantial low food score clusters were located in the South and high score clusters in the Midwest and West. Low PA score clusters were located in the South and high score clusters in the Northeast and Midwest (p < .0001). For region, the South had significantly lower food and PA environment scores. For rurality, rural counties had significantly higher food environment scores and metropolitan counties had significantly higher PA environment scores (p < .0001). This study highlights geographic clustering and disparities in food and PA access nationwide. State and region-wide environmental inequalities may be targeted using structural interventions and policy initiatives to improve food and PA access.

ParkIndex: Validation and application of a pragmatic measure of park access and use.

Composite metrics integrating park availability, features, and quality for a given address or neighborhood are lacking. The purposes of this study were to describe the validation, application, and demonstration of ParkIndex in four diverse communities. This study occurred in Fall 2018 in 128 census block groups within Seattle(WA), Brooklyn(NY), Raleigh(NC), and Greenville County(SC). All parks within a half-mile buffer were audited to calculate a composite park quality score, and select households provided data about use of proximal parks via an online, map-based survey. For each household, the number of parks, total park acreage, and average park quality score within one half-mile were calculated using GIS. Logistic regression was used to identify a parsimonious model predicting park use. ParkIndex values (representing the probability of park use) were mapped for all study areas and after scenarios involving the addition and renovation/improvement of parks. Out of 360 participants, 23.3% reported visiting a park within the past 30 days. The number of parks (OR = 1.36, 95% CI = 1.15-1.62), total park acreage (OR = 1.13, 95% CI = 1.07-1.19), and average park quality score (OR = 1.04, 95% CI = 1.01-1.06) within one half-mile were all associated with park use. Composite ParkIndex values across the study areas ranged from 0 to 100. Hypothetical additions of or renovations to study area parks resulted in ParkIndex increases of 22.7% and 19.2%, respectively. ParkIndex has substantial value for park and urban planners, citizens, and researchers as a common metric to facilitate awareness, decision-making, and intervention planning related to park access, environmental justice, and community health.

Healthy and unhealthy food environments are linked with neighbourhood socio-economic disadvantage: an innovative geospatial approach to understanding food access inequities.

OBJECTIVE: This study examined the separate relationships between socio-economic disadvantage and the density of multiple types of food outlets, and relationships between socio-economic disadvantage and composite food environment indices. DESIGN: Cross-sectional data were analysed using geospatial kernel density techniques. Food outlet data included convenience stores, discount stores, fast-food and fast casual restaurants, and grocery stores. Controlling for urbanicity and race/ethnicity, multivariate linear regression was used to examine the relationships between socio-economic disadvantage and density of food outlets. SETTING: This study occurred in a large Southeastern US county containing 255 census block groups with a total population of 474 266, of which 77·1 % was Non-Hispanic White, the median household income was $48 886 and 15·0 % of residents lived below 125 % of the federal poverty line. PARTICIPANTS: The unit of analysis was block groups; all data about neighbourhood socio-economic disadvantage and food outlets were publicly available. RESULTS: As block group socio-economic disadvantage increased, so too did access to all types of food outlets. The total food environment index, calculated as the ratio of unhealthy food outlets to all food outlets, decreased as block group disadvantage increased. CONCLUSIONS: Those who reside in more disadvantaged block groups have greater access to both healthy and unhealthy food outlets. The density of unhealthy establishments was greater in more disadvantaged areas; however, because of having greater access to grocery stores, disadvantaged populations have less obesogenic total food environments. Structural changes are needed to reduce access to unhealthy food outlets to ensure environmental injustice and reduce obesity risk.

Efficient isogeometric boundary element method for analysis of acoustic scattering from rigid bodies.

Boundary integral analysis of scattering from rigid bodies is well known. Analysis often proceeds along the following lines: representation of the geometry using a collection of triangles, representation of physics using low order ansatz functions defined on each triangle, and then solving the resulting discrete system. This prescription for the common solution stands out in terms of the low-order approximation of both geometry and representation of physics; specifically, both are C0. Taking inspiration from computer graphics literature, a framework wherein continuity of representation (both geometry and physics) can be as high as C2 is developed. In this paper, the steps necessary to develop such a iso-geometric (i.e., using the same basis functions for representing both geometry and physics) boundary integral solver are elucidated. In doing so, an efficient method based on a wideband fast multipole method to evaluate the required inner products and matrix vector products is proposed and demonstrated. Numerous examples are presented to highlight the benefits of the proposed approach.

ParkIndex: Using Key Informant Interviews to Inform the Development of a New Park Access Evaluation Tool.

The relationship between park availability, physical activity, and positive health outcomes has been documented across the globe. However, studying how people access parks and why they use the parks is difficult due to a lack of consensus with respect to measurement approaches and assessment of park environments. Establishing a parsimonious method and tool for quantifying both park availability and park quality represents a major step that could advance park and physical activity research and practice. This paper describes phase one of the effort to develop such a measurement tool, known as ParkIndex. ParkIndex is a two-year National Institutes of Health (NIH)-funded study to create an evidence-based tool that will assist citizens and professionals in understanding and using information regarding community park access and use. Phase one consisted of key informant interviews conducted with research and practice leaders to inform development and provide insight on the essential foundations of ParkIndex. Twelve professionals from practice and academia, including parks and recreation, landscape design, and public health sectors, were interviewed in fall 2016. Key informants were interviewed on four topics concerning the content, value, feasibility, and dissemination of ParkIndex. Trained research assistants employed double, emergent, open, and axial coding methods to develop key themes and concepts to guide phase 2 and further development of ParkIndex. Key themes throughout the interviews included measures for park use, including distance, safety, neighborhood characteristics, route and travel mode to park, and overall park characteristics. Park elements discussed included quality of, and availability of, amenities, activity spaces, programming, and park management, as well as the context of the park and the engagement of the local community. Respondents determined that ParkIndex could benefit park planning and community development and provide for a standardized method for evaluating park access. Interviews and themes offer parks and public health practitioners and researchers-and this specific ParkIndex development team-the opportunity to refine and evaluate measures to be included in a comprehensive park access and use tool. Key informants repeatedly referenced the need, especially within parks and recreation management, for consistent, reliable, and valid measures of park access and use, such as ParkIndex seeks to provide. We believe a well-conceived, integrated index will at the very least allow for greater comparison between parks and park systems and at best will facilitate the many park stakeholders to best design, maintain, program, research, and advocate for their local parks.

Associations between Walkability and Youth Obesity: Differences by Urbanicity.

Background: Attributes of the built environment, such as neighborhood walkability, have been linked to increased physical activity and reduced obesity risk. This relationship, however, has primarily been documented in adults; less is known about neighborhood walkability and youth obesity, as limited prior research has produced mixed findings. The purpose of this study was to examine the association between neighborhood walkability and youth obesity, including differences by urbanicity. Methods: Data were collected in 2013 from youth aged 7-14 years (n = 13,469) in a Southeastern county school district. Height and weight were objectively measured and utilized to calculate body mass index (BMI) z-scores. Youth demographic characteristics and addresses were obtained, and a Walk Score® was gathered for each youth's home address. Multilevel linear regression analysis, accounting for nesting within census block groups, was conducted to examine the association between Walk Score and BMI z-score and to test for the moderating effect of urbanicity. Separate multilevel analyses examined Walk Score and BMI z-score among urban, urban-rural mixed, and rural youth subsamples. Results: Overall, as Walk Score increased, youth BMI z-score decreased. Walk Score was positively associated with BMI z-score among urban youth and negatively associated with BMI z-score among rural youth; no relationship was observed between Walk Score and youth in urban-rural mixed areas. Conclusions: Neighborhood walkability may impact youth differently across geographic areas. Further study is warranted about how youth utilize a walkable environment and mechanisms through which walkability influences youth physical activity and obesity risk.

Development and testing of a multicomponent obesogenic built environment measure for youth using kernel density estimations.

Innovative measures can advance the measurement and understanding of obesogenic environments on health outcomes. In a southeastern US county, public parks (n = 103) were scored using detailed audit data, while two databases of food stores and restaurants were compiled (n = 1112). Using kernel density estimations, separate raster (pixel) surfaces were created for each built environment component. Each surface was scaled and summed to create an obesogenic environment measure. Health-promoting built environments were related to lower weight status in youth (ß = -0.25, p < 0.05), with differences by urban and non-urban areas. This study demonstrates a unique method to quantify and test obesogenic built environments.

'We need a safe, walkable way to connect our sisters and brothers': a qualitative study of opportunities and challenges for neighborhood-based physical activity among residents of low-income African-American communities.

OBJECTIVE: The purpose of this study was to explore perceptions of the benefits of and influencing factors for neighborhood-based physical activity (PA), and elicit suggestions for increasing neighborhood-based PA among primarily Black residents living in lower income neighborhoods. DESIGN: Eight focus groups were conducted in low-income, predominantly Black neighborhoods (n = 8) in Greenville, SC during Spring 2014. Using a semi-structured focus group guide with open-ended questions, residents were asked to describe benefits of PA, neighborhood factors associated with PA, and ways to increase PA within their neighborhoods. Trained research assistants transcribed audio recordings verbatim. Using grounded theory and an ecological perspective, emergent coding was employed to generate initial categories with open and axial coding used to achieve consensus on themes. RESULTS: Primarily Black (95%), female (72%), and older (M = 61.5 years) residents (N = 76) participated in the study. Seven themes were identified across the three main focus group topics: physical and mental health benefits of neighborhood PA, safety/hazards and social factors as influencing neighborhood PA, and improving safety, structural opportunities, and programing support to improve neighborhood PA. Most participants reported walking within their communities, despite describing several community-level barriers (e.g. drugs, safety). Residents desired structured neighborhood-based opportunities for increasing PA, including walking tracks and walking groups, and reported social benefits to being active, including increased awareness within the community and trust. Participants conveyed that walking strengthened the social environment of their community as well as the health of residents. CONCLUSION: Few studies of contextual factors and PA have focused on African-American, low-income neighborhoods. Despite diverse environmental constraints, residents reported walking within their communities as part of a healthy lifestyle. Social ecological interventions tailored to promote PA and reduce health disparities among residents of low-income communities should highlight neighborhood-based opportunities for PA, focusing on personal and collective social benefits of neighborhood walking.

Relationship of objective street quality attributes with youth physical activity: findings from the Healthy Communities Study.

BACKGROUND: Residential environments may significantly influence youth physical activity (PA). However, few studies have examined detailed street quality attributes via observational audits in relation to context-specific PA among youth. OBJECTIVES: The objective of this study was to explore whether the overall quality of street environments, as well as specific attributes, was associated with neighbourhood-based and street-based PA within a national sample of youth in the Healthy Communities Study. METHODS: Data were collected from 4616 youth from 130 communities across the USA. Youth PA in the neighbourhood and on the participant's street was captured using 7-d recall interviews. Windshield survey observational audits documented five street quality variables: burned, boarded up or abandoned residential units, litter, overall condition of residences, street type and presence of sidewalks in good condition. RESULTS: Youth with no litter on their street reported significantly lower neighbourhood-based PA and youth living on a side street, cul-de-sac, dead-end or one-way street reported greater neighbourhood-based PA. No significant associations were detected for the overall street quality index or with street-based PA. CONCLUSIONS: Specific street quality attributes may be associated with youth PA. Further research and collaboration between diverse disciplines and agencies should focus on understanding and improving street quality to promote youth PA and health.

Spatial clustering patterns of child weight status in a southeastern US county.

Youth obesity is a major public health concern due to associated physical, social, and psychological health consequences. While rates and disparities of youth obesity levels are known, less research has explored spatial clustering patterns, associated correlates of spatial clustering, comparing patterns in urban and rural areas. Therefore, this study 1) examined spatial clustering of youth weight status, 2) investigated sociodemographic correlates of spatial clustering patterns, and 3) explored spatial patterns by level of urbanization. This study occurred in a southeastern US county (pop:474,266) in 2013. Trained physical education teachers collected height and weight for all 3rd-5th grade youth (n = 13,469) and schools provided youth demographic attributes. BMI z-scores were calculated using standard procedures. Global Moran's Index and Anselin's Local Moran's I (LISA) were used detect global and local spatial clustering, respectively. To examine correlates of spatial clustering, BMI z-score residuals from a series of four linear regression models were spatially analyzed, mapped, and compared. SAS 9.4 and GeoDA were used for analyses; ArcGIS was used for mapping. Significant, positive global clustering (Index = 0.04,p < 0.001) was detected. LISA results showed that about 4.7% (n = 635) and 7.9% (n = 1058) of the sample were identified as high and low obesity localized spatial clusters (p < 0.01), respectively. Individual and neighborhood sociodemographic characteristics accounted for the majority of spatial clustering and differential patterns were observed by level of urbanization. Identifying geographic areas that contain significant spatial clusters is a powerful tool for understanding the location of and exploring contributing factors to youth obesity.

Examining Sociodemographic Differences in Playground Availability and Quality and Associations with Childhood Obesity.

BACKGROUND: Parks and playgrounds are important environmental components for promoting healthy weight among children. The purposes of this study were to examine disparities in access to playgrounds and playground quality by multiple sociodemographic characteristics and the association of playground access and quality with youth weight status. METHODS: Objectively measured height and weight were collected for all third to fifth grade youth (n = 13,469) in a southeastern US County. Detailed audits of all park playgrounds (n = 95) were concurrently conducted. Playground quality was measured by the presence of eight playground attributes (e.g., good condition and shade). Spatial (GIS) and statistical (multilevel logistic regression) analyses were used to determine access to playgrounds within a ½ mile network buffer, whether playground access and quality varied by the individual's gender, socioeconomic status (SES), and race/ethnicity, and the association between playground access and quality with youth being a healthy weight vs. overweight or obese. RESULTS: Higher SES youth were half as likely to have a playground within ½ mile. No disparities were found for playground quality by gender, SES, or race/ethnicity. In unadjusted models, youth with lower quality playgrounds nearby were more likely to be overweight/obese than children with no playground access. However, there were no significant associations for playground access/quality and weight status after adjusting for sociodemographic variables. CONCLUSION: Future research should continue to monitor disparities in diverse metrics of access to and quality of playgrounds and how these are related to weight status and other outcomes among children of different age, income, and racial/ethnic groups.

An Initiative to Facilitate Park Usage, Discovery, and Physical Activity Among Children and Adolescents in Greenville County, South Carolina, 2014.

INTRODUCTION: Parks are important settings for increasing population-level physical activity (PA). The objective of this study was to evaluate Park Hop, an incentivized scavenger-hunt-style intervention designed to influence park usage, discovery, park-based PA, and perceptions of parks among children and adolescents in Greenville County, South Carolina. METHODS: We used 2 data collection methods: matched preintervention and postintervention parent-completed surveys and in-park observations during 4 days near the midpoint of the intervention. We used paired-samples t tests and logistic regression to analyze changes in park visitation, perceptions, and PA. RESULTS: Children and adolescents visited an average of 12.1 (of 19) Park Hop parks, and discovered an average of 4.6 venues. In a subset of participants, from preintervention to postintervention, the mean number of park visits increased from 5.0 visits to 6.1 visits, the proportion of time engaged in PA during the most recent park visit increased from 77% to 87%, and parents reported more positive perceptions of the quality of park amenities. We observed more children and adolescents (n = 586) in the 2 intervention parks than in the 2 matched control parks (n = 305). However, the likelihood of children and adolescents engaging in moderate-to-vigorous PA was significantly greater in the control parks (74.3%) than in Park Hop parks (64.2%). CONCLUSION: Park Hop facilitated community-collaboration between park agencies and positively influenced park usage, park discovery, time engaged in PA during park visits, and perceptions of parks. This low-cost, replicable, and scalable model can be implemented across communities to facilitate youth and family-focused PA through parks.

Green and lean: Is neighborhood park and playground availability associated with youth obesity? Variations by gender, socioeconomic status, and race/ethnicity.

Parks and park features are important for promoting physical activity and healthy weight, especially for low-income and racial/ethnic minority youth who have disproportionately high obesity rates. This study 1) examined associations between neighborhood park and playground availability and youth obesity, and 2) assessed whether these associations were moderated by youth race/ethnicity and socioeconomic status (SES). In 2013, objectively measured height and weight were collected for all 3rd-5th grade youth (n=13.469) in a southeastern US county to determine body mass index (BMI) percentiles. Enumeration and audits of the county's parks (n=103) were concurrently conducted. Neighborhood park and playground availability were calculated as the number of each facility within or intersecting each youth's Census block group. Multilevel linear regression models were utilized to examine study objectives. For boys, no main effects were detected; however, SES moderated associations such that higher park availability was associated with lower BMI percentile for low-SES youth but higher BMI percentile for high-SES youth. For girls, the number of parks and playgrounds were significantly associated with lower BMI (b=-2.2, b=-1.1, p<0.05, respectively) and race/ethnicity and SES moderated associations between playground availability and BMI percentile. Higher playground availability was associated with lower BMI percentile for White and high-SES girls but higher BMI percentile for African American and low-SES girls. Considerable variation was detected in associations between park and playground availability and youth obesity by SES and race/ethnicity, highlighting the importance of studying the intersection of these characteristics when exploring associations between built environment features and obesity.

Pathways to Health: Association Between Trail Use, Weight Status, and Self-Rated Health Among Adults in Greenville County, South Carolina, 2014.

We examined associations between adults' use of a prominent rail-trail and their weight status and self-rated health. In 2014, a random-digit-dial survey of Greenville County, South Carolina, residents (n = 639) was used to collect data on trail use, height and weight, self-rated health, and demographics. Trail users were half as likely to be overweight or obese as trail nonusers (odds ratio [OR] = 0.56; 95% confidence interval [CI], 0.33-0.95). Similarly, trail users were significantly more likely to report high self-rated health than were trail nonusers (OR = 1.83; 95% CI, 1.13-2.97). Findings suggest that trail use is associated with healthier weight status and higher self-rated health and supports the development, maintenance, and promotion of trail resources.

ParkIndex: Development of a standardized metric of park access for research and planning.

OBJECTIVE: A lack of comprehensive and standardized metrics for measuring park exposure limits park-related research and health promotion efforts. This study aimed to develop and demonstrate an empirically-derived and spatially-represented index of park access (ParkIndex) that would allow researchers, planners, and citizens to evaluate the potential for park use for a given area. METHODS: Data used for developing ParkIndex were collected in 2010 in Kansas City, Missouri (KCMO). Adult study participants (n=891) reported whether they used a park within the past month, and all parks in KCMO were mapped and audited using ArcGIS 9.3 and the Community Park Audit Tool. Four park summary variables - distance to nearest park, and the number of parks, amount of park space, and average park quality index within 1mile were analyzed in relation to park use using logistic regression. Coefficients for significant park summary variables were used to create a raster surface (ParkIndex) representing the probability of park use for all 100m×100m cells in KCMO. RESULTS: Two park summary variables were positively associated with park use - the number of parks and the average park quality index within 1 mile. The ParkIndex probability of park use across all cells in KCMO ranged from 17 to 77 out of 100. CONCLUSION: ParkIndex represents a standardized metric of park access that combines elements of both park availability and quality, which was developed empirically and can be represented spatially. This tool has both practical and conceptual significance for researchers and professionals in diverse disciplines.