Charlotte Demant Klinker

Dynamic Accuracy of GPS Receivers for Use in Health Research: A Novel Method to Assess GPS Accuracy in Real-World Settings.

The emergence of portable global positioning system (GPS) receivers over the last 10 years has provided researchers with a means to objectively assess spatial position in free-living conditions. However, the use of GPS in free-living conditions is not without challenges and the aim of this study was to test the dynamic accuracy of a portable GPS device under real-world environmental conditions, for four modes of transport, and using three data collection intervals. We selected four routes on different bearings, passing through a variation of environmental conditions in the City of Copenhagen, Denmark, to test the dynamic accuracy of the Qstarz BT-Q1000XT GPS device. Each route consisted of a walk, bicycle, and vehicle lane in each direction. The actual width of each walking, cycling, and vehicle lane was digitized as accurately as possible using ultra-high-resolution aerial photographs as background. For each trip, we calculated the percentage that actually fell within the lane polygon, and within the 2.5, 5, and 10 m buffers respectively, as well as the mean and median error in meters. Our results showed that 49.6% of all ≈68,000 GPS points fell within 2.5 m of the expected location, 78.7% fell within 10 m and the median error was 2.9 m. The median error during walking trips was 3.9, 2.0 m for bicycle trips, 1.5 m for bus, and 0.5 m for car. The different area types showed considerable variation in the median error: 0.7 m in open areas, 2.6 m in half-open areas, and 5.2 m in urban canyons. The dynamic spatial accuracy of the tested device is not perfect, but we feel that it is within acceptable limits for larger population studies. Longer recording periods, for a larger population are likely to reduce the potentially negative effects of measurement inaccuracy. Furthermore, special care should be taken when the environment in which the study takes place could compromise the GPS signal.

Context-Specific Outdoor Time and Physical Activity among School-Children Across Gender and Age: Using Accelerometers and GPS to Advance Methods

Introduction: Being outdoors has a positive influence on health among children. Evidence in this area is limited and many studies have used self-reported measures. Objective context-specific assessment of physical activity patterns and correlates, such as outdoor time, may progress this field. Aims: To employ novel objective measures to assess age and gender differences in context-specific outdoor weekday behavior patterns among school-children [outdoor time and outdoor moderate to vigorous physical activity (MVPA)] and to investigate associations between context-specific outdoor time and MVPA. Methods: A total of 170 children had at least one weekday of 9 h combined accelerometer and global positioning system data and were included in the analyses. The data were processed using the personal activity and location measurement system (PALMS) and a purpose-built PostgreSQL database resulting in context-specific measures for outdoor time, outdoor MVPA, and overall daily MVPA. In addition, 4 domains (leisure, school, transport, and home) and 11 subdomains (e.g., urban green space and sports facilities) were created and assessed. Multilevel analyses provided results on age and gender differences and the association between outdoor time and MVPA. Results: Girls compared to boys had fewer outdoor minutes (p < 0.05), spent a smaller proportion of their overall daily time outdoors (p < 0.05), had fewer outdoor MVPA minutes during the day (p < 0.001) and in 11 contexts. Children compared to adolescents had more outdoor minutes (p < 0.05). During school and within recess, children compared to adolescents had more outdoor MVPA (p < 0.001) and outdoor time (p < 0.001). A 1-h increase in outdoor time was associated with 9.9 more minutes of MVPA (p < 0.001). Conclusion: A new methodology to assess the context-specific outdoor time and physical activity patterns has been developed and can be expanded to other populations. Different context-specific patterns were found for gender and age, suggesting different strategies may be needed to promote physical activity.

The effect of the social and physical environment on children's independent mobility to neighborhood destinations

BACKGROUND Relationships between context-specific measures of the physical and social environment and childrens independent mobility to neighborhood destination types were examined. METHODS Parents in RESIDEs fourth survey reported whether their child (8-15 years; n = 181) was allowed to travel without an adult to school, friends house, park and local shop. Objective physical environment measures were matched to each of these destinations. Social environment measures included neighborhood perceptions and items specific to local independent mobility. RESULTS Independent mobility to local destinations ranged from 30% to 48%. Independent mobility to a local park was less likely as the distance to the closest park (small and large size) increased and less likely with additional school grounds (P < .05). Independent mobility to school was less likely as the distance to the closest large park increased and if the neighborhood was perceived as unsafe (P < .05). Independent mobility to a park or shops decreased if parenting social norms were unsupportive of childrens local independent movement (P < .05). CONCLUSIONS Independent mobility appears dependent upon the specific destination being visited and the impact of neighborhood features varies according to the destination examined. Findings highlight the importance of access to different types and sizes of urban green space for childrens independent mobility to parks.

The effect of siblings and family dog ownership on children's independent mobility to neighbourhood destinations

Objective: To investigate the effect of sibling age, gender and dog ownership on childrens independent mobility and how this varies according to the destination visited.

Increases in Use and Activity Due to Urban Renewal: Effect of a Natural Experiment

INTRODUCTION Urban green space and other recreational facilities are associated with physical activity. For adolescents living in multistory housing, public outdoor spaces that support physical activity may play an important role in activity promotion strategies. However, stronger evidence for a relation between the built environment and adolescent physical activity is scarce. DESIGN A natural experiment with a pre-experimental design was used with data collected in 2010 and 2012 before and after an urban renewal. Data were analyzed in 2016. SETTING/PARTICIPANTS Adolescents aged 11-16 years spending a minimum of 10 minutes daily within a 400-m buffer of the renewal district were included in the analyses, resulting in 354 adolescents at baseline and 319 post-renewal. INTERVENTION A multicomponent urban renewal project of approximately 35 million Euros in a disadvantaged neighborhood in the capital of Denmark occurred between 2010 and 2012. MAIN OUTCOME MEASURES The main outcomes were changes in time spent and physical activity within the area among adolescents, measured by accelerometry (ActiGraph GT3X) and GPS devices (Qstarz BT-Q1000XT). RESULTS Time spent in the area was greater in 2012 than 2010 with an additional 24.6 minutes per day (p=0.017). Of this time, 7.8 minutes were spent in light and 4.5 minutes in moderate to vigorous physical activity. CONCLUSIONS The present study indicates that a multicomponent urban renewal strategy in a disadvantaged district has the potential to increase time spent and physical activity in the district for adolescents living in or close to the district.

Health in All local Policies: Lessons learned on intersectoral collaboration in a community-based health promotion network in Denmark

Health promotion increasingly involves collaboration with civil society organisations and the private sector rather than being implemented exclusively by public sector stakeholders. Health in All Policies (HiAP) is an approach that promotes health in policy-making across public sectors. This study explored intersectoral integration and collaboration for health promotion at a local community level through a qualitative single case study of a local community network in Denmark: the Husum Health Network. The paper describes and discusses strengths, weaknesses, and challenges of HiAP-inspired local efforts to build alliances and supportive environments for health within an inter-organisational community-based network. The data were generated from participant observations made at 11 meetings and events organised by the network partners and nine qualitative, semi-structured interviews with Husum Health Network partners conducted from August 2014 to February 2015. The data were analysed using a theoretical framework introduced by Axelsson and Axelsson (2006) to characterise aspects of integration and differentiation between organisations. With high levels of structural and functional differentiation between the partners, the network provided an opportunity to exercise inter-organisational integration at the local level. Integration was fostered by knowledge sharing, face-to-face interaction, and communal events. However, the loose structure of the network was a challenge to its sustainability and achievement. We argue that Health in All local Policies is a meaningful concept in the context of local community development only when referring to the polices and strategies of all stakeholder organisations involved in decision-making and agenda setting, and not just local government institutions.