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Associations between BMI and home, school and route environmental exposures estimated using GPS and GIS: do we see evidence of selective daily mobility bias in children?


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Authors

Jones, Andy P 
Namenek Brouwer, Rebecca J 
Benjamin Neelon, Sara E 

Abstract

BACKGROUND: This study examined whether objective measures of food, physical activity and built environment exposures, in home and non-home settings, contribute to children's body weight. Further, comparing GPS and GIS measures of environmental exposures along routes to and from school, we tested for evidence of selective daily mobility bias when using GPS data. METHODS: This study is a cross-sectional analysis, using objective assessments of body weight in relation to multiple environmental exposures. Data presented are from a sample of 94 school-aged children, aged 5-11 years. Children's heights and weights were measured by trained researchers, and used to calculate BMI z-scores. Participants wore a GPS device for one full week. Environmental exposures were estimated within home and school neighbourhoods, and along GIS (modelled) and GPS (actual) routes from home to school. We directly compared associations between BMI and GIS-modelled versus GPS-derived environmental exposures. The study was conducted in Mebane and Mount Airy, North Carolina, USA, in 2011. RESULTS: In adjusted regression models, greater school walkability was associated with significantly lower mean BMI. Greater home walkability was associated with increased BMI, as was greater school access to green space. Adjusted associations between BMI and route exposure characteristics were null. The use of GPS-actual route exposures did not appear to confound associations between environmental exposures and BMI in this sample. CONCLUSIONS: This study found few associations between environmental exposures in home, school and commuting domains and body weight in children. However, walkability of the school neighbourhood may be important. Of the other significant associations observed, some were in unexpected directions. Importantly, we found no evidence of selective daily mobility bias in this sample, although our study design is in need of replication in a free-living adult sample.

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Keywords

Activities of Daily Living, Body Mass Index, Child, Child, Preschool, Cross-Sectional Studies, Environment, Female, Geographic Information Systems, Humans, Male, Motor Activity, North Carolina, Students

Journal Title

Int J Health Geogr

Conference Name

Journal ISSN

1476-072X
1476-072X

Volume Title

14

Publisher

Springer Science and Business Media LLC
Sponsorship
Medical Research Council (MR/K023187/1)
Economic and Social Research Council (ES/G007462/1)
Wellcome Trust (087636/Z/08/Z)
Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research and the Wellcome Trust under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. This study was supported, in part, by a grant from the Robert Wood Johnson Foundation, Active Living Research.