title: 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?
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.
authors: UKCRC Centre for Diet and Activity Research (CEDAR), MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Box 285 Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. tb464@medschl.cam.ac.uk.
authors: Thomas
authors: T
authors: Burgoine
authors: UKCRC Centre for Diet and Activity Research (CEDAR), MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Box 285 Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. a.p.jones@uea.ac.uk.|Norwich Medical School, University of East Anglia, Norwich, NR4 7TJ, UK. a.p.jones@uea.ac.uk.
authors: Andy P
authors: AP
authors: Jones
authors: Department of Community and Family Medicine, Duke University Medical Center, 2200 W Main St, DUMC 104006, Durham, NC, 27705, USA. rebecca.brouwer@duke.edu.|Duke Global Health Institute, Duke University, 310 Trent Hall, Durham, NC, 27710, USA. rebecca.brouwer@duke.edu.
authors: Rebecca J
authors: RJ
authors: Namenek Brouwer
authors: Department of Community and Family Medicine, Duke University Medical Center, 2200 W Main St, DUMC 104006, Durham, NC, 27705, USA. sara.benjamin@duke.edu.|Duke Global Health Institute, Duke University, 310 Trent Hall, Durham, NC, 27710, USA. sara.benjamin@duke.edu.|UKCRC Centre for Diet and Activity Research (CEDAR), MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Box 285 Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. sara.benjamin@duke.edu.
authors: Sara E
authors: SE
authors: Benjamin Neelon
mesh_terms: D000203:Activities of Daily Living; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004777:Environment; D005260:Female; D040362:Geographic Information Systems / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009657:North Carolina / Q000453:epidemiology; D013334:Students / Q000706:statistics & numerical data
references: N C Med J. 2012 Sep-Oct;73(5):382-3
references: 23189430
references: Int J Behav Nutr Phys Act. 2013;10:83
references: 23803180
references: Obes Rev. 2009 Jul;10(4):393-402
references: 19389058
references: Int J Behav Nutr Phys Act. 2009 Jul 17;6:42
references: 19615073
references: Am J Prev Med. 2008 Sep;35(3):217-23
references: 18617354
references: Epidemiol Rev. 2007;29:129-43
references: 17533172
references: Prev Med. 2013 Mar;56(3-4):218-21
references: 23219681
references: Am J Prev Med. 2006 Aug;31(2):109-17
references: 16829327
references: Health Place. 2012 Sep;18(5):1172-87
references: 22717379
references: Prev Med. 1999 Dec;29(6 Pt 1):563-70
references: 10600438
references: Am J Prev Med. 2012 Oct;43(4):440-50
references: 22992364
references: Am J Prev Med. 2005 Feb;28(2 Suppl 2):117-25
references: 15694519
references: Am J Prev Med. 2010 Mar;38(3):268-78
references: 20171528
references: Int J Health Geogr. 2013;12:2
references: 23327189
references: Health Place. 2011 Sep;17(5):1122-31
references: 21741875
references: Health Place. 2013 May;21:46-51
references: 23425661
references: Am J Epidemiol. 2010 Dec 1;172(11):1324-33
references: 20961970
references: Am J Prev Med. 2012 Feb;42(2):129-35
references: 22261208
references: Int J Behav Nutr Phys Act. 2012;9:46
references: 22512874
references: Nutr Rev. 2008 Jan;66(1):2-20
references: 18254880
references: Int J Epidemiol. 2007 Apr;36(2):355-7
references: 17376797
references: J Epidemiol Community Health. 2009 Dec;63(12):967-73
references: 19833605
references: J Urban Health. 2013 Aug;90(4):653-66
references: 23392564
references: Annu Rev Public Health. 2009;30:81-105
references: 19705556
references: Acad Pediatr. 2009 Sep-Oct;9(5):339-43
references: 19560992
references: Am J Prev Med. 2006 Jan;30(1):45-51
references: 16414423
references: Int J Behav Nutr Phys Act. 2013;10:19
references: 23391296
references: Health Place. 2009 Dec;15(4):909-16
references: 19201641
references: Am J Public Health. 2005 Sep;95(9):1575-81
references: 16118369
references: Health Place. 2010 May;16(3):489-99
references: 20106710
references: Health Place. 2012 Nov;18(6):1261-9
references: 23064515
references: Prev Med. 2009 Jan;48(1):3-8
references: 19014963
references: BMC Public Health. 2013;13:70
references: 23347757
references: Health Place. 2007 Mar;13(1):111-22
references: 16387522
references: Health Place. 2010 Mar;16(2):175-90
references: 19880341
references: Int J Pediatr Obes. 2008;3(4):249-56
references: 18608630
references: Int J Behav Nutr Phys Act. 2010 Feb 19;7:18
references: 20170507
references: J Adolesc Health. 2008 Apr;42(4):418-20
references: 18346668
references: Pediatrics. 2006 Feb;117(2):417-24
references: 16452361
references: Am J Prev Med. 2012 Aug;43(2):201-4
references: 22813686
references: Am Behav Sci. 2013 Aug 1;57(8):1057-1081
references: 24707055
references: Am J Prev Med. 2011 Feb;40(2):113-21
references: 21238858
references: Soc Sci Med. 2011 May;72(9):1411-9
references: 21481505
references: Int J Behav Nutr Phys Act. 2013;10:85
references: 23806008
references: Am J Health Promot. 2005 May-Jun;19(5):330-3, ii
references: 15895534
references: Am J Prev Med. 2007 Jul;33(1):51-3
references: 17572312
references: Obes Rev. 2011 May;12(5):e95-e106
references: 20604870
references: Public Health Nutr. 2010 Nov;13(11):1773-85
references: 20409354
references: Int J Health Geogr. 2014;13:5
references: 24529075
references: Obes Rev. 2011 May;12(5):e183-9
references: 21348919
references: Am J Prev Med. 2008 Jul;35(1):38-46
references: 18541175
references: Health Place. 2013 May;21:86-93
references: 23454664
references: Am J Public Health. 2009 Mar;99(3):505-10
references: 19106421
references: Health Place. 2010 Nov;16(6):1094-103
references: 20667762