title: International comparison of observation-specific spatial buffers: maximizing the ability to estimate physical activity.
abstract: Advancements in geographic information systems over the past two decades have increased the specificity by which an individual's neighborhood environment may be spatially defined for physical activity and health research. This study investigated how different types of street network buffering methods compared in measuring a set of commonly used built environment measures (BEMs) and tested their performance on associations with physical activity outcomes.
  
  
  
  An internationally-developed set of objective BEMs using three different spatial buffering techniques were used to evaluate the relative differences in resulting explanatory power on self-reported physical activity outcomes. BEMs were developed in five countries using 'sausage,' 'detailed-trimmed,' and 'detailed,' network buffers at a distance of 1 km around participant household addresses (n = 5883).
  
  
  
  BEM values were significantly different (p < 0.05) for 96% of sausage versus detailed-trimmed buffer comparisons and 89% of sausage versus detailed network buffer comparisons. Results showed that BEM coefficients in physical activity models did not differ significantly across buffering methods, and in most cases BEM associations with physical activity outcomes had the same level of statistical significance across buffer types. However, BEM coefficients differed in significance for 9% of the sausage versus detailed models, which may warrant further investigation.
  
  
  
  Results of this study inform the selection of spatial buffering methods to estimate physical activity outcomes using an internationally consistent set of BEMs. Using three different network-based buffering methods, the findings indicate significant variation among BEM values, however associations with physical activity outcomes were similar across each buffering technique. The study advances knowledge by presenting consistently assessed relationships between three different network buffer types and utilitarian travel, sedentary behavior, and leisure-oriented physical activity outcomes.
authors.affiliation: Health and Community Design Lab, Schools of Population and Public Health and Community and Regional Planning, University of British Columbia, Vancouver, BC, Canada. lawrence.frank@ubc.ca.|Urban Design 4 Health, Inc., Rochester, NY, USA. lawrence.frank@ubc.ca.
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Frank
authors.affiliation: Urban Design 4 Health, Inc., Rochester, NY, USA.
authors.forename: Eric H
authors.initials: EH
authors.lastname: Fox
authors.affiliation: Urban Design 4 Health, Inc., Rochester, NY, USA.
authors.forename: Jared M
authors.initials: JM
authors.lastname: Ulmer
authors.affiliation: Urban Design 4 Health, Inc., Rochester, NY, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Chapman
authors.affiliation: Urban Design 4 Health, Inc., Rochester, NY, USA.
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Kershaw
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA, USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Sallis
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA, USA.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Conway
authors.affiliation: School of Public Health, The University of Hong Kong, Hong Kong, China.|Institute for Health and Ageing, Australian Catholic University, Melbourne, Australia.
authors.forename: Ester
authors.initials: E
authors.lastname: Cerin
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA, USA.
authors.forename: Kelli L
authors.initials: KL
authors.lastname: Cain
authors.affiliation: Exercise Science and Health Promotion Program, School of Nutrition and Health Promotion, Global Institute of Sustainability, Arizona State University, Phoenix, AZ, USA.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Adams
authors.affiliation: Institute for Environment, Sustainability and Regeneration, Staffordshire University, Stoke-on-Trent, UK.
authors.forename: Graham R
authors.initials: GR
authors.lastname: Smith
authors.affiliation: Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand.
authors.forename: Erica
authors.initials: E
authors.lastname: Hinckson
authors.affiliation: McCaughey VicHealth Community Wellbeing Unit, School of Population and Global Health, University of Melbourne, Melbourne, Australia.|SHORE and Whāriki Research Centre, School of Public Health, Massey University, Palmerston North, New Zealand.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Mavoa
authors.affiliation: Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Lars B
authors.initials: LB
authors.lastname: Christiansen
authors.affiliation: Department of Physical Education, School of Life Science, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil.
authors.forename: Adriano Akira F
authors.initials: AA
authors.lastname: Hino
authors.affiliation: Department of Physical Education, Centro Universitario Campos de Andrade, Curitiba, Brazil.
authors.forename: Adalberto A S
authors.initials: AA
authors.lastname: Lopes
authors.affiliation: Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Jasper
authors.initials: J
authors.lastname: Schipperijn
mesh_terms: D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D004779:Environment Design; D015444:Exercise / Q000502:physiology; D040362:Geographic Information Systems; D015438:Health Behavior / Q000502:physiology; D006801:Humans; D038622:Internationality; D009520:New Zealand / Q000453:epidemiology; D012111:Residence Characteristics; D014186:Transportation / Q000379:methods; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D016138:Walking / Q000502:physiology
keywords: Built environment; GIS methods; Network buffer; Reliability; Self-reported physical activity