title: Physical activity in relation to urban environments in 14 cities worldwide: a cross-sectional study.
abstract: BACKGROUND
  Physical inactivity is a global pandemic responsible for over 5 million deaths annually through its effects on multiple non-communicable diseases. We aimed to document how objectively measured attributes of the urban environment are related to objectively measured physical activity, in an international sample of adults.
  
  
  METHODS
  We based our analyses on the International Physical activity and Environment Network (IPEN) adult study, which was a coordinated, international, cross-sectional study. Participants were sampled from neighbourhoods with varied levels of walkability and socioeconomic status. The present analyses of data from the IPEN adult study included 6822 adults aged 18-66 years from 14 cities in ten countries on five continents. Indicators of walkability, public transport access, and park access were assessed in 1·0 km and 0·5 km street network buffers around each participant's residential address with geographic information systems. Mean daily minutes of moderate-to-vigorous-intensity physical activity were measured with 4-7 days of accelerometer monitoring. Associations between environmental attributes and physical activity were estimated using generalised additive mixed models with gamma variance and logarithmic link functions.
  
  
  RESULTS
  Four of six environmental attributes were significantly, positively, and linearly related to physical activity in the single variable models: net residential density (exp[b] 1·006 [95% CI 1·003-1·009]; p=0·001), intersection density (1·069 [1·011-1·130]; p=0·019), public transport density (1·037 [1·018-1·056]; p=0·0007), and number of parks (1·146 [1·033-1·272]; p=0·010). Mixed land use and distance to nearest public transport point were not related to physical activity. The difference in physical activity between participants living in the most and least activity-friendly neighbourhoods ranged from 68 min/week to 89 min/week, which represents 45-59% of the 150 min/week recommended by guidelines.
  
  
  CONCLUSIONS
  Design of urban environments has the potential to contribute substantially to physical activity. Similarity of findings across cities suggests the promise of engaging urban planning, transportation, and parks sectors in efforts to reduce the health burden of the global physical inactivity pandemic.
  
  
  BACKGROUND
  Funding for coordination of the IPEN adult study, including the present analysis, was provided by the National Cancer Institute of National Institutes of Health (CA127296) with studies in each country funded by different sources.
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, CA, USA. Electronic address: jsallis@ucsd.edu.
authors.forename: James F
authors.initials: JF
authors.lastname: Sallis
authors.affiliation: The University of Hong Kong, Hong Kong, China; Institute for Health and Ageing, Australian Catholic University, Melbourne, VIC, Australia.
authors.forename: Ester
authors.initials: E
authors.lastname: Cerin
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, CA, USA.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Conway
authors.affiliation: School of Nutrition and Health Promotion and Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Adams
authors.affiliation: Health and Community Design Lab, Schools of Population and Public Health and Community and Regional Planning, University of British Columbia, Vancouver, Canada.
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Frank
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Pratt
authors.affiliation: Michael and Susan Dell Center for Healthy Living, The University of Texas Health Science Center at Houston, School of Public Health, Austin Regional Campus, Austin, TX, USA; Center for Nutrition and Health Research, National Institute of Public Health of Mexico, Cuernavaca, Mexico.
authors.forename: Deborah
authors.initials: D
authors.lastname: Salvo
authors.affiliation: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Jasper
authors.initials: J
authors.lastname: Schipperijn
authors.affiliation: Institute for Environment, Sustainability and Regeneration, Staffordshire University, Stoke-on-Trent, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Smith
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, CA, USA.
authors.forename: Kelli L
authors.initials: KL
authors.lastname: Cain
authors.affiliation: Centre for Research and Action in Public Health, University of Canberra, Bruce, ACT, Australia.
authors.forename: Rachel
authors.initials: R
authors.lastname: Davey
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, CA, USA.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Kerr
authors.affiliation: Department of Geography, The University of Hong Kong, China.
authors.forename: Poh-Chin
authors.initials: PC
authors.lastname: Lai
authors.affiliation: Institute of Active Lifestyle, Faculty of Physical Culture, Palacky University, Olomouc, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Mitáš
authors.affiliation: Pontiff Catholic University of Parana, Curitiba, Brazil; Federal University of Parana, Curitiba, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Reis
authors.affiliation: School of Medicine, Universidad de los Andes, Bogota, Colombia.
authors.forename: Olga L
authors.initials: OL
authors.lastname: Sarmiento
authors.affiliation: Auckland University of Technology, Auckland, New Zealand.
authors.forename: Grant
authors.initials: G
authors.lastname: Schofield
authors.affiliation: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Troelsen
authors.affiliation: Department of Movement and Sport Sciences, Ghent University, Ghent, Belgium.
authors.forename: Delfien
authors.initials: D
authors.lastname: Van Dyck
authors.affiliation: Department of Movement and Sport Sciences, Ghent University, Ghent, Belgium.
authors.forename: Ilse
authors.initials: I
authors.lastname: De Bourdeaudhuij
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.
authors.forename: Neville
authors.initials: N
authors.lastname: Owen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002947:Cities / Q000706:statistics & numerical data*; D002958:City Planning; D003430:Cross-Sectional Studies; D004779:Environment Design; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D014504:Urban Health / Q000706:statistics & numerical data*; D016138:Walking / Q000502:physiology; D055815:Young Adult