title: The relationship of the local food environment with obesity: A systematic review of methods, study quality, and results.
abstract: OBJECTIVE
  To examine the relationship between local food environments and obesity and assess the quality of studies reviewed.
  
  
  METHODS
  Systematic keyword searches identified studies from US and Canada that assessed the relationship of obesity to local food environments. We applied a quality metric based on design, exposure and outcome measurement, and analysis.
  
  
  RESULTS
  We identified 71 studies representing 65 cohorts. Overall, study quality was low; 60 studies were cross-sectional. Associations between food outlet availability and obesity were predominantly null. Among non-null associations, we saw a trend toward inverse associations between supermarket availability and obesity (22 negative, 4 positive, 67 null) and direct associations between fast food and obesity (29 positive, 6 negative, 71 null) in adults. We saw direct associations between fast food availability and obesity in lower income children (12 positive, 7 null). Indices including multiple food outlets were most consistently associated with obesity in adults (18 expected, 1 not expected, 17 null). Limiting to higher quality studies did not affect results.
  
  
  CONCLUSIONS
  Despite the large number of studies, we found limited evidence for associations between local food environments and obesity. The predominantly null associations should be interpreted cautiously due to the low quality of available studies.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.|Welch Center for Epidemiology, Prevention and Clinical Research, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Cobb
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.|Welch Center for Epidemiology, Prevention and Clinical Research, Johns Hopkins University, Baltimore, Maryland, USA.|Division of General Internal Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Appel
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.|Department of Surgery, Medicine and Social Sciences, Social and Cardiovascular Epidemiology Research Group, School of Medicine, University of Alcala, Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Franco
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Jones-Smith
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors.forename: Alana
authors.initials: A
authors.lastname: Nur
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.|Department of Family and Preventive Medicine, University of California San Diego School of Medicine, California, USA.
authors.forename: Cheryl A M
authors.initials: CA
authors.lastname: Anderson
mesh_terms: D004777:Environment; D057140:Fast Foods; D006801:Humans; D009765:Obesity / Q000209:etiology*; D036301:Qualitative Research; D012111:Residence Characteristics