title: Associations between Food Outlets around Schools and BMI among Primary Students in England: A Cross-Classified Multi-Level Analysis.
abstract: BACKGROUND
  Researchers and policy-makers are interested in the influence that food retailing around schools may have on child obesity risk. Most previous research comes from North America, uses data aggregated at the school-level and focuses on associations between fast food outlets and school obesity rates. This study examines associations between food retailing and BMI among a large sample of primary school students in Berkshire, England. By controlling for individual, school and home characteristics and stratifying results across the primary school years, we aimed to identify if the food environment around schools had an effect on BMI, independent of socio-economic variables.
  
  
  METHODS
  We measured the densities of fast food outlets and food stores found within schoolchildren's home and school environments using Geographic Information Systems (GIS) and data from local councils. We linked these data to measures from the 2010/11 National Child Measurement Programme and used a cross-classified multi-level approach to examine associations between food retailing and BMI z-scores. Analyses were stratified among Reception (aged 4-5) and Year 6 (aged 10-11) students to measure associations across the primary school years.
  
  
  RESULTS
  Our multilevel model had three levels to account for individual (n = 16,956), home neighbourhood (n = 664) and school (n = 268) factors. After controlling for confounders, there were no significant associations between retailing near schools and student BMI, but significant positive associations between fast food outlets in home neighbourhood and BMI z-scores. Year 6 students living in areas with the highest density of fast food outlets had an average BMI z-score that was 0.12 (95% CI: 0.04, 0.20) higher than those living in areas with none.
  
  
  CONCLUSIONS
  We found little evidence to suggest that food retailing around schools influences student BMI. There is some evidence to suggest that fast food outlet densities in a child's home neighbourhood may have an effect on BMI, particularly among girls, but more research is needed to inform effective policies targeting the effects of the retail environment on child obesity.
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Julianne
authors.initials: J
authors.lastname: Williams
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Scarborough
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Nick
authors.initials: N
authors.lastname: Townsend
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Anne
authors.initials: A
authors.lastname: Matthews
authors.affiliation: UKCRC Centre for Diet and Activity Research (CEDAR), Medical Research Council (MRC) Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, CB2 0QQ United Kingdom.
authors.forename: Thomas
authors.initials: T
authors.lastname: Burgoine
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Mumtaz
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford, OX3 7LF United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Rayner
mesh_terms: D015992:Body Mass Index; D002648:Child; D004739:England; D057140:Fast Foods; D005260:Female; D005523:Food Supply; D006801:Humans; D008297:Male; D055361:Multilevel Analysis / Q000379:methods*; D012111:Residence Characteristics; D012574:Schools; D013334:Students