Howard et al. BMC Public Health 2011, 11:68 http://www.biomedcentral.com/1471-2458/11/68 outcome. Contrary to our expectations, we did not find strong support for an association between nearby fast food restaurants and higher school rates of overweight students, nor for an association between nearby super- markets and lower rates of overweight students. The limitations of our study suggest that these findings should be interpreted with caution. They do indicate, however, that public health researchers and policy- makers interested in the food environments outside schools should expand their recent focus on nearby fast food restaurants to include convenience stores, as these may also be important sources of low-nutrient, energy- dense foods for students. Acknowledgements Funding for the study was provided by Michigan State University. The authors wish to thank Dylan W. Loudon for assistance with the GIS analysis, and the reviewers for their helpful suggestions. Author details 1Department of Community, Agriculture, Recreation and Resource Studies, Michigan State University, 316 Natural Resources, East Lansing, MI, 48824, USA. 2Design, Community & Environment, 1625 Shattuck Ave, Suite 300, Berkeley, CA, 94709, USA. Authors’ contributions PHH conceived of and designed the study, participated in its coordination and drafted the manuscript. MF conducted data preparation and statistical analysis, and assisted with drafting the manuscript. BF conducted the GIS analysis and assisted with drafting the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 13 July 2010 Accepted: 31 January 2011 Published: 31 January 2011 References 1. Ogden CL, Carroll MD, Curtin LR, Lamb MM, Flegal KM: Prevalence of high body mass index in US children and adolescents, 2007-2008. JAMA 2010, 303:242-249. 2. 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