title: Systematic review and meta-analysis of the association between childhood overweight and obesity and primary school diet and physical activity policies.
abstract: Obesity is a major public health concern and there are increasing calls for policy intervention. As obesity and the related health conditions develop during childhood, schools are being seen as important locations for obesity prevention, including multifaceted interventions incorporating policy elements. The objective of this systematic review was to evaluate the effects of policies related to diet and physical activity in schools, either alone, or as part of an intervention programme on the weight status of children aged 4 to 11 years. A comprehensive and systematic search of medical, education, exercise science, and social science databases identified 21 studies which met the inclusion criteria. There were no date, location or language restrictions. The identified studies evaluated a range of either, or both, diet and physical activity related policies, or intervention programmes including such policies, using a variety of observational and experimental designs. The policies were clustered into those which sought to affect diet, those which sought to affect physical activity and those which sought to affect both diet and physical activity to undertake random effects meta-analysis. Within the diet cluster, studies of the United States of America National School Lunch and School Breakfast Programs were analysed separately; however there was significant heterogeneity in the pooled results. The pooled effects of the physical activity, and other diet related policies on BMI-SDS were non-significant. The multifaceted interventions tended to include policy elements related to both diet and physical activity (combined cluster), and although these interventions were too varied to pool their results, significant reductions in weight-related outcomes were demonstrated. The evidence from this review suggests that, when implemented alone, school diet and physical activity related policies appear insufficient to prevent or treat overweight or obesity in children, however, they do appear to have an effect when developed and implemented as part of a more extensive intervention programme. Additional evidence is required before recommendations regarding the focus of policies can be made and therefore, increased effort should be made to evaluate the effect of policies and policy containing intervention programmes upon weight status.
authors: Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), Veysey Building, Salmon Pool Lane, EX2 4SG, Exeter, Devon, UK. k.m.wyatt@exeter.ac.uk.
authors: Andrew James
authors: AJ
authors: Williams
authors: William E
authors: WE
authors: Henley
authors: Craig Anthony
authors: CA
authors: Williams
authors: Alison Jane
authors: AJ
authors: Hurst
authors: Stuart
authors: S
authors: Logan
authors: Katrina Mary
authors: KM
authors: Wyatt
mesh_terms: D000886:Anthropometry; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D004032:Diet; D006291:Health Policy; D006801:Humans; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology*; D012574:Schools; D014481:United States / Q000453:epidemiology
references: J Phys Act Health. 2009 Sep;6(5):560-7
references: 19953832
references: J Am Diet Assoc. 2009 Feb;109(2 Suppl):S108-17
references: 19166665
references: Scand J Med Sci Sports. 2008 Apr;18(2):179-87
references: 17490452
references: MMWR Recomm Rep. 2011 Sep 16;60(RR-5):1-76
references: 21918496
references: Health Place. 2011 May;17(3):710-6
references: 21474361
references: J Phys Act Health. 2011 Feb;8(2):174-81
references: 21415444
references: Prev Med. 2009 Jan;48(1):45-53
references: 19026676
references: BMJ. 1990 Nov 3;301(6759):1031-4
references: 2249053
references: Br J Nutr. 2010 Mar;103(6):781-97
references: 20070915
references: J Clin Epidemiol. 2009 Oct;62(10):1006-12
references: 19631508
references: Nutr J. 2011 Jan 24;10:9
references: 21261939
references: Stat Med. 2000 Nov 30;19(22):3127-31
references: 11113947
references: Arch Pediatr Adolesc Med. 2003 Aug;157(8):780-4
references: 12912784
references: Pediatrics. 2008 Apr;121(4):e794-802
references: 18381508
references: Lancet. 2011 Aug 27;378(9793):838-47
references: 21872752
references: BMJ. 2010 May 20;340:c2369
references: 20488915
references: Vital Health Stat 11. 2002 May;(246):1-190
references: 12043359
references: Am J Public Health. 2005 Mar;95(3):432-5
references: 15727972
references: Arch Dis Child. 2003 Sep;88(9):748-52
references: 12937090
references: BMC Pediatr. 2011 May 27;11:47
references: 21619652
references: BMJ. 2000 May 6;320(7244):1240-3
references: 10797032
references: J Am Diet Assoc. 2008 Nov;108(11):1916-20
references: 18954584
references: Int J Obes (Lond). 2008 Jul;32(7):1060-7
references: 18542082
references: Obesity (Silver Spring). 2010 Feb;18 Suppl 1:S45-53
references: 20107461
references: Arch Pediatr Adolesc Med. 2011 Apr;165(4):346-53
references: 21135318
references: Can J Public Health. 2010 Jul-Aug;101 Suppl 2:S9-13
references: 21137137
references: Obes Rev. 2012 Mar;13(3):214-33
references: 22070186
references: Obes Rev. 2007 Mar;8(2):155-67
references: 17300280
references: J Epidemiol Community Health. 2001 Sep;55(9):622-3
references: 11511639
references: J Policy Anal Manage. 2010 Summer;29(3):479-505
references: 20722187
references: Prev Med. 2009 Oct;49(4):336-41
references: 19665037
references: Res Q Exerc Sport. 2010 Sep;81(3 Suppl):S53-64
references: 21049838
references: Int J Obes (Lond). 2012 Jul;36(7):901-7
references: 22531087
references: BMJ. 2011 Feb 10;342:d549
references: 21310794
references: Am J Public Health. 2004 Sep;94(9):1501-6
references: 15333302
references: JAMA. 2001 Dec 12;286(22):2845-8
references: 11735760
references: Health Promot Int. 2008 Sep;23(3):290-7
references: 18728110
references: Obes Rev. 2006 Aug;7(3):261-9
references: 16866974
references: Int J Obes (Lond). 2013 Jan;37(1):79-85
references: 22945605
references: Nutr Res Rev. 2007 Jun;20(1):29-45
references: 19079859
references: Salud Publica Mex. 2005 Mar-Apr;47(2):126-33
references: 15889638