title: Active commuting to school and association with physical activity and adiposity among US youth.
abstract: BACKGROUND
  Walking or bicycling to school (ie, active commuting) has shown promise for improving physical activity and preventing obesity in youth. Our objectives were to examine, among US youth, whether active commuting was inversely associated with adiposity and positively associated with moderate-to-vigorous physical activity (MVPA). We also examined whether MVPA mediated the relationships between active commuting and adiposity.
  
  
  METHODS
  Using data of participants aged 12 to 19 years from the US National Health and Nutrition Examination Survey 2003 to 2004 (n=789 unweighted), we constructed multiple linear regression models that controlled for dietary energy intake and sociodemographics. The main exposure variable was active commuting. The outcomes were BMI z-score, waist circumference, skinfolds and objectively measured MVPA. The product-of-coefficients method was used to test for mediation.
  
  
  RESULTS
  Active commuting was inversely associated with BMI z-score (β=-0.07, P=.046) and skinfolds (β=-0.06, P=.029), and positively associated with overall daily (β=0.12, P=.024) and before- and after-school (β=0.20, P<.001) MVPA. Greater before- and after-school MVPA explained part of the relationship between active commuting and waist circumference (Sobel z=-1.98, P=.048).
  
  
  CONCLUSIONS
  Active commuting was associated with greater MVPA and lower measures of adiposity among US youth. Before- and after-school MVPA mediated the relationships between active commuting and waist circumference.
authors: Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
authors: Jason A
authors: JA
authors: Mendoza
authors: Kathy
authors: K
authors: Watson
authors: Nga
authors: N
authors: Nguyen
authors: Ester
authors: E
authors: Cerin
authors: Tom
authors: T
authors: Baranowski
authors: Theresa A
authors: TA
authors: Nicklas
references: BMC Public Health. 2009 May 04;9:122
references: 19413910
references: Am J Prev Med. 2005 Oct;29(3):179-84
references: 16168866
references: Child Care Health Dev. 2005 May;31(3):341-9
references: 15840154
references: Med Sci Sports Exerc. 2008 Jan;40(1):181-8
references: 18091006
references: Vital Health Stat 11. 2002 May;(246):1-190
references: 12043359
references: Obesity (Silver Spring). 2006 Oct;14(10):1771-6
references: 17062807
references: Med Sci Sports Exerc. 2006 Oct;38(10):1724-31
references: 17019293
references: Obes Res. 2005 May;13(5):868-75
references: 15919840
references: JAMA. 2008 May 28;299(20):2401-5
references: 18505949
references: Cochrane Database Syst Rev. 2006 Oct 18;(4):CD003817
references: 17054187
references: Am J Prev Med. 2003 Nov;25(4):273-6
references: 14580626
references: Public Health Nutr. 2009 Aug;12(8):1182-8
references: 18778534
references: J Phys Act Health. 2009 Sep;6(5):560-7
references: 19953832
references: Arch Pediatr Adolesc Med. 2007 Feb;161(2):153-8
references: 17283300
references: Obesity (Silver Spring). 2007 Jun;15(6):1373-83
references: 17557973
references: JAMA. 2008 Jul 16;300(3):295-305
references: 18632544
references: Med Sci Sports Exerc. 2005 Nov;37(11 Suppl):S531-43
references: 16294116
references: Addict Behav. 1980;5(4):371-88
references: 7211534
references: Prev Chronic Dis. 2008 Jul;5(3):A100
references: 18558018
references: JAMA. 2006 Apr 5;295(13):1549-55
references: 16595758
references: Int J Obes Relat Metab Disord. 2004 Oct;28(10):1238-46
references: 15314635
references: BMJ. 2004 Oct 9;329(7470):832-3
references: 15317729
references: Obes Rev. 2007 Mar;8 Suppl 1:109-14
references: 17316312
references: Obesity (Silver Spring). 2007 Dec;15(12):3056-66
references: 18198315
references: Am J Public Health. 2003 Sep;93(9):1431-4
references: 12948957
references: Med Sci Sports Exerc. 2005 Dec;37(12):2062-9
references: 16331130
references: Obes Res. 2002 Mar;10(3):150-7
references: 11886937
references: Psychol Methods. 2002 Mar;7(1):83-104
references: 11928892
references: J Am Diet Assoc. 2001 Oct;101(10):1142-3
references: 11678482
references: Pediatr Exerc Sci. 2007 Nov;19(4):393-407
references: 18089907
references: J Phys Act Health. 2008;5 Suppl 1:S1-15
references: 18364515
references: Med Sci Sports Exerc. 2004 Jul;36(7):1259-66
references: 15235335
references: J Nutr Educ Behav. 2008 Sep-Oct;40(5):324-6
references: 18725153