Measured child body mass index (BMI), children 2 to 5 years, Canada, 2004

Note:
*Body mass index (BMI) is calculated by dividing the respondent’s body weight (in kilograms) by their height (in metres) squared. The index is: neither overweight nor obese; overweight; obese. Body mass index (BMI) for children is different from that of adults as they are still maturing. This variable classifies the measured BMI of children aged 2 to 17 as “obese” or “overweight” according to the age-and-sex-specific BMI cut-off points as defined by the WHO. Based on the WHO growth curves, the WHO recommends that children whose BMI is more than two standard deviations (SDs) above the mean should be considered obese, and those whose BMI is between one and two SDs above the mean, overweight.¹

Source: CICH graphic created using data adapted from Shields and Tremblay. 2010. Canadian childhood obesity estimates based on WHO, IOTF and CDC cut-points. International Journal of Pediatric Obesity, 5: 265–273. http://www.obesitynetwork.ca/files/WHO_vs_CDC_Shields1704.pdf – accessed June 25, 2017.

Additional information on measured child body mass index (BMI) for children aged 2 to 5 years of age can be found in the Health Outcomes section of the Early Child Development Module.

In 2004, 62.8% of boys 2 to 5 years and 68.3% of girls were neither overweight or obese.

25.4% of boys were overweight, 11.8% were obese.

22.3% of girls were overweight, 9.4% were obese.

Implications

Childhood obesity is a serious public health concern in Canada, and is associated with several adverse health effects in childhood and later in life. The association between chemical exposures and obesity is not clear. Animal and cellular studies have given some evidence that chemical exposures in the environment may contribute to obesity and in children. The studies of chemical exposures and obesity in children are limited.²

In addition, in both animals and children, researchers have found that obesity may be associated with a greater susceptibility to the negative affects particulate matter and ozone.^3,4 Air pollution and childhood obesity may be associated if the number of days that children can play outside is limited by the quality of the air. This would be the case particularly for children with existing respiratory illnesses.⁵

Children’s built environments may also contribute to the increasing rates of obesity. (The term “built environment” is used to describe the physical elements of the environment for a population.) For example, a number of studies have concluded that the built environment – urban sprawl, housing density, access to food sources, and access to places where children can play – may be associated with obesity.^6,7 Children who are socioeconomically disadvantaged are more likely to live in built environments that contribute to obesity.^8,9,10

¹Shields and Tremblay. 2010. Canadian childhood obesity estimates based on WHO, IOTF and CDC cut-points. International Journal of Pediatric Obesity, 5: 265–273. http://www.obesitynetwork.ca/files/WHO_vs_CDC_Shields1704.pdf– accessed June 25, 2017.
²Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
³Chen, J.C., J.M. Cavallari, P.H. Stone, and D.C. Christiani. 2007. Obesity is a modifier of autonomic cardiac responses to fine metal particulates. Environmental Health Perspectives 115 (7):1002-6. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁴Shore, S.A., Y.M. Rivera-Sanchez, I.N. Schwartzman, and R.A. Johnston. 2003. Responses to ozone are increased in obese mice. Journal of Applied Physiology 95 (3):938-45. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁵Corbo, G.M., F. Forastiere, M. De Sario, L. Brunetti, E. Bonci, M. Bugiani, E. Chellini, S. La Grutta, E. Migliore, R. Pistelli, et al. 2008. Wheeze and asthma in children: associations with body mass index, sports, television viewing, and diet. Epidemiology 19 (5):747-55. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁶Papas, M.A., A.J. Alberg, R. Ewing, K.J. Helzlsouer, T.L. Gary, and A.C. Klassen. 2007. The built environment and obesity. Epidemiologic Reviews 29:129-43. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁷Sallis, J.F., and K. Glanz. 2006. The role of built environments in physical activity, eating, and obesity in childhood. The Future of Children 16 (1):89-108. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁸Cutts, B.B., K.J. Darby, C.G. Boone, and A. Brewis. 2009. City structure, obesity, and environmental justice: an integrated analysis of physical and social barriers to walkable streets and park access. Social Science & Medicine 69 (9):1314-22.  In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
⁹Redwood, Y., A.J. Schulz, B.A. Israel, M. Yoshihama, C.C. Wang, and M. Kreuter. 2010. Social, economic, and political processes that create built environment inequities: perspectives from urban African Americans in Atlanta. Family & Community Health 33 (1):53-67. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf – accessed May 22, 2017.
¹⁰Taylor, W.C., J.T. Hepworth, E. Lees, K. Feliz, S. Ahsan, A. Cassells, D.C. Volding, and J.N. Tobin. 2008. Obesity, physical activity, and the environment: is there a legal basis for environmental injustices? Environmental Justice 1 (1):45-48. In Environmental Protection Agency. Children’s Health and the Environment Third Edition. 2013. https://www.epa.gov/sites/production/files/2015-06/documents/ace3_2013.pdf- accessed May 22, 2017.