Description  | Specific Indicators |  Ontario Public Health Standards (OPHS) |   Corresponding Health Indicator(s) from Statistics Canada and CIHI   |  Corresponding Indicator(s) from Other Sources |   Data Sources |  Survey Questions |  Analysis Check List |  Method of Calculation |  Basic Categories |  Indicator Comments |  Definitions  | Cross-References to Other Indicators  | Cited References| Other References |  Changes Made

 Description

• Proportion of adolescents, aged 12-17, that is "overweight or obese" according to the age-and-sex-specific BMI cut-off points as defined by Cole et al using self-reported height and weight.

Note: this indicator excludes female respondents aged 15 to 17 who were pregnant or did not answer the pregnancy question and lactating women

Specific Indicators

• Body Mass Index (BMI) for adolescents

The Ontario Public Health Standards (OPHS) establish requirements for the fundamental public health programs and services carried out by boards of health, which include assessment and surveillance, health promotion and policy development, disease and injury prevention, and health protection. The OPHS consist of one Foundational Standard and 13 Program Standards that articulate broad societal goals that result from the activities undertaken by boards of health and many others, including community partners, non-governmental organizations, and governmental bodies. These results have been expressed in terms of two levels of outcomes: societal outcomes and board of health outcomes. Societal outcomes entail changes in health status, organizations, systems, norms, policies, environments, and practices and result from the work of many sectors of society, including boards of health, for the improvement of the overall health of the population. Board of health outcomes are the results of endeavours by boards of health and often focus on changes in awareness, knowledge, attitudes, skills, practices, environments, and policies. Boards of health are accountable for these outcomes. The standards also outline the requirements that boards of health must implement to achieve the stated results. 

Outcomes Related to this Indicator

• Societal Outcome (Chronic Disease Prevention): An increased proportion of the population lives, works, plays, and learns in healthy environments that contribute to chronic disease prevention.
• Societal Outcome (Chronic Disease Prevention): There is increased adoption of behaviours and skills associated with reducing the risk of chronic diseases of public health importance.   

Assessment and Surveillance Requirements Related to this Indicator

• The board of health shall conduct epidemiological analysis of surveillance data...in the areas of healthy weights (Chronic Disease Prevention).

http://www.ontario.ca/publichealthstandards 
 

Corresponding Health Indicator from Statistics Canada and CIHI 

• Youth body mass index (BMI) (as defined by Cole et al.)

http://www.statcan.gc.ca/start-debut-eng.html 
 
Click on Publications.
Type in ‘Health Indicators' into search box. 
Scroll down and click on the html version of ‘Health Indicators'.
Click on "Data Tables and Maps" and then "Youth Body Mass Index"

Corresponding Indicator(s) from Other Sources

Proportion of persons aged 2-17 years who are overweight or obese based on the age-sex specific cut-offs for overweight developed by Cole et al. (2000)

Australian Institute of Health and Welfare:
http://www.aihw.gov.au/index.cfm

Click on ‘Data online' > ‘Chronic Disease Indicators' > ‘Arthritis and musculoskeletal problems' > ‘Proportion of persons aged 2-17 years who are overweight or obese'

Data Sources

Numerator & Denominator: Canadian Community Health Survey (CCHS)
Original source: Statistics Canada
Distributed by:
1. Ontario Ministry of Health and Long-Term Care (MOHLTC)
2. Statistics Canada
Suggested citation (see Data Citation Notes):
1. Canadian Community Health Survey [year], Statistics Canada, Share File, Ontario Ministry of Health and Long-Term Care.
2. Canadian Community Health Survey [year], Statistics Canada, Public Use Microdata File, Statistics Canada.

The Height and Weight module of the CCHS collects self-reported height and weight measures which are used to derive BMI and BMI classification categories.

Note: Syntax files exist to derive Adolescent BMI for earlier years of the CCHS as defined by Cole et al. More information on the syntax files is included in the Analysis Check List.

Analysis Check List

• The syntax files called "CCHS 2003 BMI Recode" and "CCHS 2000-01 BMI Recode" provide syntax for deriving adolescent BMI for CCHS 2000/01 and 2003).
• The "overweight or obese" category was chosen to report on for consistency and comparability with the "overweight or obese" category in the Adult Body Mass Index indicator and to increase the sample size for each public health unit. As compared to the "neither obese nor overweight" category, we recommend reporting on the "obese or overweight" category as it provides information from a risk factor perspective, which can then be the source of information for obesity prevention programs. The "neither overweight nor obese" category includes the residual cases but this category is hard to interpret since it would include the underweight and normal weight cases. If the counts in the "obese or overweight" category are too low, then public health units may choose to report on the "neither overweight nor obese" category.

Basic Categories

• Sex: Males and females
• Geographic areas for: CCHS - all 36 Health Unit areas in Ontario

• This indicator uses new methods to calculate body mass index for adolescents.  Compared to the 2000 BMI Charts from the Centers for Disease Control and Prevention, the newly employed International Obesity Task Force (IOTF) cut-off points "...may be considered more internationally acceptable because they were based on pooled reference data from six countries geographically spread out around the world."¹ Furthermore, "for comparing prevalence data for BMI of Canadian populations against other populations, use of the international BMI charts is recommended for their geographical diversity".¹ 
• The "overweight or obese" category was chosen to report on for consistency and comparability with the "overweight or obese" category in the Adult Body Mass Index indicator and to increase the sample size for each public health unit.
• Growth assessment is the single most useful tool for defining health and nutritional status in children at both the individual and population levels.¹
• The prevalence of overweight and obese children has been increasing in Canada^1,2 and in other countries around the globe.¹
• The most critical long-term consequence of childhood obesity is persistence into adulthood, with associated risk for its co-morbidities³ including cardiovascular disease, hypertension, abnormal lipids, type II diabetes and social, emotional, and cognitive difficulties.^1,4,5
• Obesity in children and youth is measured using a method established by the International Obesity Task Force (IOTF). BMI cut-points for overweight and obesity are lower for children and adolescents than for adults, are sex-specific and rise incrementally with every year of age.⁶ Using thirty years' worth of data (1963-1993) from six large nationally representative cross-sectional growth studies in Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States, BMI centile curves were derived to pass through the points of 25 (overweight) and 30 (obesity) at age 18. Also, since pubertal development influences body fat, the IOTF cut-points are sensitive to sexual maturation.⁷ The obesity rates in this analysis are based on the IOTF criteria.
• Many low-income Canadians to do not have access to enough food or enough nutritious food. Further, having a low income can impact food choices, weight and health⁸.  In a Canadian study, grade 5 students in high-income neighbourhoods were half as likely to be obese as their peers living in low-income neighbourhoods⁵.
• Eating a diet rich in vegetables and fruit contributes to the maintenance of a healthy body weight.⁹ Canadian adults and children who ate vegetables and fruit less than five times a day are significantly more likely to be overweight or obese.¹⁰
• A study which examined the relation between children's physical activity, sedentary behaviours, and body mass index (BMI) found evidence supporting the link between physical inactivity and obesity in Canadian children.¹¹
• Based on the Ontario sample from CCHS 2005, 5.8% of adolescent males and 2.9% of adolescent females were obese, 18.1% of adolescent males and 12.0% of adolescent females were overweight and 23.9% of adolescent males and 14.9% of adolescent females were overweight or obese (Unknowns were excluded from the analysis). By comparison, measured obesity among Ontario adolescents in 2004 was 11% for males and 7% for females.¹²
• Respondents in self-reported surveys tend to understate their weight and overstate their height, leading to an underestimation of derived BMI.

• Body Mass Index (BMI) - the ratio of body weight to height squared (kg/m²).
• The following table from Cole et al.⁶ provides the BMI cut-off points for classifying adolescents as overweight or obese. Adolescents that do not fall into these two categories are classified as "neither overweight nor obese."

Cross-References to Other Indicators

• Adult Body Mass Index (Section 5D: Behaviour and Health: Nutrition)
• Food insecurity (Section 2A: Social Environment and Health)
• Vegetable and Fruit Consumption (Section 5D. Nutrition and Healthy Weights)
• Physical Activity Index (Section 5C. Physical Activity)

Cited References

1. Dietitians of Canada, Canadian Paediatric Society, The College of Family Physicians of Canada, and Community Health Nurses Association of Canada. The use of growth charts for assessing and monitoring growth in Canadian infants and children. Can J Diet Prac Res 2004;65:22-32. Available online at: http://www.dietitians.ca/resources/resourcesearch.asp?fn=view&contentid=2175 (Accessed January 14, 2009).
2. Carrière G. Parent and child factors associated with youth obesity. Health Reports. Special Issue, Supplement to Volume 14, 2003: How healthy are Canadians?
3. WHO Technical Report Series 894. Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation. Geneva: WHO, 2000.
4. Must A and Strauss RF.  Risks and consequences of childhood and adolescent obesity. Intl J Obesity 1999:23 Suppl 2, S2-S11.
5. Veuglers PJ and Fitzgerlad AL. Prevalence of and risk factors for childhood overweight and obesity. CMAJ  2005: 173(6):607-613.
6. Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 2000;320(7244);1240-3.
7. Cole TJ, Rolland-Cachera MF. Measurement and definition. In: Burniat W, Cole T, Lissau I, et al, eds. Childhood and Adolescent Obesity: Causes and Consequences, Prevention and Management. Cambridge: Cambridge University Press, 2002: 3-27.
8. CMOH Report. Chief Medical Officer of Health. Healthy Weights, Healthy Lives. Ontario: Ministry of Health, 2004. Available online at: http://www.mhp.gov.on.ca/English/health/healthy_weights_112404.pdf
9. Tohill BC, Seymour J, Serdula M et al. What epidemiological studies tell us about the relationships between fruit and vegetable consumption and body weight. Nutrition Reviews 2004; 62:365-374.
10. Shields, Margot. Nutrition: Findings from the Canadian Community Health Survey, Issue no. 1- Measured Obesity Overweight Canadian Children and Adolescents (Component of Statistics Canada Catalogue no. 82-620-MWE2005001). Ottawa, ON: Statistics Canada, 2004.
11. Tremblay, MS and Willms, JD. Is the Canadian childhood obesity epidemic related to physical inactivity? International Journal of Obesity 2003; 27:1100–1105.
12. Cancer Care Ontario. Cancer System Quality Index, 2007- Prevention Indicators, Selected Modifiable Cancer Risk Factors. Cancer Care Ontario, 2007. Available online at: http://www.cancercare.on.ca/images/documents/Obesity-CSQI-2007.pdf (Accessed January 13, 2009).