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5D Adolescent Body Mass Index

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


  • 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

Ontario Public Health Standards

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 the areas of healthy weights (Chronic Disease Prevention).

Corresponding Health Indicator from Statistics Canada and CIHI 
  • Youth body mass index (BMI) (as defined by Cole et al.) 


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:

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.

Survey Questions

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.


Data Source


Question/ Description

Response Categories




Height and weight - Self-reported


BMI classification for children aged 12 to 17 (self-reported) - Cole classification system


Neither obese nor overweight,
Not applicable,
Not stated,
Don't know,



bmi_adol (syntax file available)


bmi_adol (syntax file available)






Are you still breastfeeding?

Not Applicable,
Not Stated,
Don't Know,



Maternal Experiences

Are you still breastfeeding?

Not Applicable,
Not Stated,
Don't Know,








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.


  • Although calculation of BMI is not recommended for lactating women, the index provided by Statistics Canada in the share file is calculated for women who report that they are breastfeeding (MEXn_05 = 1). These women should be excluded from the analysis.
  • Counts by sex may not be reportable for all public health units. Refer to information on release guidelines below (see Statistics Canada's release guidelines for more information)
  • It is recommended that public health units use the share file provided by the Ministry of Health and Long-Term Care rather than public use file (PUMF) provided by Statistics Canada. The share file has a slightly smaller sample size because respondents must agree to share their information with the province to be included; however, the share file has more variables and fewer grouped categories within variables. The share file is a cleaner dataset for Ontario analysis because all variables that were not common content, theme content or optional content for Ontario have been removed.
  • There may be slight differences between results from the share file and data published on the Statistics Canada website for the Health Indicators because rates calculated for Health Indicators use the master CCHS data file.
  • Not applicable respondents should be excluded; however, it is important to understand who these respondents are from the questionnaire skip patterns to be able to describe the relevant population.
  • Users need to consider whether or not to exclude the ‘Refusal, 'Don't Know' and ‘Not Stated' response categories in the denominator. Rates published in most reports, including Statistics Canada's publication Health Reports generally exclude these response categories.  In removing not stated responses from the denominator, the assumption is that the missing values are random, and this is not always the case.  This is particularly important when the proportion in these response categories is high.
  • Estimates must be appropriately weighted (generally the share weight for the CCHS) and rounded.
  • Users of the CCHS Ontario share file must adhere to Statistics Canada's release guidelines for the CCHS data when publishing or releasing data derived from the file in any form. Refer to the appropriate user guide for guidelines for tabulation, analysis and release of data from the CCHS. In general, when calculating the CV from the share file using the bootstrap weights, users should not use or release weighted estimates when the unweighted cell count is below 10. For ratios or proportions, this rule should be applied to the numerator of the ratio.  Statistics Canada uses this approach for the tabular data on their website. When using only the Approximate Sampling Variability (CV) lookup tables for the share file, data may not be released when the unweighted cell count is below 30. This rule should be applied to the numerator for ratios or proportions.  This provides a margin of safety in terms of data quality, given the CV being utilized is only approximate.
  • Before releasing and/or publishing data, users should determine the CV of the rounded weighted estimate and follow the guidelines below:
    • Acceptable (CV of 0.0 - 16.5) Estimates can be considered for general unrestricted release. Requires no special notation.
    • Marginal (CV of 16.6 - 33.3) Estimates can be considered for general unrestricted release but should be accompanied by a warning cautioning subsequent users of the high sampling variability associated with the estimates. Such estimates should be identified by the letter E (or in some other similar fashion).
    • Unacceptable (CV greater than 33.3) Statistics Canada recommends not to release estimates of unacceptable quality. However, if the user chooses to do so then estimates should be flagged with the letter F (or in some other fashion) and the following warning should accompany the estimates: "The user is advised that...(specify the data) not meet Statistics Canada's quality standards for this statistical program. Conclusions based on these data will be unreliable and most likely invalid". These data and any consequent findings should not be published. If the user chooses to publish these data or findings, then this disclaimer must be published with the data.
  • Caution should be taken when comparing the results from CCHS 2000/01 to subsequent years of the survey, due to a change in the mode of data collection.  The sample in CCHS 2000/01 had a higher proportion of respondents interviewed in person, which affected the comparability of some key health indicators.  Please refer to for a full text copy of the Statistics Canada article entitled "Mode effects in the Canadian Community Health Survey: a Comparison of CAPI and CATI".

Method of Calculation 

Weighted Population aged 12-17 years overweight or obese

Total population aged 12-17 years
 X 100

Basic Categories

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

Indicator Comments

  • 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".
  • 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 Canada1,2 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."



Overweight cut-off BMI greater than or equal to:


Obese cut-off BMI greater than or equal to:








Age (years)


































































































Cross-References to Other Indicators

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: (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:
  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: (Accessed January 13, 2009).

Other References
  • He M. Measuring childhood obesity: A public health perspective. PHERO 2003;14(9):151-156.
  • Health Canada. Canadian Guidelines for Body Weight Classification in Adults, 2003 (Cat no: H49-179/2003E). Ottawa, ON: Health Canada, 2003. Available online at: (Accessed January 14, 2009).
  • Abraham S, Luscombe G, Boyd C, Olesen I. Predictors of the accuracy of self-reported height and weight in adolescent female school students. Int J Eat Disord 2004;36:76-82.
  • Goodman E, Hinden BR, Khandelwal S. Accuracy of teen and parental reports of obesity and body mass index. Pediatrics 2000;106(1):52-58.
  • Himes J, Faricy A. Validity and reliability of self-reported stature and weight of US adolescents. Am J of Human Biol 2001;13:255-260.

Changes Made


Formal Review or Ad Hoc?

Changes made by


June 5, 2009

Formal review.

Healthy Eating and Active Living subgroup of Core Indicators.

  • A new section on Outcomes from the Ontario Public Health Standards was added to replace the section on Corresponding Mandatory Objectives.
  • All sections were updated.
  • This indicator was aligned with Cole et al's BMI criteria for adolescents and this replaced the previous alignment of this indicator to the CDC standards. This indicator is now in alignment with the CCHS derived variable on adolescent BMI and incorporates the new international standard set out by Cole.
  • New syntax files were created to calculate adolescent BMI from CCHS 2000/01 and 2003.

June 29, 2009

Ad hoc

Harleen Sahota on behalf of CIWG

  • Removed an out-of-date point in the Analysis Check List on how the Health Indicators department at Statistics Canada handles 'Not Stated' respondents when using CCHS data.
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