Obesity Rate (18+)

Definition:

Obesity Rates (Percent) of the Population 18 and over – self reported body mass index (BMI)

Methods and Limitations:

Body mass index (BMI) is a method of classifying body weight according to health risk. According to the World Health Organization (WHO) and Health Canada guidelines, health risk levels are associated with each of the following BMI categories: normal weight = least health risk; underweight and overweight = increased health risk; obese, class I = high health risk; obese, class II = very high health risk; obese, class III = extremely high health risk.

Body mass index (BMI) is calculated by dividing the respondent’s body weight (in kilograms) by their height (in metres) squared.

Body mass index (BMI) is calculated for the population aged 12 and over, excluding pregnant females and persons less than 3 feet (0.914 metres) tall or greater than 6 feet 11 inches (2.108 metres).

According to the World Health Organization (WHO) and Health Canada guidelines, the index for body weight classification for the population aged 18 and older is: less than 18.50 (underweight); 18.50 to 24.99 (normal weight); 25.00 to 29.99 (overweight); 30.00 to 34.99 (obese, class I); 35.00 to 39.99 (obese, class II); 40.00 or greater (obese, class III). The population aged 12 to 17 is classified as “severely obese”, “obese”, or “overweight” according to age and sex specific cut-off points defined by the World Health Organization.

A systematic review of the literature concluded that the use of self-reported data among adults underestimates weight and overestimates height, resulting in lower estimates of obesity than those obtained from measured data. Using data from the 2005 Canadian Community Health Survey (CCHS) subsample, where both measured and self-reported height and weight were collected, BMI correction equations have been developed. This table presents obesity estimates adjusted using these equations.

The Canadian Community Health Survey (CCHS) – Annual, the Canadian Health Measures Survey (CHMS) and the 2015 CCHS – Nutrition, all collect height and weight data and derive obesity rates based on Body Mass Index (BMI). Users should take note of the data collection method, the target population and the classification system used by each survey in order to select the appropriate data set.

Data for the Canadian Community Health Survey (CCHS) are collected yearly from a sample of approximately 65,000 respondents. The Canadian Health Indicators are tabulated by sex and age group in two main tables. The table 13-10-0096-01 presents the most up-to-date population health estimates for the ten provinces and is updated yearly. The table 13-10-0113-01 presents estimates from two-year combined data and features breakdown by all provinces and territories as well as by health regions. These estimates are less current than annual estimates, but have higher precision given the larger sample (less variability).

Users should refer to the annual data table 13-10-0096-01 as the primary source for the most current estimates from the survey as well as to obtain data from previous years (where available). However, where data quality flags indicate suppression (F) or higher variability (E), the two-year data table 13-10-0113-01 should be used.

Health regions are administrative areas defined by provincial ministries of health according to provincial legislation. The health regions presented in this table are based on boundaries and names in effect as of 2015. For complete Canadian coverage, each northern territory represents a health region.

Due to changes in content and methodology, this table now replaces table 13-10-0452-01, which will now only be made available for historical revisions. As a result of the changes, users should use caution when comparing data in this table with the data in 13-10-0452-01.

Due to changes in content and methodology, this table now replaces table 13-10-0464-01, which will now only be made available for historical revisions. As a result of the changes, users should use caution when comparing data in this table with the data in 13-10-0464-01.

As a result of the 2015 redesign, Canadian Community Health Survey (CCHS) has a new collection strategy, a new sample design, and has undergone major content revisions. With all these factors taken together, caution should be taken when comparing data from previous cycles to data released for the 2015 cycle onwards.

The COVID-19 pandemic had major impacts on the data collection operations for Statistics Canada, Canadian Community Health Survey (CCHS) 2020. The collection was stopped mid-March, towards the end of the first collection period, and did not resume until September. The second, third and fourth quarterly samples were collected during very short collection periods, each of about five weeks, from September to December. The impossibility of conducting in-person interviews, the shorter collection periods and collection capacity issues resulted in a significant decrease in the response rates. As for previous CCHS cycles, survey weights were adjusted to minimise any potential bias that could arise from survey non-response; non-response adjustments and calibration using available auxiliary information were applied and are reflected in the survey weights provided with the data file. Extensive validations of survey estimates were also performed and examined from a bias analysis perspective. Despite these rigorous adjustments and validations, the high non-response increases the risk of a remaining bias and the magnitude with which such a bias could impact estimates produced using the survey data. Therefore, users are advised to use the CCHS 2020 data with caution, especially when creating estimates for small sub-populations or when comparing to other CCHS years.

Source(s):

Statistics Canada. Table 13-10-0805-01  Health characteristics, two-year period estimates, census metropolitan areas and population centres

Statistics Canada. Table 13-10-0113-01  Health characteristics, two-year period estimates