Obesity in Canada – Prevalence among aboriginal populations

Prevalence Among Aboriginal Populations

Box 3. Estimating Obesity Among First Nations, Inuit and Métis: Key Surveys

In addition to the Canadian Community Health Survey (CCHS; see Box 1), the following key surveys are discussed in this chapter:

First Nations Regional Longitudinal Health Survey28 29

The First Nations Regional Longitudinal Health Survey (RHS) provides estimates of obesity, based on self-reported data, among on-reserve First Nations populations. For the 2002/03 survey, the final sample included 10,962 adults, 4,983 youth and 6,657 children from 238 communities across Canada. The 2007/08 RHS has been completed; however, results were not available at the time this report was prepared. Initiation of Phases 3 and 4 of the RHS are anticipated in 2011 and 2015, respectively.

Aboriginal Peoples Survey 200630

The Aboriginal Peoples Survey (APS) 2006 is a national survey of Aboriginal peoples (First Nations peoples living off-reserve, Métis and Inuit) living in urban, rural, and northern locations throughout Canada. The survey provides data on the social and economic conditions of Aboriginal children and youth (6-14 years) and Aboriginal people (15 years and over). Although First Nations living on-reserve were not included in the provinces, Aboriginal people living in the territories were included.

The APS is a post-censal survey, that is, the sample was selected from people living in households whose response on their 2006 Census questionnaire indicated that they (i) had Aboriginal ancestors; and/or (ii) identified as North American Indian and/or Métis and/or Inuit; and/or (iii) had treaty or registered Indian status; and/or (iv) had Indian Band membership.

Approximate sample sizes for youth and adults by population were as follows: all Aboriginal responses and multiple respondents (9,160 youth, 17,000 adults), North American Indian respondents (4,500 youth, 7,700 adults), Métis respondents (3,800 youth, 6,500 adults) and Inuit respondents (500 youth, 1,900 adults). Obesity estimates for Aboriginal groups are based on single responses for Aboriginal identity. For the purposes of this report, the term "First Nations off-reserve " is used in lieu of "North American Indian" when discussing findings from the APS.

The methods for calculating the prevalence of obesity and using BMI to determine weight classes are consistent with the methodology of the CCHS (including the use of self-reported data). However, as the findings included in this report were based on the public use microdata file, statistical significance testing was not performed.

Other Data Sources

Other data sources referenced in this chapter include the Nunavut Inuit Child Health Survey as well as region-specific surveys.

Because there is no one data source for obesity among all First Nations, Inuit and Métis peoples in Canada, this section provides a picture of obesity prevalence in Aboriginal populations by summarizing the findings from a number of relevant surveys (see Box 3). It begins by presenting recent estimates of obesity and research results for Aboriginal people including First Nations off-reserve, Inuit and Métis, and continues with separate group-specific data for First Nations (on and off-reserve), Inuit and Métis populations.

The use of BMI to estimate obesity among Aboriginal peoples provides a common reference point for comparing data among Aboriginal populations as well as with non-Aboriginal populations. However, it has been suggested that, among the Inuit, BMI may overestimate the prevalence of overweight and obesity, and their associated health risks.31 32 Further research is needed to confirm the prevalence of unhealthy body weights and their metabolic effects among the Inuit and in other Aboriginal populations.7

  • Aboriginal peoples living off-reserve: Some health data pertaining to First Nations off-reserve, Inuit and Métis is available through the CCHS. According to the self-reported 2007/08 CCHS, just over one-quarter (25.7%) of Aboriginal adults (excluding First Nations on-reserve) were obese (Table 2 and Figure 8). This is comparable to the 26.0% estimate from the 2006 Aboriginal Peoples Survey (APS; also based on self-reported data). However, as with the general population, prevalence estimates among Aboriginal peoples are lower when based on self-reported data than when measured data are used. For example, on the basis of measured heights and weights, the 2004 CCHS estimated that 37.8% of off-reserve Aboriginal adults were obese.33 Among children and youth, 18.8% of Aboriginal peoples (excluding First Nations on-reserve) aged 6 to 14 were obese, according to the 2006 APS. Results were not available from the APS for those under 6 years or those 15 to 17 years, although data from the 2007/08 CCHS indicate that 6.7% of Aboriginal youth aged 12 to 17 were obese. Obesity among young children in Aboriginal populations is high but tends to be lower among youth across all Aboriginal groups (Table 2).
Table 2: Prevalence of Obesity Among Aboriginal Peoples in Canada by Age, Sex, and Source
  2007/08 CCHS Aboriginal Peoples Survey 2006 2002/03 RHS
Total Aboriginal population (excluding First Nations on-reserve) Total Aboriginal population (excluding First Nations on-reserve) First Nations Off-reserve Métis Inuit First Nations On-reserve
Children and youth (6 to 14) 18.8 20.0 16.9 25.6
Males 20.4 21.3 19.1 24.9
Females 17.2 18.7 14.8 26.3
Adults (18 and over) 25.7 26.0 26.1 26.4 23.9 36.0
Males 27.3 27.0 26.1 28.4 22.8 31.8
Females 24.0 25.1 26.1 24.5 25.2 41.1
Age Group
3 to 5 48.7
6 to 8 32.8 35.2 28.6 45.8 41.2
9 to 11(14)* 13.1 14.0 12.1 16.5 26.4
12 to 17 6.7 14.1
18 to 24 11.8 13.2 13.8 13.0 11.8
25 to 34 22.6 24.3 24.2 24.9 30.0
35 to 44 27.6 29.5 29.8 29.1 24.5
45 to 54 33.7 30.1 30.3 29.8 28.2
55 and over 31.9 29.9 29.4 31.8 27.2
Notes: *Aboriginal Peoples Survey age group represented is ages 9 to 14 years.

Source: 2007/08 Canadian Community Health Survey Share File, Statistics Canada (excludes non-responses); 2006 Aboriginal Peoples Survey Public Use File; 2002/03 First Nations Regional Longitudinal Health Survey.28

  • First Nations On-reserve: The First Nations Regional Longitudinal Health Survey (RHS) provides estimates for obesity (based on self-reported data) among First Nations living on-reserve. Analyses of the 2002/03 RHS estimated obesity[i] prevalence to be 36.0% among adults aged 18 and older (31.8% of males, 41.1% of females). Among youth ages 12-17, 14.1% were found to be obese, while among children 11 years and under, obesity ranged from 26.4% among 9-11 year olds to 48.7% among 3-5 year olds (see Table 2).28
  • First Nations Off-reserve: According to analysis of the 2006 APS, 26.1% of off-reserve First Nations adults and 20.0% of children ages 6 to 14 were estimated to be obese (see Table 2). Results were not available from the APS for those under 6 years or those 15 years and older.
  • Métis: According to the 2006 APS, the prevalence of obesity in the Métis population was 26.4% among adults 18 and over. Among children ages 6 to 14, 16.9% were obese (see Table 2).
  • Inuit: Among Inuit adults, 23.9% were obese, according to the 2006 APS. Among Inuit children ages 6 to 14, 25.6% were obese (Table 2).

Although the APS did not include children under the age of 6 years in its sample, results from the Nunavut Inuit Child Health Survey, conducted in Nunavut and involving 388 children aged 3 to 5 years, have estimated the prevalence of obesity to be 28%.34

Changes over time

Limited data are available to examine changes in obesity prevalence over time in Aboriginal populations.

Surveys of the Inuit populations in Nunavik, a 500,000 km2 region of Quebec located north of the 55th parallel, were conducted in 1992 and again in 2004. Findings, based on measured data, indicate that obesity prevalence among adults ages 18 to 74 had increased by 49% (from 19% to 28%). Although prevalence rose among both sexes, the increase was more substantial among males than females (73% increase vs. 31% increase, respectively).35

According to self-reported CCHS data, obesity among Aboriginal people (excluding First Nations on-reserve) living both in the North (i.e., Yukon, Northwest Territories, and Nunavut) and in southern Canada appear to have increased between 2000/01 and 2005: in the North, from 20.2% to 25.4%, and in southern Canada, from 22.7% to 25.3%. However, only among North-residing Aboriginals ages 55 and older was the difference over time statistically significant.36 When the effects of age and sex were taken into account, the odds ratio of being obese was greater for Aboriginal people living in the North than for those in the south.36 Additionally, a 2007 review paper of recent epidemiological evidence of obesity among the Inuit in the circumpolar region also concluded that obesity prevalence has "very likely" increased over the past several decades.37

Comparison between Aboriginal and non-Aboriginal populations

Self-reported obesity prevalence was significantly higher among Aboriginal people (excluding First Nations on-reserve) than non-Aboriginal people in Quebec, Ontario, Manitoba, Alberta and Canada as a whole (Figure 8). In most other provinces and territories the data seemed to follow the same pattern, but differences were not statistically significant. Additional analysis of the 2007/08 CCHS found obesity prevalence among Aboriginal youth (excluding First Nations on-reserve) aged 12 to 17 years to be 6.7%, compared with 4.4% among non-Aboriginal youth. This difference was not statistically significant.

Higher prevalence of obesity in Aboriginal than non-Aboriginal peoples has also been observed in other studies at both the national33 38 and regional levels – for example, among members of the Six Nations of the Grand River in southern Ontario,39 First Nations and Métis populations in Alberta,40 members of the Nuxalk Nation in British Columbia41 and Aboriginal women in Manitoba.42

Figure 8: Prevalence of Self-reported Obesity of Aboriginal and non-Aboriginal Adults Aged 18 Years and Older by Province/Territory, Canada 2007/08

Figure 8: Prevalence of Self-reported Obesity of Aboriginal and non-Aboriginal Adults Aged 18 Years and Older
Figure 8 - Text equivalent

Figure 8 shows the prevalence of self-reported obesity for Aboriginal and non-Aboriginal adults in 2007/08, by province/territory: Canada (25.7% among Aboriginal adults versus 16.9% among non-Aboriginal adults); Yukon (28.0% versus 21.0%); the Northwest Territories (25.7% versus 22.4%); Nunavut (22.2% versus 25.6%); British Columbia (13.9% versus 12.8%); Alberta (28.0% versus 18.6%); Saskatchewan (27.4% versus 23.5%); Manitoba (31.2% versus 18.6%); Ontario (27.6% versus 16.8%); Quebec (25.6% versus 15.5%); New Brunswick (28.2% versus 22.1%); Nova Scotia (31.4% versus 22.9%); and Newfoundland and Labrador (33.1% versus 25.0%).

Notes:
  • * Statistically different from non-Aboriginal people at p<0.05.
  • E High sampling variability, interpret with caution.
  • # Prince Edward Island was excluded from the analysis because of the small sample.

Source: Analysis of the 2007/08 Canadian Community Health Survey, Statistics Canada.

Key points

  • Obesity in Canada remains higher in Aboriginal populations compared with non-Aboriginal populations. At the provincial and territorial level, differences are statistically significant in Alberta, Manitoba, Ontario, and Quebec.
  • 25.7% of Aboriginal adults (excluding First Nations on-reserve) were estimated to be obese on the basis of self-reported height and weight data from the 2007/08 CCHS.
  • As with the general population, self- estimates are lower than measured data – from the 2004 CCHS, an estimated 37.8% of Aboriginal adults (excluding First Nations on-reserve) were obese according to measured height and weight data.
  • Adult obesity is similar for Inuit, Métis and off-reserve First Nations populations (23.9%, 26.4%, and 26.1%, respectively; 2006 APS).
  • Over one-third (36.0%) of on-reserve First Nation adults are estimated to be obese, according to self-reported data (RHS 2002/03).
  • Obesity among children and youth is also high, varying from 16.9% among Métis to 20.0% among off-reserve First Nations to 25.6% among Inuit (ages 6 to 14 years; self-reported data from the 2006 APS).
  • Although no single source offers a comprehensive assessment of obesity among First Nations, Inuit, and Métis populations, estimated prevalence among Aboriginal peoples in Canada can be derived from several sources, leading to a picture that shows obesity is a concern.
Footnote i

The RHS reports data separately for "obese" (30.0 kg/m 2 > BMI > 40.0 kg/m 2) and "morbidly obese" (BMI > 40.0 kg/m 2) body mass index groups. For comparability, these results are combined in this report into a single "obese" category (i.e., BMI > 30.0 kg/m 2).

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