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Canadian Institute for Health Information

Obesity in CanadaA joint report from the Public Health Agency of Canada and the Canadian Institute for Health Information

Released June 20, 2011

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Peer Reviewers

• Renée Lyons, Director, Atlantic Health Promotion Research Centre, Dalhousie University, Nova Scotia

• Kim Raine, Professor, Centre for Health Promotion Studies, School of Public Health, University of Alberta

• Jeff Reading, Director, Centre for Aboriginal Health Research, University of Victoria, British Columbia

• Mark Tremblay, Director, Healthy Active Living and Obesity Research, Children’s Hospital of Eastern Ontario

• First Nations Inuit Health Branch (FNIHB) of Health Canada

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Outline

• The report brings together the following:

– Prevalence of obesity among adults, children and youth, and Aboriginal Peoples, combining new and existing estimates

– New analyses of the determinants of obesity, including an innovative measure of the impact of modifying determinants

– Updated estimates of the health and economic costs of obesity

– A synthesis of opportunities for intervention in preventing and reducing obesity in populations

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Prevalence

Among Different Populations

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Adults

• More than one in four adults in Canada are obese, based on measured height and weight from 2007 to 2009.

• When based on self-reported height and weight of Canadian adults, obesity is lower (17.4%):

– Varies from 5.3% to 35.9% across health regions in Canada (2007–2008).

• Obesity tends to increase with age until age 65.

• Whether males or females are more likely to be obese depends on the population and measurement.

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Children and Youth

• Measured obesity was 8.6% among children and youth age 6 to 17 from 2007 to 2009; 6.3% of children age 2 to 5 are obese (from 2004 data).

• There are different systems for defining obesity at different ages among children and youth, but based on all measures, prevalence has increased over the last 30 years:

– Among youth age 12 to 17, measured obesity tripled from 3% to 9.4% between 1978–1979 and 2004.

– However, obesity based on self-reported heights and weights was stable among youth age 12 to 17 between 2000 and 2008.

• Obesity tends to be more prevalent among boys than girls.7

Aboriginal Peoples

• 38% of off-reserve Aboriginal adults are estimated to be obese based on measured height and weight (2004).

• Based on self-reported height and weight,

– 26% of off-reserve Aboriginal adults are estimated to be obese (2006):o 24% of Inuit;

o 26% of First Nations (off reserve); and

o 26% of Métis populations are estimated to be obese.

– 36% of on-reserve First Nations are estimated to be obese (2002–2003).

• Obesity among children and youth age 6 to 14 varies (2006):

– Métis (17%);

– Off-reserve First Nations (20%); and

– Inuit (26%).

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Aboriginal Peoples

Comparing Aboriginal and Non-Aboriginal Populations

• The prevalence of obesity is significantly higher for Aboriginal compared with non-Aboriginal populations, particularly in Alberta, Manitoba, Ontario and Quebec. This is not the case in Nunavut.

• However, among off-reserve Aboriginal adults in B.C., obesity is lower (13.9%) than for all of Canada (17.1%).

Limitations

• Studies suggest that body mass index (BMI) cut-offs may not apply in the same way to Aboriginal populations—that BMI may overestimate the obesity-related health risks, among Inuit in particular.

• There is no one data source for information about obesity among all First Nations, Inuit and Métis peoples in Canada.

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Determinants and Contributing Factors

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Determinants Associated With Obesity• A wide range of genetic, lifestyle, social, cultural and environmental factors contribute

to variations in obesity; however, determinants differ by population.

• Lower levels of income and education were risk factors in both Aboriginal and non-Aboriginal female populations, but there was no clear pattern for males.

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Prevalence of Self-Reported Obesity Among Aboriginal Peoples, by Sex and Income, Age 18 and Older, 2006

SourceAnalysis of the Aboriginal Peoples Survey 2006 Public Use File, Statistics Canada.

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Determinants Associated With Obesity• Analysis showed that obesity tended to be more prevalent in more deprived areas

in Canada’s census metropolitan areas, but not in all cases.

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SourceAnalysis of the 2005 and 2007/08 Canadian Community Health Surveys, Statistics Canada.

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Obesity by Area Socio-Economic Status (SES), Selected Census Metropolitan Areas, 2005 to 2008

Multiple Determinants Associated With Obesity• Physical inactivity had the strongest association with obesity at the population level for both

sexes, after adjusting for other factors.

• However, social determinants such as rural residence are still linked to obesity after accounting for behaviours.

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NoteError bars represent 95% confidence intervals based on bootstrap variance estimates. SourceR. Hawes and P. Stewart, unpublished manuscript prepared for the Public Health Agency of Canada; based on analysis of pooled 2000/01, 2003 and 2005 Canadian Community Health Surveys, Statistics Canada.

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Immigrant Status

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Population Attributable Risk of Self-Reported Obesity, by Risk Factor and Sex, Age 18 and Older, Canada

Social Determinants Health Behaviours

Health and Economic Implications

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Health and Economic Burden of Obesity

• Obesity significantly increases the risk of several chronic diseases (for example, type 2 diabetes, cardiovascular disease, cancer, osteoarthritis and psychological health).

• The risk of death appears to be greatest for those who are in extreme weight categories (underweight and obese).

• The availability of Canadian data on the long-term health impacts of obesity, particularly for children and youth, is rare.

• Estimates of the economic burden of obesity in Canada range from $4.6 billion to $7.1 billion annually.

• A better understanding of the contribution of obesity to morbidity and mortality could help to develop more accurate economic costs.

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Opportunities for Intervention

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Identifying Potential for Action

• Approaches to reducing and preventing obesity can be categorized as follows:

– Health services and clinical interventions that target individuals;

– Community-level interventions in key settings, as well as broad educational outreach to influence behaviours; and

– Public policies that target broad social or environmental determinants.

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Identifying Potential for Action

• Clinical practice guidelines suggest tailoring to patients, and can include one or more of the following:

– Behaviour modification therapy, dietary interventions, physical activity and bariatric surgery

• Community-based obesity interventions—ActNow BC and ParticipACTION, for example—are delivered in the community and in settings such as workplaces and schools.

• A number of public policy approaches—such as regulations on food labelling and marketing to children—can be undertaken to address obesity at the population level.

• There is unlikely to be a single solution that will reverse the rising prevalence of obesity in Canada; rather, a comprehensive, multi-sectoral response is needed.

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Thank You!