ARCHIVED - Your Health Research Dollars at Work 2005-2006

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Obesity

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The Canadian Institutes of Health Research (CIHR) is the Government of Canada's agency for health research. Through CIHR, the Government of Canada invested approximately $19.9 million in 2005-06 in research on obesity across Canada.

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The Facts

• In 2004, 23% of Canadian adults were considered obese, with a body mass index (BMI) of more than 30, compared to just 14% in 1978. One in four seniors over the age of 75 was obese.
• One-quarter of Canadians who were overweight in 1994-95 had become obese by 2002-03; only 10% had returned to a healthy weight.
• Deaths attributable to complications of overweight and obesity nearly doubled between 1985 and 2000.
• In 2004, 18% of children aged 2 to 17 were overweight and 8% were obese - together accounting for more than one-quarter of all children.
• Obesity is a risk factor for heart disease, stroke, type 2 diabetes, gallbladder disease and some forms of cancer. It has also been associated with hypertension (high blood pressure), osteoarthritis and sleep disorders such as sleep apnea.
• The health costs of obesity, including hospital care, physician services and drugs, were estimated to be more than $4.3 billion in 2001, or 2.2% of total healthcare expenditures for all diseases in that year.
• The World Health Organization has identified obesity as the major neglected public health issue.

Research Finding Solutions to Obesity

• Obesity is a well-established risk fact for heart disease - but there is little agreement on the best way to measure obesity to determine the true risk. For example, obesity is commonly defined in terms of Body Mass Index (BMI). But the BMI has had only varying success as a measurement for the risk of a heart attack. In separate studies, CIHR-supported researchers Drs. Salim Yusuf (McMaster University), Jean Després (Université de Montréal) and Peter Katzmarzyk (Queen's University) have all compared waist-to-hip ratio and BMI as risk predictors of cardiovascular disease. All reported the superiority of waist-to-hip ratios, particularly for some ethnic populations. Their findings will allow healthcare professionals to predict the risk of heart attacks with greater accuracy.

• Having difficulty saying no to food is not just a matter of poor self control; it may have genetic causes as well. CIHR-funded researcher Dr. Louis Pérusse at Université Laval has identified a gene linked to eating behaviours and obesity. A mutated version of the gene is related to a lowered ability to stop eating, as well as a susceptibility to hunger. Over a six-year period, people with the mutation gained more than twice as much body fat as people without the mutation.

• Having poor eating habits now does not mean having them for life, especially if you're living with someone who makes healthy food choices. CIHR-funded researcher Dr. Gwen Chapman at the University of British Columbia researched the possibility that healthy eating habits can be shared or improved in a cohabitation relationship. By recording food journals and interviews, Dr. Chapman found that, as time progressed, the partner with the healthier eating habits was able to influence the eating habits of the other partner. Dieticians can use this information to better direct and encourage changes in the eating habits of their clientele.

• New CIHR-funded research by Dr. Meizi He at The University of Western Ontario suggests that parents concerned about television viewing habits should worry less about the content their children are watching and more about the amount of time spent in front of the television set. Dr. He surveyed the parents of children from 2 to 5 years in age about parental concerns with regards to television. She found that most parents were not concerned with the amount of time spent watching, but rather the content.

In the Pipeline...
Targeting Obesity

Premenopausal and post-menopausal women are at different stages in their lives, but face many of the same challenges when it comes to weight.

For premenopausal women, too much attention to weight could cause fertility problems and bone loss. Chronic dieting increases the likelihood of disturbances in menstrual cycles and results in higher levels of the stress hormone cortisol, which is linked to bone loss. Dr. Susan Barr at the University of British Columbia will be studying both premenopausal and postmenopausal women to learn more about the possible health risks of excessive dieting.

Two-thirds of post-menopausal women, meanwhile, are overweight. Menopause may trigger metabolic and behavioral changes that increase the risk of obesity and associated problems. A CIHR-funded multidisciplinary research team from the Universities of Montreal and Ottawa, led by University of Ottawa researcher Dr. Denis Prud'homme, are studying the physiological, behavioural and biomechanical factors underlying weight gain, weight loss and weight regain in women during and after menopause.

The Researchers...
Dr. Guang Sun - Searching for the Causes of Childhood Obesity

Dr. Guang Sun of Memorial University in Newfoundland and Labrador has established a track record in studying the problem of adult obesity. He's now applying this expertise as part of a CIHR-supported pilot project on childhood obesity.

"I consider obesity as a disease, and we need to keep raising awareness. It's not a question of body image. With obesity, there's a long-term risk of developing other serious disorders," Dr. Sun notes.

According to Dr. Sun, there are as many as 600 genes that could be linked to obesity; such genes can affect appetite and overall metabolism or regulate the way fat is stored in the body. Of the 600, seven have been selected for the present study of childhood obesity.

"With this study, we will be recruiting 100 families where there are one or more children who are obese," Dr. Sun notes. The team will be taking genetic samples from participants and screening them to see which of the seven genes are present.

Newfoundland and Labrador enjoys a somewhat unique status in the world of genetics research because, similar to Iceland or the Lac Saint-Jean region of Quebec, the population shares a somewhat homogenous genetic profile. This makes it easier to spot the obesity genes, and makes it easier to analyze and compare the family histories of people with these genes.

The project is also unique in the way in which it's linking data from genetic testing to physical testing. Participants will be scanned using an instrument originally developed for measuring osteoporosis, a bone densitometer. The scan measures not only the quantity of fat but also the location of this fat, since not all types of fat are equal.

"Central body fat is far more harmful than lower body fat," Dr. Sun notes. "With this technique, we get much more focused information that we can use to accurately measure the genetic effect."

The plan is to expand the pilot into a larger study involving 300 children and then to design gene chips for even faster screening.

"It's a first," Dr. Sun says of the study.

The CIHR Institute

Obesity is not rocket science, says Dr. Diane Finegood, Scientific Director of CIHR's Institute of Nutrition, Metabolism and Diabetes - it's more complex. That's why, after extensive consultation with stakeholders, the Institute declared its primary priority to be the growing problem of obesity and the maintenance of a healthy body weight, an issue that cuts across all areas of its mandate. INMD is mandated to support research to enhance health in relation to diet, digestion, excretion and metabolism.

About CIHR

The Canadian Institutes of Health Research (CIHR) is the Government of Canada's agency for health research. CIHR's mission is to create new scientific knowledge and to catalyze its translation into improved health, more effective health services and products, and a strengthened Canadian healthcare system. Composed of 13 Institutes, CIHR provides leadership and support to more than 10,000 health researchers and trainees across Canada.

Canadian Institutes of Health Research
160 Elgin Street, 9th Floor, Ottawa, ON K1A 0W9
http://www.cihr-irsc.gc.ca/