The Obesity Epidemic: Reductionist approaches to unpacking the issue won’t work. Health science writer Paul Webster takes a closer look at the complexities surrounding obesity.
The Good Food Junction, a grocery store housed in a utilitarian bunker in Saskatoon’s gritty west end, seems like any other ordinary no-nonsense urban grocer/groceteria. But many people living near the store consider it to be somewhat of a miracle. Long-abandoned by major supermarket chains, food security experts describe the area around the store as a “food desert”. To overcome the lack of access to good food in the area, community members formed a co-op, built the store, and opened it for business in October 2012. “This all began with a dream,” explains co-op board member Karen Archibald. “We needed a food store in a neighbourhood where the major food retailers had abandoned the inner city.”
According to a study published earlier this summer by researchers with the Saskatoon Health Region’s Public Health Observatory, Saskatoon’s most deprived neighbourhoods have significantly fewer supermarkets than its wealthy neighbourhoods do (see figure on next page), while hosting significantly more fast food outlets. The Good Food Junction was created specifically to help rebalance the situation. Now, at the University of Saskatoon, nutritionist Rachel Engler-Stringer is probing whether the opening of the Good Food Junction is yielding health benefits to residents in the area.
Using data from a city-wide dietary survey conducted within a set of studies of the food environment for families with children in Saskatoon, over the course of the next two years, Engler-Stringer will closely monitor health conditions, including body weight, among children in the neighbourhood to probe whether supermarket access is a risk factor for obesity. It’s all part of “Smart Cities, Health Kids,” a multi-year investigation funded by the Canadian Institutes for Health Research (CIHR), the Saskatchewan Health Research Foundation, and the Heart and Stroke Foundation. “We want to understand the factors that drive obesity better,” Engler-Stringer explains.
The interest in obesity and its causes is hardly unique to Saskatoon. With approximately one in four Canadian adults and almost ten percent of children and youth aged six to 17 obese, according to Obesity in Canada – a 2011 report co-published by Public Health Agency of Canada (PHAC) and the Canadian Institute for Health Information (CIHI), obesity risk factors are an increasingly dynamic research area.
Between 1981 and 2007/08, obesity rates roughly doubled, the PHAC/CIHI report reveals. But as the report notes, explanations for why this is happening remain tentative. And while factors that are known to influence obesity include physical activity, diet, socio-economic status, ethnicity, immigration, and environmental conditions, the report notes, “our collective understanding of the determinants of obesity will continue to evolve” as risk factor research becomes more refined.
“Our collective understanding of the determinants of obesity will continue to evolve.”
Numerous significant initiatives related to childhood obesity and physical inactivity have been kickstarted in recent years, notes Mark Tremblay, Director of Healthy Active Living and Obesity Research at the Children’s Hospital of Eastern Ontario, in Kingston, Ontario. These include a >> Federal/Provincial/Territorial framework for action to promote healthy weights, implementation of the nutrition labelling initiative, announcement of the Public Health Agency of Canada's innovation strategy funding related to obesity, publication of the Canadian Health Measures Survey physical activity findings, release of new Canadian physical activity and sedentary behaviour guidelines, the start of the Canadian Paediatric Weight Management Registry, and a National Obesity Summit in Vancouver last May.
Alongside these efforts, Tremblay urges, Canada needs to craft innovative approaches to investigating the nature of the obesity epidemic itself, as well as the factors driving the epidemic. By way of example, Tremblay points to the need for more refined observations of the linkages between physical inactivity – or sedentary behaviour, as he calls it – and obesity. To really understand what drives obesity, Tremblay argues, researchers need to begin closely studying the ways that Canadians eat, sleep, and move. “We need to know much more about lifestyle factors to know what’s driving it,” he argues. “The minutiae of our daily activities has changed, and we need to shift risk factor research to understand how this drives obesity.”
Michelle Stone, assistant professor of kinesiology at Dalhousie University in Halifax, Nova Scotia, agrees. After conducting a series of studies on physical inactivity among Toronto schoolchildren, she concluded that alongside limits on sports and vigorous physical activities, risk factors for childhood obesity include the ability of children to have independent, unsupervised mobility and outdoor play.
Patricia Parkin, Research Director with the Paediatric Outcomes Research Team at Sick Kids Hospital in Toronto, and a member of the Canadian Task Force on Preventive Health Care, notes that preschoolers in Canada are dramatically understudied. The main national dataset on obesity, the Canadian Health Measures Survey, launched in 2007, collects direct physical measurements such as >> blood pressure, height, weight and physical fitness, alongside information related to nutrition, smoking habits, alcohol use, medical history, current health status, sexual behaviour, lifestyle and physical activity, the environment and housing characteristics, as well as demographic and socio-economic variables. But it does not track children under the age of three, Parkin notes. “That’s a huge gap,” she worries, while calling for research on risk factors such as children’s eating patterns, dietary self-regulation, bottle use, and breastfeeding prevalence. Even the use of child strollers warrants attention as a risk factor for child obesity, she asserts.
Risk factor specialists interested in obesity should also be looking at mental health issues, suggests Yue Chen, a professor in the Department of Epidemiology and Community Medicine at the University of Ottawa. In a recent study, Chen established that lifelong stress is associated with obesity. The trouble is, Chen explains, it’s not clear whether stress leads to obesity, or vice versa. “Mental health is clearly an important issue these days, yet very few studies have probed the links between stress and obesity.” Chen also suggests that risk factor researchers look at the role of chemicals – known as obesogons – in the environment that may drive obesity. A growing body of research indicates that environmental contaminants such as flame retardant chemicals used in plastics, carpets and textiles may play a role in driving obesity.
After echoing Parkin’s warning about the lack of attention to preschoolers, David Lau, a University of Calgary medical professor who serves as President of Obesity Canada, warns that national surveillance efforts are piecemeal and incomplete compared to those of the United States, where the Centres for Disease Control’s National Health and Nutrition Examination Survey stages a program of studies designed to assess the health and nutritional status of adults and children in the United States using interviews and physical examinations.
“There aren’t many national datasets available here in Canada,” Lau laments. “There are significant gaps in our understanding of obesity prevalence. I’d call it a dire lack of basic information to inform public health policies.” <>
SIDE STORY 1: Obesity: Lifestyle or Disease?
The American Medical Association has recognized obesity as a disease. Paul Webster explains why this is controversial.
Resolution 420 from the American Medical Association’s (AMA) annual general meeting in Chicago last June recognized obesity “as a disease state”.
It was a startling decision. Not surprisingly, the AMA resolution included copious ammunition to defend it.
In labelling obesity as a disease, the AMA cited “an overabundance of clinical evidence to identify obesity as a multi-metabolic and hormonal disease state including impaired functioning of appetite dysregulation, abnormal energy balanced, endocrine dysfunction including elevated leptin levels and insulin resistance, infertility, dysregulated adipokine signaling, abnormal endothelial function and blood pressure elevation, nonalcoholic fatty liver disease, dyslipidemia, and systemic and adipose tissue inflammation.”
Obesity, the AMA resolution continued, “is directly related to co-morbidities including type 2 diabetes, cardiovascular disease, some cancers, osteoporosis, polycystic ovary syndrome.”
And obesity is a treatable disease the AMA asserted, citing “progress in the development of lifestyle modification therapy, pharmacotherapy, and bariatric surgery options has now enabled a more robust medical model for the management of obesity as a chronic disease”.
“Crude diagnoses of obesity based on Body Mass Index measurements can be misleading and harmful.“
Given all of this, the AMA resolution charged, suggesting that obesity is not a disease but rather a consequence of a chosen lifestyle, “is equivalent to suggesting that lung cancer is not a disease because it was brought about by individual choice to smoke cigarettes.”
The AMA’s decision is not unique. The World Health Organization, the US Food and Drug Administration, the US National Institutes of Health, the American Association of Clinical Endocrinologists, the US Internal Revenue Service, and CIGNA – one of the largest US health insurance companies, have all recognized obesity as a disease.
But there are many organizations and experts who disagree with this position. Just days before the AMA resolution passed, the AMA’s very own Council on Science and Public Health issued a report warning that “without a single, clear, authoritative, and widely accepted definition of disease, it is difficult to determine conclusively whether or not obesity is a medical disease state. Similarly, a sensitive and clinically practical diagnostic indicator of obesity remains elusive."
The Canadian Medical Association responded to the AMA resolution cautiously, suggesting it would welcome a debate.
Dr. David Lau, Professor of Medicine, Biochemistry and Molecular Biology at the University of Calgary and President of Obesity Canada, a not-for-profit organization, says labelling obesity as a disease in Canada would be an “expedient” way to promote action.
But Dr. Arya Sharma, Professor of Medicine & Chair in Obesity Research and Management at the University of Alberta and founder and Scientific Director of the Canadian Obesity Network – a network of over 6000 obesity researchers and clinicians, warms that crude diagnoses of obesity based on Body Mass Index measurements can be misleading and harmful and may result in the over-treatment or under-treatment of millions of individuals deemed to be in one category or another simply because their body weight divided by the square of their height happens to fall below or above a rather arbitrary cut-off. “Health cannot be measured by stepping on a scale,” he warns.
“This is a very messy question” observes Diane Finegood, President and CEO Michael Smith Foundation for Health Research and Professor in the Department of Biomedical Physiology and Kinesiology at Simon Fraser University. “It’s complex. I can see some of the arguments on both sides.” The best argument in supporting of classifying obesity as a disease, says Finegood, is that it helps practitioners and therapeutics innovators take it more seriously. The best argument opposing categorization is that it reinforces stigmas and may pathologize people who are perfectly healthy. <>
SIDE STORY 2: Risk Factor Myopia...
In an interview with the CARRFS eNews health science writer Paul Webster, Dr. Diane Finegood outlines her view on how misguided risk factor surveillance, and a reductionist perspective for understanding obesity, can be.
Dr. Diane Finegood was appointed President and CEO Michael Smith Foundation for Health Research, British Columbia in March, 2012. She is also a Professor in the Department of Biomedical Physiology and Kinesiology at Simon Fraser University, Vancouver (on leave). From 2000-2008, Dr. Finegood was inaugural Scientific Director, Institute of Nutrition, Metabolism and Diabetes, part of the Canadian Institutes of Health Research. In that role, she guided the national health research agenda across that Institute’s mandate and within its own strategic priority of obesity and healthy body weight. Dr. Finegood’s efforts helped stimulate obesity research and knowledge translation through the support of innovative research platforms and partnerships. Dr. Finegood has received numerous awards, including the 2006 Canada’s Top 100 Women Award in recognition of her trailblazing and trendsetting work and the 2008 Frederick G. Banting Award from the Canadian Diabetes Association for her leadership and significant contributions in the Canadian diabetes community. She obtained her doctoral degree in physiology and biophysics from the University of Southern California and held appointments at the University of Alberta before coming to BC.
What are the innovations risk factor specialists should be pursuing?
The challenge here is that obesity is complex. There are hundreds of relevant and interdependent factors that contribute to obesity. As a result, looking for the causes through risk factor surveillance may not be all that helpful. We are used to looking for causal relationships underlying a problem and then focusing interventions on these causes. But when a problem is complex and there are many interdependencies, this is not all that helpful. Solutions to complex problems may not have anything to do with the causes of the problem; and because of the large number of interdependencies, addressing complex problems by first looking for the cause may have unintended consequences. Reductionist approaches want to believe that if you understand a problem, you can fix it. And I don’t believe that.
So, traditional risk factor surveillance pinpointing specific causes is unsuitable to the obesity problem?
When I think about risk factor surveillance, the first things that come to mind are about individuals, e.g. blood pressure and other things at the level of the individual. If we start to go to the level of the system – food security is about the system – then it’s a little better. If I think about risk factors in terms of individuals and in terms of clinical parameters or genetic parameters or family-based parameters, I worry because it reinforces that we are trying to figure out the causes for an individual, so we can solve them. If we think about the system – things like food security – I’m less worried because I think those are important upstream factors and I don’t think they are as steeped in the reductionist paradigm of the epidemiologist.
“A reductionist perspective is not very helpful. The solutions may not have anything to do with the causes of the problem.”
What are the most important innovations in obesity risk factor surveillance you would recommend?
I want a much more solution-oriented approach. What we should be monitoring are process variables not outcomes. Things like how many schools have become full-fledged health promoting schools over a period of time? What is the shift in food company portfolios from non-healthy to healthy products? Things like skills in preparing healthy food. Outcomes take longer to achieve; and if you don’t reach your target, the outcome variable does not tell you why. Functional goals and the metrics of whether they have been achieved are more process-oriented and will help you know what to do if the result is not as intended. <>