Readers of these pages will be quite familiar with the Edmonton Obesity Staging System (EOSS) that is increasingly used in clinical practice to stratify patients presenting with overweight or obesity in terms of actual health status (rather than just BMI).
Previous studies have shown that EOSS is a far better predictor of cardiovascular and overall mortality than BMI or waist circumference. However, its performance compared to other measures of cardiometabolic risk is not known.
Now, a study by Keisuke Ejima and colleagues, published in Obesity, compares the predictive value for mortality and years of life lost between EOSS and Cardiometabolic Disease Staging (CMDS) in NHANES.
Whereas CMDS is scored based on the the presence of cardiometabolic risk factors, EOSS is scored on a much broader range of parameters including mental, medical, and functional health.
In their analyses, both CMDS and EOSS consistently identified individuals at higher mortality risk. Thus, the median years of life lost for EOSS scores 2 and 3 (low to high risk) for a reference person were 1.19 and 6.76 years. Those for CMDS scores 1, 2, 3, and 4 (low to high risk) were 1.53, 2.90, 3.91, and 8.51 years.
In their interpretation of these findings, the authors discuss that CMDS may have greater clinical utility not only because it appears to have better discriminatory power but also uses fewer items to risk stratify.
To me the findings are not surprising and if all you are interested in is mortality, then clearly all you need to calculate is CMDS – which was specifically designed and validated to assess cardiometbolic risk.
However, in clinical practice, mortality is only one of the parameters of interest. Many may argue that other parameters including mental health, chronic pain, or even just quality of life may be as, if not more important to patients, than whether or not they live a couple of years longer or not. Thus, clinical decisions around treatments need to take more into account than just cardiometabolic risk.
It is for this very reason that EOSS was conceptualised as a much broader assessment of health than just cardiometabolic risk.
Thus, it may well be that both staging systems may find their place in clinical practice – CMDS for clinicians and patients who prefer a narrower focus on mortality risk and life expectancy, EOSS for clinicians and patients who prefer to consider a broader definition of health that includes other medical issues (e.g. chronic pain, fertility issues, etc.), as well as mental and functional health.
Last week, the Dietitians of Canada (DC) released a Backgrounder on Obesity and Weight Stigma. In it, the authors, who have backgrounds both in conventional dietetics and in the Health at Every Size/Critical Dietetics field, thoughtfully (and rather comprehensively) review the literature on weight stigma and its possible impact on clinical practice, and take a close look at three narratives regarding the issue of weight and obesity.
The first narrative, referred to as the “weight-centric approach”, which unfortunately still remains dominant, defines obesity based on BMI (a measure of size). According to this narrative, anyone above the BMI cut off of 30, would be considered as having obesity and would be considered a candidate for a weight-loss intervention. The main criteria for escalation of weight-loss treatments (from behaviour modification to medication to surgery) is based on BMI and often sets a weight-loss goal.
The second narrative, referred to as the “health/complication-centric approach”, which appears to be rapidly emerging amongst clinical obesity experts and professional organisations (including Obesity Canada), takes a non BMI-centric approach that primarily considers actual health status in its definition of obesity and has a primary goal aimed at improving mental, physical, and social health, whereby interventions may or may not involve treatments to promote weight loss (including behaviour modification, psychological interventions, medications, and surgery).
The third narrative, referred to as the “critical non-weight-centric approach”, frames different body weights as a part of normal diversity of body size, does not define obesity as a disease (indeed discourages the use of the term), challenges medicalization of fatness, and promotes the treatment of health issues/concerns regardless of weight (and generally does not consider the use of anti-obesity medication or surgery).
The paper discusses the background, evolution, and pros and cons of each narrative and their potential impact on weight-bias as well as clinical practice.
Clearly, as readers of these pages will be well aware, I have been one of the most vocal critics of using BMI (or any other anthropometric) measure as the primary definition of obesity and would certainly not support a “weight-centric approach” to obesity management.
Rather, my approach would fall firmly within the health-complication-centric approach (indeed the Edmonton Obesity Staging System, which now increasingly being used to guide obesity management, was developed to move the focus from size to health). I have also long-propagated a definition of obesity based on actual health assessments and have championed the notion that any obesity management intervention needs to be assessed on its impact on overall health and not just weight-loss. Fortunately, this notion of obesity is increasingly finding its way into the medical literature and clinical practice guidelines.
But I also see a role for the critical/non-weight centric approach, especially for individual patients, where past experiences dictate that any focus or even mention of body weight or use of the term obesity may exacerbate past traumatic experiences and could potentially promote unhealthy weight preoccupation, highly restrictive unhealthy eating behaviours, excessive exercise behaviours, or overt mental health issues including depression, anxiety, or compulsive behaviours. Thus, clinicians would be well advised to also familiarise themselves with the critical/non-weight centric approach and consider this an option for individual patients, who would likely be harmed or distressed by a more conventional approach.
No matter, which of the latter two approaches one may favour, the good news for all concerned should be that a rapidly growing number of experts in the field as well as professional organisations now recognise that although BMI may still have some value as a population surveillance measure and perhaps as a screening (not diagnostic!) tool in clinical practice, the weight-centric approach based on BMI alone is definitely on its way out (even amongst surgeons, who are now increasingly basing their indications for surgery and assessment of outcomes on the presence of metabolic and other health parameters rather than size).
Thus, if we consider the “weight-centric narrative” as the rim (side) of the coin, it is fair to say that the coin is definitely getting remarkably thinner.
The backgrounder will be available here for the next couple of days, before it disappears behind a firewall (still accessible to people who have access to PEN).
Obesity, defined as the presence of abnormal or excess body fat that impairs health, by definition, impairs health and is increasingly recognised as a chronic disease not unlike hypertension or diabetes.
But what exactly is the disease process?
Here an analogy with chronic kidney disease may be helpful.
For one, like chronic kidney disease, obesity can have a wide range of different underlying drivers. These can be genetic, environmental, iatrogenic (medications), or some other (unrelated) disease process.
Thus, in the same way that chronic kidney disease can result from polycystic kidney disease (genetic), lead toxicity (environmental), non-steroidal anti-inflammatory drugs (medications), or plasmocytoma (unrelated disease), obesity can result from Prader-Willi syndrome (genetic), highly processed foods (environmental), atypical anti-psychotics (medications), or craniopharyngioma (unrelated disease).
In kidney disease, each of these causes have different disease pathways, timelines, and prognosis, the end result, however, is an often progressive and irreversible loss of kidney function, which in extreme cases can end with the patient needing renal replacement therapy (like dialysis of kidney transplant).
Similarly, irrespective of the underlying cause, obesity, once established, generally becomes a life-long problem, which can often progress over time and may, in extreme cases, result in terminal incapacitating illness.
Secondly, irrespective of the underlying cause, chronic kidney disease, like obesity, can result in a wide range of associated disease processes.
Thus, irrespective of the underlying cause, progressive loss of kidney function results in a common pathway of related disease processes that can lead to fluid retention, hypertension, anemia, hyperparathyroidism, bone disease, and increased risk for infections and cardiovascular complications.
Similarly, irrespective of the underlying cause, progressive accumulation of abnormal or excessive body fat can result in a range of related disease processes ranging from metabolic problems (type 2 diabetes, gout, dyslipidemia, fertility issues), to mechanical issues (obstructive sleep apnea, GERD, plantar fasciitis, gonarthritis, urinary incontinence), to cancers (endometrial, breast, colon).
In addition, both chronic kidney disease and obesity can significantly affect overall physical and emotional well-being and quality of life.
As in chronic kidney disease, the exact processes by which obesity affects various aspects of health are distinct and involve specific pathophysiological pathways.
Thus, in the same way that we now understand how loss of kidney function can result in complications like anemia (loss of erythropoietin) or hyperparathyroidism (loss of activation of Vitamin D), we understand how accumulation of abnormal or excess body fat can lead to type 2 diabetes (reduced levels of adiponectin and increased intramyocellular lipid accumulation leading to insulin resistance) or obstructive sleep apnea (increased pharyngeal fat accumulation).
As in chronic kidney disease, not every patient with obesity develops every possible complication. Thus, for e.g. in the same way that not every patient with chronic kidney disease develops hypertension or bone disease, not every patient with obesity necessarily develops type 2 diabetes or sleep apnea.
In summary, as in patients with chronic kidney disease, where we now appreciate that irrespective of the different causal pathways leading to the loss of kidney function, there are discrete common pathways leading to typical complications, in patients presenting with obesity, irrespective of the wide range of pathways that can lead to the accumulation of abnormal or excessive body fat, there are discrete common pathways leading to the typical complications associated with obesity.
Incidentally, this view of obesity has important clinical consequences. Thus, as in patients with chronic kidney disease, obesity management had three distinct goals, each of which may require a different management strategy:
- Addressing the underlying drivers
- Halting or slowing progression
- Preventing or managing the complications
Busan, South Korea
To most of us, the word “obesity” is associated with a wide range of strongly negative connotations. The persistent and widespread weight-bias and fat-phobia promoted by stereotypical (but misleading) images, associations, and assumptions, together with widespread misinformation and misrepresentation, makes a dispassionate and objective use of this term difficult – to the degree that we may wish to avoid it altogether.
Indeed, the term “obesity” means different things to different people – the spectrum is extraordinarily vast, ranging from it being hurled as a personal insult to its use as a medical diagnosis. It is the latter use that I will concern myself with in this post (not to imply that analysing and acknowledging other uses of the term may well be as important).
In a medical context, the term has generally been applied to all individuals, whose body mass index (BMI) appears above a certain cut-off. This practice has long been criticised (not least by me) on the basis that weight or size is simply not an objective measure of health and that BMI does a rather poor job of characterizing individual health risks. Indeed, it is now well established that good health is possible over a wide range of body shapes and sizes and therefore attempting to base a disease definition on numbers on a scale or measuring tape without additional measures of health, fitness, or well-being are fundamentally flawed.
Thus, with the push for recognition of obesity as a chronic disease (more on this in future posts), there has also been a push for modifying the definition of what constitutes obesity in a medical sense. The emerging consensus shared by various medical bodies and experts in the field, is that the diagnosis of obesity needs to be based on actual measures of health rather than simple anthropometric measures.
A current working definition of what constitutes obesity in a medical sense, is the presence of excess or abnormal body fat that impairs health, the operative word here being “impairs”. Without an impairment in health, there is no disease, ergo, no obesity. This definition immediately excludes all individuals, who, irrespective of shape or size, are in perfect health.
Another important aspect of this definition is that there should exist a direct link between the presence of abnormal or excessive body fat and the health impairment. This is a lot less straightforward than it appears, as most health problems can have more than one cause and not every health problem in a person with abnormal or excess body fat is necessarily related to their adiposity. Here one may have to look for evidence that weight gain makes the problem worse and weight loss makes the problem better before concluding that someone has obesity.
Thus, the medical diagnosis of obesity requires substantially more than just a scale or a measuring tape. It actually requires a medical encounter that includes clinical assessment and the use of clinical judgement and may well require additional diagnostic laboratory and imaging studies or even treatment attempts. Purists may find this cumbersome and somewhat fuzzy, but they should perhaps be reminded that there are countless medical diagnoses that require similar levels of assessment and clinical judgement – in fact, only a rather small group of medical diagnosis are based on a single discrete and objective measure.
To make matters even more complicated, obesity, like many other medical conditions, is extraordinarily heterogeneous as to its causes, its manifestations, its response to treatment, and prognosis. I have previously likened this to cancers, which all share the condition of “malignancy” but are vastly different in terms of clinical presentations and prognoses. Thus, others and I have sometimes used the term “obesities” rather than just “obesity”.
I can readily see why this degree of complexity in defining what obesity actually is (at least in the medical sense), can be extremely dissatisfying to practitioners, patients, policy makers, and the general public, all of who would likely prefer simpler solutions. Unfortunately, things in medicine are rarely neat and tidy or set in stone – a certain fluidity and plasticity in definitions and disease paradigms is the rule rather than the exception.
So, while in medicine, I can see an emerging consensus that characterisation of obesity as a disease needs to be based on actual measures of health rather than just numbers on a scale, I also understand why the use of this term outside of medicine remains highly problematic. Here, I can readily see why, given its strong negative connotations, many would want to abandon the use of this term altogether and frankly, I do not disagree.
Even within the context of medicine, we must be cautious in how we use and to whom we apply the term. For one, we must consistently adhere to the principles of people-first language – there are no “obese” people, only people who have “obesity”! We must also acknowledge and recognise that this term has strong negative connotations for most people, and that we need to take the time to ensure that clients understand exactly what we mean by this term when we use it in our charts, medical records, and inter-professional communication.
A few days ago I posted an article with the tongue-in-cheek rhetorical title, “Is there a role for dietitians in obesity management?”, to which, as readers should note, my clear answer (or so I thought) was “ABSOLUTELY!”.
Interestingly, the response to this post from the dietitian community was both humbling and indeed an honour. Not only did the post receive an unusually large number of lengthy and passionate comments (both here and on social media), but I also received a most thoughtful letter signed by well over 200 dietitians, suggesting I reconsider or at least clarify my post.
This overwhelming response to my post was humbling, because, I do not believe that there is anything I could possibly have written that would have elicited an even remotely similar prompt and passionate response from my own medical colleagues – clearly dietitians care strongly about what they do. Apparently, they also appear to pay attention to what I have to say – which is an honour indeed!
That said, I agree very much that some clarification is in order.
For one, as stated above, the title of the post was indeed entirely rhetorical – if I did, for even a second, have any doubts as to the important role that dietitians have in obesity management, I would probably not have bothered writing the post at all.
Secondly, I would have thought that both my opening and closing paragraphs would have made it entirely evident just how much respect I have for the professional expertise that dietitians have with regard to their discipline and their essential role in obesity management. I truly believe that it would be entirely fair to say that dietitians’ knowledge of biochemistry, disease processes, counseling techniques, client-centred care, and clinical passion are second to none (and I happily include my own colleagues in the comparator).
Furthermore, nowhere did I state or imply that my comments apply to ALL (or even the majority of) dietitians – in fact, I thought I had made it clear that the issues I raised applied to a small minority (perhaps no more than a handful?) of dietitians. (I did not single out anyone by name, as I do not believe in, nor intended, any ad hominem attacks).
In my post, I touched on a few different but related issues:
1) The unequivocal endorsement of obesity as a chronic disease.
2) Potential gaps in specific obesity training.
3) Reluctance (of at least some practitioners) to consider weight loss as a realistic (and often necessary) therapeutic option.
Apart from the fact (as I have done in countless previous posts) that I have called out members of my own (or for that matter, any) medical profession on the exact same issues, I am also fully aware that within any health profession there is a wide range of expertise, experience, and opinion on virtually any issue.
But, I do believe that each of the above-mentioned issues is of importance (not just for dietitians), and I will happily clarify my stance and thinking on each of them in subsequent posts.
As to why, if my comments apply to all health professions, I decided to single out dietitians for this particular post, the reasons are simple:
1) This specific post happened to be prompted by actual conversations over the past few months with several dietitians from across Canada, who all (independently!) raised similar concerns about what they thought was perhaps amiss amongst some (younger?) members within their profession when it comes to obesity management (again, no names!).
2) Ten years of blogging have taught me that to initiate a lively discussion with any post, it needs to be opinionated, one-sided, strongly worded, and provocative – anything less, is a waste of time (sadly, balance is boring!). If nothing else, my post certainly achieved that.
3) I truly do consider the role that dietitians have to play in obesity management of the utmost importance. Dietitians are in fact “THE” profession, that other health professionals most often look to when it comes to obesity management. With that comes immense responsibility, which I know dietitians take very seriously.
I promise that I will attempt to do my utmost to clarify and expand on the specific issues raised in my previous post in subsequent posts.
Hopefully these “clarifications” will be taken in the respectful and constructive spirit in which they are offered – I am fully aware that nothing in medicine is black and white; we all happily operate in shades of grey (as I always emphasize to my patients). I’m also very aware that today’s certainties may well turn out to be yesterday’s follies – as our understanding of disease processes and treatments evolve, so do our clinical approaches (as they should).
All I ask of you, is to bear with me…
“On November 13th the Camera dei Deputati of the Italian Parliament voted unanimously to approve a motion that recognises obesity as a chronic disease and asks the Government to implement specific actions to promote and improve obesity prevention and management.“ Luca Busetto, co-chair of the EASO Obesity Management Task Force.
Why is this important? Because only through the unequivocal recognition of obesity as a chronic disease can governments mobilise the immense resources need to prevent and manage it in people living with this chronic disease.
To be clear, not everyone living in a larger body has obesity – as I have written countless times before, health cannot be measured with scales or measuring tapes.
The disease “obesity” only exists when abnormal or excess adiposity affects health. Thus, the term “healthy” obesity is in fact a misnomer – there is no such thing. By definition the clinical term “obesity” should refer only to people who have a clear health impairment as a direct result of their adiposity.
That said, the Italian Governments all-party declaration of obesity as a chronic disease, will hopefully mean that Italians living with this chronic disease now have better access to preventive and therapeutic interventions.
I am thus happy to see that among the various commitments made towards a national plan, the Italian government also emphasizes full access to diagnostic procedures for comorbidities, to dietary interventions, as well as psychological, pharmacological and surgical approaches as indicated.
Hopefully other European countries, and in fact, countries the world over will follow this example and ensure that people living with obesity are no longer treated as second-class citizens when it comes to access to treatment for their chronic disease.