In clinical practice, it is not uncommon to meet individuals who, despite meeting the BMI criteria for obesity, appear metabolically healthy: their glucose, lipid and blood pressure levels are well within the normal range. According to the Edmonton Obesity Staging System (EOSS), we would refer to these individuals as having “Stage O” obesity.

But are these apparently metabolically healthy obese individuals really healthy in that they have a lower mortality risk than obese individuals with metabolic abnormalities?

This question was addressed by Jennifer Kuk and colleagues from York University, Toronto, Canada, in a paper just published in Diabetes Care.

Kuk and colleagues examined data from 6,011 men and women from the Third National Health and Nutrition Examination Survey (NHANES III) where metabolically abnormal was defined as having insulin resistance (IR) or two or more metabolic syndrome (MetS) criteria.

A total of 30% of obese subjects had IR, and 38.4% had two or more MetS factors, whereas only 6.0% (or 1.6% of the whole population) were free from both IR and all MetSyn factors.

Based on the mortality data over 8 years, both the metabolically healthy and metabolically abnormal obese individuals had around the same roughly 2.5 to 3-fold elevation in mortality risk compared to the metabolically normal normal-weight individuals.

The authors conclude that even in the absence of overt metabolic aberrations, excess weight is associated with increased all-cause mortality risk.

Thus, as I’ve said before, it appears that there is no such thing as “benign” obesity. Eventually excess weight will increase the risk for a wide range of health problems including cancers, osteoarthritis and obstructive sleep apnea. This is why it is critical to include the assessment of all four Ms in patients presenting with excess weight.

So how do these findings impact on weight loss recommendations in obese individuals who appear metabolically normal (EOSS 0)?

As blogged before, the first step in weight management is prevention of weight gain. As a rule, this will require substantial changes in diet and activity levels as well as mitigation of any underlying root causes of positive energy balance - this alone can be difficult enough to achieve.

With current conservative obesity treatments only a small minority of patients will achieve and maintain clinically relevant weight loss - the vast majority of weight-losers will simply yo-yo back to their excess weight. I therefore maintain that for most obese individuals weight stabilization may be a far more realistic and sustainable goal than losing weight and keeping it off.

It is also important to remember that associations (as in this paper) do not imply causality and that these new findings therefore cannot be seen as certain proof that weight loss will decrease risk or increase longevity. This question can only be resolved with appropriately designed and conducted intervention trials.

Nevertheless the data should give caution to the notion that excess weight in metabolically healthy adults is harmless.

Prevention of weight gain is likely beneficial irrespective of obesity stage and should be the primary goal of all weight management interventions.

AMS
Edmonton, Alberta

Asan Medical Centre, Seoul

Yesterday morning, I had the pleasure of presenting the Plenary Key Note Lecture at the 31st Annual Scientific Conference of the Korean Society for the Study of Obesity (KSSO).

The session was chaired by Professors Kwang-Won Kim (President) and Hye-Soon Park (Chair, Board of Directors) of KSSO at the most impressive Asan Medical Centre, a sprawling ~2500-bed hospital complex, one of the largest and most modern of Korean academic hospitals. The hospital is named after Asan, Chung Ju-Yung, the founder of Hyundai and the Asan Foundation.

While my talk focused on an etiological approach to obesity management (soon to be published in Obesity Reviews), I also spoke about the Edmonton Obesity Staging System (EOSS) and our early experience with this system in clinical practice. My Korean colleagues found this system most interesting and timely, as the issue of which obese people to prioritize for treatment is as relevant in Korea as it is in Canada.

While Korea, as do other Asian countries, defines obesity as a BMI greater than 25, this should not pose a barrier to applying EOSS to their population. Indeed, the advantage of EOSS is that it characterizes the degree of obesity not simply by size but rather based on the clinical assessment of mental and physical comorbidities.

I am most grateful to my Korean colleagues for the invitation and their incredibile hospitality and very much look forward to hearing about how they plan to adopt EOSS for Koreans.

AMS
Edmonton, Alberta

Yesterday, I blogged about the proposed Edmonton Obesity Staging System. This prompted a number of comments and questions.

Here a few quick answers regarding the Staging System:

1) The terms mild, moderate, and severe are of course subjective. In some cases there are objective measures (e.g. valid scales) to assess the severity of symptoms but in other cases, this call is really to be made by the medical professional based on the interview, physical exam and other assessments.

Although there may be some variability in judgement between clinicians, hopefully, the inter-rater reliability will not be too far off.

2) What is the definition of obesity related comorbidity?

Unfortunately, excess weight can lead to a wide range of health problems. However, it is often not entirely clear whether or not a specific problem in a given patient is really entirely weight related.

Thus for e.g. although obesity is a common cause of fatty liver disease, there are many other factors that can lead to excess accumulation of liver fat. Often it may only be possible to tell if a problem is obesity related when the problem actually gets better or even disappears with weight loss.

I generally suggest that in order to be considered obesity related, a problem has to meet at least two of the following three criteria.

1) There is good epidemiological evidence that the condition is more common in people with overweight or obesity.

2) There is evidence that the condition actually gets worse with weight gain and/or better with weight loss.

3) There is a plausible biological link between the condition and excess weight.

It the condition meets at least two of these criteria, it may be fair to assume that it is likely weight-related unless there is substantial reason to suspect another cause.

Once again, the final proof that a specific condition is in fact weight-related can only come from the demonstration that the condition actually does get better with weight loss (This of course does not apply to conditions like obesity related cancers, which, once established are unlikely to disappear or get better with weight loss).

Hopefully, these explanations provide some clarification. Several research projects are currently underway to further validate this staging system to increase its utility in medical research and practice.

Once again, all ideas and comments are greatly appreciated.

AMS
Edmonton, Alberta

Readers of these pages will recall that earlier this year Robert Kushner and I published a proposal for a new clinical obesity staging system in the International Journal of Obesity.

Rather than BMI (a measure of weight), the Edmonton Obesity Staging System (EOSS) ranks severity of obesity based on clinical assessment of weight-related health problems, mental health and quality of life. We proposed that this system would provide a far better guide to clinical decision making than using BMI class alone.

As we have now implemented the use of this system in our clinic and in the referral requirements to our program, we have also developed a simple chart and pocket tool that can be used as a reminder in a clinical setting.

Click here for Edmonton Obesity Staging System Chart

Click here for Edmonton Obesity Staging System Pocket Card

All comments are greatly appreciated.

AMS
Edmonton, Alberta

While I am taking a brief break from clinics and other obligations (including daily blog posts), I will be reposting past articles, which I still believe to be relevant but may have escaped the attention of the 100s of new readers who have signed up in the past months.

The following was first posted on 08/19/08

Many readers of this blog are familiar with the ongoing (endless?) discussion about whether or not obesity is a risk factor, a disease, a condition, or simply an extreme of the normal “bell curve” of body weights. Today, I want to throw in another term into this discussion. In fact, the more I think about it, the more I am convinced that we should look at obesity as a clinical sign - not unlike edema.

In the same manner that edema reflects the excess accumulation of fluid, obesity reflects the excess accumulation of body fat. As edema is a clinical sign of a perturbation of fluid homeostasis, excess fat accumulation is indicative of a perturbation in energy balance.

In a patient with edema, we can of course opt to simply provide symptomatic treatment by restricting salt and water intake, but my guess is that most experienced clinicians will likely make an effort to understand whether the fluid retention is a result of abnormal cardiac function, renal failure, venous or lymphatic stasis, vasodilatory drugs or a list of other possible causes of fluid retention.

Similarly, in a patient with excess body fat, we can simply prescribe “symptomatic treatment” by restricting food intake or increasing activity, or we can make an effort to truly understand the factors that are causing the patient to overeat or “undermove” (apologies for coining this term, but I kind of think it conveys the point). Obviously, whether or not the overeating is a result of peer pressure, hunger (meal skipping), depression, binge-eating, olanzapine, sugar-addiction, MC-4 receptor defect, or a craniopharyngeoma may well influence the choice of treatments.

Similarly, whether or not the “undermoving” results from lack of time, unsafe neighbourhoods, obstructive sleep apnea, anxiety disorders, depression, back pain, fibromyalgia, plantar fasciitis, vital exhaustion or quadroplegia will (hopefully) help determine the most appropriate and effective management strategy.

The idea that all people with excess body fat should simply eat less and move more is not unlike the notion that all people with edema should simply restrict their fluid intake and cut the salt.

If obesity is simply a “sign”, then “overeating” and “undermoving” are just symptoms!

The differential diagnosis of overeating and undermoving is complex and can involve sociocultural, psychological, medical and iatrogenic causes.

Let’s get more sophisticated in our diagnostics - hopefully our ability to address the underlying causes will follow.

AMS
Edmonton, Alberta