Tuesday, July 8, 2014

Does BMI Underestimate Adiposity in Kids?

sharma-obesity-kids-scale2Regular readers are well aware of my reservations regarding the use of BMI as a diagnostic parameter in clinical practice. After all, while BMI may tell us how big someone is, it certainly is not a good measure of how sick someone is.

But to be honest, BMI was never intended as a measure of disease – it was (at best) introduced as a surrogate measure of adiposity (fatness).

Nevertheless, supporters of BMI continue to argue that it is still a good measure of fatness and as such should remain part of standard assessment – even in kids.

Now, a paper by Javed and colleagues, published in Pediatric Obesity, examines how well BMI performs as a means to identify obesity as defined by body fatness in children and adolescents.

The authors conducted a systematic review and meta-analysis of 37 studies in over 53,000 participants assessing the diagnostic performance of BMI to detect adiposity in children up to 18 years.

While the commonly used BMI cut-offs for obesity showed showed a high specificity (0.93) to detect high adiposity, the sensitivity was much lower (0.73) – particularly in boys.

This means that kids who exceed the current BMI cut-offs are indeed very likely to have fatter bodies (for what it’s worth).

On the other hand, relying on BMI cut-offs alone will miss as many as 25% of kids whose body fat percentage exceeds current definitions of adiposity.

Thus, assuming that bod fatness or adiposity is indeed a clinically useful measure of health, the use of BMI alone will ‘underdiagnose’ adiposity in a significant proportion of kids (especially boys) who may well be at risk from excess fat.

A word of caution about fatness is certainly in order – as in adults, much depends on exactly where the fat is located (abdominal or ectopic vs. subcutaneous) and other factors (e.g. cell size, inflammation, insulin sensitivity, etc.).

Thus, even if BMI was a perfect measure of body fat, it would probably still require further examinations and tests to determine exactly whether or not this “extra” fat poses a health risk.

As in adults, a clinical staging system similar to the Edmonton Obesity Staging System may be a fat better indicator of determining which kids may need to worry about their body fat and which don’t.

@DrSharma
Edmonton, AB

Hat tip to Kristi Adamo for pointing me to this study

ResearchBlogging.orgJaved A, Jumean M, Murad MH, Okorodudu D, Kumar S, Somers VK, Sochor O, & Lopez-Jimenez F (2014). Diagnostic performance of body mass index to identify obesity as defined by body adiposity in children and adolescents: a systematic review and meta-analysis. Pediatric obesity PMID: 24961794

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Wednesday, June 18, 2014

4th Canadian Obesity student Meeting (COSM 2014)

Uwaterloo_sealOver the next three days, I will be in Waterloo, Ontario, attending the 4th biennial Canadian Obesity Student Meeting (COSM 2014), a rather unique capacity building event organised by the Canadian Obesity Network’s Students and New Professionals (CON-SNP).

CON-SNP consist of an extensive network within CON, comprising of over 1000 trainees organised in about 30 chapters at universities and colleges across Canada.

Students and trainees in this network come from a wide range of backgrounds and span faculties and research interests as diverse as molecular genetics and public health, kinesiology and bariatric surgery, education and marketing, or energy metabolism and ingestive behaviour.

Over the past eight years, since the 1st COSM was hosted by laval university in Quebec, these meetings have been attended by over 600 students, most presenting their original research work, often for the first time to an audience of peers.

Indeed, it is the peer-led nature of this meeting that makes it so unique. COSM is entirely organised by CON-SNP – the students select the site, book the venues, review the abstracts, design the program, chair the sessions, and lead the discussions.

Although a few senior faculty are invited, they are largely observers, at best participating in discussions and giving the odd plenary lecture. But 85% of the program is delivered by the trainees themselves.

Apart from the sheer pleasure of sharing in the excitement of the participants, it has been particularly rewarding to follow the careers of many of the trainees who attended the first COSMs – many now themselves hold faculty positions and have trainees of their own.

As my readers are well aware, I regularly attend professional meetings around the world – none match the excitement and intensity of COSM.

I look forward to another succesful meeting as we continue to build the next generation of Canadian obesity researchers, health professionals and policy makers.

You can follow live tweets from this meeting at #COSM2014

@DrSharma
Waterloo, Ontario

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Monday, June 16, 2014

Diagnosing Obesity

sharma-obesity-scale3I am currently attending the 74th Scientific Session of the American Diabetes Association in San Francisco, where obesity is certainly a topic that permeates its way through much of the program.

However, despite all this talk, obesity continues to not be “formally” recognized as a “diagnosis” when it comes to patient care.

Thus, a paper by Canadian Obesity Network boot camper Bliie-Jean Martin and colleagues from the University of Calgary, published in BMC Health Services Research, the coding for obesity in administrative data bases and hospital discharge data is rather sketchy.

For their study, Martin and colleagues used a large coronary catheterization registry and a hospital discharge abstract database, which together consisted of more than 17,000 patients.

Based on how often the ICD-10 codes for obesity (E65-68) appeared in these datasets, it is evident that obesity was poorly coded for in the discharge database – in fact, only 2.4% of the discharge abstracts had this diagnosis (in contrast to about 20% of patients in the cardiac registry – which is likely to be more accurate).

Assuming the actual prevalence of obesity to be at least as high in patients discharged from hospital, as it is in the cardiac registry, the sensitivity of identifying obese patients based on the coding of the diagnosis is only about 8% – this means the vast majority of cases of obesity would be missed.

On the other hand, in the few cases where obesity codes were included in the discharge data set, this label was indeed correct (99% specificity).

As the authors conclude, given this state of affairs, hospital discharge databases are highly unreliable when it comes to determining obesity prevalence or burden of disease.

While there may certainly be other conditions that are “under diagnosed” and do not find themselves well reflected in such databases, nowhere is the discrepancy between prevalence and coding likely to be as great as for obesity.

This rather cavalier attitude towards coding for obesity must change if we hope to better understand the importance of obesity related morbidity in the health care system.

@DrSharma
San Francisco, CA

ResearchBlogging.orgMartin BJ, Chen G, Graham M, & Quan H (2014). Coding of obesity in administrative hospital discharge abstract data: accuracy and impact for future research studies. BMC health services research, 14 PMID: 24524687

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Friday, June 13, 2014

AMA Calls For Better Access To Obesity Treatments

American-Medical-Association-logoOn the anniversary of the American Medical Association (AMA) “recognising” obesity as a disease, the AMA delegation yesterday passed a resolution on “Patient Access to Evidence-Based Obesity Services”, which gives the AMA decisive direction to support advocacy efforts to improve patient access to all evidence-based obesity treatments.

These treatments for obesity range from bariatric surgery and obesity drugs to intensive lifestyle interventions and nutrition counseling.

Regular readers will recall my previous posts on the various US organisations that are now not only viewing obesity as a chronic disease but are also demanding better access to obesity treatments for people with this condition.

This decision is widely applauded by other organisations including The Obesity Society and the American Society of Bariatric Physicians.

Hopefully, these efforts will go a long way towards reducing the bias and discrimination that people with obesity face in the healthcare system (and elsewhere) and help dispel the myth that all it takes to control your weight is a healthy dose of willpower.

Indeed, there is reason to believe that this AMA resolution will have significant implications for patients and the health care communityincluding:

  • improved training in obesity at medical schools and residency programs,
  • reduced stigma of obesity by the public and physicians,
  • improved insurance benefits for obesity-specific treatment, and
  • increased research funding for both prevention and treatment strategies.

Unfortunately, in Canada we have yet to see the Canadian Medical Association take a leadership role in this regard – hopefully, this is just a matter of time.

@DrSharma
Edmonton, Alberta

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Tuesday, May 6, 2014

Cancer Is Not a Disease

Metastasizing Cancer Cell

Metastasizing Cancer Cell

Warning: this satirical post may be offensive to the cancerous or people that you love, who may happen to be cancerous[1]. It is loosely based on David Katz’s perspective on obesity, published in Nature Outlook - no offence!

CANCER IS NOT A DISEASE

The misguided urge to pathologize this condition reflects society’s failure to come to terms with the need for prevention

The World Health Organisation has long declared cancer to be a disease. This well-intentioned move is misguided in that it implies that tens of millions of people must have bodies or minds, or both, that are not working properly. Even seemingly healthy people— adults and children alike —, who may well harbour cancerous cells in them, are now, by definition, diseased. Imposing such a status has broad ramifications for society and requires careful reflection.

The standard definition of cancer is that of having cells in your body that divide without control and are able to invade other tissues. These cancerous cells are associated with an increased risk of illness, disability and death. However, a risk factor is not a disease, because each can occur independently of the other.

Cancer is an important contributor to the prevailing burden of chronic disease, lying on the causal pathway to much of what plagues modern society and its people — cachexia and organ failure to name two of the most serious [2]. However, not only can these problems develop in the absence of cancer, but not everyone with cancerous cells in them develops any such condition [3].

The categorization of cancer as a disease could have a pernicious influence on efforts to remedy the problem at its true origins [4]. The treatment of diseases customarily involves drugs, medical technology, clinic visits and surgical procedures. If cancer is a disease, the therapeutic advances on which its management depends presumably reside in these domains.

MALIGNANT COSTS

The disease approach would impose substantial costs. Cancers affect many tens of millions of adults and children in the United States alone [5]. If we were now to conclude that all these individuals warrant disease treatment, the collective need for drugs and cancer surgery would be staggering. That would mean not only a huge financial outlay, but the imposition of a vast array of side effects on the cancerous population. Even the best of drugs are prone to side effects, and to date, cancer management has been forced to rely on anything but the best of drugs [6]. The long-term effects of cancer surgery are still highly uncertain as well — particularly for ever younger candidates. Even if surgery proves sustainably effective, the need to rely on the rearrangement of natural gastrointestinal anatomy (as in the case of GI cancers) as an alternative to better use of feet and forks seems a societal travesty.

The consequences of labelling cancer a disease seem to be a price the medical profession is willing to pay to legitimize the condition. It may also be an attempt to own it, and the profits that come with treating it [7].

Our bodies, physiologies and genes are the same as they ever were [8]. What has changed while cancer has gone from rare to pandemic is not within, but all around us. We are drowning in cancerogens including those in foods engineered to be irresistible [9]. Although lack of physical activity is well-known to substantially increase the risk of cancers, we are awash in labour-saving technologies and a societal mindset that urges us to use all that we invent [10].

LIFEGUARDS

Like breathing air, our capacity to get cancers is part of normal biology [11]. The dividing line between normal and abnormal cell division has nothing to do with cell division per se, but rather whether or not these cancerous cells are detected and destroyed by our immune systems, a fundamental survival strategy of omnivorous and carnivorous animals. In our ancestral context, they were; in our modern context, our immune systems may be less efficient [12].

We don’t wait for people to drown and devote our focus to resuscitation [13]. Instead, we do everything we can to prevent drowning in the first place: we erect fences around swimming pools, station lifeguards at beaches, offer swimming lessons, and keep a close eye on one another at the water’s edge. People still drown [14], so we need medical intervention as well. But that is a last resort, far less good than prevention, and applied far less commonly [15].

There is an analogous array of approaches to cancer prevention and control. These include environmental reforms, such as making stairs, pavements and bike lanes more readily available, and altering food service settings to encourage the more healthy choices; social reforms, such as making physical activity programming a standard aspect of every work and school day; policy reforms, such as regulation of both food formulations and food marketing; and skill-building, including teaching adults and children how to identify more nutritious foods and how to cook [16].

Cancer warrants medical as well as cultural legitimacy and respect, but needs not be a disease to earn them [17]. Calling cancer a disease contradicts the functioning of our bodies, and implies a blame residing there. But the blame for hyperendemic cancer, and its best remediation, resides not within bodies that work as they ever did, but all around, with the collective actions of the body politic [18]. ■

@DrSharma
Edmonton, AB

Notes:

1. If the term “the cancerous” appear offensive to you, suck it up! After all, this is exactly the way that people with obesity get referred to all the time (as in “the obese”).

2. In fact, no one actually ever dies of cancer. Cancerous people die of infections, cachexia, organ failure and toxic effects of chemotherapy – having cancerous cells growing in you is a risk factor for all of these problems, but the cancer cells themselves will rarely kill you.

3. Interestingly enough, a surprisingly large number of cancerous people live on to die of natural and unnatural causes entirely unrelated to their cancers.

4. For which we know that environmental factors play a major role – not just diet and physical activity, throw in environmental toxins, pollutants, cigarette smoke, sunlight, naturally occurring radiation and perhaps even electromagnetic smog (although I don’t quite buy the latter). Yes, some cancers may be genetic – but then again, so are some forms of obesity – if anything,  I’d call it even.

5. According to this source, the prevalence of cancer in the US is over 13,000,000.

6. Seriously, cancer drugs are anything but safe (they are in fact designed to be toxic!).

7. Yes, let us leave making money off the cancerous to charlatans and the commercial tumor-loss industry – never trust Doctors – they’re only in it for the money.

8. OK, this is true, i.e. if you choose to ignore the entire body of literature on epigenetics and how environmental factors (e.g. the uterine environment) can alter gene expression by permanently(!) modifying (i.e. changing the chemical structure of)  our DNA.

9. As an interesting aside, virtually every dish, prepared by a chef worth her salt, is designed to be “irresistible”. In fact, that’s the whole point of culinary skills (and cooking shows). Indeed, I can attest to the fact that nothing beats the addictive nature of Michelin-starred cuisine – the only thing holding me back from living out this addiction is the rather unfortunate price tag (which is why I’ll just stick with hot sauce).

10. I cannot but help think of all the poor inventors who sit on countless worthless patents for inventions that will never see the day of light. Like I say in my show – obesity is largely Edison’s fault – had he not invented the electric bulb, we’d all be in bed at dusk and up at dawn (which is why We The North, do need afternoon naps – especially in Winter).

11. Or at least normal biology – I simply cannot resist quoting Dr. Oz on this one, who, according to a certain Dr. Li featured on his show (apparently the President and Director of the Angiogenesis Foundation ), explains that,

..the human body is made up of more than 50 trillion cells that are continuously dividing to keep us healthy. But if just one of those cells makes a mistake or “mutates” than presto! we have formed a potentially microscopic cancer. The good news is that most of these abnormal cells will never become dangerous because our bodies have excellent defenses against cancer. Our immune system is one defense and another defense is our body’s ability to resist blood vessels from growing into and feeding cancers.

12. Apparently, the “secret sauce” we are missing to keep these naturally occurring cancer cells at bay, are the ‘essential’ supplements and “miraculous” super foods we should be adding to in our diets.

13. No, we certainly don’t.

14. In fact according to this WHO source, there are 359,000 annual drowning deaths worldwide, which makes drowning the 3rd leading cause of unintentional injury death, accounting for 7% of all injury-related deaths world wide.

15. Too bad, because I wonder how many of the 359,000 deaths could be saved if we taught more people the basics of cardiopulmonary resuscitation.

16. Indeed! Only the already rather extensive length of this post stops me from listing all the other potential strategies that we could embrace to remarkably reduce the incidence of cancers. For the Readers Digest’s recommended 31 Simple Ways to Prevent Cancer (from eating more sauerkraut to calling up your bowling pal) click here

17. After all, it’s only a “risk factor” – remember?

18. Amen!

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In The News

Diabetics in most need of bariatric surgery, university study finds

Oct. 18, 2013 – Ottawa Citizen: "Encouraging more men to consider bariatric surgery is also important, since it's the best treatment and can stop diabetic patients from needing insulin, said Dr. Arya Sharma, chair in obesity research and management at the University of Alberta." Read article

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