Friday, August 29, 2014

2014 Scopinaro Lecture

Nicola Scopinaro, MD, Professor of Surgery, University of Genoa Medical School, Italy

Nicola Scopinaro, MD, Professor of Surgery, University of Genoa Medical School, Italy

This morning, at the XIX World Congress of the International Federation of Surgery for Obesity and Metabolic Disorders (IFSO2014), I have the great honour of presenting the 2014 Scopinaro Lecture.

This lecture is named after Nicola Scopinaro, who in 1976 performed the first biliopancreatic diversion for the treatment of obesity.

The Scopinaro Lecture is the highest recognition for a non-surgeon to be awarded by IFSO.

In thinking about what to present, I settled on discussing the topic of whether or not obesity is a disease. Looking back over the work that I have done over the past 25 years, I came to realise that the issue of why some people with excess weight develop health problems and others don’t, has indeed fascinated me for a long time.

Initially, this interest was focussed on trying to understand why some people with obesity develop high blood pressure and others don’t. We were indeed able to show that part of this may be explained by differences in the expression of hormones involved in blood pressure regulation from fat tissue.

More recently, as many regular readers are well aware, I have broadened this interest in describing the limitations of BMI and advocating for a clinical staging system that classifies overweight and obese individuals based on how “sick” they are rather than how “big” they are.

Clearly, this work is of considerable interest to those involved in bariatric care (including bariatric surgeons), as it provides a framework for better prioritizing and assessing risk/benefit ratios than BMI or other anthropometric measures alone.

As I point out in my talk,

- The etiology of obesity is complex and multifactorial.

- The physiology of energy regulation is complex and subverts volitional attempts at weight loss.

- Access to obesity prevention and treatments must be driven by the recognised medical needs to address this condition.

- Multidisciplinary management of this life-long disorder requires resources similar to those required for other chronic diseases

In receiving this honour, I am fully aware that all of my work stands on the shoulders of the many researchers and clinicians who came before me and the considerable support and help that I have been fortunate enough to receive from my many students, trainees, colleagues and supervisors.

This award will certainly serve an a strong incentive to continue my work and advocacy for better treatments for obesity and the advancement of bariatric care.

@DrSharma
Montreal, QC

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Thursday, August 28, 2014

Call For Abstracts: Canadian Obesity Summit, Toronto, April 28-May 2, 2015

COS2015 toronto callBuilding on the resounding success of Kananaskis, Montreal and Vancouver, the biennial Canadian Obesity Summit is now setting its sights on Toronto.

If you have a professional interest in obesity, it’s your #1 destination for learning, sharing and networking with experts from across Canada around the world.

In 2015, the Canadian Obesity Network (CON-RCO) and the Canadian Association of Bariatric Physicians and Surgeons (CABPS) are combining resources to hold their scientific meetings under one roof.

The 4th Canadian Obesity Summit (#COS2015) will provide the latest information on obesity research, prevention and management to scientists, health care practitioners, policy makers, partner organizations and industry stakeholders working to reduce the social, mental and physical burden of obesity on Canadians.

The COS 2015 program will include plenary presentations, original scientific oral and poster presentations, interactive workshops and a large exhibit hall. Most importantly, COS 2015 will provide ample opportunity for networking and knowledge exchange for anyone with a professional interest in this field.

Abstract submission is now open – click here

Key Dates

  • Abstract submission deadline: October 23, 2014
  • Notification of abstract review: January 8, 2014
  • Early registration deadline: March 5, 2015

For exhibitor and sponsorship information – click here

To join the Canadian Obesity Network – click here

I look forward to seeing you in Toronto next year!

@DrSharma
Montreal, QC

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Friday, August 8, 2014

Healthy Obesity: More Questions Than Answers?

sharma-obesity-visceral-fat-mriRegular readers will be well aware of the evidence that a subset of people living with obesity can be remarkably healthy despite carrying a rather large amount of body fat.

This issue of “healthy obesity” was the topic of the 13th Stock Conference of the International Association of the Study of Obesity, the proceeding of which are now published in Obesity Reviews.

As the authors note,

“The ‘healthy obese’ phenotype was described in the 1980s, but major advancements in its characterization were only made in the past five years. During this time, several new mechanisms that may be involved in health preservation in obesity were proposed through the use of transgenic animal models, use of sophisticated imaging techniques and in vivo measurements of insulin sensitivity. However, the main obstacle in advancing our understanding of the metabolically healthy obese phenotype and its related long-term health risks is the lack of a standardized definition.”

The latter is a real problem because finding people with obesity, who are truly metabolically and otherwise healthy becomes harder the higher the BMI gets – this makes the study of this phenomenon rather challenging.

Nevertheless,

“One of the most consistent characteristics of metabolic health in obesity across studies in humans is reduced liver lipid. This is likely the consequence of increased capacity for storing fat coupled with improved mitochondrial function in adipose tissue and decreased de novo lipogenesis in liver. This can also result in decreased deposition of lipids, including bioactive species, in skeletal muscle. Decreased adipose tissue inflammation with decreased macrophages and a unique T-cell signature with an anti-inflammatory circulating milieu were also suggested to characterize metabolic health in obesity. Anecdotal data support a possible role for healthier lifestyle, including increased level of physical activity and healthier diet. It remains to be established whether a favourable metagenomic signature is a characteristic of metabolic health in obesity.”

Finland’s, Dr Kirsi Pietiläinen explained that,

“..three energy dissipation pathways, oxidative phosphorylation, fat oxidation and amino acid catabolism showed preserved pathway activities in subjects who are MHO at a level similar to their lean counterparts. In contrast, these pathways were significantly down-regulated in adipose samples from obese twins with metabolic disturbances. Another potential hallmark of metabolic health, a favourable inflammatory profile of the adipose tissue was also observed in the MHO twins. Also, the fat cells of the MHO twins were smaller with evidence of more active differentiation processes within the fat tissue. As multiple mitochondrial pathways are vital in adipocyte differentiation [29], it is possible that mitochondrial malfunction impairs the development of new fat cells, which in turn results in an inability of the adipose tissue to expand under conditions of energy excess. This failure of fat cell proliferation has long been suspected to constitute the framework for ectopic fat storage, insulin resistance and type 2 diabetes.”

Other speakers discussed other aspects including immune function and microbiata in this phenomenon.

Finally, the authors concluded that,

“identifying underlying factors and mechanisms associated with this phenotype will eventually be invaluable in helping the scientific and medical community understand factors that predispose, delay or protect obese individuals from metabolic disturbances. It is essential to underscore that the MHO concept presently only address the cardio-metabolic risks associated with obesity; it is therefore important that patients who are MHO are still very likely to present many other obesity-related complications such as altered physical and/or physiological functional status, sleep problems, articulation and postural problems, stigma, etc. Importantly, the MHO concept supports the fact that classification based on excess adiposity per se (e.g. BMI or body composition if available) should be supplemented with obesity-related comorbidities, e.g. with fasting insulin as proposed by the Edmonton obesity classification system.”

Certainly a space to watch as we learn more and more about the “healthy obesity” phenotype.

@DrSharma
Edmonton, AB

ResearchBlogging.orgSamocha-Bonet D, Dixit VD, Kahn CR, Leibel RL, Lin X, Nieuwdorp M, Pietiläinen KH, Rabasa-Lhoret R, Roden M, Scherer PE, Klein S, & Ravussin E (2014). Metabolically healthy and unhealthy obese – the 2013 Stock Conference report. Obesity reviews : an official journal of the International Association for the Study of Obesity PMID: 25059108

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Thursday, July 31, 2014

Low Adipocyte Formation Is Associated With Abdominal Obesity

sharma-obesity-adipocytes3One of the key concepts about the deposition of visceral and ectopic fat is the inability of “healthy” subcutaneous to readily expand to accommodate excess calories. This is why people with large fat cells and those with less or no subcutaneous fat (as in partial or complete lipodystrophy) display features of the metabolic syndrome.

In line with these observations, a study by Andre Tchernof and colleagues from the University of Laval, Quebec, in a paper published in ADIPOCYTE show that low adipogenic capacity of subcutaneous adipose tissue is associated with visceral obesity, visceral adipocyte hypertrophy, and a dysmetabolic state.

The researchers studied adipocytes and preadipocytes isolated from subcutaneous and visceral fat samples from 35 women undergoing gynecological surgery and assessed body fat distribution by CT as well as fasting plasma lipids and glycemia.

Using an in vitro differentiation assay, they found that lower adipogenic rates were strongly associated with increased visceral cell size and dyslipidemia.

In addition, When matched for BMI, women with low subcutaneous preadipocyte adipogenic rates had a higher visceral adipose tissue area, omental adipocyte hypertrophy, higher VLDL-lipid content and higher fasting glycemia.

All of these findings are in line with the notion that low subcutaneous preadipocyte differentiation capacity in vitro is associated with visceral obesity, visceral adipocyte hypertrophy, and a dysmetabolic state.

Once again, as regular readers should be aware, not all fat is equal.

@DrSharma
Edmonton, AB

ResearchBlogging.orgLessard J, Laforest S, Pelletier M, Leboeuf M, Blackburn L, & Tchernof A (2014). Low abdominal subcutaneous preadipocyte adipogenesis is associated with visceral obesity, visceral adipocyte hypertrophy, and a dysmetabolic state. Adipocyte, 3 (3), 197-205 PMID: 25068086

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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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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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