Dr. Sharma's Obesity Notes

As regular readers will be well aware, our recent publications on the Edmonton Obesity Staging System clearly show that BMI alone is a rather poor measure of mortality risk associated with excess weight.

Thus, according to our analyses of the NHANES population, 20-30% of obese individuals (Stage 0/1) had virtually no increased mortality risk even over the almost 20 year observation period, compared to Stage 2/3 individuals, who had substantially increased risk. Conversely, even in the ‘overweight’ category (BMI 25-30), almost 50% of individuals had a mortality risk as high of that of obese Stage 2/3 individuals.

This means that indications for obesity treatment based on BMI alone will overtreat a substantial number of obese individuals, who may have little benefit in terms of mortality, and miss an even greater number of individuals, who may well benefit from such treatments.

These observations are directly relevant to yesterday’s post on the findings of the SOS study.

As readers will recall, not only was there no relationship between BMI levels and cardiovascular outcomes in the SOS population but the overall cardiovascular risk of these participants - despite the majority being ’severely’ obese - was surprisingly low. In fact, the annual risk for experiencing an adverse cardiovascular outcome for SOS participants was well under 1% per year!

This risk level is highly reminiscent of the overall risk of Stage 0 obese individuals in our NHANES analyses.

Thus, it is readily apparent why it took almost 15 years to demonstrate any cardiovascular benefit of bariatric surgery in the SOS study - clearly this was a very ‘low-risk’ obese population.

Contrast this to the almost 3% annual cardiovascular event rate for the participants in the SCOUT trial, which, by definition, consisted exclusively of Stage 2/3 individuals. In this population, it took less than 3.5 years of even very modest weight-loss (3 to 10 kg) to significantly reduce cardiovascular outcomes.

But did surgery prove more beneficial in higher-risk participants in the SOS trial? It certainly did!

In fact, the only predictor of greater benefit of having bariatric surgery in the SOS paper proved to be having an elevated plasma insulin level - a rather crude marker of insulin resistance. It is fair to assume that these participants were in fact those with higher obesity Stages (elevated fasting insulin levels alone, would already suggest at least Stage 1 obesity).

The importance of this difference is reflected in the numbers-needed-to-treat (NNT): as low as 21 in participants with baseline plasma insulin concentrations above the median (>17.0 mU/L) and as high as 173 in individuals below or at the median (≤17.0 mU/L) insulin concentration.

This essentially means that you would need to operate only 21 patients with Stage 1+ obesity to ’save’ one life (over 15 years) but 173 Stage 0 patients for the same benefit. It does not take a financial genius to figure out that from a ‘cost-per-life-saved’ perspective, operating on Stage 1+ patients is a ‘no-brainer’ whereas operating on Stage 0 patients would (and should) probably raise some eyebrows (especially in a publicly funded healthcare system).

Thus, as we have argued before (and argued by Livingstone in an editorial accompanying the SOS paper in JAMA), it is high time we fully appreciate the “inadequacy of BMI as an indication for bariatric surgery” and begin adopting more sophisticated criteria (such as those of the Edmonton Obesity Staging System) to ensure that this treatment is available to those who are likely to benefit the most.

AMS
London, UK

Padwal RS, Pajewski NM, Allison DB, & Sharma AM (2011). Using the Edmonton obesity staging system to predict mortality in a population-representative cohort of people with overweight and obesity. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne, 183 (14) PMID: 21844111

Livingston EH (2012). Inadequacy of BMI as an indicator for bariatric surgery. JAMA : the journal of the American Medical Association, 307 (1), 88-9 PMID: 22215170

One of the major concerns around the childhood obesity epidemic is that early onset obesity may be associated with greater health risks when these kids grow into obese adults compared to individuals who only become obese as adults.

This hypothesis was recently tested in a study Markus Juonala (Finland) and colleagues in a study published last month in the New England Journal of Medicine.

The researchers examined data from four prospective cohort studies that measured childhood and adult BMI with a mean length of follow-up was 23 years.

Data were compared between four groups:

Group 1: nonobese kids who grew into nonobese adults(n=4742)
Group 2: obese kids who grew into nonobese adults (n=274)
Group 3: obese kids who grew into obese adults (n=500)
Group 4: nonobese kids who grew into obese adults (n=812)

All analyses were adjusted for age, sex, height, length of follow-up, and their respective cohorts.

The not so good new is that when childhood obesity persists into adulthood (Group 3), the risk is markedly higher than in Group 1 (never obese) - unfortunately, this is what happens to most of obese kids as 82% of them grew into obese adults.

The good news, however, is that there was absolutely no difference in the cardiovascular risk factors (diabetes, hypertension, dyslipidemia, or intima-media thickess) between Group 1 (never obese) and Group 2 (only obese as kids but not as adults) - this suggests that any increased risk associated with being an obese kid can be virtually completely reversed if they manage to grow into nonobese adults.

Unfortunately, the health risks associated with adult-onset obesity (Group 4) were exactly as bad as with childhood-onset obesity. In other words, even if you managed to get through childhood with normal weight - gaining weight as an adult put you at the same risk as if you’d been obese all your life.

These findings certainly provide important nuances to the discussions about where obesity prevention and treatment resources should be focussed.

Obviously, if you can prevent or treat childhood obesity, thereby reducing the number of obese adults, you would substantially lower risk. But this may be easier said than done, as so far, we are not exactly sure that ’successful’ obesity treatment in childhood actually prevents adult obesity (we certainly hope it does but no one has yet shown this to be the case). In fact, in this study, two out of three obese adults were nonobese as kids!

On the other hand, even if you get through childhood with normal weight only to go on and become an obese adult, you may as well have been obese all your life. This finding suggests that potential benefits of treating adult obesity may not depend on whether or not you were an obese kid or not. Incidentally, we are also not sure that treatment success in adulthood is any different between childhood-onset and adult-onset obesity.

I am also very much intrigued by the finding that growing into a nonobese adult essentially reverses all of the risk (and damage?) that may have incurred from childhood obesity. This is in someway reminiscent of how the risks of tobacco smoking are now known to be largely reversed within a few years of smoking cessation.

So, on the one hand, it looks like it may never be too late (even as an adult) to lose the excess weight (at least if you do have weight-related risk factors - EOSS 1+).

On the other hand, any cardiometabolic benefits of preventing or treating childhood obesity will only be relevant to population health if this actually prevents or reduces the burden of obesity in adulthood - simply ‘delaying’ the onset of obesity into adulthood by focussing most of our efforts on kids (as suggested recently by Canada’s Health Ministers), may have less benefit than some of us may suspect.

I look forward to hopefully lively discussion on this issue.

AMS
Edmonton, Alberta

p.s. Registration for the International School on Obesity Research and Management (ISORAM 2012, Lake Louise March 25-30 is now open - click here to register).

Juonala M, Magnussen CG, Berenson GS, Venn A, Burns TL, Sabin MA, Srinivasan SR, Daniels SR, Davis PH, Chen W, Sun C, Cheung M, Viikari JS, Dwyer T, & Raitakari OT (2011). Childhood adiposity, adult adiposity, and cardiovascular risk factors. The New England journal of medicine, 365 (20), 1876-85 PMID: 22087679

Long-time readers will recall previous posts on the environmental impact of food production and how closely the societal root causes of the obesity epidemic may be linked to global warming (in more ways than one would think).

I now came across a most interesting and remarkably comprehensive and insightful analysis of the true environmental impact of our food environment.

This document, released by the Barilla Centre for Food and Nutrition (yes, the pasta folks are involved in this), answers important questions on just how different the carbon footprint of preparing pasta depends on how much water you use to cook 500 g of pasta (assuming a ± 20% pasta/water variable ratio and 10 min cooking time).

Such, ‘light-hearted’ trivia aside, the report actually provides some amazing insights into the ‘field-to-fork’ impact of food production and how it relates to everything from environmental impact to economies of scale.

The centre piece of the report is The Double Food-Environmental Pyramid, where one pyramid represents the traditional food recommendations and the other once (upside down) represents the environmental impact of those foods.

As it turns out (not surprisingly perhaps), in general, the more recommended foods tend to have a lower impact on the environment that the foods recommended for a lower consumption.

Thus, the double pyramid exemplifies how the food pyramid actually meets two important goals -maintains people’s health and protects the environment. In other words, eating ‘healthy’ is not just good for you but also for the planet (this is somehow reminiscent of ‘passive smoking’ because suddenly what YOU eat affects MY environment and, therefore, MY health).

Rather than fascinate you with an incredible amount of highly interesting trivia in this report, I suggest you download the original document here for a most interesting Holiday read.

Buon appetito!

AMS
Edmonton, Alberta

p.s. Hat tip to Annette Anderwald for pointing me to this publication!

So on the final day of the World Diabetes Congress, I attended a debate on whether an organization like the International Diabetes Federation, should be accepting money from corporations.

The ‘in favour’ position was argued by Sir Michael Hirst from the United Kingdom, who is currently the President-Elect of IDF and will take the office of President of the Federation in 2012.

The ‘opposed’ postion was argued by John Yudkin, Chairman of the International Insulin Foundation and Emeritus Professor of the London School of Hygiene.

Hirst eloquently (and predictably) pointed to all the good that IDF does by driving the global diabetes agenda, fostering the international diabetes community, increasing diabetes awareness, engaging governments, publishing position papers and the diabetes atlas, and hosting countless roundtables, task-forces, and congresses like this one, would not be even remotely possible without strong corporate sponsorship.

As he noted, diabetes simply does not have the same appeal of infectious diseases like malaria or HIV/AIDS, which draws a flock of Hollywood celebrities, philanthropic associations (Gates Foundation), and publicity seeking politicians to throw money at the problem.

Focussing on the relationship with the pharmaceutical industry (which provides most of the corporate funding for IDF), Hirst argues that without an organization like the IDF, these companies would simply hold their own conferences and educational events - with no checks and balances - without any need for transparency or ethical standards - events would be driven solely by profit.

In contrast, with IDF in charge, it provides a credible channel, can impose checks and balances, provide and enforce an ethical framework, and clearly drive the agenda of these meetings and publications.

Thus, as was plainly evident at this (and all medical conferences I tend to go to), speakers have to publicly declare their ‘conflicts of interest’, ’sponsored symposia’ are clearly marked and declared as such, and the industry exhibits are recognizably exactly what they are - industry exhibits.

In his counterargument, Yudkin (also rather predictably) argued that although pharma companies do make and continue to develop effective treatments for diabetes, these newer treatments are often far too expensive for people in developing countries (where most people with diabetes live).

Thus, although generic insulin is listed in the WHO compendium of essential drugs and newer (more expensive) insulins have yet to prove their clinical benefits, when prescribers (read ‘doctors’) come to conferences such as this World Congress, and learn about all the latest diabetes treatments, they are far more likely to return to their countries and prescribe these expensive drugs to their patients, thereby using up more of the health care budgets in their countries than would actually be required.

Yudkin also pointed out that the 95% of IDF funding (about 8-10 million in a non-congress year) comes directly from corporate support makes up a tiny fraction (2%) of these company’s sales - so it is easy to see how every dollar spent on the IDF likely delivers 100-fold in returns to their bottom line.

Yudkin challenges the notion that Codes of Conduct or Ethical Frameworks do much to counteract corporate influence. He also notes that by accepting corporate funding, it will be impossible for IDF to demonstrate real ‘outrage’ about corporate promotion of expensive (and not necessarily more effete) drugs in these countries.

He held up the International Union Against Tuberculosis and Lung Disease as a shining (albeit only) example of a major health organization that does not accept core funding from pharma. The Union interestingly gets all of their over $50 million in annual funding from governmental developmental funds, major charitable and philanthropic foundations, and (interestingly) Big Oil (who all appear to have jumped on the infectious disease cause).

So, all in all, a very predictable debate with very predictable arguments on an issue that will likely remain as unresolved in the future as it is now.

Somewhat disappointingly, the entire debate focussed on taking money from pharma - no discussion of engaging with food companies, city builders, car manufacturers or any of the other countless industries that one would assume are both part of the problem as well as potentially parts of the solution.

In balance, I believe I am more for disclosures, codes of conduct, and transparency when engaging industry as partners to actually get something done, rather than simply waiting and hoping for governments or benevolent billionaires to step up to the plate (remember governments and billionaires also have their own ‘agendas’).

I guess there is a fine but distinct line between dancing and sleeping with a porcupine.

AMS
London, UK

In my continuing coverage from the World Diabetes Congress, I thought it may be appropriate to share with my readers the Global Diabetes Plan 2011-2012, recently released by the International Diabetes Federation.

The objectives of this ambitious plan are to

1) Improve health outcomes of people with diabetes - early diagnosis, cost effective treatment and self-management education can prevent or significantly delay devastating diabetes-related complications and save lives.

2) Prevent the development of type 2 diabetes - lifestyle interventions and socially responsible policies and market interventions within and beyond the health sector can promote healthy nutrition and physical activity and prevent diabetes.

3) Stop discrimination against people with diabetes - people with diabetes can play an important role in their own health outcomes and combating diabetes more generally. Supportive legal and policy frameworks, awareness campaigns and patient-centred services uphold the rights of people with diabetes and prevent discrimination.

The key strategy of the plan is to call on governments to implement National Diabetes Programmes - Comprehensive policy and delivery approaches enhance the organisation, quality and reach of diabetes prevention and care. It is feasible and desirable for all countries to have a national diabetes programme and successful models are already in place in some countries.

The hope is that this strategy will deliver the following results:

1) Strengthen institutional frameworks - strengthen UN and country-level leadership across multiple sectors to ensure coherent, innovative and effective global and national responses to diabetes, and achieve the best possible return on investment.

2) Integrate and optimise human resources and health services - re-orient, equip and build capacity of health systems to respond effectively to the challenge of diabetes through training and workforce devel- opment, particularly at primary care level.

3) Review and streamline supply systems - optimise the provision of essential diabetes medicines and technologies through reliable and transparent procurement and distribution systems.

4) Generate and use research evidence strategically - develop a prioritised research agenda, build research capacity and apply evidence to policy and practice.

5) Monitor, evaluate and communicate outcomes - use health information systems and robust moni- toring and evaluation to assess progress.

6) Allocate appropriate and sustainable domestic and international resources - achieve innovative, sustained and predict- able resourcing for diabetes, including Official Development Assistance (ODA) for low-and middle-income countries.

7) Adopt a whole of society approach - engage governments, the private sector and civil society (including healthcare workers, academia and people with diabetes) in working together to turn the tide on diabetes.

With regard to point 7, the report comes out very much in favour of engaging business and industry in an attempt to encourage:

- property developers to improve building design for physical activity and social inclusion.

- the food industry to support wide availability of nutritious and affordable food and bever- ages, reduce marketing of unhealthy food and to adopt socially responsible business policies and practices.

In fact, this afternoon (too late for this blog post), I will attend a debate on how such interactions with industry could work and perhaps, more specifically, whether or not an organization like the IDF (or for that matter any NGO) should accept funding from industry - including those, who may be deemed to be “part of the problem”.

As the Scientific Director and CEO of the Canadian Obesity Network, Canada’s only national non-profit organization dedicated to obesity prevention and management, which, despite enthusiastic public proclamations by health ministers on their intent to address the obesity problem, currently has no sustainable public funding, this topic is obviously of considerable interest.

I look forward to reporting, on what I hope will be an enlightening debate in tomorrow’s post.

AMS
Dubai, UAE

p.s. a copy of the IDF Global Diabetes Plan is available here