Monday, December 1, 2014

Are Sedentary Moms Promoting Childhood Obesity?

Edward Archer, PhD, University of Alabama Birmingham

Edward Archer, PhD, University of Alabama Birmingham

Last week, Edward Archer from the University of Alabama at Birmingham (UAB), published a paper in the Mayo Clinic Proceedings (to much media fanfare), suggesting that the primary driver of childhood obesity is the shifting of nutrient energy to fetal adipose tissue as a result of increased maternal energy availability paired with decreased maternal energy expenditure, resulting in fetal pancreatic b-cell and adipocyte hyperplasia – a theory, which Edwards labels the “maternal resource hypothesis”.

The primary process for these changes, as readers of these pages will have read before, is through epigenetic modification of DNA, which, together with other non-genetic modes of transmission including learned behaviours and environmental exposures (socioenvironmental evolution), leads to “phenotypic evolution”, which Edward describes as,

“…a unidirectional, progressive alteration in ontogeny that is propagated over multiple successive generations and may be quantified as the change over time in the population mean for the trait under examination (eg, height and obesity).”

Since the beginning of the 20th century, socioevironmental factors have significantly altered the energy balance equation for humans

“Socioenvironmental evolution has altered the evolution of human energy metabolism by inducing substantial decrements in EE imposed by daily life while improving both the quality and the quantity of nutrient-energy availability.”

“For example, as thermoneutral environments became ubiquitous, the energy cost of thermoregulation declined, and improved sanitation (eg, clean water and safer food) and vaccinations decreased the energy cost of supporting parasites (eg, fleas) and resisting pathogens (eg, communicable diseases and diarrheal infections).”

Over the past century, these developments have led to profound phenotypic changes including,

“progressive and cumulative increases in height, body stature and mass, birthweight, organ mass, head circumference, fat mass/adiposity as well as decreases in the age at which adolescents attain sexual maturity…”

Archer goes on to describe some of the many factors that may have changed in the past century, whereby, he singles out sedentariness as one of the key drivers of these developments (not surprising given Archer’s background in exercise science).

Thus, although one could perhaps make very similar arguments for any number of factor that may have changed in the past century to, in turn, affect insulin resistance and ultimately energy partitioning (change in diet, sleep deprivation, increasing maternal age, endocrine disruptors, antibiotic use, gut microbiota, medication use and many other factors I ca think of), Archer chooses to elevate sedentariness to being the main culprit.

While this may or may not be the full story, it does not change the thrust of the paper, which implies that we need to look for the key drivers of childhood obesity in the changes to the maternal-fetal (and early childhood) environment that have put us on this self-perpetuating unidirectional cycle of phenotypic evolution.

Ergo, the solution lies in focussing on the health behaviours (again, Archer emphasizes the role of physical activity) of moms.

While Archer largely focusses on maternal transmission, we should perhaps not forget that there is now some also evidence implicating a role for epigenetic modification and intergenerational transmission through paternal DNA – yes, dads are getting older and more sedentary too (not to mention fatter).

I do however agree with Edward, that this line of thinking may well have important implications for how we approach this epidemic.

For one,

“…the acknowledgment that obesity is the result of non-genetic evolutionary forces and not gluttony and sloth may help to alter the moralizing and demoralizing social and scientific discourse that pervades both public and clinical settings.”

Secondly,

“Future research may be most productive if funding is directed away from naive examinations of energy balance per se and redirected to investigations of interventions that alter the competitive strategies of various tissues.”

Thirdly,

“From the standpoint of the clinician, accurate patient phenotyping (inclusive of family obstetric history and metabolic profiling) may allow the targeting of women most likely to be a part of populations that have evolved beyond the metabolic tipping point and therefore require significant preconception intervention.”

While none of this may be easier or more feasible than other current efforts, they may well point us in a different direction than conventional theories about what is driving childhood obesity.

@DrSharma
Calgary, AB

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Wednesday, November 26, 2014

McKinsey on Obesity: Doing Something Beats Doing Nothing

McKinsey Overcoming ObesityLast week the McKinsey Global Institute, with much media fanfare, released a 120 page discussion paper titled, “Overcoming obesity: An initial economic analysis“, which estimates that the economic cost of the global obesity epidemic is upwards of $2 trillion, a number similar to the economic cost of tobacco consumption or armed conflicts.

The report identifies 74 interventions in 18 areas (ranging from policy and population health to health care) deemed to be cost effective, which, if implemented, could lead to annual savings of $1.2 billion in the UK National Health Services alone.

However, when it comes to the actual impact of these 74 strategies, the report is far more sobering in that it notes that many of these interventions are far from proven:

“The evidence base on the clinical and behavioral interventions to reduce obesity is far from complete, and ongoing investment in research is imperative. However, in many cases this is proving a barrier to action. It need not be so. We should experiment with solutions and try them out rather than waiting for perfect proof of what works, especially in the many areas where interventions are low risk. We have enough knowledge to be taking more action than we currently are.”

In other words, let’s not wait to find out what works – let’s just do something – anything (and keep our fingers crossed).

Thus, the report urges us to

“(1) deploy as many interventions as possible at scale and delivered effectively by the full range of sectors in society; (2) understand how to align incentives and build cooperation; and (3) do not focus unduly on prioritizing interventions because this can hamper constructive action.”

I can see why politicians would welcome these recommendations, as they are essentially a carte blanche to either doing nothing (we don’t have the evidence) or doing whatever they want (anything is better than nothing).

The fact that,

“Based on existing evidence, any single intervention is likely to have only a small overall impact on its own. A systemic, sustained portfolio of initiatives, delivered at scale, is needed to address the health burden.”

means that when any measure fails, it is not because it was the wrong measure but because there was either not enough of it or it was not complemented by additional measures.

Again, a free pass for politicians, who can pass whatever measures they want (based on their political ideologies or populistic pressure from their constituencies), without having to demonstrate that what they did, had any effect at all.

Of course, no report on obesity would be complete without also stressing the importance of “personal responsibility”, as if this was somehow more important for obesity than it is for diabetes, lung disease, heart disease, or any other disease I can think of.

Unfortunately, the report also includes rather nonsensical statements like,

“44 interventions bring 20% of overweight/obese Britons back to normal weight”

a sentence that defies the very chronic nature of obesity, where once established excess weight is vigorously “defended” by complex neuroendocrine responses that will counteract any change in energy balance to sustain excess body weight.

Thus, unfortunately, the authors fall into the common misconception about obesity simply being a matter of calories in and calories out, a balance that can be volitionally adjusted to achieve whatever body weight you wish to have.

Indeed, there is very little discussion in this “discussion paper” of the underlying biology of obesity, although it is acknowledged in passing:

“Even though there are important outstanding questions about diet composition, gut microbiome, and epigenetics, we are not walking blind with no sense of what to address. However, interventions to increase physical activity, reduce energy consumption, and address diet composition cannot just seek to reverse the historical trends that have left the population where it is today. For example, we cannot, nor would we wish to, reverse the invention of the Internet or the industrialization of agriculture. We need to assess what interventions make sense and are feasible in 2014.”

Will this report move governments to action? Or, even more importantly, will this report bring us any closer to reversing the epidemic or providing better treatments to people who already have obesity?

Readers may appreciate that I am not holding my breath quite yet.

ƒƒ@DrSharma
Edmonton, AB
ƒƒ

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Friday, November 21, 2014

Obesity Myth: Exercise is the Best Way to Lose Weight

sharma-obesity-exercise2Here is what we had to say about the role of exercise in weight management in our recent article published in Canadian Family Physician:

There is now a consistent body of evidence showing that exercise alone, despite a range of health benefits associated with regular exercise, results in rather modest weight loss (less than 2 kg on average).

One of the explanations is that exercise is often accompanied by an increase in sedentary activities and appetite and a decrease in dietary restraint that counteract the increased energy expenditure of exercise.

However, increased exercise has been shown to reduce visceral adiposity (even with minimal changes in body weight).

Individuals who include regular exercise and active living as part of a weight-loss program are more likely to improve their overall health and keep the weight off.22 This latter finding might be attributable to the effect of regular exercise on caloric intake rather than on caloric expenditure per se.

Exercise alone generally promotes modest weight loss; however, individuals who exercise regularly might improve their overall health independent of weight loss and are more likely to keep their weight off.

@DrSharma
Wellington, NZ

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Tuesday, October 28, 2014

Should A Political Prescription For Obesity Not Also Include Better Treatments?

sharma-obesity-policy1In the latest issue of the Canadian Medical Association Journal, the editors opine on the need for a political prescription for obesity – in short taxation and regulation of  high-calorie and nutrient-poor food products as the only viable approach to the obesity epidemic. As may be expected, they use the analogy of tobacco as a justification for this approach (given that actual data from government intervention on reducing the consumption of the said foods is so far lacking).

Be that as it may, what caught my attention in the article was the following passage:

“Treating obesity does not work well; preventing it would be better. The global failure to manage obesity, now considered by the American Medical Association to be a disease, may be considered a failure of the evidence-based medicine approach to treating disease….We know that most restrictive diets result in only short-term weight loss that frequently reverses and worsens in the long term, but dietary changes that are sustainable as a lifestyle choice may work. Physical activity is not enough to prevent or treat obesity and overweight, unless it is combined with some kind of dietary intervention. Family and community interventions may work somewhat better than interventions aimed at individuals, but their implementation is patchy. Bariatric surgery has good results in the treatment of morbid obesity, but its use is always going to be limited and a last resort. Pharmaceutical agents may work to some extent, but may have nasty adverse effects.”

The interesting thought here is that the authors parade the lack of effective treatment as a justification for prevention, when I would rather have used this state of affairs to call for greater investments in finding better treatments.

Not that I am not in favour of prevention – indeed, I am all for preventing heart disease, diabetes, cancer, depression, bone and joint disease and everything else.

But, at no point would I ever call for prevention as an alternative to finding better treatments for any of these conditions.

The fact that people still die of cancer should never justify us abandoning the search for better treatments – indeed, as far I can see, the whole Pink Ribbon Industry apparently focusses on “finding the cure” – not on “finding better ways to prevent breast cancer” (even if most experts believe that much of breast cancer is indeed preventable).

Just because  we still have no effective treatments for a host of other conditions, should we abandon the search for better treatments for these conditions?

In short, what irks me most about this article is not the call for prevention – indeed I am all for it!

But when the lack of effective (or safe) treatments is used to justify this call, I must disagree.

No matter how much we restrict and tax the food industry, there will always be people around, who despite their best efforts, will struggle with excess weight. Indeed, there is no reason to believe (at least not for anyone who understands the physiology of obesity) that any form of “prevention” will reverse the epidemic in those who already have the problem – i.e. in about 6 Mill Canadians. (even if we somehow miraculously reduced obesity in the population by 30% through “preventive measures” (well beyond even the most optimistic predictions) – we would still need treatments for 4 Mill Canadians – adults and kids!)

The longer we wait to find and implement effective treatments, the longer these individuals will struggle with a condition that should deserve the same efforts at treatment as we afford individuals with other “lifestyle” diseases (including heart disease, diabetes and cancer).

Let us not forget that treatments for other common conditions (e.g. hypertension, hypercholesterolemia and diabetes) were once lacking – today millions around the world benefit from these treatments – indeed, it is probably safe to say that these medications probably save more lives each year than any known efforts at regulating industry that I know of.

Indeed, if we wish to find more effective ways to manage obesity, we need to vastly increase our efforts at finding better treatments – not abandon them.

Prevention is never an alternative to also having effective treatments. The two go hand-in-hand.

@DrSharma
Edmonton, AB

 

 

 

 

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Friday, October 24, 2014

Social Network Analysis of the Obesity Research Boot Camp

bootcamp_pin_finalRegular readers may recall that for the past nine years, I have had the privilege and pleasure of serving as faculty of the Canadian Obesity Network’s annual Obesity Research Summer Bootcamp.

The camp is open to a select group of graduate and post-graduate trainees from a wide range of disciplines with an interest in obesity research. Over nine days, the trainees are mentored and have a chance to learn about obesity research in areas ranging from basic science to epidemiology and childhood obesity to health policy.

Now, a formal network analysis of bootcamp attendees, published by Jenny Godley and colleagues in the Journal of Interdisciplinary Healthcare, documents the substantial impact that this camp has on the careers of the trainees.

As the analysis of trainees who attended this camp over its first 5 years of operation (2006-2010) shows, camp attendance had a profound positive impact on their career development, particularly in terms of establishing contacts and professional relationships.

Thus, both the quantitative and the qualitative results demonstrate the importance of interdisciplinary training and relationships for career development in obesity researcher (and possibly beyond).

Personally, participation at this camp has been one of the most rewarding experiences of my career and I look forward to continuing this annual exercise for years to come.

To apply for the 2015 Bootcamp, which is also open to international trainees – click here.

@DrSharma
Toronto, ON

ResearchBlogging.orgGodley J, Glenn NM, Sharma AM, & Spence JC (2014). Networks of trainees: examining the effects of attending an interdisciplinary research training camp on the careers of new obesity scholars. Journal of multidisciplinary healthcare, 7, 459-70 PMID: 25336965

 

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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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