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, 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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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

  • Notification of abstract review: January 8, 2015
  • Call for late breaking abstracts open: Jan 12-30, 2015
  • Notification of late breaking abstracts and handouts and slides due : Feb 27, 2015
  • Early registration deadline: March 3, 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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Thursday, July 17, 2014

Infant Antibiotic Exposure and Obesity Risk

sharma-obesity-gut-buts1With all the interest in the role of the gut bacteriome in the development of obesity, it was only a matter of time before someone examined the relationship between antibiotic use and obesity risk.

This is exactly what Anita Kozyrskyj and colleagues from the University of Alberta, Edmonton, Canada, explored in a paper now published in the International Journal of Obesity.

For their study they linked rovincial healthcare records to clinical and survey data from a Canadian longitudinal birth cohort study, whereby antibiotic exposure during the first year of life was documented from prescription records.

Overweight and central adiposity were determined from anthropometric measurements at ages 9 (n=616) and 12 (n=431) years.

According to this analysis, infants receiving antibiotics in the first year of life were about twice as likely to be overweight later in childhood compared to those who were unexposed.

However, after adjustment for birth weight, breastfeeding, maternal overweight and other potential confounders, this association persisted in boys but not in girls. The reason for this discrepancy is not clear.

Although these findings are in line with the notion that early use of antibiotics may predispose to obesity, it is important to not that these type of studies cannot prove causality.

It may well be that other non-measured factors could explain this association (e.g. overprotective or lower SES parents may be more likely to use antibiotics in their infants – both factors are independently associated with higher rates of obesity).

Nevertheless, given the rather high rates of antibiotic exposure in infants it appears that this may well be a promising area for further research not just in the context of obesity but also for many of the other conditions that are now believed to be influenced by intestinal flora.

@DrSharma
Edmonton, AB

ResearchBlogging.orgAzad MB, Bridgman SL, Becker AB, & Kozyrskyj AL (2014). Infant antibiotic exposure and the development of childhood overweight and central adiposity. International journal of obesity (2005) PMID: 25012772

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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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