Wednesday, October 8, 2014

Can Education Offset The Genetic Risk For Obesity?

sharma-obesity-dna_molecule9Obesity is a highly heritable condition with considerable penetrance, especially in our obesogenic enviroment.

However, as I have pointed out before, having a genetic predisposition for obesity (like having a genetic predisposition for other diseases such as diabetes or high blood pressure) does not mean your fate is chiseled in stone. Lifestyle changes can significantly reduce the risk, but those with a stronger genetic predisposition will have to work a lot harder at not gaining weight than those who are naturally slender.

That said, a new study by Liu and colleagues from Harvard University, published in Social Science & Medicine, shows that better education may offset a substantial proportion of the genetic risk for obesity and/or diabetes.

The researchers created genetic risk scores for obesity and diabetes based on single nucleotide polymorphism (SNPs) confirmed as genome-wide significant predictors for BMI (29 SNPs) and diabetes risk (39 SNPs) in over 8000 participants in the Health and Retirement Study.

Linear regression models with years of schooling indicate that the effect of genetic risk on both HbA1c and BMI was smaller among people with more years of schooling and larger among those with less than a high school (HS) degree compared to HS degree-holders.

As one may expect, estimates from the quantile regression models consistently indicated stronger associations for years of schooling and genetic risk scores at the higher end of the outcome distribution, where individuals are at actual risk for diabetes and obesity.

In other words, the greater the genetic risk for diabetes or obesity, the greater the positive impact of finishing high-school or college.

In contrast, having less than a high-school education augmented the genetic risk for these conditions.

From these findings the authors conclude that,

“Our findings provide some support for the social trigger model, which speculates that the social environment can attenuate or exacerbate inherent genetic risks. Furthermore, it suggests social stratification may shape how genetic vulnerability is expressed. Social hierarchies based on socioeconomic status determine the health status of individuals. According to fundamental cause theory, policies and interventions must address social factors directly to have a population-level impact on disease risk . Our results show how education, a fundamental cause of health and disease, can serve as a valuable resource that offsets even innate biological risk. Education increases an individual’s ability to adapt, modify, and use surrounding resources. As such, polices that reduce disparities in education may help offset underlying genetic risk.”

This study strongly supports my view that one cannot (and should not) ignore genetic risk when studying the effect of environmental or behavioural factors in populations or individuals. Indeed, the greatest benefit of these interventions clearly appear to be found in those with the highest genetic risk.

@DrSharma
Ottawa, ON

ResearchBlogging.orgLiu SY, Walter S, Marden J, Rehkopf DH, Kubzansky LD, Nguyen T, & Glymour MM (2014). Genetic vulnerability to diabetes and obesity: Does education offset the risk? Social science & medicine (1982) PMID: 25245452

 

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Tuesday, October 7, 2014

The Freshmen 15 Are Neither 15 Nor Limited to Freshmen

sharma-obesity-black-studentsAccording to popular belief, the first year of college can be associated with a 15 pound weight gain – often referred to as “the freshman 15″.

Now, a study by Micheal Fedewa and colleagues from the University of Georgia, look at the weight trajectory in college studies in a paper published in the American Journal of Preventive Medicine.

Their systematic review and meta-analysis includes 49 studies evaluating the effect of the first year of college (and beyond) on the dependent body weight and or %body fat.

While the researchers found a statistically significant change in body weight among students, the average weight gain was a rather modest 1.6 kg during a typical 4-year college career. Interestingly, this finding is similar to previous estimates suggesting average increases ranging from 1.1. to 2.1 kg in the first year of college.

Thus, the actual average weight gain comes nowhere close to the notorious “15″.

Also, the authors found that most of the weight gain is progressive and continues throughout college – there is little evidence that most of the weight gained (if any) happens in the first year.

Thus, despite individual anecdotal experiences of weight gain, that may sometimes approach or even exceed 15 lbs, there is little scientific basis or reason for concern about the freshman 15.

Or, as the authors put it,

These results suggest that the “Freshman 15” may not pose a significant risk to students’ health, but unhealthy behaviors throughout college may lead to unfavorable changes in body weight, as weight change does not appear to stabilize as previously reported.

Perhaps it is time to put this idea to rest and move on to study issues that may be more important than this.

@DrSharma
Guelph, ON

ResearchBlogging.orgFedewa MV, Das BM, Evans EM, & Dishman RK (2014). Change in Weight and Adiposity in College Students: A Systematic Review and Meta-Analysis. American journal of preventive medicine PMID: 25241201

 

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Tuesday, September 23, 2014

5th Conference on Childhood and Adolescent Obesity, Winnipeg, Sept 23-26, 2014

The next couple of days, I will be attending the 5th Conference on Childhood and Adolescent Obesity in Winnipeg.

For a previous post on this conference and a copy of the program, click here.

For tickets to the Dr. Sharma Show in Winnipeg on September 24th, click here.

@DrSharma
Winnipeg, MB

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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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Tuesday, August 19, 2014

Can a Non-Profit Urban Food Initiative Alleviate Food Insecurity?

Doug Rauch, former President of Trader Joe's

Doug Rauch, former President of Trader Joe’s

Healthy eating (especially produce) is well out of reach for many who have hungry mouths to feed (despite ivory tower experts who proclaim that you can eat healthy for under $2 a day if you only follow their “tips”).

As food insecurity is certainly one of the key drivers of obesity especially within the lower socioeconomic strata, I was very interested in a paper by Deepak Palakshappa and colleagues, who describe a non-profit initiative to address food insecurity, in a paper published in JAMA Pediatrics.

This initiative, that has yet to open its first store, is to be launched by Doug Rauch, former president of Trader Joe’s grocery chain, who believes that nonprofit supermarkets in low-income neighborhoods can help provide nutritious low-cost foods by selling food gathered from the fresh produce and perishables that are discarded from other supermarkets. (The first store, named the Daily Table, has been proposed to open in Dorchester, a low-income neighborhood in Boston, Massachusetts.)

Indeed, there is an incredible amount of food that goes waste because it either does not meet the high standards of appearance of supermarket chains or is close to or past its “best-before” date.

As the authors point out,

“While most people believe these dates are based on safety, manufacturers and retailers focus on a product’s shelf life, which is based on peak freshness, which is a function of how the food looks and smells. Many manufacturers date their products earlier because of concerns about protecting their brand image. The US Department of Agriculture states the labels are not safety dates and if food is handled and stored properly, it should be safe to consume even if it is past the date. The confusion specifically regarding date labeling is estimated to lead to 32 billion pounds of avoidable food waste a year.”

The paper also discusses whether such an approach would be deemed ethical. As the authors are quick to point out, the first store has yet to be opened so exactly how things will play out in real life awaits to be seen. 

However, there are good reasons to assume that this initiative has the potential to increase the consumption of fruits and vegetables and offers option of purchasing low-cost healthy foods rather than mandating their consumption of healthy foods. The location of these stores in low-income neighbourhoods should help addresses the disparity in access to healthy foods by providing a convenient place for individuals who otherwise may not have healthy foods readily available.

The stores will also offer cooking and health eating classes to promote the autonomy of clients to determine with items to purchase.

The authors also hope that this approach, rather than blaming the individual, will provide an environment conducive to healthier eating while also respecting local social and cultural values.

Of course, whether all of this will work and whether or not such an initiative can be economically viable in the long term remains to be seen. Nevertheless, the initiators of this idea should at least be commended on giving this a shot.

@DrSharma
Edmonton, AB 

Hat tip to Geoff and Ximena for bringing this article to my attention

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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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