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Friday, May 30, 2008

Early Obesity Predicts Early Disability?

Given the strong relationship between excess weight and emotional, physical and economic health, it may be reasonable to pose the question whether obesity is a risk factor for early disability?

This question was just addressed by Martin Neovius and colleagues from the Karolinska Institute, Stockholm, Sweden, who examined the association between obesity status in young adulthood and disability pension in Sweden (International Journal of Obesity).

The aim of this study was to investigate risk of future disability pension according to body mass index (BMI) in young adulthood. BMI was measured at military conscription (1969-1994) in 1,191,027 young male recruits. Date and cause of disability pension, death and emigration dates were collected from national registers (1971-2006).

During 28.4 million person-years, 60,024 subjects were granted disability pension. The hazard ratios (HRs) for overweight (1.36), moderate (1.87) and morbid obesity (3.04) were significantly elevated compared to normal weight individuals.

Excess disability was associated with problems related to circulatory, musculoskeletal, tumor, nervous system, and psychiatric disorders.

Based on these data, the authors suggest that productivity losses associated with adverse BMI in young adulthood appear to be large (a rather stark understatement, if I ever heard one).

Remember, this was a study on people whose BMI's were high as far back as 1969. Given our present obesity epidemic in children and young adults, I wonder what disabilty rates will look like 20 years from now.

I don't want to be the fella spreading doom and gloom all over, but it sure makes me wonder whether, despite all the talk, we are really doing all we can to prevent and treat obesity.

Edmonton, Alberta

Thursday, May 29, 2008

Addiction Drug for Obesity?

This week, Orexigen, a biopharmaceutical company in La Jolla, CA, announced that it won a patent covering its obesity drug Contrave.

Contrave actually consists of a sustained-release version of two older drugs: bupropion, which is currently used as an antidepressant and smoking cessation aid, and naltrexone, which is used for opioid addiction and alcoholism. Contrave is currently undergoing Phase III trials for obesity and the company hopes to file for FDA approval in late 2009.

Why is Contrave, a combination of two drugs that have been around for a while, novel?

Firstly, there is no doubt that depression is a common problem in treatment-seeking obese individuals, many of whom are "self-medicating" with food - i.e. eating highly palatable foods that increase serotonin levels in the brain to improve their mood (albeit temporarily). There is indeed evidence that buproprion may help some people lose weight.

Secondly, many patients with obesity will be the first to admit that for them eating is akin to an addiction - a statement that is not surprising given that opioid-mediated reward mechanisms may play an important role in the hedonic aspects of ingestive behaviour and that this behaviour may well involve exactly the same neurocircuitary that plays a role in other addictions.

So the idea of combining two drugs that address depression and addiction, respectively, is certainly one with merit and may well prove to be highly effective in obese patients in whom depression and hedonic eating are significantly contributing to hyperphagia.

I have not seen data from these trials and have no relationship with Orexigen. I do however, like the concept of this drug and can't wait to try it on some of my patients, who I can well imagine would benefit.

Obviously, we need to await the results of the Phase III program and certainly need to very carefully look at the side effect profile of the two drugs used in combination.

But I do think that this could indeed be a useful drug for some patients battling obesity - although it is unlikely to be the "magic bullet" for everyone.

Remember, obesity is a highly complex and heterogeneous disorder and there is absolutely no reason why any one treatment should work for all.

Edmonton, Alberta

Wednesday, May 28, 2008

End of US Childhood Obesity Epidemic?

So the big news yesterday in the US media and elsewhere was that the increase in childhood obesity seen over the last two decades appears to be leveling off.

This "news" comes from a paper just out in JAMA by Cynthia Ogden and colleagues from the National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland, who examined the prevalence of overweight among US children and adolescents based on data from the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey (NHANES).

Overall, in 2003-2006, 11.3% of children and adolescents aged 2 through 19 years were at or above the 97th percentile of the 2000 BMI-for-age growth charts, 16.3% were at or above the 95th percentile, and 31.9% were at or above the 85th percentile.

But the key finding of this paper is that there was no significant increase in the prevalence of obesity over the 4 time periods (1999-2000, 2001-2002, 2003-2004, and 2005-2006) for either boys or girls.

From this the authors enthusiastically conclude that the prevalence of high BMI for age among US children and adolescents showed no significant changes between 2003-2004 and 2005-2006 and no significant trends between 1999 and 2006.

So what do we make of this?

The "glass-half-full" folks will of course see this as proof that public awareness and prevention interventions are working. The "glass-half-empty" folks will be sceptical, call this a statistical "blip" and point to the fact that even a true leveling off at such a high level is nothing to be complacent about.

The real cynics will say that this is no surprise at all because any kid who can potentially get obese already is - the rest are simply "obesity resistant".

So now what? Do we pat our US colleagues on the shoulder and compliment them on the great success of their prevention efforts or do we point out that irrespective of whether the trend is leveling off or not, the current obesity rates in kids are simply unacceptable and they need to double (if not treble) their efforts at combating this epidemic?

I tend towards the latter - I think that not only in the US but also here in Canada and elsewhere we need to continue increasing our prevention efforts (and actually show that they work!), while at the same time expanding treatment options for those already struggling with excess weight.

30% obesity in kids is simply unacceptable!

Edmonton, Alberta

image by Derek Jensen

Tuesday, May 27, 2008

Paternalism and Ethical Obesity Policies

Yesterday I attended a talk by Angus Dawson, Senior Lecturer and founding Director of the Centre for Professional Ethics, Keele University, UK, who is currently a Visiting Professor, Centre for Ethics, University of Toronto.

His presentation with the title: "Ethical Obesity Policy: Paternalism, Preference Change and the Good Life" was part of the University of Alberta Health Law Institute Research Seminar series.

Dawson's basic thesis was that when it comes to preventing obesity simply providing information does not work, some form or "paternalism" (not to use the term coercion) will be required to help people change behaviours.

This is in contrast to what is happening where most policy makers (and some public health workers) still treat obesity as a matter of individual choice and focus their prevention efforts at individuals rather than addressing this issue at the more complex system level.

This is unfortunate because there is little evidence that a key contributer to the obesity epidemic is indeed epistemic or lack of knowledge - therefore trying to remedy obesity by providing knowledge does not address the root cause of the problem.

In fact, Dawson argues, there is no evidence that people today are less knowledgeable about healthy behaviours than previous generations, nor are they weaker willed or more prone to obesity by "choice".

Rather, the obesity epidemic is a consequence of systemic factors such as removing physical activity from the workplace, less time to spend at home with the family, less physical demands on commute and travel and industrialisation of our food supply.

Thus, obesity is not a result of people making poor choices but rather the result of societal changes that leave most individuals with little choice (but to become obese or fight weight gain by swimming against the stream).

This raises the issue of collective action: individuals are limited in their choice by the choices that the majority makes. For e.g. if you live in a neighbourhood where people prefer to eat at fast food restaurants and drive cars then you may have no choice but to also eat fast food and drive a car unless you are prepared to leave your neighbouhood to find a healthier restaurant and are willing to risk being run over on your bike.

Getting the majority to change their behaviour is unlikely to happen without some form of paternalism, which raises the ethical dilemma of how much individual "freedom" society as a whole is willing to sacrifice for the common good.

Examples that were cited included laws requiring the use of seat belts or helmets - issues that are surprisingly still contended by some who reserve "the right to be foolish".

Overall, not much that I have not heard before but certainly a nice summary of how complex some of the issues around obesity prevention actually are.

When it comes to obesity prevention - don't hold your breath!

Edmonton, Alberta

Monday, May 26, 2008

Do School-Based Obesity Interventions Work?

In light of the increasing number of overweight and obese kids, demand and focus on interventions aimed at school kids is increasing.

The questions, however, are:

1) is the school really the best place to intervene - or in other words, can the school compensate for poor environments in the home and the often poor parenting skills that may promote childhood obesity?

and perhaps more importantly,

2) do school-based invterventions actually work?

The latter issue was recently studied by Jonathan Kropski and colleagues from the Vanderbilt Centre for Evidence-Based Medicine, Nashville, Tennessee in a paper just out in OBESITY.

Kropski and colleagues performed a systematic review of all research published on this issue since 1990 and found only fourteen studies that were of sufficient quality to draw any conclusions. These included one nutrition-only progam, two physical activity promotion inverventions and eleven studies that combined both nutrition and activity interventions.

Based on the quality and results of these studies, only one study was designated as providing strong (grade 4 = randomzed controlled trial) evidence for the prevention of excessive weight gain in girls. Four weaker studies (observational data) provided some evidence of efficacy in boys and girls. The rest of the studies provided even weaker evidence for significantly improving measures of dietary intake, physical activity or both.

The bottom line is that from the current data, no conclusive evidence can be drawn regarding either the benefit or lack thereof for school-based intervention programs. There is certainly no evidence whatsoever that school-based interventions will indeed translate into less overweight or obesity in young adults.

Does this mean we sit back and give up? Certainly not - however, we must realise that pouring all our money into school programs as our primary approach to taming the obesity giant is based more on wishful thinking than on hard evidence.

The authors believe that despite the rather poor body of evidence, schools will play an important role in stemming current trends in overweight and obesity in children - but that is exactly it - for now this is nothing more than a "belief".

Clearly, we need more high-quality studies to determine whether or not investing in school programs is indeed cost-effective.

My guess is that without parents taking on an active role and policy makers doing all they can to reduce our current obesogenic environment, schools will have little say in the matter - but of course, I am happy to be proven wrong.

Edmonton, Alberta

Friday, May 23, 2008

Rehabilitation Research in Severe Obesity

Severe obesity, an increasingly common condition, is posing an important challenge not just for patients with this disease but also for health professionals attempting to provide the best possible care for this population.

From doors not wide enough for oversized wheelchairs to limited weight capacity of diagnostic equipment, patients with severe obesity face a wide range of important obstacles to accessing and benefiting from urgently needed health care.

We recently examined this in an article published in the Journal of Advanced Nursing, in which we reported on the need for specialized equipment and staff education to ensure adequate management of obese patients in the emergency department.

Yesterday, I attended a full-day invitation-only Think Thank on Bariatric Rehabilitation co-hosted by the Canadian Obesity Network, the University of Alberta School for Rehabilitation and Capital Health held at the TELUS Centre for Professional Development, Edmonton.

The meeting was attended by over 50 participants including University of Alberta researchers from a wide range of areas including occupational therapy, physiotherapy, rehabilitation medicine, nursing, biomechanical engineering, mechanical engineering, civil and environmental engineering, physical education, and other relevant areas.

On the Capital Health side there were several high-level administrators responsible for acute care, long-term care and community care services as well as front line health professionals from various regional hospitals and health regions.

Other stakeholders included the Canadian Association of Occupational Therapists, Emergency Medical Services as well as suppliers for bariatric equipment.

It was clear to all that there is a wide knowledge gap regarding providing the proper medical care and rehabilitative services to patients with severe obesity and that the range of challenges to the healthcare system and particularly to front-line health professionals are largely unrecognized and unstudied.

There was a consensus that bariatric rehabilitation should be high on the research agenda of various faculties within the University of Alberta and could build on many strengths in rehabilitation services that already exist within the Capital Health Region and Alberta.

I learnt a lot and look forward to working with all attendees to develop a detailed research agenda to better understand the needs and find solutions to this important but largely invisible problem.

Edmonton, Alberta

Thursday, May 22, 2008

Obesity and Hip Replacements

Overweight and obesity are well-established risk factors for osteoarthritis and a major factor in driving the increasing demand for hip and knee replacements.

How does being overweight or obese affect functional outcomes of hip surgery?

This question was addressed by André Busato and colleagues from the Institute for Evaluative Research in Orthopaedic Surgery, University of Berne, Switzerland in a paper just out in Obesity Surgery.

Busato and colleagues quantified the role of high preoperative BMI on long-term pain status and functional outcome after total hip replacements in a multi-center cohort of 20,553 primary hip replacements (18,968 patients) and 43,562 postoperative clinical examinations for a follow-up period of up to 15 years.

Despite equal pain relief in obese and lean patients, there was an almost perfect dose-effect relationship between preoperative BMI and decreased ambulation during the follow-up period.

This means that despite improvement in pain, patients with higher BMIs tend to regain less mobility following the hip replacement.

While the authors suggest that lifestyle management and pre- or post-surgical weight loss will improve outcomes, this has yet to be demonstrated in a large randomized trial.

It may well be that other factors unrelated to pain may be affecting mobility in heavier patients. In fact many factors that may have led to the weight gain in the first place may not be resolved simply by having a hip replacement.

This observation is not different from that of a previous study that I recently blogged on which reported that back surgery for pain relief in patients with spinal stenosis does not automatically result in increased mobility or weight loss.

Obesity is a multifactorial chronic disease and the long-term impact of educational and behavioural interventions is modest at best.

When present, obesity has to be addressed with the same interdisciplinary acumen and persistence as any other chronic disease.

Edmonton, Alberta

Wednesday, May 21, 2008

Obesity: It's Not TV - It's TV Dinners

People who watch more TV tend to be heavier that people who don't. The question, however, is whether it is the lack of physical activity associated with TV watching or the snacking that often goes with it that accounts for the weight gain.

This question was recently addressed by Verity Cleland and colleagues from the Menzies Research Institute, Hobart, Tasmania, Australia, in a paper just out in the American Journal of Clinical Nutrition.

This study involved a cross-sectional analysis of data from 2001 Australian adults aged 26-36 y. Waist circumference (WC) was measured at study clinics, and TV viewing time, frequency of food and beverage consumption during TV viewing, leisure time physical activity, and demographic characteristics were self-reported.

In both men and women, watching more than 3 hrs of TV per day was associated with a roughly two-fold higher risk of abdominal obesity compared to men or women watching an hour or less per day.

Interestingly, adjusting for leisure time physical activity did not change this relationship, whereas adjusting for food and beverage consumption during TV viewing did.

The authors conclude that the impact of TV viewing on weight is more likely due to the associated snacking than due to the sedentariness of sitting in front of the TV.

So if you do watch a lot of TV, watch out for those snacks and drinks.

Remember, one of the best weight management tips has always been: do not eat in front of the TV!

Edmonton, Alberta

Tuesday, May 20, 2008

Research Canada Looks at Science and Media

Yesterday, I blogged about how the Australian TV-media provides a rather nutrition-focused view of the obesity epidemic.

This raises the issue of how public media, especially in Canada, actually reports on science, especially obesity.

Those of you interested in this topic may wish to look at the just released report on Research Canada’s first Media Science Forum, Communicating Health Research in an Era of Headline News, which examined how best to communicate research findings and research issues to Canadians, elected officials and other stakeholders.

One full session was devoted to media discussion of obesity - the event was strongly supported by the Canadian Obesity Network.

The full report is available here.

A webcast of the event is available here.

Diane Finegood (picture), Director of CIHR-INMD summed the key issues around obesity as follows:

"There are barriers to really getting the change and momentum for change, as the public still sees obesity as a personal responsibility. In reality, it is a mix of societal and systemic issues. There will be no policy changes without societal demand. Scientists need to work together with the media to create this. "
I have little to add.

Edmonton, Alberta

Monday, May 19, 2008

Media on Obesity: Its Your Diet!

Clearly, judging by the daily media stories on obesity, one can hardly claim that this topic is being ignored.

But despite the barrage of reports, does the media really contribute to a better public understanding of obesity? What is being reported? And perhaps more importantly, what is not being reported?

I don’t have stats for Canadian media, but a recent study from Australia, if applicable to Canada, certainly raises a few flags.

Catrioni Bonfiglioli from the University of Sydney conducted an analysis of 50 representative TV news and current affairs items about overweight and obesity broadcast by five free-to-air television channels in New South Wales between May and October 2005.

According to the results published last year in the Medical Journal of Australia, the researchers found that the media tends to overwhelmingly focus on obesity as a problem of individuals with poor nutrition as the major cause.

I found the type of story themes noteworthy and have therefore copied them here:

Modern medical miracles: e.g Lapband surgery saves lives

Surprise or quirky news: e.g. wine may help with weight loss

Individual success stories: e.g. workplace weight-loss winner

Hunting the Holy Grail of weight loss: e.g. a diet that works

Danger in the familiar: e.g. coffee more fattening than a Big Mac

Health scare: e.g. obesity epidemic a danger to all

David and Goliath battle: e.g. McDonald’s sues activists for libel

Debunking myths: e.g. ten weight-loss myths debunked

The elixir of life: e.g. eating less and moving more is the key to living longer

Big bucks - obesity is big business: e.g. $3 mill spent on children’s survey

Government in bed with business: e.g. US government acts to stop fast food industry being sued over obesity

Celebrity: e.g. sportsman calls for activity to stop childhood obesity

Food fight: conflicts: e.g. ABC celebrates debate on food issues

Junk food TV advertising to blame: e.g. health experts and parents attack junk food advertising

Parents to blame: e.g. parents of overweight children accused of neglegt

Pester power: e.g. battle to get kids to eat healthy

Don’t brand fat children: e.g. labeling children as obese is cruel

Obesity is genetic: e.g. obesity runs in the family

The most common factor blamed for obesity was nutrition (72% of items) while inactivity (including computer games) was blamed in only 14% of items.

Individuals were blamed in 66%, industry in 8%, and society in 6%.

Overall, the general tenor of the media reports were on obesity essentially as a result of individual lifestyles and presented solutions that focused on personal responsibility for individual change – i.e. the rhetoric of “choice”.

Whether intended or unintended, clearly the Australian media reports take the spotlight off the idea that government and industry may share a responsibility for reshaping the obesogenic environment.

The focus on individual nutrition sure takes the focus off structural issues such as need to work long hours in sedentary jobs, poor urban planning, long commutes, lack of public transportation and other issues that may be key to solving the obesity epidemic, but are less comfortable to policy makers (and other stakeholders) than simply blaming the “victims”.

By promoting the idea of individual responsibility and individual solutions, the media certainly plays its part in promoting the widespread bias and discrimination against people with overweight and obesity by choosing which topics to report about and which to ignore.

I can only wonder if an analysis of the Canadian press’ reporting on obesity would reveal similar results.

Edmonton, Alberta

Friday, May 16, 2008

Meet the Canadians

Last night, the Canadian Obesity Network once again hosted a "Meet the Canadians" reception at the European Congress of Obesity in Geneva.

Once again, attendance was surprisingly enthusiastic.

As pointed out by Francois Laberge, Counseller and Consul, Canadian Embassy, Berne, Canada stands in high regard both as a destination for trainees but also for highly-qualified immigrants seeking to work in research and health care.

I was personally most happy to see so many Canadian and International CON members at the reception, including several CON Students and New Professionals.

No question, there is a growing and well respected Obesity research community in Canada that is making its mark at international meetings like ECO.

CON certainly does its part to help shine the spotlight on obesity research and expertise from Canada.

Geneva, Switzerland

Thursday, May 15, 2008

I'll Take Catch-Up With Those Fries

Yesterday, I attended the "Crosstalk" symposium at ECO 2008 here in Geneva.

Once again, I was fascinated by Abdul Dulloo's (Co-Chair of the Symposium) talk on the phenomenon of "catch-up" fat.

Simply stated, this phenomenon describes the preferential accumulation of fat tissue as part of any weight-gain process that follows an energy deprived state (See Dulloo's excellent 2008 review for more on this topic).

Interestingly, this phenomenon occurs irrespective of whether the energy-deprived state is caused by voluntary or enforced starvation, dieting, anorexia or severe illness including sepsis or cancer.

In fact, it even occurs in small-for-gestational-age babies, who manage to rapidly make up for their low birth weight by rapidly tucking away those calories in those chubby fat depots.

Even more interestingly, data suggest that the excess calories that are tucked away are only partly derived from increased caloric intake. Most of them come from preferential partitioning of energy to the fat stores, largely by dramatically turning down skeletal muscle thermogenesis.

This means than even if you are careful not to "overfeed", your lean tissue will happily deprive itself for the benefit of those fat depots.

In animal experiments, high-fat refeeding appears to make this phenomenon even more pronounced.

All of this appears to be related to substantial insulin resistance that occurs during this "regain" phase and researchers are still trying to figure out what exactly makes the muscle "slow down" in order for the fat to accumulate.

Teleologically all of this makes sense. The idea perhaps is to rapidly take up those calories (following the famine or illness) and store them away - let's worry about rebuilding the lean mass later.

Unfortunately, at least in animals, this process may be detrimental in the long term. There is now a fairly consistent body of evidence that shows "catch-up" growth to be a risk factor for the development of cardiometabolic risk factors including abdominal obesity, type 2 diabetes, and dyslipidemia - all eventually leading to heart disease.

As regular readers may recall, I recently blogged about the apparent increased risk for the metabolic syndrome with weight cycling - perhaps a reflection of this phenomenon.

Whatever the causes and consequences of catch-up weight, the phenomenon is very real - people tend to get fatter with every diet; patients recovering from cancer tend to put on massive amounts of fat when they recover - most interesting indeed.

What if abdominal obesity is not a consequence of overeating alone but rather a result of past deprivation?

I guess I was not too far off the mark, when the New York Times recently quoted me as saying,"You might want to focus on being as healthy as you can and not obsess about your weight”.

Certainly no point losing weight if it just comes back as fat - i.e. unless you seriously believe you can keep it off by sticking to your weight management strategy for life!

Geneva, Switzerland

Wednesday, May 14, 2008

Waist Management in Switzerland

This week I am at the 16th European Congress on Obesity in Geneva, Switzerland.

I have been attending ECO for the last 10 years or so and there is no question that over this time, ECO has matured into a pretty serious affair - complete with satellite meetings, treatment workshops, and young investigator events.

I am particularly proud of the fact that once again (as last year in Budapest), the Canadian Obesity Network is hosting a "Meet the Canadians" reception. This event gives the ECO attendees a chance to meet and mingle with the many Canadians who attend ECO.

My own active part at this meeting kicks off with a plenary lecture with the catchy title "A Physician's Guide to Waist Management". This talk is part of a precongress satellite symposium called "Adipose-Muscle Crosstalks in the Pathogenesis of Metabolic Syndrome" hosted by the Swiss Association for the Study of Obesity.

Other presenters include "old" friends like Abdul Dulloo (Switzerland), Hans Hauner (Germany), Gema Fruhbeck (Spain), Max Lafontan (France), Steve Smith (USA) and others.

Lots at this symposium (and congress) on adipose tissue and adipokines and how these affect metabolism and vascular function - definitely a hot topic!

Looks like an exciting week in Geneva,

Geneva, Switzerland

Tuesday, May 13, 2008

If You Think You're Too Big - You May Get Depressed

There is a widespread notion that obesity and depression go hand in hand.

This is not true. In fact, thin people are as likely to get depressed as people with overweight or obesity.

However, depression rates are higher in people who are trying to lose weight, particularly in those seeking help to do so.

So why is there more depression in the latter group?

One explanation, according to Evan Atlantis and Kylie Ball from the University of Sydney, published in the International Journal of Obesity, may be that dissatisfaction with your weight may increase your risk for psychological distress and thus depression.

Atlantis and Ball conducted a cross-sectional study on data from 17,253 individuals participating in the Australian National Health Survey 2004-2005. All variables, including weight status, weight perception and scores for psychological distress were collected by self-report.

Overweight and underweight perception increased the odds of psychological distress, whereas the actual weight status did not. This finding applied to both genders.

The authors conclude that people who perceive themselves as over- (or under-) weight are more likely to have psychological distress that may promote depression than people who do not fuss about their weight.

Whether or not this perception is actually changed by weight loss (or weight gain) remains to be seen.

Edmonton, Alberta

Monday, May 12, 2008

In Obesity Variety is Bad

Humans are omnivores and apparently our hunter-gatherer ancestors ate an extraordinary range of plant and animal foods.

The advent of culinary skills and use of spices and seasonings further enhanced the variety, taste, flavour, appearance, texture and consistency of foods.

Today, the apparently limitless choice of foods in our supermarkets, restaurants and homes is a sure sign of the importance we place on variety and variation when it comes to eating.

When trying to manage your weight, however, variety may be your downfall.

This at least is the gist of a recent study by Ramona Guerrieri and colleagues from the Department of Experimental Psychology, Maastricht University, in The Netherlands, who examined the interaction between impulsivity and a varied food environment and its influence on on food intake and overweight, published in the International Journal of Obesity.

The study is based on two observations:

1) Our current food environment offers a large variety of cheap and easily available sweet and fatty foods


2) Impulsive people may be reward sensitive and are generally less successful at inhibiting prepotent responses (i.e. a response that is or has been previously associated with positive reinforcement)

Using a rather complicated experimental design masquerading as a taste test, Guerrieri and colleagues studied 78 healthy primary school children (age: 8-10 years) regarding two aspects of impulsivity: reward sensitivity and deficient response inhibition.

The kids were studied in two groups: one was offered rather monotonous foods; the other was offered foods varied in colour, form, taste and texture.

As expected, reward sensitivity interacted with variety. In the "monotony group" there was no difference in food intake between the less and more reward-sensitive children (183 kcal+/-23 s.d. versus 180 kcal+/-21 s.d.).

However, in the "variety group" the more reward-sensitive children ate almost 70% more calories than the less reward-sensitive children (237 kcal+/-30 s.d. versus 141 kcal+/-19 s.d.).

While reward sensitivity in itself was not linked to overweight, deficient response inhibition (a measure of impulsivity) was.

Clearly, the kids with poor impulse control were handicapped when it came to dealing with variety.

Why is this important?

What the data suggest is that kids (and adults?) who have poor impulse control are more likely to overeat when faced with variety. Therefore, the incredible variety and choices of food that we have available to us, may indeed be a major factor in the problem of overeating.

As blogged previously, attention deficit disorders (ADD) are surprisingly common in obese children and adults - in our currently environment, this increased impulsivity may be an important factor contributing to their weight gain.

If your problem is impulse control - the less choices you give yourself the better.

Edmonton, Alberta

Friday, May 9, 2008

Did Someone Mention Weight?

Given its impact on health, body weight is something that is often discussed in encounters with health professionals.

The problem is that patients may not be listening or physicians may simply not be clear enough when mentioning the topic.

This at least is the result of a recent study by Allen Greiner and colleagues from the Department of Family Medicine, University of Kansas Medical Center, Kansas City, published in the Journal of General Internal Medicine.

Post-visit survey assessments of patients (456) and physicians (30) were assessed regarding whether or not they discussed weight, physical activity (PA), and diet immediately after office visits. Patient - Physician agreement was only 61%.

There was disagreement on one of the items (weight, PA, or diet) for 23% of office visits, and for 2 or more of the items for 16% of the visits.

Agreement was relatively greater for discussing weight than for discussing diet or physical activity. Physicians reported discussing weight issues more often than did patients.

The bottom line is that patients and physicians disagreed substantially about whether or not weight issues were discussed in a large number of primary care encounters in this study.

The authors suggest that physicians may be able to improve care for their obese patients by focusing discussions on specific details of diet and physical activity behaviors, and by clarifying that patients perceive weight-related information has been shared.

Whatever the case, don't assume that just because you mention weight your patient is hearing you (and vice versa?).

Edmonton, Alberta

Thursday, May 8, 2008

Genes for Weight and Weight Gain are Different

We know from twin studies that measures of weight (e.g. BMI) tend to be highly heritable - i.e. monozygotic twins are far more likely to resemble each other in terms of weight than dizygotic twins.

We also know that the ability to gain (and lose) weight is very much determined by genetic factors - i.e. for the same degree of excess energy (or energy restriction), monozygotic twins tend to resemble each other in weight gain (or loss) more than dizygotic twins. For e.g. identical twins lose virtually the same amount of weight following obesity surgery, when surgery is performed in the same setting (Hagedorn et. al).

Given this relationship, one may easily assume that genes that control body weight are the same that control weight gain.

A new study by Jacob Hjelmborg from the University of Southern Denmark, Odense together with colleagues from Finland, Italy and the US, just published in OBESITY, suggest that this may not be the case.

Hjelmsberg and colleagues anlaysed data from the longitudinal twin study of the cohort of Finnish twins (N = 10,556 twin individuals) aged 20-46 years at baseline followed up for 15 years.

Simply stated, they found a high level of heritability of BMI levels at baseline (we knew this) and a relatively high heritability of weight gain over the observation period (this is also not new).

However, in their models, it turns out that the two phenomena only show rather modest correlation at the genetic level.

What this means is that while both baseline BMI and weight gain are genetically determined, they are probably each regulated by a different set of genes.

So, while one set of genes may determine how big you are, other genes may determine how large you can get.

We know that some people are large and just stay that way all their life without losing or gaining much. Others may start out at a given size and end up gaining a lot of weight. All depends on your genetic background (and of course how this interacts with your lifestyle and other environmental factors).

Just a reminder how complex genetics actually is.

Edmonton, Alberta

Wednesday, May 7, 2008

Why Hunger Makes You Eat Crap

The best recipe for poor food choices and weight gain is to only eat when you are hungry.

This is best done by skipping meals and allowing yourself to get so hungry that you will end up eating anything edible, no matter how bad for you.

Obviously, if you are hungry and have the choice, last night's leftover pizza will prevail over carrot sticks.

So why is it more difficult to make healthy food choices when you are hungry?

Because healthy foods are seldom your favorite foods and usually not the ones that trigger your reward centres and make you feel happy and content.

Hey wait a minute! Did you not in a previous blog entry remember me making the distinction between hunger (homeostatic) eating and appetitive (hedonic) eating?

Well, it turns out the two systems are more closely linked than we may have thought - at least according to a new paper by Saima Malik and colleagues from McGill University, Montreal, Canada, just out in CELL METABOLISM.

Malik and colleagues infused the "hunger-hormone" ghrelin into volunteers and used functional MRI to look at what parts of the brain were activated in response to pictures of junk foods or scenery (controls).

It turns out that not only did ghrelin (as expected) increase the sensation of hunger, but it also increased brain activity in the amygdala, orbitofrontal cortex, anterior insula, and striatum which form part of the mesolimbic reward system involved in addictive behaviours.

This finding is new, because so far ghrelin was largely associated with the homeostatic system - i.e. the system that is more concerned with ensuring energy balance rather than the hedonic system - i.e. the system that is more about the reward you get from eating foods you like.

When you think about it, this finding sure makes sense. After all if you are hungry (and have a choice) you may as well eat the foods that you enjoy.

Unfortunately in today's world that may also mean that you are more likely to chose energy-dense foods that make you feel good, which in turn makes you eat too much - a sure recipe for weight gain.

So while in clinical practice it may make sense to distinguish between homeostatic and hedonic hyperphagia, it is important to remember that biologically the systems are linked and ingestive behaviour may well display characteristics of both systems at a given meal.

It is indeed a fine line between biological need and addiction.

Edmonton, Alberta

Tuesday, May 6, 2008

Does Presurgical Weight Loss Predict Outcomes?

Contrary to popular belief, patients who undergo obesity surgery do indeed have to make substantial lifestyle changes to be successful - obesity surgery is therefore never a "quick fix".

Therefore, many bariatric programs, including ours, often use modest presurgical weight loss as a screening tool to determine whether patients can indeed make lifestyle changes that would help them be successful after obesity surgery.

The theory is that if someone is unable to make even modest changes to their lifestyles before surgery, they will have difficulty making those changes after surgery, thereby limiting their chances for success.

But does presurgical weight loss truly predict outcomes?

This question was examined by Bushr Mrad and colleagues who performed a retrospective chart review of 562 patients who underwent surgery in our program. The results of this study were just published in the American Journal of Surgery.

One hundred forty-six patients met the inclusion criteria (23 men and 123 women). The mean age was 39.5 years, and the mean body mass index (BMI) was 52.6 kg/m(2). Comorbid disease includes diabetes (15.7%), hypertension (30.8%), mental illness (38.4%), and musculoskeletal disease (56.8%). Procedures performed were 16 vertical band gastroplasties, 43 open gastric bypasses, 52 laparoscopic gastric bypasses, and 35 laparoscopic adjustable gastric bands.

Preoperative weight change was as follows: 31 patients gained weight (21.2%), 56 patients lost weight (38.3%), and 59 patients maintained their weight (40.4%).

While in women, there was no relationship between pre- and postoperative weight loss, men who gained weight preoperatively had significantly worse outcomes.

This study shows that while in women, ability to achieve a modest presurgical weight loss may not matter, in men inability to lose weight may predict poorer success.

Obviously, this study has methodological limitations and only included 23 men - perhaps not enough to make ruling statements about how men do with surgery.

Nevertheless, for now, our program continues to expect patients to demonstrate compliance with lifestyle changes including self-monitoring before considering anyone for bariatric surgery.

Edmonton, Alberta

Monday, May 5, 2008

IFSO Guidelines for Bariatric Centres

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO), at its Council Meeting in Porto, Portugal, September 2007, approved new guidelines for Bariatric Surgical Centres.

This not only reflects the global interest in this rapidly growing field of bariatric care, but also the need for guidelines that ensure at least a minimum standard of care for patients undergoing surgery for severe obesity.

The summary document, authored by John Melissas, IFSO President (2006-2007) and Head of the Bariatric Unit, at the University Hospital Heraklion, Greece, appears in this month's issue of OBESITY SURGERY.

While most of the recommendations make good sense - this document, not surprisingly, provides a view from the surgical perspective rather than providing a framework for overall bariatric care. There is no doubt that currently the surgeons have the upper hand in this discussion, given that the data increasingly supports the role of surgery as the most effective (if not only) treatment for severe obesity.

However, as I have blogged before, obesity surgery is not just about surgery!

The following are my comments on some of the IFSO recommendations:

"Ensure that individuals who provide services in the bariatric surgery program are adequately qualified to provide such services."
Fully agree, and would probably extend this recommendation to ANYONE dealing with bariatric patients - surgery or no surgery.
"Provide ancillary services such as specialized nursing care, dietary instruction, counseling, and psychological assistance if and when needed."
Another "no-brainer" - again, not only should these ancillary services be available, but health providers in these services should all have undergone basic training in bariatric care including sensitivity training and have at least a basic understanding of the nature of severe obesity, its complications and treatment.
"Have readily available consultants in cardiology, pulmonology, psychiatry, and rehabilitation with previous experience in treating bariatric surgery patients."
I would add to the list general internists, endocrinologists, gastroenterologists, intensivists, hospitalists, pharmacists and perhaps a few other specialities.
"Ensure that basic equipment necessary for the obese patients such as scales, operating room tables, instruments, and supplies specifically designed for bariatric laparoscopic and open surgery, laparoscopic towers, wheelchairs, various other articles of furniture, and lifts that can accommodate stretchers are available, as well as a recovery room capable of providing critical care to morbidly obese patients and an intensive care unit with similar capacity."
This should be an essential requirement for ANY hospital regularly admitting severely obese patients - unfortunately, this is now the case in virtually every hospital in the Western World.
"Have the complete line of necessary equipment, instruments, items of furniture, wheel chairs, operating room tables, beds, radiology facilities such as CT scan and other facilities specially designed and suitable for morbidly and super obese patients."
Same as above - should probably have such lists available in every hospital or medical facility in Canada.
"Have experienced interventional radiologists available to take over the non- surgical management of possible anastomotic leaks and strictures."
Good one! Sometimes these would be interventional gastroenterologists. As often some of these services can be urgently needed, it may not be enough to train only one individual to deal with these issues (travel, vacation, etc.). Obviously, radiology facilities for bariatric patients would be essential (see above).
"Has supervised support groups for bariatric patients."
I agree, support groups can be most helpful for these patients - but they do need supervision to not take off on "tangents".
"Provides lifetime follow-up for the majority and not less than 75% of all bariatric surgical patients."
Obviously, patients with bariatric surgery require life-long follow up - I only do not think that this is best done by the surgeon or "surgical" centres - in fact issues in follow-up are rarely surgical.

They are more often related to nutrition, rehabilitation and psychosocial issues that can ultimately determine outcome. Ideally counseling for these problems would be provided by primary care providers, who are adequately trained in looking after these patients - it is after all not "rocket science" - the majority of patients (if correctly selected prior to surgery) will probably do well with nutritional monitoring, regular lab work and access to psychosocial services as the need arises - all the job of primary care, not that of a surgeon.

Overall the IFSO recommendations are sensible and will hopefully be adopted by policy makers and health authorities in most countries, including Canada. Personally though, I prefer the route taken by the Canadian Association of Bariatric Physicians and Surgeons (CABPS), which ensures that ALL treatment options, both surgical and non-surgical find their place in the management of these complex patients - it is unlikely that surgeons will always provide the best "non-surgical" advise to their patients.

Obesity is indeed an ideal ground for fostering interprofessional practice.

Edmonton, Alberta

Friday, May 2, 2008

Obesity Can Make you Pee Your Pants

Not a very pleasant picture: wetting your pants every time you laugh, sneeze, lift a heavy load, exercise, drink too much coffee - the medical term for this common but rarely talked about problem is urinary incontinence.

For anatomical reasons, this problem (the involuntary leakage of urine) is largely limited to women.

Experts essentially speak of three common types of incontinence (there are others):

1) Stress incontinence: loss of small amounts of urine with coughing, laughing, sneezing, exercising or other movements that increase intraabdominal pressure and thus increase pressure on the bladder.

2) Urge incontinence: involuntary loss of urine often due to (nervous) overactivity of the bladder resulting in the sudden need or urge to urinate, sometimes after drinking a glass of water or even hearing the sound of running water.

3) Mixed incontinence: as the name says - when aspects of both forms of incontinence are present.

Obesity can not only increase the risk for urinary incontinence but also makes it worse in people who have it for other reasons (e.g. after childbirth).

So how strong is the link between urinary incontinence and obesity?

This was the question asked by Townsend and colleagues from Harvard in a recent article pulbished in OBESITY.

The researchers examined the associations of BMI and waist circumference with new-onset urinary incontinence among women aged 54-79 years in the Nurses' Health Study. From 2000 to 2002, they identified 6,790 women who reported at least monthly episodes of incontinence among 35,754 women reporting no UI in 2000. They also looked at the type of incontinence in individuals who had at least weekly incontinence.

There were highly significant trends of increasing risk of urinary incontinence with increasing BMI and waist circumferenc. Women with a BMI>35 were around 70% more likely to have incontinence compared to women with BMI 21-22.9.

Interestingly, while BMI was associated with urge and mixed, but not stress incontinence, waist circumference was associated only with stress urinary incontinence.

Fortunately, urinary incontinence is a very treatable condition, whereby, when present, obesity treatment can have a significant benefit.

As I have noted before - obesity affects virtually every organ system. The distress of having obesity-related urinary incontinence can far outweigh the "inconvenience" of having high blood pressure or dyslipidemia.

Always important to remember, obesity is not just about the heart!

Edmonton, Alberta

Thursday, May 1, 2008

Lifestyle not a Determinant of Obesity in Teens?

Now here is a counter intuitive finding from Catherine Sabiston, of McGill University, and P.R.E. Crocker, of the University of British Columbia (UBC) published in the Journal of Adolescent Health earlier this year.

In their study of 900 Vancouver-area 16-18 year-old teenagers in Grades 10 through 12, neither was there a link between body mass index (BMI) values and levels of physical activity nor did the physically active teens eat a markedly healthier diet than their less-active counterparts.

If anything, the heavier teens were actually the ones making healthier food choices while the teens with “healthier” BMI values were no more likely to be physically active than those with higher, “unhealthier” values.

According to Dr. Sabiston (quoted in a press release from McGill University)

A lot of people are surprised, but when you think about it, BMI doesn’t have a huge impact on physical activity. And in terms of diet, it actually makes sense that someone who is not happy with their body might try to eat more healthily. What this study really says, is that one cannot assume that someone who is physically active necessarily eats a healthy diet – or the reverse, that someone who is more sedentary or has a high BMI by definition eats a diet of junk food."
To me the findings aren't all that surprising. I have always maintained that health cannot be simply deducted from the number on your scale and that for every overweight kid who eats mostly junk food and spends every spare minute on his Xbox, there's a skinny kid out there who's no better.

The simple truth is that eating healthy and exercising is important at any weight!

On the other hand, just as simply eating poorly and not exercising by no means guarantees weight gain - simply eating healthy and exercising does not guarantee a so-called "healthy" weight.

When everyone eats too much and no one moves, it's likely the poor kids with the "wrong" genes that pack on the pounds - the kids with the "right" genes are simply lucky and can apparently get away with their lousy lifestyles - who says life has to be fair!

Of course, the words "wrong" and "right" in the previous sentence refer to these genes in today's world. Until not all too long ago in the history of mankind, the "wrong" genes would have been just "right" and vice versa (talking of thinking in circles).

Edmonton, Alberta

[Hat tip to Michael Dwyer of CIHR for sending me the McGill press release]