Thursday, December 11, 2014

How Effective Is Obesity Management In Primary Care?

sharma-obesity-doctor-kidLosing weight with behavioural interventions in the context of a clinical trial, where you are often dealing with volunteers who are generally provided interventions that are far better structured and standardised than we can ever hope to deliver in a primary care settings, tells us little about the effectiveness of such interventions in real life.

Now a paper by Tom Wadden and colleagues from the University of Pennsylvania, published in JAMA, presents a systematic review of the behavioral treatment of obesity in patients encountered in primary care settings as delivered by primary care practitioners working alone or with trained interventionists (eg, medical assistants, registered dietitians), or by trained interventionists working independently..

A search of the literature yielded 12 trials, involving 3893 participants, that met inclusion-exclusion criteria and prespecified quality ratings.

At 6-months weight changes in the intervention groups ranged from a loss of 0.3 kg to 6.6 kg compared to a gain of 0.9 kg to a loss of 2.0 kg in the control group.

As one may expect, interventions that prescribed both reduced energy intake (eg, ≥ 500 kcal/d) and increased physical activity (eg, ≥150 minutes a week of walking), with traditional behavioral therapy, generally produced larger weight loss than interventions without all three specific components.

Also, more treatment sessions (in person or by telephone) were associated with greater mean weight loss and likelihood of patients losing 5% or more of baseline weight.

Unfortunately, overtime, weight loss in both groups declined with longer follow-up (12-24 months).

Thus, the authors conclude that,

“Intensive behavioral counseling can induce clinically meaningful weight loss, but there is little research on primary care practitioners providing such care. The present findings suggest that a range of trained interventionists, who deliver counseling in person or by telephone, could be considered for treating overweight or obesity in patients encountered in primary care settings.”

Whether any of this is worth the cost and effort was not discussed. My guess is that to see greater success in primary care we need better treatments that move well beyond the rather simplistic ‘eat-less move-more’ paradigm.

@DrSharma
Edmonton, AB

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Monday, December 8, 2014

Effectiveness Of Obesity Management For Osteoarthritis

sharma-obesity-knee-osteoarthritis1Osteoarthritis is one of the most common and disabling complications of obesity. Irrespective of whether or not the osteoarthritis is directly caused by excess weight, there is little doubt that the sheer mechanical forces acting on the affected joints will significantly impact mobility and quality of life.

Now the Canadian Agency for Drugs and Technologies in Health (CADTH) has released a report on the Clinical Effectiveness of Obesity Management Interventions Delivered in Primary Care for Patients with Osteoarthritis.

This systematic review of the literature leads to the following findings:

1) Dietary weight loss interventions, either alone or in combination with exercise produce greater reductions in the peak knee compressive force and plasma levels of interleukin-6 (IL-6) in knee OA patients compared with exercise-induced weight loss.

2) There is a significantly greater reduction in pain and improvements in functions in patients who received diet plus exercise interventions compared with either diet–only or exercise–only interventions.

3) Regardless of the type of weight-loss interventions, participants who lost 10% or more of baseline body weight had greater reductions in knee compressive force, systemic IL-6 concentrations, and pain, as well as gained greater improvement in function than those who lost less of their baseline weight.

4) Participants who lost the most weight also experienced greater loss of bone mass density at the femoral neck and hip, but not the spine, without a significant change of their baseline clinical classification with regards to osteoporosis or osteopenia.

Thus, in summary, weight loss, particularly when achieved through a combination of both diet and exercise can result in significant improvement in physical function, mobility, and pain scores in individuals with osteoarthritis.

Unfortunately, this is by no means easy to achieve and even harder to sustain.

Although I may sound like a broken record – we desperately need better treatments for obesity.

@DrSharma
Edmonton, AB

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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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Friday, November 28, 2014

When Something is Not Better Than Nothing

diet journalThis is the title of a recent article by Nikhil Dhurandar and other members of the Energy Balance Measurement Working Group (of which I am a member), published in the International Journal of Obesity and refers to the inadequacies of our current methods for assessing energy intake and expenditure.

In the paper, the authors argue that while an assessment of energy balance may well be a critical issue both for research and clinical practice, our current methods for assessing this are woefully inaccurate and may well be leading us in the wrong direction.

Thus, for example, there is no shortage of information on the fact that self-reported dietary energy intake (EI) is woefully inaccurate (despite all efforts over the past decades to try and make this more accurate) to the point of being near useless in individuals and even less meaningful in population studies – at least when it comes to the assessment of energy balance.

The same is unfortunately true for assessments of physical activity energy expenditure (PAEE) where errors ranging in the 100s of calories are the norm rather than the exception.

This leads the authors to the rather sweeping conclusion that,

“…self-reports of EI and PAEE are so poor that they are wholly unacceptable for scientific research on EI and PAEE. While new strategies for objectively determining energy balance are in their infancy, it is unacceptable to use decidedly inaccurate instruments, which may misguide health care policies, future research, and clinical judgment. The scientific and medical communities should discontinue reliance on self-reported EI and PAEE.”

While this may well hold true for research, I am not that sure about the implications for clinical practice.

This is because, the very act of self-monitoring has been shown to influence behaviour – irrespective of the precision of such monitoring (at least I am not aware of a single study showing that the accuracy of food records makes any difference to the outcome).

There is indeed overwhelming evidence that patients who use any form of self-monitoring (pen and paper or electronic) eat better and are more physically active than people who don’t.

While trying to determine someone’s precise energy balance by poring over these records is a rather futile exercise (the difference between the records and what actually happens may be in the 100s of calories), I do know that my patients who keep food and activity records do better than those who don’t.

Nevertheless, as far as research is concerned (or making clinical decisions based on assuming that the actual energy balance is anywhere close to the deceptively precise numbers calculated from such record), I agree with the authors that our current methods are highly inadequate and, what is worse, may well be misleading.

I, for one,happily ignore most of the data that comes from self-reported studies on diet or activity (which, incidentally is the vast majority of research on these issues), never mind that much of these data come from epidemiological studies, where any inference of causality is speculation at best.

On the other hand, precise or not, I do encourage all of my patients to self-monitor as I know this changes behaviour – no matter if these records are off by 100s of calories.

@DrSharma
Barcelona, Spain

ResearchBlogging.orgDhurandhar NV, Schoeller D, Brown AW, Heymsfield SB, Thomas D, Sørensen TI, Speakman JR, Jeansonne M, & Allison DB (2014). Energy balance measurement: when something is not better than nothing. International journal of obesity (2005) PMID: 25394308

 

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Wednesday, November 19, 2014

Obesity Myth: Dieting Is The Best Way To Control Your Weight

sharma-obesity-fat-dietingHere is what we had to say about the third common misconception in our paper published in Canadian Family Medicine:

Approximately two-thirds of people who lose weight will regain it within 1 year, and almost all of them will regain it within 5 years.

Although dieting (ie, caloric restriction) to lose weight is a difficult task, the maintenance of lost weight requires the patient to deploy even greater efforts.

Rather than a simple lack of willpower, the relapse of most individuals to their previous weight after otherwise successful weight loss is largely driven by the coordinated actions of metabolic, neuroendocrine, autonomic, and behavioural changes that oppose the maintenance of reduced body weight.

The few individuals successful at maintaining weight loss (at least 13.6 kg for at least 1 year) generally have common behaviour and strategies that include consuming low-energy, low-fat diets; engaging in high levels of physical activity; consistent self-monitoring of body weight and food intake; eating breakfast regularly; and demonstrating a high level of dietary restraint.

It is highly unlikely that some of this behaviour can be emulated by most of the population with excess weight.

There is also concern that unhealthy weight control methods (eg, fasting, meal skipping, laxatives, diuretics, stimulants) might ultimately lead to a larger weight regain and pose a risk to both mental and physical health.

Thus, although sustained weight loss with diet alone can be possible for some individuals, agreeing on realistic weight-loss expectations and sustainable behavioural changes is critical to avoid disappointment and nonadherence.

Weight regain (relapse) should not be framed as failure but as an expected consequence of dealing with a chronic and complex condition like obesity.

@DrSharma
Wellington, NZ

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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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