Follow me on

Does Childhood Obesity Prevention Only Work In Rich Kids?

sharma-obesity-pima-indian-kidsRecent publications suggest that the increase in childhood obesity seen in the US over the past several decades may finally be leveling off – an observation happily interpreted as a sign that not all is lost and that preventive measures may be working.

However, as a paper by Ashlesha Datar and Paul Chung, just published in JAMA pediatrics, these findings may be misleading in that they hide the increasing disparities in the prevalence of childhood obesity across ethnic and social groups.

The authors analysed data from the Early Childhood Longitudinal Study kindergarten class (ECLS-K), consisting of two separate nationally representative cohorts recruited as kindergarteners during the 1998 to 1999 and 2010 to 2011 school years, which includes approximately 17,000 and 15,560 kindergarteners, respectively.

Between 1998 and 2010, with a nearly 20% overall increase in obesity prevalence, obesity decreased nonsignificantly for the highest quintile of socioeconomic class, increased nonsignificantly for the second-highest quintile, and increased significantly for the lowest three quintiles. The greatest increase was seen in non-Hispanic black kids.

Thus, the authors point out that not only have childhood obesity rates substantially increased during the time periods of this study, but also that this increase was accompanied by a substantial increase in socioeconomic disparities as obesity decreased in children with higher socioeconomic backgrounds but increased among children with lower socioeconomic backgrounds.

Perhaps our childhood prevention measures are not reaching the kids who need them the most?

@DrSharma
Edmonton, AB

VN:F [1.9.22_1171]
Rating: 0.0/10 (0 votes cast)
VN:F [1.9.22_1171]
Rating: 0 (from 0 votes)

Comments

Variation In Access To Bariatric Surgery in Canada

sharma-obesity-canadaBased on the recent report from the Canadian Institute of Health Information on bariatric surgery in Canada, it is evident that there is considerable (almost 800%) variation in access to bariatric surgery for people with severe obesity living across Canada.

While the overall rate of surgeries in 2012-2013 for all Canadians was 4.9/ 1000 individuals with a BMI>35 (2010), this number was as high as 7.9/1,000 in Quebec and as low as 1.1./1,000 in Nova Scotia.

The only other province that comes anywhere close to the rate of surgery in Quebec is Ontario with 6.0/1,000.

The middle field, ranging from 3.0 – 3.6/1,000, is held by Newfoundland and Labrador (3.0), New Brunswick (3.1) and Alberta (3.6).

The lowest numbers, ranging from 1.1 – 1.8/1,000, are in Nova Scotia (1.1), Saskatchewan (1.7), British Columbia (1,7) and Manitoba (1.8).

To catch up with the current rate of surgery in Quebec, Alberta would need to perform an additional 613 procedures a year, while BC would need an additional 649 and Nova Scotia an additional 383 per year.

Overall, bringing the rate of surgery across Canada to the current rate in Quebec, would require an additional 3,666 surgeries per year.

Remember, even in Quebec we are talking about only 7.9 patients out of 1,000 living with a BMI greater than 35 having surgery per year.

Thus, while the overall increase of over 400% for bariatric surgery in Canada sounds impressive, it is important to note that there is considerable inequity in access across jurisdictions.

If I was a Nova Scotian seeking bariatric surgery, I’d sure be moving to Quebec.

@DrSharma
Edmonton, AB

VN:F [1.9.22_1171]
Rating: 10.0/10 (1 vote cast)
VN:F [1.9.22_1171]
Rating: 0 (from 0 votes)

Comments

Bariatric Surgery in Canada 2015

sharma-obesity-cihi-logoLast week the Canadian Institute of Health Information released a new study on the recent developments in Bariatric Surgery across Canada.

The following are the main findings:

  1. In 2012–2013, about 6,000 bariatric surgeries were performed in Canadian hospitals. This represents an almost four-fold increase over six years, due largely to increased capacity for bariatric surgery in Ontario.
  2. The typical bariatric surgery patient is a woman in her 40s who has obesity and other conditions such as diabetes, hypertension or sleep disorders. These characteristics have remained relatively consistent since 2006–2007.
  3. Overall, 5% of bariatric surgery patients experienced complications during their hospitalization for the surgery, and 6% were readmitted to hospital within 30 days of discharge. This study shows that complication and readmission rates have declined over time and are comparable to rates reported in other countries. As well, the readmission rate is similar to that for surgical patients overall in Canada (6.5%).
  4. Short-term increases in use of hospital care often follow bariatric surgery. Some patients have a noticeable change in their pattern of health care utilization after bariatric surgery. In some cases, this represents readmissions or follow-up care directly related to their surgery. In others, it may represent deferred procedures, such as joint replacements or hernia repairs, which could not be provided to patients at their starting weights. While this study examined only pre- and post-surgery hospital care, other studies have found that the surgery can reduce health care use and costs in other areas, such as prescribed medication.

The full report is available here

@DrSharma
Edmonton, AB

VN:F [1.9.22_1171]
Rating: 10.0/10 (1 vote cast)
VN:F [1.9.22_1171]
Rating: +1 (from 1 vote)

Comments

Post-Weight Loss Fat Gain in US Rangers

army-rangersAnd finally, to conclude this week’s discussion of evidence to support the notion that weight cycling predicts weight (fat) gain especially in normal weight individuals, I turn back to the paper by Dulloo and colleagues published in Obesity Reviews, which quotes these interesting findings in US Rangers:

“…U.S. Army Ranger School where about 12% of weight loss was observed following 8–9 weeks of training in a multi-stressor environment that includes energy deficit. Nindl et al. reported that at week 5 in the post-training recovery phase, body weight had overshot by 5 kg, reflected primarily in large gains in fat mass, and that all the 10 subjects in that study had higher fat mass than before weight lost. Similarly, in another 8 weeks of U.S. Army Ranger training course that consisted of four repeated cycles of restricted energy intake and refeeding, Friedl et al. showed that more weight was regained than was lost after 5 weeks of recovery following training cessation, with substantial fat overshooting (∼4 kg on average) representing an absolute increase of 40% in body fat compared with pre-training levels. From the data obtained in a parallel group of subjects, they showed that hyperphagia peaked at ∼4 weeks post-training, thereby suggesting that hyperphagia was likely persisting over the last week of refeeding, during which body fat had already exceeded baseline levels.”

Obviously, association (even in a prospective cohort) does not prove causality or, for that matter, provide insights into the physiological mechanisms underlying this observation.

All we can conclude, is that these observations in US Rangers (and the other studies cited in Dulloo’s article) are consistent with the notion that weight loss in normal weight individuals can be followed by significant weight gain, often overshooting initial weight.

Incidentally, these findings are also consistent with observational studies in women recovering from anorexia nervosa, famine, cancer survivors and other situations resulting in significant weight loss in normal weight individuals.

Certainly enough evidence to consider a work of caution against “recreational” weight loss, especially in individuals of normal weight.

@DrSharma
Edmonton, AB

ResearchBlogging.orgDulloo AG, Jacquet J, Montani JP, & Schutz Y (2015). How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery. Obesity reviews : an official journal of the International Association for the Study of Obesity, 16 Suppl 1, 25-35 PMID: 25614201

VN:F [1.9.22_1171]
Rating: 10.0/10 (2 votes cast)
VN:F [1.9.22_1171]
Rating: +2 (from 2 votes)

Comments

Will Dieting Make You Fatter? Only If You Are Skinny!

Professor Abdul Dulloo, University of Fribourg, Switzerland

Professor Abdul Dulloo, University of Fribourg, Switzerland

At the recent European Congress on Obesity, I had the occasion for a long chat with my friend and colleague Abdul Dulloo, from Friburg in Switzerland, who has worked extensively on the issue of weight regain.

I asked him how much evidence there is to support the common notion that losing weight makes you fatter – something many dieters claim to have experienced.

Indeed, both in animals and humans, weight loss, as a rule, is followed by a more rapid regain of body fat than lean body mass (i.e. preferential catch-up fat) than of lean body mass, as a result of which body composition post-weight regain results in a greater proportion of fat mass than before. But does this increased “fatness” persist over time?

This is where Dulloo made me aware of a recent paper he published in Obesity Reviews that examines this question.

What his analysis of prospective studies on this issue revealed is that paradoxically, people within a the normal weight range appear much more prone to weight gain over time with dieting than people who already have overweight or obesity.

Indeed as he points out,

“…it is dieting to lose weight in people who are in the healthy normal range of body weight, rather than in those who are overweight or obese, that most strongly and consistently predict future weight gain.”

The reasons for this rather unexpected finding are unclear and some have argued that repeated dieting to lose weight in normalweight people may represents unsuccessful attempts to counter genetic and familial predispositions to obesity – these people are genetically prone to weight gain, which is why they are dieting in the first place. Thus, rather than a causal relationship, the association between dieting and subsequent weight gain is just what would have happened to them anyway.

Others have argued that the metabolic effects resulting from the psychological “fear of fatness” (which prompts dieting) per se may increase the risk for weight gain hence a contributing factor to the obesity epidemic.

However, as Dulloo and colleagues discuss at length, based on their reanalysis of a wide range of human studies of weight loss and refeeding on body composition data on fat mass and fat-free mass (FFM) losses and regains, there is increasing support for the biological plausibility that dieting predisposes lean individuals (rather than those with overweight or obesity) to regaining more body fat than what had been lost (i.e. fat overshooting).

Overall the findings suggest that perhaps the reason why lean people regain fat faster is because their feedback signals in response to the depletion of both fat mass (i.e. adipostats) and fat-free mass (i.e. proteinstats), through the modulation of energy intake and adaptive thermogenesis, are more effective than in individuals with overweight or obesity, thus resulting in a faster rate of fat recovery relative to recovery of lean tissue (i.e. preferential catch-up fat).

In fact, it appears that lean people overshoot in terms of weight gain because the state of hyperphagia (in response to weight loss) appears to persist well beyond complete recovery of fat mass and interestingly until fat free mass is fully recovered (which may take months during which time fat gain continues).

Thus, it appears that in lean individuals “fat overshooting” following a diet is a prerequisite to allow complete recovery of fat-free mass (in obese individuals this may be less of an issue as recovery of fat-free mass is stimulated simply by the need to carry around a greater body weight).

Thus, it is easy to understand why repeated dieting and weight cycling would increase the risks for trajectories from leanness to fatness particularly in people who have a normal weight to begin with.

These findings have important public health implications and for promoting a “fear of fat”.

As Dulloo notes,

“Given the increasing prevalence of dieting in normal-weight female and male among young adults, adolescents and even children who perceive themselves as too fat (due to media, family and societal pressures), together with the high prevalence of dieting for optimizing performance among athletes in weight-sensitive sports, the notion that dieting and weight cycling may be predisposing a substantial proportion of the population to weight gain and obesity deserves greater scientific scrutiny.”

Indeed, I wonder how much of the obesity epidemic is directly attributable to normal weight people trying to lose weight for no good reason other than to look better.

@DrSharma
Edmonton, AB

ResearchBlogging.orgDulloo AG, Jacquet J, Montani JP, & Schutz Y (2015). How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery. Obesity reviews : an official journal of the International Association for the Study of Obesity, 16 Suppl 1, 25-35 PMID: 25614201

.

VN:F [1.9.22_1171]
Rating: 10.0/10 (3 votes cast)
VN:F [1.9.22_1171]
Rating: +2 (from 2 votes)

Comments
Blog Widget by LinkWithin