Yesterday, I attended the inaugural networking event of the Canadian Obesity Network’s Toronto Chapter. Judging by the enthusiasm of the almost 100 folks who came out to this event, this chapter appears off to a great start.
As expected for any CON event, the participants came from virtually every walk of interest in obesity – from professional to personal – research, prevention, clinic, policy, industry, NGOs.
Hopefully, we will see similar activities and chapters starting across Canada in the coming months – the success off this event shows that there is a dire need for local networking to address local issues related to obesity prevention and management.
For more information on the Toronto Chapter (CON-YYZ) click here.
For more information on how to start a CON chapter in your city click here.
Thus, a study by Asheley Skinner and colleagues, published in the New England Journal of Medicine, shows that increased cardiometabolic risk is tightly linked with severe obesity both in children and young adults.
The study looks at cross-sectional data from overweight or obese children and young adults (3-19 yrs) who were included in the US National Health and Nutrition Examination Survey (NHANES) from 1999 through 2012.
Among 8579 children and young adults with a body-mass index at the 85th percentile or higher (according to the Centers for Disease Control and Prevention growth charts), 46.9% were overweight, 36.4% had class I obesity, 11.9% had class II obesity, and 4.8% had class III obesity.
Overall, for a given weight, males tended to have higher cardiometabolic risk than females.
Even after controlling for age, race or ethnic group, more severe obesity maps more likely to be associated with low HDL cholesterol level, high systolic and diastolic blood pressures, and high triglyceride and glycated hemoglobin levels.
Importantly, while this relationship was constantly present in males, the there were fewer significant differences in these variables according to weight category among female participants, suggesting that for a given body weight, girls were less likely to be at cardiometabolic risk compared to boys.
Thus, while body weight (or body fat) may not be a precise measure of individual health, the risk for having one or more cardiometabolic risk factor increases substantially with increasing severity of obesity.
However, it is also important to note that even in kids and youth with class III obesity, 70% of participants had normal lipids and about 90% of participants did not have elevated blood pressure or glycated hemoglobin.
This points to the fact that for a given body weight there is indeed wide variability in whether or not someone actually has cardiometabolic risk factors.
Thus, whether or not it makes sense to target every kid that presents with an elevated BMI for intervention, remains to be shown – most likely such an approach would probably not be cost-effective.
As in adults, it seems that interventions in kids are probably best targeted by global risk rather than simply by numbers on a scale.
Readers may be aware of the “Resource Dilution Hypothesis”, which postulates that there is a dilution of familial resources available to children in large families, and a concentration of such resources in small ones.
This “dilution” effect could not only affect material factors (including food, participation in organized sports, higher education, etc.) but also emotional factors (including parents undivided attention, time, interaction, etc.).
While the importance of this “dilution” effect remains hotly debated, at face value, it sounds plausible.
Indeed, there is no doubt that in most Western countries (with increasing standard of living), recent decades have seen a substantial reduction in the number of offspring per family, resulting in a significant increase in first and second-borns as part of the overall population.
Now, a large longitudinal study by José Derraik and colleagues, published in the Journal of Epidemiology and Community Health, reports that first-born women (in Sweden) tend to be significantly heavier (and slightly taller) than second-born women, leading the authors to suggest that decreasing family size may have something to do with the increase in obesity seen over time in that country.
Indeed, based on this study involving 13,406 pairs of sisters who were either first-born or second-born (n=26 812), the first-born were about 2.4% heavier than their second-born sisters with a 30-40% greater chance of having overweight or obesity.
While this difference may seem rather subtle, at a population level, over generations, such effects can well result in substantial shifts in the population BMI, as a greater proportion of people are first-born. (if every family had 5 children, 20% of kids would be a first-born, If every family has 2 children, 50% of kids would be a first-born, if every family had only 1 kid, 100% of kids would be a first-born)
As interesting as this idea may seem, there are several issues with this type of analysis, which may well be confounded by all kinds of issues and can hardly prove causality. Nevertheless, a similar finding has been reported in male first-borns and the hypothesis certainly has significant face value.
Paradoxically, however, although overall family sizes have decreased, people in lower socioeconomic strata, who tend to have more kids, also tend to have the highest obesity rates. The obvious explanation for this would perhaps also implicate the “resource dilution hypothesis”, as more kids means less money for food, resulting in more (cheaper) caloric-dense processed foods and greater food insecurity.
Accordingly, I would predict that there may well be a “U” or “J” shaped relationship between family size and obesity in the offspring – if anyone has data on this, I’d certainly be interested.
While there is evidence that weight loss can be beneficial for the treatment of polycystic ovary syndrome (PCOS), there are few studies that have actually done this in a controlled fashion – even fewer in adolescents.
To test the feasibility of a dietary intervention aimed at weight loss in adolescents, Wong and colleagues from Boston Children’s Hospital, conducted a study, the results of which are published in Pediatric Obesity.
The study was conducted in 19 overweight and obese adolescents with PCOS and not using hormonal contraceptives, who were randomised either to a a low-glycaemic load or a low-fat diet.
In the 16 participants who completed the study, reduction in body fat on either diet was minimal (between 1.2 and 2.2%) with no changes in bioavailable testosterone (as the primary outcome of the study).
Not only did recruiting adolescents for this study pose a challenge (in part due to widespread use of hormonal contraception) but also the impact on weight and biochemical hyperandrogenism were marginal at best.
Clearly, as the authors note,
“Innovative strategies are needed to recruit adolescents for studies aimed at assessing independent effects of diet on features of PCOS.”
Exactly what those innovative strategies may look like, remains an open question.
According to a study conducted by a team of researchers from the US, Canada, Australia and Iceland, published in Pediatric Obesity, weight-based bullying in children and youth is the most prevalent form of youth bullying in these countries, exceeding by a substantial margin other forms of bullying including race/ethnicity, sexual orientation or religion.
According to the almost 3000 participants in this study, parents, teachers and health professionals were seen as those with the greatest potential of reducing weight-based bullying.
In addition, the majority of participants (65-87%) supported government augmentation of anti-bullying laws to include prohibiting weight-based bullying.
While these findings may not strike anyone living with obesity as surprising, they should be a reminder to the rest of us that weight-based bullying, with all of its negative consequences for mental, physical and social health, is something to be taken very seriously and needs to be opposed as much as we would oppose any other forms of bullying.