Childhood Obesity: Still a Growing Problem
William F. Balistreri, MD: Hello. I'm Dr. Bill Balistreri, Professor of Pediatric Medicine at the University of Cincinnati and Cincinnati Children's Hospital. We are here today on Medscape via Skype to discuss the issue of bariatric surgery in children and adolescents.
Let me introduce my colleagues. Dr. Valerio Nobili in Rome, Italy, is Chief of the Hepatic and Metabolic Disease Unit at the Bambino Gesù Children's Hospital in Vatican City. He is also the Head of the Liver Research Laboratory. Dr. Rohit Kohli is an Associate Professor in the Department of Pediatrics here at the University of Cincinnati College of Medicine. He also serves as Co-director of the Steatohepatitis Center at the Cincinnati Children's Hospital Medical Center.
Recently published studies suggest that the rate of severe childhood obesity has doubled in the past decade. For example, data on approximately 26,000 children in the United States who participated in the National Health and Nutrition Examination Survey indicate that the rates of overweight and obesity have continued to rise since 1999, and most concerning is the fact that there has been a significant increase in the number of children with severe forms of obesity, those whose body mass index (BMI) measured 120%-140% higher than children of average healthy weight.[1,2,3]
Childhood obesity will have a significant impact on morbidity, including quality of life, comorbid conditions such as diabetes and obstructive sleep apnea, as well as mortality rates. In addition, over the course of a lifetime, the medical costs associated with childhood obesity are high.
So, what can be done? Our initial efforts must focus on prevention and healthy lifestyles for all children. However, for the severely obese patient, bariatric surgical procedures are viewed as effective treatment, reducing weight and improving comorbid conditions such as glucose intolerance.
Our colleague Tom Inge has reported favorable short-term outcomes and safety among adolescents with a median BMI higher than 50 kg/m2 who have undergone various bariatric surgical procedures. Documented beneficial effects included durable weight loss with improved physical and metabolic health as well as health-related quality of life. Most of the procedures (92%) were done without major complications.
Of specific note, metabolic improvements seen after bariatric operations may occur before substantial weight loss, suggesting that other processes may be involved. A team of researchers, including Drs. Karen Ryan; Rohit Kohli, my colleague; and Randy Seeley, here at the University of Cincinnati, have recently deciphered potential mechanisms, suggesting new targets for nonsurgical interventions to treat obesity.
I would like to turn to Dr. Kohli and ask him to review this research with us. Dr. Kohli?
How Does Bariatric Surgery Really Work?
Rohit Kohli, MBBS: Thank you so much, Dr. Balistreri and Medscape, for this opportunity. Bariatric procedures have gained prominence over the last decade to 15 years, especially within the pediatric realm of children and adolescents who are morbidly obese. For those failing other presurgical methodologies for weight loss, we have seen the laparoscopic adjustable gastric band, the Roux-en-Y gastric bypass, and, more recently, the sleeve gastrectomy gaining prominence.
The issue with these procedures has always been: How do they work? For the more logical thinker, it would be obvious that these surgical procedures are either cutting down the size of the stomach, as in the case of the Roux-en-Y gastric bypass or the sleeve gastrectomy, or constricting the top of the stomach, as in the case of the laparoscopic adjustable gastric band.
But is it just that? Is it a restrictive procedure that is causing the individual to eat less? Our work has shown (in collaboration with researchers across the world, even in Sweden with Fredrik Bäckhed's group) that not to be the case; this is more of a metabolic procedure than it is a restrictive procedure. The reason we say that is when measured carefully in terms of calorie intake, individuals can take in the same amount of calories and still lose weight and derive metabolic benefits from this surgical procedure. Specifically, when we look at sleeve gastrectomy in a mouse model of obesity, we have seen that a particular target of bile acid signaling called farnesoid X receptor (FXR) seems to be a key metabolic parameter that changes after sleeve gastrectomy. If we match weight loss by restricting calories in terms of what is available to a mouse to eat, without doing any surgery, the same mechanisms are not in play, and the metabolic benefits are not achieved similar to what a sleeve gastrectomy does. So in essence, the metabolic changes after these procedures are more important than the so-called restriction or making the stomach smaller.
Dr. Balistreri: Rohit, let me ask you, before we turn to Dr. Nobili: Does this open up opportunities for us to medically treat obesity without having to exercise the option of bariatric surgery?
Dr. Kohli: I think so, and I say that because we now understand more about how these procedures work. Through many clinical and preclinical experimental datasets, we have seen that bile acids are elevated after bariatric procedures. Maybe not so much in the case of the gastric band, but in other procedures such as Roux-en-Y gastric bypass and the sleeve gastrectomy, it has been replicated in many cohorts.
The issue then becomes: Why are these bile acids elevated, and what do they do in terms of metabolic physiologic changes? That's where the science comes in. We can now see that these metabolic processes, once set in motion, are signaling to targets that control energy expenditure, such as the membrane protein TGR5 or this nuclear receptor, FXR. If we target either the protein or the nuclear receptor, we can definitely start to see how the surgeons can be put out of business -- not that that is the target, but it would be a much safer alternative if we can find bariatric mimetics.
The European Experience
Dr. Balistreri: Thank you, Rohit. Let me now ask Dr. Nobili, before the surgeons go out of business, to discuss relevant guidelines in the efficacy and safety of these various bariatric surgical procedures in children. Dr. Nobili is coauthor of the guidelines for the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN), so he is well positioned to discuss this. Valerio, please?
Valerio Nobili, MD: First, let me thank Medscape for this kind invitation and also Professor Balistreri. It is always nice to speak with you. I'm just back from London, as you said before, for approving the ESPGHAN guidelines for bariatric surgery in pediatric patients, and this guideline was approved by the Hepatology Committee of the ESPGHAN. We believe that the biggest problem is to identify the children who need the bariatric surgery. This is, in our opinion, the most important aspect because, as you know, bariatric surgery is a very invasive technique, and we must carefully choose the candidates for this procedure.
As Professor Balistreri said, BMI is the cornerstone of our decision, along with all of the symptoms related to BMI such as diabetes, nonalcoholic steatohepatitis (NASH), hypertension, liver fibrosis, and so on. Another important aspect of our guideline is the technique we choose for surgery or for an intragastric device.
In our hospital, we are experimenting with an intragastric device, a 1-L balloon, inflated with 250 mL of nitrogen and placed in the antrum of the stomach to suppress the ghrelin axis and improve satiety. The most important data we lack at the moment are the long-term follow-up data for children who have undergone bariatric surgery. The weight loss should be sustained for a long time; otherwise, the procedure is probably useless.
Dr. Balistreri: Valerio, we talked about the data here in Cincinnati from Tom Inge. What experience have you had in your own center? Could you perhaps share some of the European data with us?
Dr. Nobili: The experience is still very young. We started our experience just last year, but it has not been quite as good. We performed, for example, 20 sleeve gastrectomies in very obese patients, and loss of weight was satisfactory. What was less satisfactory was the improvement of metabolic parameters, and in particular those related to nonalcoholic fatty liver disease. At the moment, we have performed only a few biopsies, and we have not observed what we hoped to with respect to liver histology. We observed improvement in inflammation but not in fibrosis.
Psychological and Ethical Issues
Dr. Balistreri: The bariatric surgical procedure brings with it many potential benefits, and as you gain more experience, perhaps you will see the same issues that we have seen here. There have been complications, without question. There are also questions about when this should be done, and this raises many psychological and ethical issues. I'm going to ask Rohit to highlight some of these issues to frame the discussion.
Dr. Kohli: There are complications from any surgery that we should be thinking about, and we also need to consider the appropriate age, maturity level, and physiological maturity level for these children. We are obviously talking about teenagers here. There are case reports now in the literature and in the public domain in which 4- or 5-year-old children have undergone bariatric procedures. We should definitely think about this, as a community, with open eyes. There are consequences for bone development and metabolic concerns such as mineral and vitamin B12 deficiency or beriberi developing in these children. When we put all of this together as a consequence of a bariatric procedure and weigh it against the benefits that we have just outlined, it is a fine line that we need to walk.
As a pediatrician, first and foremost, I have learned to say, "Do no harm." We need to take a step back, acknowledge that these procedures work, but in the same breath try to understand the consequences, both moral and physiological. The studies now ongoing in the United States and in Europe in which we are looking at the long-term effects of the procedures are going to be critical.
Prevention of Obesity
Dr. Balistreri: I can't help but be reminded of the line from Hamlet by Shakespeare: "Diseases desperate grown are by desperate appliance cured or not at all," and this is clearly a major desperate appliance. But I want to end on a positive note, and I'm going to ask Dr. Nobili to get us back to what pediatricians should do best, and that is prevent this problem so that we do not have a line of individuals preparing for bariatric surgery. Valerio, you have had good success with using lifestyle changes, so could you briefly tell us about your efforts at prevention or medical treatment of obesity before we apply this desperate appliance?
Dr. Nobili: When we need to use bariatric surgery, it is probably too late for that child. Prevention is the cornerstone of the treatment of obesity. Unfortunately, as you know, changes in diet and lifestyle are very hard to achieve. In our experience in more than 3000 children, only 10% reached the target BMI. Too much time elapses before the parents follow our suggestions. Sometimes, it is too late to influence insulin parameters and liver disease.
That is why we have started a lot of clinical trials (more than 5 at the moment are ongoing in our department) looking for a therapeutic approach, such as docosahexaenoic acid (DHA), vitamin E, and choline, or DHA and vitamin D. This is a new era for these patients. We observed, with only 3 months of treatment, a very impressive improvement for fatty liver disease and for the entire cluster of symptoms related to metabolic syndrome. Insulin resistance was improved more than it was with metformin, and lipid profiles are normalized after 5-6 months. We believe that the treatment should be started as soon as possible.
Establishing Criteria for Surgery in Children
Dr. Nobili: I would also like to ask another question. From your experience, what is the best time for deciding whether the child needs bariatric surgery? Should we establish a time, should we wait for a certain BMI, or are there other criteria?
Dr. Balistreri: Dr. Kohli, would you like to address that?
Dr. Kohli: I would like to address that using the same parameters that our center -- led by Drs. Tom Inge and Stavra Xanthakos -- uses, and that is to wait for a minimum age of 14 years. That is not a line in the sand; every 14-year-old is not the same. There can be exceptions, but you have to start with some guideposts. That is a relatively solid guidepost in that you are looking at both sexual maturity and physiological maturity beyond 14 years of age.
The BMI is very important as well. If you add that, in terms of being above the 99th percentile or above the 95th percentile with major comorbidities such as NASH and diabetes, I think those 2 things together -- the BMI with or without comorbid conditions plus the age -- give us a good idea of when to start thinking about these procedures.
Dr. Balistreri: Great. I want to thank both of you for raising awareness of this issue. It will take a community effort for us to prevent children from reaching the level of obesity that requires such major procedures. On the other hand, we have raised awareness of the potential benefits and, more importantly, of the mechanisms as we move forward, so perhaps we can have a better future for our children.
I want to thank both of you for your outstanding perspectives and insight. From Medscape, this is Dr. Bill Balistreri. Thank you all for listening.
Medscape Gastroenterology © 2014 WebMD, LLC
Cite this: Bariatric Surgery in Children: Is This the Right Approach? - Medscape - May 06, 2014.