Apovian, Caroline M.a; Mechanick, Jeffrey I.b
aBoston University School of Medicine, Boston, Massachusetts
bMount Sinai School of Medicine, New York, New York, USA
Correspondence to Caroline M. Apovian, MD, Section of Endocrinology, Diabetes, and Nutrition, Boston Medical Center, 88 East Newton Street, Robinson Building, Suite 4400, Boston, MA 02118, USA. Tel: +1 617 638 8556; e-mail: Caroline.Apovian@BMC.Org
For many years, the medical literature, including seminal opinion papers in Current Opinions in Endocrinology, has described the characteristic pathophysiological state referred to as ‘Obesity’ and, in essence, defended the position that obesity is a disease.
This last year heralded the first certification examination for the subspecialty of Obesity Medicine by the American Board of Obesity Medicine.
In June 2013, the American Medical Association (AMA) formally recognized ‘Obesity’ as a disease. This resulted after a spirited debate by the Reference Committee and then the AMA House of Delegates, in which resolution 420, written by the American Association of Clinical Endocrinologists (AACE) and cosponsored by many other medical societies, was adopted. This declaration now joins The Obesity Society, The American Society of Metabolic and Bariatric Surgery, as well as the US Internal Revenue Service, the National Institutes of Health, and the World Health Organization to create solidarity and set the stage for a paradigm shift in obesity prevention and treatment.
But is this enough?
Beyond the semantics and residual counter-arguments that obesity is not a disease – predicated on a dominant effect of lifestyle choice, and that obesity should not be declared a disease, predicated on a fear that short-term expenses will never be outweighed by the long-term gains – there are still scientific obstacles.
Even though BMI is the currently accepted means to define obesity, it is a crude estimate of body fat and the correlation between body fat and risk of mortality from diabetes and heart disease is not perfect. In this issue of Current Opinion, we offer a summary of the work of Denis and Hamilton (pp. 369–376) at the Boston University Medical Center who have investigated the metabolically unhealthy obese (MUO), compared to the metabolically healthy obese (MHO), and found that a distinguishing factor could be the accumulation of not just visceral body fat but ectopic fat in the pericardial space. In fact, not all bariatric surgery patients who lose weight lose it from all areas, and there are some who gain pericardial fat while losing fat in other areas. These patients may be at further cardiovascular risk than those who lose fat in these visceral areas after surgery. More research is needed in this area as it is clear that BMI will not stand the test of time as a marker of unhealthy fat and metabolic disease. Moreover, imaging studies are also not a panacea; we need a convenient and cost-effective screening tool for metabolic disease from sick fat beyond BMI. Obesity scoring systems that are complications-centric offer a better methodology to gauge severity and direct intervention, but these tools will need to be validated in many settings. The study by Daniel et al. (pp. 377–388) discusses such scoring systems and some have been published recently such as the Edmonton Obesity Staging System  and the AACE Complications-Centric Obesity algorithm .
The study by Kushner and Webb-Sorensen (pp. 389–395) addresses a preventive strategy for obesity which is termed ‘lifestyle medicine’. Dietary indiscretion plus physical inactivity results in the number 2 cause of mortality in the USA, highlighting the preventable nature of obesity. However, in order for this strategy to work, the medical community must support preventive interventions such as lifestyle medicine. The adoption of obesity as a disease will likely propel comprehensive preventive and lifestyle medicine into the realm of reimbursement for medical services.
We are learning that preventive treatment of obesity must begin early in the life cycle. The study by van Grouw and Volpe (pp. 396–400) addresses the prevention and treatment of childhood obesity by novel means. This approach requires system-wide collaboration among medical, social, governmental, educational, and family communities to modulate the obesogenic environment our children confront. In order for this strategy to succeed, antiobesity legislation to promote wellness needs to target a critical mass of obesogenic threats and not just a few threats . Some examples of obesogenic cultural targets include subsidies for fruit and vegetable farming, taxation of processed and ‘junk’ foods, provisioning of more parks, exercise facilities, and sidewalks for walking, and, as opined by Welsh et al. (pp. 401–406), discouragement of sugar-sweetened beverages.
Beyond prevention, there must be a comprehensive obesity treatment strategy. Medical and surgical treatments are indeed available, though for the moment, medical interventions are few and far between. In addition, medications for obesity are rarely covered by the third-party payors. This medical inertia is compounded by the Food and Drug Administration (FDA) that has resisted approvals of antiobesity therapies, at least until recently with the appearance of phentermine/topiramate extended release and lorcaserin in the marketplace. The study by Boulghassoul-Pietrzykowska et al. (pp. 407–411) captures the new obesity treatments plus those in the pipeline near FDA approval. Medical therapy is necessary and without it, the schism between surgery and lifestyle becomes counterproductive.
Obesity may be an exemplar of how many distinct disease states interact with the layers of complexity to create a unique expression. For instance, in Asian Indians, epigenomic, dietary, cultural, and other lifestyle factors create an obese phenotype with decreased muscle mass despite a normal BMI (<23 kg/m2). Bouchonville and Villereal (pp. 412–419) discuss sarcopenia and obesity, and the confluence of these two diseases in older age groups. As experts in obesity medicine, different phenotypes will need to be recognized and interventions appropriately tailored.
The surgical management of obesity has been popularized by an expectation of expedient results and a paucity of competing strategies with comparable success. Notwithstanding the advances addressing this latter point – that lifestyle and medical interventions are now becoming more successful – there is still a clear role for bariatric surgery. Future prospects of hybridized approaches with devices and targeted medication hope to achieve total weight loss in the 25–32% range. In contrast, medications in combination with the lifestyle changes can approach 10% weight loss. The study by Neff et al. (pp. 420–428) investigates new strategies in surgical and endoscopic procedures for obesity. Endoscopic procedures which can achieve nearly 20% weight loss may serve as a bridge between medication and bariatric surgery.
The study by Ryan and Jensen (pp. 429–433) discusses the development of the second edition of the Obesity guidelines that were originally published in 2000, and have just been updated. In essence, the rigor of the literature search has exposed the difficulties of conducting obesity research in an era where obesity was not considered a disease. Hence, bariatric surgery, having been considered a last resort, dangerous, or a cop-out by patients who think that they have no willpower, has not had the focus that it deserves and the research dollars it needs to conduct sufficient randomized controlled clinical trials with appropriate comparator groups. The literature on medications for obesity is so problematic in terms of attrition in both placebo and treatment groups that the medications for obesity treatment were not even included in the critical questions asked of the literature search for the guideline update (personal communication). Perhaps, the third edition of the Obesity guidelines will have more rigorous research to summarize. In short, the future of clinical obesity research should include methods of identifying those who will develop disease from those who will stay metabolically healthy despite excess body fat. Adaptive designs may also be useful to avoid inconclusive, long-term effects of intervention as control group behaviors change over time.
Finally, all of the above commentary is moot unless physicians and the totality of the healthcare system are properly trained in obesity medicine. As we have discussed many times over, nutritional and obesity medicine training in the USA falls pathetically short of the level required to stem the tide of rising cardiometabolic disease, complications of insulin resistance, and chronic debilitation from overeating and sedentary lifestyles. We are very proud to finally write on obesity as a disease, to follow up not on words, but on action.
Conflicts of interest
J.I.M. received honoraria from Abbott Nutrition for lectures and program development.
C.M.A. has participated on the advisory boards for Amylin, Merck, Johnson and Johnson, Arena, Nutrisystem, Zafgen and Sanofi-Aventis, and has received research funding from Lilly, Amylin, Pfizer, Sanofi-Aventis, Orexigen, MetaProteomics, and the Dr Robert C. and Veronica Atkins Foundation.
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