Recommendations for obesity management and prevention have come a long way.

Abstract

The obesity epidemic continues to fuel the rising global prevalence of type 2 diabetes mellitus (1Sharma A.M. Lau D.C.W. Obesity and type 2 diabetes mellitus.Can J Diabetes. 2013; 37: 63-64Abstract Full Text Full Text PDF Scopus (8) Google Scholar). By 2035, the World Health Organization predicts that 592 million people globally will have diabetes, a whopping 70% increase from 382 million people in 2013 (2Guariguata L. Whiting D.R. Hambleton I. et al.Global estimates of diabetes prevalence for 2013 and projections for 2035.Diabetes Res Clin Pract. 2014; 103: 137-149Abstract Full Text Full Text PDF PubMed Scopus (3067) Google Scholar). Based on self-reported body mass indexes (BMIs), 67% of Canadian men and 54% of Canadian women 18 years of age and older are overweight (BMI ≥25 kg/m2) or obese (BMI ≥30 kg/m2) (3Statistics Canada Obesity. Statistics Canada, Ottawa2013http://www.statcan.gc.ca/search-recherche/bb/info/obesity-obesite-eng.htmGoogle Scholar). Canada's obesity prevalence rate of 25.5% ranks fourth among the countries in the Organisation for Economic Co-operation and Development, behind the United States (US) (34.3%), Mexico (30%) and New Zealand (26.5%) and ahead of the United Kingdom (24%) (1Sharma A.M. Lau D.C.W. Obesity and type 2 diabetes mellitus.Can J Diabetes. 2013; 37: 63-64Abstract Full Text Full Text PDF Scopus (8) Google Scholar). The number of overweight or obese Canadians has continued to rise over the past 5 years, from 12.1 million in 2007 to 13.2 million in 2011 (an 8.8% increase) (4Obesity in Canada Canadian Institute for Health Information and Public Health Agency of Canada 2011. Ottawa, 2011: 1-62Google Scholar). It is important to note that 20% of Canadian youths are overweight or obese, and the number continues to rise, notably in the Maritime provinces (4Obesity in Canada Canadian Institute for Health Information and Public Health Agency of Canada 2011. Ottawa, 2011: 1-62Google Scholar). People with less education and lower socioeconomic status are more likely to be obese, and the gap is generally larger in women. Obesity, or excess adiposity, is the result of an imbalance between energy overconsumption and energy expenditure by an individual. It is associated with many chronic diseases, notably type 2 diabetes, cardiovascular disease, various forms of cancer, degenerative arthritis, back pain and disability. The causes of obesity are complex and result from interactions among biologic, behavioural, psychosocial and environmental factors, with the latter thought to be the proximal cause of the dramatic rise in the prevalence of obesity (5Swinburn B.A. Sacks G. Hall K.D. et al.The global obesity pandemic: Shaped by global drivers and local environments.Lancet. 2011; 378: 804-814Abstract Full Text Full Text PDF PubMed Scopus (2911) Google Scholar). Research over the past 3 decades has provided compelling evidence that obesity is associated with increased morbidity and mortality and that interventions could reap significant health benefits. This has led a growing number of countries to develop multi-stakeholder frameworks involving the public and business and governments at all levels so as to enact health and public health policies to prevent obesity from spreading further. Primary healthcare providers can clearly play an important role in managing and preventing overweight and obesity through counselling and other services offered to their patients. Health behaviour modification remains the cornerstone of weight management for people who are overweight or obese. Pharmacotherapy and bariatric surgery are indicated as adjuncts to health behaviour modification when patients fail to achieve or maintain the desired weight loss to improve their health status. The US Preventive Services Task Force (USPSTF) updated their recommendations in 2012 and called on clinicians to screen adults for obesity and offer intensive, multicomponent behavioural interventions to those with a class 1 obesity BMI of 30 kg/m2 or higher (6Moyer V.A. Screening for and management of obesity in adults: U.S. Preventive Services Task Force recommendation statement.Ann Intern Med. 2012; 157: 373-378Crossref PubMed Scopus (400) Google Scholar). The USPSTF reviewed new evidence regarding the potential benefits and harms of screening, as well as the safety and efficacy of nonsurgical weight-loss interventions that clinicians could feasibly offer in primary care or by referral to other providers. They concluded that there was adequate evidence that intensive, multicomponent behavioural interventions, such as individual or group counselling for obese adults, could result in an average weight loss of 4 to 7 kg (8.8 to 15.4 pounds). In addition, these interventions also appeared to improve glucose tolerance and other physiologic risk factors for cardiovascular disease. The USPSTF guidelines also recommended providing obese, but not overweight patients, with intensive, multicomponent behavioural interventions that could be carried out in the primary care setting or via referral (6Moyer V.A. Screening for and management of obesity in adults: U.S. Preventive Services Task Force recommendation statement.Ann Intern Med. 2012; 157: 373-378Crossref PubMed Scopus (400) Google Scholar). The Canadian Task Force on Preventive Health Care (CTFPHC) recently updated their evidenced-based recommendations for the prevention and management of obesity in adults (7Brauer P. Connor Gorber S. Shaw E. et al.Recommendations for prevention of weight gain and use of behavioural and pharmacologic interventions to manage overweight and obesity in adults in primary care.CMAJ. 2015; (www.cmaj.ca. DOI: 10.1503/cmaj.140887. Published online January 26, 2015.)PubMed Google Scholar). The CTFPHC focused on prevention of weight gain and the use of behavioural and pharmacologic interventions for weight loss to manage overweight and obesity in adults. The CTFPHC recommends measuring height and weight and calculating the BMIs of all Canadian adults at appropriate primary care visits. For adults who are obese and are at high risk for diabetes, the CTFPHC recommends that practitioners offer or refer their patients to structured behavioural interventions aimed at weight loss. The CTFPHC acknowledges that health-behaviour intervention reduces body weight by a modest 3.13 kg (8Peirson L. Douketis J. Ciliska D. et al.Treatment for overweight and obesity in adult populations: A systematic review and meta-analysis.CMAJ Open. 2014; 2: E306-E317Crossref Google Scholar). However, the CTFPHC stopped short of making recommendations for pharmacologic interventions (orlistat or metformin) for weight loss because of adverse side effects that occurred when compared to controls. Bariatric surgery was outside the scope of the CTFPHC updated guidelines. The updated CTFPHC and the USPSTF guidelines have come a long way since their previous recommendations in 2006 and 2003, respectively. However, even their current recommendations fall short compared to the much more comprehensive evidence-based Canadian and, more recently, the US clinical practice guidelines concerning the management and prevention of obesity (9Lau D.C. Douketis J.D. Morrison K.M. et al.2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children [summary].CMAJ. 2007; 176: S1-13Crossref PubMed Scopus (796) Google Scholar, 102013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society.Circulation. 2014; 129: S102-S138Crossref PubMed Scopus (1741) Google Scholar). The most recent clinical practice guidelines, published by the US Endocrine Society, are focused on the pharmacologic management of obesity, which has just appeared online (11Apovian C.M. Aronne L.J. Bessesen D.H. et al.Pharmacological management of obesity: An Endocrine Society clinical practice guideline.J Clin Endocrinol Metab. 2015; (Published online January 15, 2015)https://doi.org/10.1210/jc.2014-3415Crossref PubMed Scopus (679) Google Scholar). The Endocrine Society clinical practice guidelines, which are also endorsed by the Obesity Society and the American Society for Metabolic and Bariatric Surgery, represent a paradigm shift by recommending pharmacologic and health behaviour therapy to treat the weight first before addressing the obesity-related comorbidities. With the rapid advance in knowledge of the pathogenesis of obesity, the list of potential antiobesity agents has increased considerably. Antiobesity drugs lower body weight by 5% to 15% and fall into 3 major groups: centrally acting medications that inhibit appetite or promote satiety, or both; drugs that act peripherally to impair nutrient absorption; and drugs that increase energy expenditure. Orlistat, a lipase inhibitor that decreases fat absorption by 30%, is the only antiobesity agent approved for long-term therapy in Canada (12Lau D.C.W. Evidence-based Canadian obesity clinical practice guidelines: Relevance to diabetes management.Can J Diabetes. 2007; 31: 148-152Abstract Full Text Full Text PDF Scopus (2) Google Scholar). Phentermine and diethylpropion are adrenergic stimulants that inhibit appetite by increasing the release and reuptake of norepinephrine and dopamine in the brain. They are approved only for short-term use because of habit-forming properties and adverse side effects. Several drugs that have been approved in the US and elsewhere will likely become available in Canada over the next 2 years. These novel agents will add to the armamentarium and will facilitate the management of obesity by primary care practitioners. A low-dose combination of phentermine and extended-release topiramate, an antiepileptic drug, has recently been approved in the US (13Allison D.B. Gadde K.M. Garvey W.T. et al.Controlled-release phentermine/topiramate in severely obese adults: A randomized controlled trial (EQUIP).Obesity. 2012; 20: 330-342Crossref PubMed Scopus (408) Google Scholar). Lorcaserin is another centrally acting agent that decreases food consumption and promotes satiety by selectively activating 5-HT2C receptors on the anorexigenic pro-opiomelanocortin (POMC) neurons located in the hypothalamus (14Smith S.R. Weissman N.J. Anderson C.M. et al.Multicenter, placebo-controlled trial of lorcaserin for weight management.N Engl J Med. 2010; 363: 245-256Crossref PubMed Scopus (690) Google Scholar). Another combination pill approved by the US Food and Drug Administration (FDA), bupropion and naltrexone, increases dopamine activity in the brain and heightens energy expenditure by increasing the activity of POMC neurons (15Greenway F.L. Fujioka K. Plodkowski R.A. et al.Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): A multicentre, randomised, double-blind, placebo-controlled, phase 3 trial.Lancet. 2010; 376: 595-605Abstract Full Text Full Text PDF PubMed Scopus (574) Google Scholar). It regulates the dopamine reward system and controls food cravings and overeating. The most recent FDA-approved drug is liraglutide 3.0 mg, an incretin analogue that inhibits appetite and energy intake (16Astrup A. Carraro R. Finer N. et al.Safety, tolerability and sustained weight loss over 2 years with the once-daily human GLP-1 analog, liraglutide.Int J Obes (Lond). 2012; 36: 843-854Crossref PubMed Scopus (443) Google Scholar). Liraglutide at a lower dosage of 1.8 mg has already been approved in most countries for glycemic management in type 2 diabetes. An important emphasis in the Endocrine Society's clinical practice guidelines is the identification of medications, commonly prescribed for diabetes, depression and psychiatric illnesses and other chronic diseases, that might induce or be associated with weight gain. Bariatric surgery has rapidly emerged as a viable, realistic and successful long-term treatment option in obesity management. It also holds great promises as an innovative and cost-effective strategy in the treatment of type 2 diabetes. Bariatric surgery is now available in almost all the provinces across Canada and the number of procedures has increased exponentially over the past several years. The science that underlies the mechanism of weight loss and health benefits following bariatric surgery is in its infancy but is advancing at a lightning pace. The management and prevention of obesity are complex and not without controversy and debate. The supplement to this issue of Canadian Journal of Diabetes contains the abstracts submitted to the Fourth Canadian Obesity Summit and the Canadian Association of Bariatric Physicians and Surgeons. This will be the first time that the 2 organizations will be holding a joint conference together in Toronto (April 28 to May 2, 2015). It will be the largest conference that brings interested obesity researchers, clinicians, health professionals and policy makers together from across Canada, and it promises to advance knowledge of the science and practice of obesity medicine. Canadian Journal of Diabetes is proud to play its part as a strong supporter and a forum to bring to our readers the exciting advances in obesity management and prevention.