Obesity - The need for an interdisciplinary approach to the prevention and treatment of a global epidemic

This report summarizes the highlights of the international symposium “Obesity - Research and Clinical Practice - a Multidimensional Perspective”; the symposium was supported by the Deutsche Forschungsgemeinschaft (DFG), the German Endocrine Society (DGE), and the German Committee of Psychosomatic Medicine (DKPM). Many renowned scientists both from abroad and from Germany gathered to discuss from various perspectives the subject of obesity - at present both scientifically and clinically a highly relevant topic. The congress was organized by the Clinic of Psychotherapy and Psychosomatics and the Department of Endocrinology, University of Essen. The meeting included more than 70 scientific presentations from basic scientists and clinicians who had gathered from North America, Canada, and Europe in Essen, Germany 23.3. - 25.3.2000.

For a long time, neither research nor public opinion paid very much attention to the clinical picture of obesity. However, the alarming prevalence of obesity not only among adults but especially among children and adolescents in the industrialized countries has aroused an up to now unknown interest in obesity and associated risk factors. There are now as many obese people in the world as there are people suffering from hunger. The financial burden, health risks, and impact on quality of life associated with this epidemic warrant a better understanding of the complex pathogenesis of obesity which covers a wide spectrum from genetic to environmental factors, neuroendocrine mechanisms, and also interpsychic and intrapsychic aspects. The emphasis of the congress was placed on an integration of biological and psychic aspects in etiology and treatment of obesity.

J. C. Seidell (Amsterdam, The Netherlands) reviewed the global epidemiological data of obesity and its implications for public health. In clinical practice and in epidemiological studies, obesity is generally defined by a body mass index (BMI) of > 30 kg/m², and overweight by a BMI between 25 and 30 kg/m². About half the adult population in Europe are either overweight or obese. There is a close relationship between BMI and the incidence of several diseases including type 2 diabetes, hypertension, coronary heart disease, and also overall mortality. All these risks are lowest in the range of BMI between 18.5 and 25 kg/m² and are greatly increased for obese subjects with a BMI above 30 kg/m². The increasing prevalence of obesity in our modern societies is the result of a combination of genetic susceptibility, increased availability of high-energy foods, and decreased physical activity. As M. Toeller (Düsseldorf, Germany) pointed out, there is a clear relation in epidemiological studies between nutritional intake and body weight. Particularly, societies with a high fat intake, accompanied by low carbohydrate and fibre intake show a higher prevalence of overweight, hyperlipidemia, and cardiovascular disease. The important role of dietary fat and low fat interventions in the prevention and treatment of obesity was further emphasized by A. Astrup (Kopenhagen, Denmark). J. Hebebrand (Marburg, Germany) summarised the current knowledge on the genetics of obesity. Genetic influences mainly operate through susceptibility genes that increase the risk but do not necessarily cause obesity. Several candidate genes have been associated with human obesity and its metabolic complications. They include genes that are important in the regulation of thermogenesis or genes that are involved in appetite regulation. Recently, the melanocortin-4 receptor gene (MC4-R) has been implicated in weight regulation and may play an important role in human obesity. W. Siffert (Essen, Germany) presented data on the association of the G protein beta subunit 825T allele with hypertension and obesity. The high frequency of the 825T allele in old ethnic populations such as pygmies, bushmen, and Australian aborigines is well compatible with the thrifty genotype hypothesis. P. Platte (Trier, Germany) provided evidence that environmental factors like high or low physical activity have to be regarded when the influences of genetic factors on body weight are investigated. D. Müller-Wieland (Cologne, Germany) reported on molecular mechanisms of insulin resistance and the role of insulin-regulated transcription factors. His data may establish a link between genetic factors, metabolic effects of obesity, and cardiovascular risk factors. An enormous number of studies have been undertaken during the last years to elucidate the role of the gene product of the ob gene, termed leptin. The biology of leptin was reviewed by P. Trayhurn (Aberdeen, U.K.) who pointed out that leptin is involved in a wide range of biological processes and is required for the normal regulation of body weight. There is, however, little evidence that the leptin system is central to the development of human obesity. P. Björntorp (Goteborg, Sweden) emphasized the clinical importance of visceral obesity which is very closely related to the risk of type 2 diabetes and cardiovascular disease. It is now well established that the accumulation of visceral fat is regulated by endocrine mechanisms. Malfunctions of the hypothalamic-pituitary-adrenal axis with elevated levels of cortisol and reductions of levels of sex steroids and growth hormone have been shown in patients with visceral obesity. J. Licinio (Los Angelos, USA) reviewed his data on the interaction between leptin and the hypothalamo-pituitary function. He could show that human leptin levels are pulsatile and are inversely related to pituitary-adrenal function. Furthermore, leptin seems also to be involved in the regulation of luteinizing hormone and growth hormone. J. Blundell (Leeds, U.K.) demonstrated the complex control of appetite and body weight as the products of a network of interactions among elements forming part of a psychobiological system. Blundell presented first data of low and high fat consumers within a sample of 3000 people in Leeds. As expected, there was only one obese proband among the low fat consumers and numerous obese probands among the high fat consumers. Blundell directed attention to the sub-sample of high fat consumers who were normal weight or even underweight discussing possible mechanisms of weight control in these probands.

J. Margraf (Basel, Switzerland) presented a representative epidemiologic study of 2063 young women in Dresden, Germany. The aim of the study was interview-based evaluation of the prevalence and incidence of the most important psychiatric disorders and the assessment of risk and protective factors influencing pathogenesis. Margraf found a clear relationship between the frequency of psychiatric disorders and the BMI. More than half of the obese women had fulfilled the criteria of a psychiatric disorder once in their life. J. Polivy (Toronto, Canada) discussed obesity as “The false hope syndrome” based on the sobering results of weight reduction programs. One view suggests that obesity is the result of a fundamental lack of discipline on the part of affected individuals. This view is undoubtedly advanced by society and the diet industry in promoting the notion that the only thing separating an individual from his or her “dream” physique is willpower and the implementation of a few simple nostrums. Unreasonable expectations usually are met. The individual is likely to feel frustrated and despondent, and to give up. The unrealistic anticipations with which one begins the self-change attempt - and the corresponding unattainable criteria for success - may thus be responsible for the failure of the attempt, creating a false hope and then dashing it. R. A. Sansone (Miamisburg, USA) presented data on the co-morbidity of obesity and Borderline Personality Disorder (BPD), a psychiatric disorder which is characterized by identity disturbance, impulsiveness and affective instability. Recent studies like the one demonstrated by Margraf have suggested a possible relationship, although not necessarily causal, between obesity and psychopathology in some individuals. According to Sansone's own data the prevalence of BP/symptomatology in obese people ranged between 7% and 25% depending on the diagnostic instrument (diagnostic interview/questionnaire). de Zwaan (Vienna, Austria) discussed the Binge Eating Disorder (BED) as a new eating disorder with its special relevance to obesity. BED is characterized by recurrent episodes of binge eating in the absence of regular compensatory behaviour such as vomiting or laxative abuse. In community samples, the prevalence of BED has been found to be 2 - 5%, in individuals who seek weight control treatment the prevalence is 30%. Although only few intervention studies have been conducted up to now, it is recommended today that treatment should first be directed at the disordered eating and associated psychopathology and then at weight loss strategies.

W. Kiess (Leipzig, Germany) gave an overview on clinical aspects of childhood obesity. In Central Europe, about 20% of children are obese and obesity is associated not only with intake of high energy food but even more important with reduced physical activity and with a lot of time spent watching television. Mueller (Kiel, Germany) presented the elegant Kiel Obesity Prevention Study (KOPS), an ongoing representative 8-year follow-up study of 1640 children. A reverse social gradient in childhood overweight as well as health related behaviours could be observed. Moreover, parental fatness had a strong influence on childhood overweight. Combined “school-” and “family-based” interventions induced a considerable change in health-related behaviours within one year. First results of KOPS are promising. J. Westenhöfer (Hamburg, Germany) compared common behavioural weight loss strategies with acquiring a driving license. What they have in common is the frequency of learning sessions of about 20 hours, although there is a wide difference between the ability to drive a car and changing eating behaviour. Westenhöfer cited the impressive 4-year follow-up trial of a combined behavioural modification program of Björvell and Rössner consisting of an initial inpatient treatment and weekly outpatient booster sessions. Mean weight loss was 11.7 kg at the end of the program which stayed pretty stable at the 10 to 12 year follow-up. Westenhöfer emphasized the need for long lasting behavioural therapy in order to achieve long term effects.

H. Hauner (Düsseldorf, Germany) summarized the current pharmacological approaches in the treatment of obesity. Drug treatment should be considered in patients with a BMI > 30 kg/m², as well as in those with a BMI > 27, if co-morbidities are present. Drug treatment should have its place as a useful part of the treatment program at least for some patients with obesity. Currently approved drugs for treatment of obesity include sibutramine, which inhibits food intake, and orlistat, which blocks fat digestion. J. Kral (New York, USA) gave an overview of surgical techniques for treating obesity. Vertical banded gastroplasty and Roux-Y gastric bypass are the main operations for obesity. Modifications of intestinal bypass reserved for special cases require particular expertise in long-term management. With regard to the increasing number of centres offering surgical especially endoscopic interventions for morbidly obese patients, he stressed the need for a careful education before the operation and professional aftercare. G. F. Adami (Genova, Italy) described the dynamics of weight-related attitudes of obese patients such as cognitive restraint, binge eating, night eating, body image disparagement, and shape over-concern following biliopancreatic diversion. He pointed out that in most obese patients after surgery, the abandoning of any preoccupation with food and dieting and the stable attainment of a socially acceptable body shape correspond to a sharp improvement in eating behaviour, body image, and psychological functioning. J. S. Torgerson (Goteborg, Sweden) presented the impressive ongoing Swedish Obese Subjects (SOS) intervention trial designed to determine whether the mortality and morbidity rates among obese individuals, who lose weight by surgical means, differ from the rates associated with conventional treatment. The results so far show that operated patients reduced their body weight by about 30 kg to 40 kg in the first 2 years. In contrast, conventional treatment did not on average cause any weight reduction at all.

The lively and rather open discussions throughout the entire congress made it clear that obesity research is expanding rapidly and going in many directions. All participants agreed to the need for interdisciplinary discussions in order to enhance both diagnostic and therapeutic potentials.