Éducation et prévention de l’obésité de l’enfant. bilan des études en population

The prevalences of overweight and obesity are increasing in France as well as in many countries around the world. Results of randomised controlled primary prevention studies in schools are summarized. They show the feasibility of improving school meals and energy expenditure during PE classes. However, the effect on overweight and obesity prevention are often modest. It is clear that the out-of-school life can totally compensate the effect of an intervention at school. Studies that have been able to modify the children's sedentary and active behaviours out of school have shown the most promising results. The National Nutrition and Health Plan in France comprises a set of actions targeting the whole population, from young children to the elderly, for several years. In that context, we may hope that the different actions undertaken in France including those at school will end with more favourable results.     

Évaluation des sites francophones spécialisés dans l’obésité accessibles au public

Obesity has now become a major public health issue. Obese people have at their disposal a huge amount of information and search for data related to their disease increasingly via the internet, while they don’t have sufficient medical knowledge.Using net scoring we have selected the ten best web sites dealing with obesity, in compliance with strict/harsh requirements. They include quality contents even though they might be criticised somehow. The internet must remain a means of finding help and advice for obese people. This source of information for motivated people, is an additional tool but cannot replace a traditional health care system.     

Morphologie et alimentation de l’enfant : Évolution au cours des dernières décennies

Growth is a favourable period to study the association between environmental factors and body composition, as many body parameters can be investigated. The analysis of secular trends in nutrition and growth could suggest hypotheses about the factors responsible for the body parameter changes over time.We have conducted several studies at different periods to assess secular trends. We also have developed growth indicators such as the BMI growth curves, the adiposity rebound and the arm muscle and arm fat areas.Since many years, increased stature has been recorded in various countries. The same trend was recorded in our studies. Mean stature in 2000 was 1.31m and 1.30m in 8-year-old boys and girls respectively. In 1960, in the French reference study, these figures were 1.27 and 1.26m, corresponding to a 4cm increase over the last 40 years. A comparison between two longitudinal studies conducted 30 years apart, indicates that the higher stature recorded at adult age in the more recent study, mainly results from an increase stature in early life. This increase mainly results from increased leg length. Birth weight recorded in studies conducted at different periods did not reveal any changes. By contrast, in school children, an increase in weight has been recorded in the last decades. Studies conducted in 10-year-old children at different time periods revealed that the prevalence of overweight defined by the 97^th centile of the French reference values was about 3% in 1965, 6% in 1980, 12% in 1995 and 16% in 2000. The age at adiposity rebound was 6.2 years in children born in 1965 and 5.6 in those born 30 years later. The earlier rebound recorded in the more recent study reflects an acceleration of growth.While children are taller, fatter, and grow faster, mean energy intake decreases over time, particularly due to a decrease in fat intake. The infant diet in many countries (by the age of 6-12 months) is characterised by high levels of proteins and low levels of fat. The high protein diet in infancy could explain the rapid growth process observed nowadays. Various studies have suggested that an accelerated growth in early life is associated with risk factors. Like in adults, obesity in children, is associated with metabolic diseases.In conclusion, growth is the period when environmental factors can have long lasting influence on body composition. The secular trends reported in many countries, such as increased stature, accelerated growth or the increasing prevalence of obesity, could result from influences taking place early in life. It is then important to develop research focussing on the identification of the early environmental factors which influence adult health.     

Rôle du préavis psychiatrique dans l’évaluation préopératoire des patients candidats à la chirurgie de l’obésité

The increase of obesity prevalence and severity, the failure of conservative treatment and the request for a long term efficient solution have given to surgery a rising role in the treatment of obesity. The psychiatric evaluation for bariatric surgery, the preparation and follow up of the patients are essential aims to reduce surgical risks and complications and improve the eating tolerance imposed by bariatric surgery.In this context the multidisciplinary team is very important, each complementary advice allowing the setting of strategies to better anticipate and manage post operative changes.The psychiatric evaluation includes the detection of formal contra-indications, the appreciation of relative indications and the assessment of eating disorders.     

Quelques aspects de la motivation à manger en fonction de l’index de masse corporelle (de la maigreur à l’obésité massive) dans un groupe de 2 509 adultes

This study examines how chronic dietary restraint, disinhibition, and hunger, as assessed by the Eating Inventory (also called the “Three Factor Eating Questionnaire”), vary over a broad range of Body Mass Index (BMI) values from leanness to massive obesity, in subjects with family obesity. EI factors were also studied as a function of personal weight history. Subjects were 2509 participants in a genetic study of obesity. BMIs ranged from 15 to 87kg/m². Multivariate analyses showed that restraint and disinhibition were significantly associated with the BMI in men, while only disinhibition was in women. Further analyses were performed after subdividing the population in 6 BMI groups. Disinhibition scores correlated strongly with hunger scores in both genders in all BMI categories; dietary restraint tended to correlate with the other two factors positively in leaner subjects, and negatively in highest BMI categories. The highest restraint scores were observed in nonobese adult women with previous obesity in childhood and/or adolescence, suggesting a beneficial influence of restraint on body weight loss. The role of behaviors associated with disinhibition in the development of body adiposity deserves further investigation.     

La publicité, quel impact sur l’alimentation de l’enfant ?

Advertisements who target children pose a real problem in health and ethical terms given the current context of the rise of obesity levels. The solutions open to legislators are, however, far from clear as highlighted by the results of research undertaken in various countries. The options tested range from a total ban of the messages to a stiffer monitoring of their contents. This article tries to shed light on the current debate and emphasizes the role that food culture can play in this context.     

De quelques maux de la prévention contemporaine. Le cas de l’obésité et du surpoids

Overweight and obesity are considered major public health issues, and many preventive campaigns are designed to prevent unhealthy eating habits among the French. But these campaigns may be ineffective, and even sometimes counterproductive. Firstly, because prevention is a moral enterprise that can lead to stigmatizing targeted people. Secondly, because the ‘merchandization’ of prevention fuels a ‘dietary cacophony’. Thirdly, the medicalisation of overweight/obesity involves some shortcomings: it can prevent us from understanding eating habits, and many general physicians are insufficiently trained to take care of overweight or obese patients.     

Que devient le tissu adipeux dans l’obésité ?

Adipose tissue exerts multiples functions related to glucose and lipid homeostasis. The adipose tissue is a site of low-grade inflammation in obese subjects, evidenced by immune cells accumulation, mainly macrophages. Pro-inflammatory factors produced by macrophages alter adipocytes biology and may contribute to the severity of metabolic complications, including insulin resistance and hepatic diseases. However, macrophages might also be beneficial to tissue homeostasis through the elimination of deficient adipocytes or pro-angiogenic effects. The cellular and molecular mechanisms of macrophage infiltration are related, at least in part, to a dialogue among hypertrophied adipocytes, macrophages and other cell-types, including lymphocytes, pre-adipocytes and endothelial cells within adipose tissue. A newly discovered consequence of adipose tissue inflammation is fibrosis that is organized both in bundles and around adipocytes. These cellular and structural alterations are only partly reversible after weight loss and reflect the pathology of adipose tissue that may contribute to the chronicity of obesity. In this context, identification of pharmacological means to maintain adipose tissue integrity remains a major challenge in the field.     

Alimentation, activité physique et surpoids chez des enfants de l’est Algérien

The prevalence of overweight and obesity were measured in a sample of 251 children aged 8 to 12 year in an urban area of the Eastern part of Algeria. IOTF references are used in order to define overweight and obesity.The overall prevalence of overweight and obesity is 21.5 %. 15.9 %. Overweight alone is found in 15.9% and obesity in 5,6 % of the children. Obese children consume less often a breakfast and less milk than that normal weight children and eat more often high fat, high carbohydrates foods. Mean caloric intakes are similar. Meals and snacking take often place while watching television. Energy percent derived from proteins but not their absolute amount and fat intakes are higher in overweight children. Most of the overweight children (78 %) do not practice any sport activity. Fat intake adjusted on energy intake is positively correlated with sport duration.This preliminary study suggest that childhood obesity is now a public health threat in Algeria.     

Obésité : que nous dit l’épidémiologie ?

In most developed and developing countries, a regular increase of the prevalence of obesity has been documented during the last decade(s) of the xxth century. The last figure from the USA is for the first time discordant with this general trend by showing a clear slowing down since year 2000. In children likewise, a rapid increase in the prevalence of obesity took place in the second half of the xxth century but recent publications from France, Switzerland, UK, USA also report a stabilization of childhood overweight and obesity prevalences. The experience of developing countries clearly shows the impact of socioeconomic status improvement and urbanization on the prevalence of obesity. In developed countries like France, a striking element was the diffuse nature of the adult obesity epidemic observed from the 1990s. The general improvement of living conditions after the Second World War probably explains the diffuse nature of the epidemics. Specifically, the changes in the nutritional status of children that happened at that time have long lasting consequences for adult obesity epidemics. Indeed, a new current in epidemiology, lifecourse epidemiology, has prompted over the past decade a new approach of the pathophysiology of chronic diseases, including obesity. Lifecourse epidemiology considers factors affecting the susceptibility to diseases over the whole life with critical periods during developmental phases. Critical periods for the susceptibility to obesity have been documented in prenatal life, during the first 6 months of postnatal life and from 3 years on starting at the time of the adiposity rebound. Parental obesity is involved at each of the critical periods. The transgenerational transmission of obesity is explained by genetic factors, shared lifestyle but also epigenetics especially during the early developmental periods. The slowing down of the childhood obesity epidemics observed in several developed countries may signal that factors affecting the early susceptibility to obesity have recently changed.     

Obésité, corpulence et souci de minceur: inégalités sociales en France et aux États-Unis

Obesity is not comparable in France and in the United States, from its width, its evolution, its age and gender distribution. Between 1970 and 2000, obesity progressed very quickly in the United States, whereas we can observe a stability in France until the middle of the 1990′s, then a deterioration. For as much, for 30 years, the relations between obesity among women - and more largely corpulence - and social hierarchy have been marked in the two countries: obesity concerns more the people - especially the women - of the working-class categories, the least rich and the least graduate people. With equal corpulence, people of the working-class categories, even if they share some of the standards of thinness, are much less concerned about excesses of weight: the women most touched by obesity belong to the groups where the average corpulence is highest and where the attention to weight is the least strong. A preventive policy of public health concerning the members of theses working-class categories could be a good objective.     

Physiopathologie de l’insulinorésistance dans le muscle squelettique et implication des fonctions mitochondriales

In modern societies, decreased physical activity, nutritional transition and aging contribute to the increase in the prevalence of obesity and its associated pathologies (as cardiovascular diseases and type 2 diabetes). Obesity is tightly correlated with insulin resistance, which appears in the early stages of type 2 diabetes. As skeletal muscle is quantitatively the main tissue involved in glucose transport in response to insulin, muscle insulin resistance is a key step in the etiology of type 2 diabetes. Several alterations of skeletal muscle insulin signaling in various models of obesity or type 2 diabetes have been evidenced and numerous underlying mechanisms have been hypothesized. Among them, muscle lipotoxicity, obesity-induced adipose tissue inflammation and oxidative stress following excess of energetic substrates could be involved, independently or synergically, in the development of muscle insulin resistance. Moreover, mitochondrial alterations have been reported in the skeletal muscle of obese or diabetic patients and animals. This suggests that mitochondrion, through its capacity of regulating cellular fatty acids flux and redox state, may play a key role in obesity-induced skeletal muscle insulin resistance.     

Lieu de contrôle chez les obèses : traduction et première étude de validation de l’échelle du lieu de contrôle du poids de saltzer

The objectives of this study are to enable the use of the concept of locus of control in the treatment of obese subjects and to verify if the presence of an alimentary disorder influences the belief in the weight’s control. The translation and validation in French is also part of the objective. We translated into French Saltzer’s specific scale of Weight Locus of Control (WLOC: weight locus of control) and then examined it’s validity. Then we compared it on general scales of the place of control (IPC of Levenson and SOC-3 of Paulhus). The subjects were both classified according to the presence of eating disorders (ED). A sample of 46 obese women (IMC>30) was tested, 20 of them without ED, and 26 with, associated to the presence ED, according to the criteria of the DSM-IV.The internal validity of WLOC is rather satisfactory. It correlates negatively with internality (IPC), personal control and interpersonal control (SOC-3). ED at the obese subjects are related on the externality of weight control and the externality of personal control. Obese subjects without ED believe more in weight control by themselves and personal control that the obese subjects with ED (Eating Disorders). Finally the scale of weight locus of control (WLOC) remains the most adapted in the treatment and the study of the obese subject.     

Rôles physiologiques des endocannabinoïdes dans le contrôle de l’homéostasie énergétique

Endocannabinoids are endogenous lipids which modulate the release of neurotransmitters and activate different signaling pathways, through the binding to cannabinoïd receptors, CB1 and CB2. Endocannabinoids are involved in the control of a variety of behavioural and neuroendocrine functions, including feeding behaviour. In the central nervous system, they essentially modulate the expression of orexigen or anorexigen neuropeptides thus resulting in the stimulation of food intake. Their peripheral targets are mainly the liver and the white adipose tissue where they stimulate lipogenesis, through the modulation of several enzymes and proteins expressions. Cannabinoïd receptor agonists are nowadays prescribed to improve appetite of people suffering from cancer or AIDS. In the same way, CB1 antagonist, such as Rimonabant, could provide efficient treatment of obesity.