Research on eating disorders: current status and future prospects

Investigating the Link between Eating Attitudes, Taste and Odour Preferences and the Chemical Senses

OBJECTIVES

To examine if higher degrees of pathological eating attitudes in a non-clinical sample are associated with odour and taste perception and preferences based on psychophysical ratings.

PARTICIPANTS AND METHODS

A total of 80 female university students completed the eating attitudes test (EAT-26), followed by four chemosensory measures including olfactory and gustatory perception plus perceptual ratings and preferences for food odours and tastes.

RESULTS

There were no significant correlations between EAT-26 scores and measures of olfactory and gustatory perception. However, a significant interaction effect indicated higher degrees of pathological eating attitudes may be associated with differential sensitivity to sweet and fatty food odours compared to those with lower levels of pathological eating attitudes.

CONCLUSIONS

This was the first study to examine pathological eating attitudes using food stimuli with a non-clinical sample. The results remain preliminary until replication. However, the findings highlight the need for development of measures of disordered eating attitudes and behaviours that go beyond caloric restriction.

Decision-Making Deficits Are Associated With Learning Impairments in Female College Students at High Risk for Anorexia Nervosa: Iowa Gambling Task and Prospect Valence Learning Model

This study investigated deficits in decision-making ability in female college students at high risk for anorexia nervosa (AN) using the Iowa Gambling Task (IGT) and the prospect valence learning (PVL) model. Based on scores on the Korean version of the Eating Attitude Test-26 (KEAT-26), participants were assigned to either the high risk for AN group (n = 42) or the control group (n = 43). The high risk for AN group exhibited significantly lower total net scores and block net scores on the third, fourth, and fifth blocks of the IGT than the control group did. The high risk for AN group selected cards significantly more often from the disadvantageous A and B decks and less often from the advantageous D deck than the control group did. In addition, the block net scores of the high risk for AN group did not differ across the five blocks, whereas those of the control group increased as the trials progressed. There was a significant negative correlation between IGT total net score and total score on the KEAT-26. The high risk for AN group had significantly lower values than the control group on the learning and response consistency parameters of the PVL model. These results indicate that female college students at high risk for AN have deficits in decision-making ability, and that these deficits are related to difficulties in remembering experience obtained from earlier trials and applying it to later trials. These difficulties further lead them to make decisions randomly.

Reprint of "Repeated adolescent activity-based anorexia influences central estrogen signaling and adulthood anxiety-like behaviors in rats"

Anorexia nervosa (AN) typically presents in adolescence and is highly comorbid with anxiety and depression, which often persist after elimination of AN symptomology. The activity-based anorexia (ABA) paradigm allows for evaluation of behavioral and neuroendocrine consequences of AN-like behaviors, including voluntary anorexia, hyperactivity, and disruption of the hypothalamic-pituitary-gonadal (HPG) and the hypothalamic pituitary adrenal (HPA) axis. Because ABA in adolescent females results in increased anxiety-like behavior in adulthood and the estrogen signaling system has been shown to play a role in anxiety and food intake, we investigated the role of ovarian hormones in adolescent ABA-treated rats, and long-term effects of mid- and late adolescent ABA exposure on behavior and estrogen signaling. While previous research demonstrated that two bouts of ABA during adolescence resulted in decreased time in the open arm of the elevated plus maze (EPM) and increased activity of the HPA axis in response to a novel stressor, here we show that one bout of ABA in mid-or late-adolescence did not result in the same behavioral outcome. Two exposures to ABA during adolescence were necessary to produce long-term anxiety-like behavior on the EPM. Finally, removal of ovarian hormones by ovariectomy (OVX) prior to puberty did not attenuate long-term behavioral consequences of ABA in adolescence, and estrogen receptor β (ERβ) expression level in the amygdala of ABA rats was significantly lower than control subjects. Taken together, these studies identify enduring effects of ABA in adolescent females that may be mediated by ABA-induced changes to CNS ERβ signaling that increase anxiety-like behaviors.

Eating Disorders in the Adolescent Population:

Adolescents become vulnerable to developing eating disorders as they mature. Very little is known about the prevalence, etiology, assessment, treatment, and outcome of eating disorders among adolescents. In general, research on eating disorders continues to be plagued with design flaws. Future studies need to be prospective research based on larger, more diverse samples of adolescents that represent all developmental stages of adolescence. Consistent diagnostic criteria and definitions of treatment interventions and outcomes also need to be employed. In addition, research should address the identification of protective and risk factors that predict who will actually develop an eating disorder.

When Does the “Duty to Protect” Apply with a Client Who has Anorexia Nervosa?

Individuals with eating disorders, especially those with anorexia nervosa, have the potential to experience significant harm and even death as a result of behaviors related to their condition. Because of this risk, the authors argue that there is a duty to protect (i.e., an obligation to take some action when a person is engaging or considering engaging in a behavior that may lead to self-harm) when a client's anorexia-related behavior has progressed to the point of medical jeopardy—that is, her or his life is in danger. This article reviews information on anorexia, including mortality data; ethical and legal issues when a client is believed to be a harm-to-self; and the literature related to involuntary hospitalization and compulsory treatment of clients with anorexia. The article concludes with a set of guidelines for when the duty to protect when a client has anorexia nervosa begins and with suggestions for interventions.

Prevalence of Eating Disorders Among Adolescents in the Northwest of Iran

Background:

Perceived sociocultural pressure to be thin has an important impact on disordered eating during early and middle adolescence, but less is known about late adolescence. Adolescents face special problems that are less common during childhood. Several studies indicate that the prevalence of eating disorders has been increased among adolescents.

Objectives:

The aim of the present study was to investigate the occurrence, prevalence and correlates of eating disorders (ED) among adolescents in two cities of Iran, Urmia and Tabriz.

Patients and Methods:

This was a cross-sectional survey in which 1990 adolescent boys and girls were selected through multistage random sampling. The study was based on self-report questionnaires including eating attitudes test (EAT-26) and DSM-IV criteria for the presence of eating disorders. To analyze the obtained data we calculated measures of central tendency and dispersion, linear and logistic regression and Fisher’s exact test.

Results:

According to diagnostic criteria of EAT-26, 492 students (24.2%) were at risk of ED and scored above the recommended cut-off point on EAT-26. Among 1990 students, a total of 51 cases (0.25%) of eating disorder (14 anorexia nervosa, 18 bulimia nervosa, and 19 eating disorder not otherwise specified) were diagnosed.

Conclusions:

The obtained prevalence of ED in our study was higher than previous studies in Iran. We found high numbers of boys with ED. Overweight adolescents were shown to be more susceptible to strict dieting than normal-weight adolescents. These results suggest that it is necessary to provide screening and treatment services for Iranian adolescents. Further research is needed to develop intervention programs to control eating disorders among Iranian adolescents.

Are adolescent treatment studies of eating disorders utilizing clinically relevant samples? A comparison of RCT and clinic treatment-seeking youth with eating disorders

OBJECTIVE

To assess potential selection bias in participant recruitment for randomized controlled trials (RCTs) of adolescent eating disorders (EDs), we compared participants recruited for RCTs evaluating psychosocial treatments with individuals seeking fee-for-service outpatient ED treatment [clinic treatment-seeking (CTS)].

METHOD

Participants were 214 adolescents presenting to an outpatient ED research-clinical program (92.1% female; M age = 15.4 ± 1.8 years). ANOVA and chi-square tests assessed differences between CTS participants and those presenting for no-cost treatment through RCTs. A secondary analysis compared RCT participants to participants eligible for the RCTs that opted for fee-for-service treatment.

RESULTS

RCT participants had greater baseline ED and general psychopathology (p < .001); however, CTS participants were more likely to present with a comorbid psychiatric disorder (p < .05) and higher family income (p < .05).

DISCUSSION

Results suggest that RCT participants did not have less pathology than CTS participants. While preliminary, results do not indicate a systematic population bias in selecting healthier patients for RCTs involving adolescent ED.

The role of "mixed" orexigenic and anorexigenic signals and autoantibodies reacting with appetite-regulating neuropeptides and peptides of the adipose tissue-gut-brain axis: relevance to food intake and nutritional status in patients with anorexia nervosa and bulimia nervosa

Eating disorders such as anorexia (AN) and bulimia nervosa (BN) are characterized by abnormal eating behavior. The essential aspect of AN is that the individual refuses to maintain a minimal normal body weight. The main features of BN are binge eating and inappropriate compensatory methods to prevent weight gain. The gut-brain-adipose tissue (AT) peptides and neutralizing autoantibodies play an important role in the regulation of eating behavior and growth hormone release. The mechanisms for controlling food intake involve an interplay between gut, brain, and AT. Parasympathetic, sympathetic, and serotoninergic systems are required for communication between brain satiety centre, gut, and AT. These neuronal circuits include neuropeptides ghrelin, neuropeptide Y (NPY), peptide YY (PYY), cholecystokinin (CCK), leptin, putative anorexigen obestatin, monoamines dopamine, norepinephrine (NE), serotonin, and neutralizing autoantibodies. This extensive and detailed report reviews data that demonstrate that hunger-satiety signals play an important role in the pathogenesis of eating disorders. Neuroendocrine dysregulations of the AT-gut-brain axis peptides and neutralizing autoantibodies may result in AN and BN. The circulating autoantibodies can be purified and used as pharmacological tools in AN and BN. Further research is required to investigate the orexigenic/anorexigenic synthetic analogs and monoclonal antibodies for potential treatment of eating disorders in clinical practice.

Self-esteem and social anxiety in an adolescent female eating disorder population: age and diagnostic effects

This study explored symptoms of social anxiety and multidimensional self-esteem in a clinical, adolescent female eating disorder population. Using self-report measures, data from 344 females revealed significant negative relationships between dimensions of self-esteem and social anxiety. A diagnostic difference emerged, with the restricting subgroup reporting significantly higher perceived physical appearance and global self-worth than those with binge/purge symptoms or bulimia nervosa. No significant age differences or age by diagnosis interaction effects emerged. These findings suggest that in clinical samples of adolescent eating disorders, self-esteem and social anxiety share a significant inverse relationship and seem to remain fairly constant across adolescence.

The HOPE (Helping to Outline Paediatric Eating Disorders) Project: development and debut of a paediatric clinical eating disorder registry

BACKGROUND

The HOPE (Helping to Outline Paediatric Eating Disorders) Project is an ongoing registry study made up of a sequential cross-sectional sample prospectively recruited over 17 years, and is designed to answer empirical questions about paediatric eating disorders. This paper introduces the HOPE Project, describes the registry sample to-date, and discusses future directions and challenges and accomplishments. The project and clinical service were established in a tertiary academic hospital in Western Australia in 1996 with a service development grant. Research processes were inbuilt into the initial protocols and data collection was maintained in the following years. Recognisable progress with the research agenda accelerated only when dedicated research resources were obtained. The registry sample consists of consecutive children and adolescents assessed at the eating disorder program from 1996 onward. Standardised multidisciplinary data collected from family intake interview, parent and child clinical interviews, medical review, parent, child and teacher psychometric assessments, and inpatient admission records populate the HOPE Project database.

RESULTS

The registry database to-date contains 941 assessments, of whom 685 met DSM-IV diagnostic criteria for an eating disorder at admission. The majority of the sample were females (91%) from metropolitan Perth (83%). The cases with eating disorders consist of eating disorders not otherwise specified (68%), anorexia nervosa (25%) and bulimia nervosa (7%). Among those with eating disorders, a history of weight loss since illness onset was almost universal (96%) with fear of weight gain (71%) common, and the median duration of illness was 8 months.

CONCLUSIONS

Over the next five years and more, we expect that the HOPE Project will make a strong scientific contribution to paediatric eating disorders research and will have important real-world applications to clinical practice and policy as the research unfolds.

Factors associated with abnormal eating attitudes among Greek adolescents

OBJECTIVE

To estimate the prevalence of abnormal eating attitudes among Greek adolescents and identify possible risk factors associated with these attitudes.

DESIGN

Cross-sectional, school-based study.

SETTING

Six randomly selected schools in Patras, southern Greece.

PARTICIPANTS

The study population consisted of 540 Greek students aged 13-18 years, and the response rate was 97%.

MAIN OUTCOME MEASURE

The dependent variable was scores on the Eating Attitudes Test-26, with scores > or = 20 indicating abnormal eating attitudes.

ANALYSIS

Bivariate analysis included independent Student t test, chi-square test, and Fisher's exact test. Multivariate logistic regression analysis was applied for the identification of the predictive factors, which were associated independently with abnormal eating attitudes. A 2-sided P value of less than .05 was considered statistically significant.

RESULTS

The prevalence of abnormal eating attitudes was 16.7%. Multivariate logistic regression analysis demonstrated that females, urban residents, and those with a body mass index outside normal range, a perception of being overweight, body dissatisfaction, and a family member on a diet were independently related to abnormal eating attitudes.

CONCLUSIONS AND IMPLICATIONS

The results indicate that a proportion of Greek adolescents report abnormal eating attitudes and suggest that multiple factors contribute to the development of these attitudes. These findings are useful for further research into this topic and would be valuable in designing preventive interventions.

Anorexia nervosa: towards an integrative neuroscience model

We reviewed the evidence for emotion-related disturbances in anorexia nervosa (AN) from behavioural, cognitive, biological and genetic domains of study. These domains were brought together within the framework of an integrative neuroscience model that emphasizes the role of emotion and feeling and their regulation, in brain organization. PsychInfo and Medline searches were performed to identify published peer-reviewed papers on AN within each domain. This review revealed evidence for 'Emotion', 'Thinking and Feeling' and 'Self-regulation' disturbances in AN that span non-conscious to conscious processes. An integrative neuroscience framework was then applied to develop a model of AN, from which hypotheses for empirical investigation are generated. We propose that AN reflects a core disturbance in emotion at the earliest time stage of information processing with subsequent effects on the later stages of thinking, feeling and self-regulation.

Adolescent activity-based anorexia increases anxiety-like behavior in adulthood

Activity-based anorexia is a paradigm that induces increased physical activity, reduced food intake, and heightened activity of the hypothalamic-pituitary-adrenal axis in adult rats. To investigate whether experience with activity-based anorexia produced enduring effects on brain and behavior, female adolescent rats experienced activity-based anorexia during adolescence and were tested in adulthood for anxiety-like behavior on an elevated plus maze and in an open field. Analysis of elevated plus maze and open field behavior in adulthood revealed that rats that experienced activity-based anorexia during adolescence, but not rats that were simply food restricted, displayed increased anxiety-like behavior in adulthood. Plasma corticosterone and expression levels of corticotropin-releasing hormone mRNA in the hypothalamic paraventricular nucleus and in the central nucleus of the amygdala were significantly elevated in adult rats that had undergone activity-based anorexia in adolescence in response to the open field exposure, as compared to control rats. These data demonstrate enduring effects of adolescent activity-based anorexia on anxiety-like behavior and neuroendocrine factors critical in stress responsivity in adulthood. Furthermore, we demonstrate that activity-based anorexia during adolescence serves as a model whereby prolonged anxiety is induced, allowing for evaluation of the behavioral and neural correlates of mediating anxiety-like behaviors in adulthood.

Anorexia nervosa in identical triplets

The cause of anorexia nervosa (AN) is unclear, but is likely multifactorial, including psychological, familial, environmental, societal, genetic, and other biological factors. This case report of identical 12-year-old female triplets simultaneously concordant for AN illustrates the importance of addressing all these components in evaluation and treatment, and the difficulty of determining the relative importance of each factor in the cause of an individual's eating disorder. An overly close relationship and competitiveness between the girls, treated at times as a triplet group rather than as individuals, as well as stressful family dynamics, were probably important antecedents to the girls' AN. The girls encouraged each other and competed to lose weight. Brief individual and family psychotherapy, parent counseling, nutritional counseling, and psychoeducation led to successful treatment. The triplets were encouraged in treatment to compete with and encourage each other to obtain treatment goals, including eating more healthily and achieving healthy weights. A literature review of AN twins studies is also presented, as these studies add to our understanding of the relative importance of shared genes and shared environment in the development of AN. These studies also add insight into treating individuals from families with multiple affected relatives.

Gustatory and olfactory sensitivity in patients with anorexia and bulimia in the course of treatment

BACKGROUND

The majority of studies on taste and smell in eating disorders have revealed several alterations of olfactory or gustatory functions. Aim of this prospective study was to employ detailed olfactory and gustatory testing in female subjects of three homogenous groups - anorexia nervosa, bulimia nervosa and healthy controls - and to look at the effects of treatment on these measures.

METHODS

Sixteen hospitalized female patients with anorexia (restricting type, mean age [M]=24.5 years), 24 female patients with bulimia (purging type, M=24.3 years) as well as 23 healthy controls (M=24.5 years) received olfactory ("Sniffin' Sticks") and gustatory testing ("Taste Strips"). Group differences in olfactory and gustatory sensitivity, body mass index (BMI), the Beck depression inventory, the eating attitudes test (EAT), and the influence of therapy on gustatory and olfactory function were investigated.

RESULTS

(1) Group differences were present for odor discrimination and overall olfactory function with anorexic patients having the lowest scores. (2) Regarding taste function, controls scored higher than patients with anorexia. (3) At admission small but significant correlations were found between overall olfactory function and body weight (r(63)=0.35), BMI (r(63) = 0.37), and EAT score (r(63) = -0.27). Similarly, (4) the taste test score correlated significantly with body weight (r(63)= 0.48), and BMI (r(63) = 0.45). Finally, (5) at discharge overall olfactory and gustatory function were significantly higher compared to admission in anorexic patients.

CONCLUSIONS

As compared to healthy controls and bulimic patients our results show lowered olfactory and gustatory sensitivities in anorexic patients that improved with increasing BMI and decreasing eating pathology in the course of treatment.

Eating disorders across the lifespan

Eating disorders have traditionally been considered afflictions of adolescents and young women. Recent evidence, however, suggests that eating disorders often occur across the life span. Although the incidence of these disorders among mid-life and older women appears to be on the rise, it is not clear if this reflects a true increase in prevalence, better recognition among clinicians, or both. This paper presents an overview of the etiology and treatment of eating disorders, with particular emphasis on developmental factors impacting older women. Recommendations for the treatment of eating disorders among older women are offered. An emerging clinical literature suggests various lines of research that are needed to explore the development and treatment of eating disorders in older women.

Eating disorders and body image concerns in Asian American women: assessment and treatment from a multicultural and feminist perspective

Eating disorders are one of the most lethal psychiatric illnesses and affect millions of individuals worldwide. While they have been more typically attributed to middle class, Caucasian, adolescent females, current research suggests that there is a similar prevalence of eating disorders and their symptoms, especially body dissatisfaction, among Asian American girls and women. Despite this, very little research has investigated how culture and gender may impact the assessment and treatment of eating disorders for Asian American women. This review examines the literature on the prevalence of eating disorders and negative body image in Asian American women and describes current research on the efficacy of a variety of theoretical approaches for treatment, including psychodynamic, cognitive-behavioral, and feminist perspectives. Recommendations for considering culture and gender when working clinically with Asian American women who experience eating concerns as well as suggestions for future research directions are provided.

Insulin, glucose, and pancreatic polypeptide responses to a test meal in restricting type anorexia nervosa before and after weight restoration

Prolonged malnutrition in individuals with anorexia nervosa (AN) has been associated with alterations in endocrine function that may play a sustaining role in the disorder. We hypothesized that abnormalities in endocrine responses to ingestion of a meal in AN are reversible and depend on weight restoration. We measured meal-induced endocrine responses in AN subjects at three time points during hospitalization: before refeeding (n = 13, mean BMI 16.7 kg/m(2)), after 2 wk of refeeding (mean BMI 18.0 kg/m(2)), and in the weight-restored state (mean BMI 20.3 kg/m(2)). Control subjects (n = 13, BMI 19-24.9 kg/m(2)) were tested once. Tests were 2.5-h sessions in which blood was drawn every 15 min before, during, and after a approximately 650-kcal test breakfast. Relative to controls, peak levels of glucose were depressed and peak levels of insulin in response to ingestion of the test meal were delayed, with response patterns in the third trial most similar to controls. Pancreatic polypeptide (PP) levels were increased in AN relative to controls regardless of weight status. The delay in insulin release and elevated PP levels did not correct with short-term refeeding and may contribute to the high relapse rates and maintenance of AN.

Essstörungen im Kindes- und Jugendalter

Eating disorders are included in the category of mental and behavioural disorders (ICD 10). They are among the most common chronic health problems encountered in children and adolescents. A total of 7,498 children and adolescents (weighted) aged 11 to 17 years answered the SCOFF questionnaire, a screening instrument to identify cases of suspected eating disorder. Parallel to the SCOFF questionnaire, further factors for possible eating disorders, such as the Body Mass Index (BMI), information on abnormal behaviour (using the Strengths and Difficulties Questionnaire, SDQ) smoking, sexual and body self-image assessment, were gathered to substantiate the results. In total, 21.9 % of the children and adolescents in Germany aged 11 to 17 years showed symptoms of eating disorders. With 28.9%, girls are more frequently affected than boys (15.2 %); this difference is highly significant. In the presence of almost identical initial values, the rate of subjects with abnormal SCOFF scores increases, starting from age 11 years, in girls as they age, while it drops in boys. Children and adolescents with low socioeconomic status (SES) are, with 27.6 %, almost twice as often affected than those with high SES (15.6 %). Migrants have an approx. 50 % higher rate compared to non-migrants. A 2.5-fold increase in the percentage of individuals with normal weight who perceive themselves as too fat is found among those with abnormal SCOFF scores. Individuals with abnormal SCOFF scores smoke more and report more frequently about sexual harassment. Because of the severity, the tendency to chronification and the protracted therapy of the clinically apparent disorders, effective concepts for prevention should be developed.

Administration of recombinant human growth hormone normalizes GH-IGF1 axis and improves malnutrition-related disorders in patients with anorexia nervosa

High serum level of GH in the presence of low plasma level of insulin-like growth factor-I (IGF-I) is one of the endocrinological features of anorexia nervosa (AN). Whether the amount of endogenous GH is not enough to increase IGF-I is not certain. We studied the effect of recombinant human growth hormone (rhGH) on the GH-IGF-I axis and on malnutrition-related disorders in this syndrome. Twenty patients with AN were divided into two groups; one (N = 13) was given rhGH (0.33 mg/day), and the other (N = 7) was given placebo for 6 or 12 months, respectively. During each treatment, levels of serum GH, plasma IGF-I, serum thyroid hormones, serum cholesterol, fasting plasma glucose and cardiac function were monitored. Changes in body mass index (BMI) and calorie taken were also evaluated. Plasma IGF-I level increased from 74.4 +/- 41.9 to 269.0 +/- 31.2 microg/L (P<0.001) during administration of rhGH, which associated with a decrease in serum GH level from 17.0 +/- 15.0 to 1.6 +/- 0.8 microg/L (P<0.001). Administration of rhGH increased BMI, body temperature, fasting plasma glucose level, and food intake. Serum level of triiodothyronine, but not thyroxine, increased during treatment with rhGH. The treatment decreased serum levels of both total and HDL-cholesterol. Studies with echocardiography showed an increase in cardiac output during the treatment with rhGH. These improvements were not observed in patients treated with placebo. Administration of rhGH is recommended as one of the methods of managing the patients with AN.

Anorexia nervosa or otherwise? The usefulness of adult diagnostic systems in child and adolescent eating disorders

We report on the case of a 15-year-old boy referred to Warrenstown inpatient unit for management of what appeared to be a typical case of anorexia nervosa. Over the course of his admission however, this diagnosis was no longer considered appropriate and substituted for a food avoidance emotional disorder. This is one of a number of cases of young males who have recently been referred for inpatient management of anorexia nervosa but which emerged into something quite atypical. The limited usefulness of the ICD-10/DSM-IV criteria in the diagnosis of an eating disorder in childhood and adolescence in this case reflects a broader level of discontent with the application of such diagnostic classification systems in a paediatric population.

A genetic approach for investigating vagal sensory roles in regulation of gastrointestinal function and food intake

Sensory innervation of the gastrointestinal (GI) tract by the vagus nerve plays important roles in regulation of GI function and feeding behavior. This innervation is composed of a large number of sensory pathways, each arising from a different population of sensory receptors. Progress in understanding the functions of these pathways has been impeded by their close association with vagal efferent, sympathetic, and enteric systems, which makes it difficult to selectively label or manipulate them. We suggest that a genetic approach may overcome these barriers. To illustrate the potential value of this strategy, as well as to gain insights into its application, investigations of CNS pathways and peripheral tissues involved in energy balance that benefited from the use of gene manipulations are reviewed. Next, our studies examining the feasibility of using mutations of developmental genes for manipulating individual vagal afferent pathways are reviewed. These experiments characterized mechanoreceptor morphology, density and distribution, and feeding patterns in four viable mutant mouse strains. In each strain a single population of vagal mechanoreceptors innervating the muscle wall of the GI tract was altered, and was associated with selective effects on feeding patterns, thus supporting the feasibility of this strategy. However, two limitations of this approach must be addressed for it to achieve its full potential. First, mutation effects in tissues outside the GI tract can contribute to changes in GI function or feeding. Additionally, knockouts of developmental genes are often lethal, preventing analysis of mature innervation and ingestive behavior. To address these issues, we propose to develop conditional gene knockouts restricted to specific GI tract tissues. Two genes of interest are brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), which are essential for vagal afferent development. Creating conditional knockouts of these genes requires knowledge of their GI tract expression during development, which little is known about. Preliminary investigation revealed that during development BDNF and NT-3 are each expressed in several GI tract regions, and that their expression patterns overlap in some tissues, but are distinct in others. Importantly, GI tissues that express BDNF or NT-3 are innervated by vagal afferents, and expression of these neurotrophins occurs during the periods of axon invasion and receptor formation, consistent with roles for BDNF or NT-3 in these processes and in receptor survival. These results provide a basis for targeting BDNF or NT-3 knockouts to specific GI tract tissues, and potentially altering vagal afferent innervation only in that tissue (e.g., smooth muscle vs. mucosa). Conditional BDNF or NT-3 knockouts that are successful in selectively altering a vagal GI afferent pathway will be valuable for developing an understanding of that pathway's roles in GI function and food intake.

Eating Disorders

HEALTH ISSUE: Eating disorders are an increasing public health problem among young women. Anorexia and bulimia may give rise to serious physical conditions such as hypothermia, hypotension, electrolyte imbalance, endocrine disorders, and kidney failure. KEY ISSUES: Eating disorders are primarily a problem among women. In Ontario in 1995, over 90% of reported hospitalized cases of anorexia and bulimia were women. In addition to eating disorders, preoccupation with weight, body image and self-concept disturbances, are more prevalent among women than men.Women with eating disorders are also at risk for long-term psychological and social problems, including depression, anxiety, substance abuse and suicide. For instance, in 2000, the prevalence of depression among women who were hospitalized with a diagnosis of anorexia (11.5%) or bulimia (15.4 %) was more than twice the rate of depression (5.7 %) among the general population of Canadian women. The highest incidence of depression was found in women aged 25 to 39 years for both anorexia and bulimia. DATA GAPS AND RECOMMENDATIONS: Hospitalization data are the most recent and accessible information available. However, this data captures only the more severe cases. It does not include the individuals with eating disorders who may visit clinics or family doctors, or use hospital outpatient services or no services at all. Currently, there is no process for collecting this information systematically across Canada; consequently, the number of cases obtained from hospitalization data is underestimated. Other limitations noted during the literature review include the overuse of clinical samples, lack of longitudinal data, appropriate comparison groups, large samples, and ethnic group analysis.

Risk factors for anorexia nervosa: a national cohort study

OBJECTIVE

To identify possible risk factors for anorexia nervosa through national registers.

METHOD

The study includes the entire Swedish population of 989,871 individuals born between 1973 and 1982. Patients with anorexia nervosa were identified through the Swedish Hospital Discharge Register from November 1990 to December 1999. Information about sociodemographic, perinatal, and psychosocial variables was obtained from different national registers. Attributable risk (AR) was calculated for potential risk factors.

RESULTS

Females had the highest AR for hospital admission because of anorexia nervosa (89.2%). Another important risk factor was having parents born in northern, central, or eastern Europe (AR: 49.3%). Psychosocial risk factors also were associated with an increased risk for anorexia nervosa (AR: 7.6%), whereas perinatal complications had an AR of only 3.6%.

DISCUSSION

The most important risk factors were related to the sociocultural context of the individual, thus supporting hypotheses of a sociocultural etiology of anorexia nervosa.

The differential effects of food restriction on 5-HT1A and 5-HT1B receptor mediated control of serotonergic transmission in the hippocampus and hypothalamus of rats

Serotonergic pathways are considered important in the regulation of appetite. We have determined, in female rats, the effects of 4 weeks food restriction (FR) on serotonin function, using in vivo microdialysis. We recorded basal 5-HT release in the hypothalamus and hippocampus, and the sensitivity of the somatodendritic 5-HT1A autoreceptors in the raphe nuclei, and the nerve terminal 5-HT1B autoreceptors which together regulate the synthesis and release of 5-HT in these regions. Sensitivity of the somatodendritic 5-HT1A autoreceptors was assessed by measuring the reduction in extracellular 5-HT induced by systemic administration of the 5-HT1A receptor agonist 8-hydroxy-2-di-n-(propylamino)-tetralin (8-OH-DPAT), while sensitivity of nerve terminal 5-HT1B autoreceptors was measured by observing the increase in 5-HT release after systemic injection of the 5-HT1B receptor antagonist GR 127935. Basal release of 5-HT was not affected by FR. 8-OH-DPAT decreased 5-HT release in the hippocampus and hypothalamus in both groups, while GR 127935 increased 5-HT release in both areas in the control animals but not in the hypothalamus of the FR animals. Since 5-HT1B receptors regulate 5-HT release by a negative feedback mechanism, the decrease in sensitivity of 5-HT1B receptors in the hypothalamus of FR rats indicates increased serotonergic transmission in these rats. The fact that such differential effects on 5-HT release appeared only in the hypothalamus, the center of regulation of energy balance, suggests a compensatory role in FR by increasing 5-HT secretion, thereby reducing feeding behavior.

Adolescents with eating disorders. Primary care screening, identification, and early intervention

The identification and treatment of eating disorders in adolescents is a challenging and time-consuming commitment. Early identification and treatment requires a multi-disciplinary team of health care professionals and provides an improved prognosis for these complex conditions. Nurses in all levels of practice are in ideal positions to influence early detection through careful screening (identification of risk factors, patient history, and physical exam), close follow-up, and prompt specialty referral with disease progression.

[Current topics in pediatric nutrition]

As main current topics in pediatric nutrition we have considered the results of the continuing research on the long term consequences of fetal malnutrition and intra-uterine growth retardation with the concept of metabolic imprinting leading to chronic disease in adulthood, the progresses of knowledge in the fields of iron metabolism and regulatory mechanisms of satiety, hunger and energetic balance, a better determination of recommended docosahexanoic and arachidonic acids intake in the first months of life for premature and term infants, and the studies on probiotics and prebiotics utilization for preventive and curative purposes. The concerns about vitamin D insufficiency in France have markedly decreased with the generalization ten years ago of cholecalciferol supplementation of infant formula, and more recently the authorization of dairy products supplementation. On the contrary the problem of iron deficiency in young children remains, as well as two major nutritional concerns: the very low percentage of breast-fed infants and the dramatic increase of childhood obesity which affects presently 14% of 10 year old children versus 5% in 1980.

Childhood and adolescent anorexia nervosa

Eating disorders are common during childhood and adolescence. Early intervention is associated with the best prognosis. Treatment interventions that focus on achieving ideal body weight and use various family therapy approaches are most likely to be effective. Much remains to be learned about the origin of AN, but there are promising recent advances.

Eating disorders: a guide for the primary care physician

The diagnostic criteria for eating disorders are described, including assessment of complications related to semi-starvation, binge eating, and purging. The key components of treatment are presented, including normalization of eating, individual and family therapy, and cognitive behavioral therapy. The role of the primary care physician in diagnosis and treatment is outlined.

Integrative time-limited group therapy for bulimia nervosa

This article presents an integrative group therapy model for the treatment of bulimia nervosa (BN) and describes the 12-session format, incorporating components of cognitive-behavioral therapy (CBT), psychoeducation, interpersonal therapy (IPT), and relational therapy (RT), in detail. Previous reports have found CBT, IPT, and RT to be effective approaches for BN when used separately. The integrative approach may have the advantage of achieving symptom reduction by two different mediating mechanisms, those that directly affect eating behaviors and those that address the interpersonal and relational context in which the disordered eating has developed. The group approach makes use of the peer group in providing new opportunities for self-exploration and self-correction. One advantage of an integrative model is patients' exposure to several different treatment modalities from which they can identify specific approaches that are most helpful to their recovery. This identification is valuable in directing future treatment, if needed. Pilot data for this approach are presented.

Bulimia nervosa: an update and treatment recommendations

Bulimia nervosa is a common eating disorder in adolescent women. Biological, psychological, and social factors are implicated in onset and important in treatment. Diagnosis of the syndrome, but not its subtypes, can be made well using the DSM-IV system. Screening tools, laboratory findings, and physical findings can be helpful in making the diagnosis. Comorbid disorders include affective disorders, addictive disorders, anxiety disorders, personality disorders, and anorexia nervosa. The etiology of bulimia nervosa is complex, with biologic, psychological, social, and family factors, which likely differ somewhat from patient to patient. Treatment, accordingly, should be comprehensive, individualized, and multifaceted. Many patients respond well to the use of an antidepressant, and cognitive-behavioral therapy is a useful approach for many patients. Combining these two treatments seems to be a good strategy. Environmental and family issues also need to be addressed. Many patients are treated insufficiently. More research on bulimia nervosa specific to adolescence is needed.

Neural substrates of anorexia nervosa: a behavioral challenge study with positron emission tomography

OBJECTIVE

To delineate functional brain abnormalities associated with anorexia nervosa (AN).

STUDY DESIGN

Positron emission tomographic measurements of regional cerebral blood flow (rCBF) were performed on 8 female patients with AN and 8 healthy female control subjects during exposure to 3 types of stimuli: high-calorie foods, low-calorie foods, and non-food items. Heart rate and internal state analog scale scores were also obtained. Stereotactic transformation and statistical parametric mapping techniques were used to analyze imaging data.

RESULTS

During the high-calorie condition, control subjects reported a significant desire to eat, whereas subjects with AN reported elevated anxiety and exhibited increases in heart rate. Patients with AN had elevated bilateral medial temporal lobe rCBF compared with control subjects. Planned comparisons for group-by-condition interactions demonstrated greater activation within left occipital cortex and right temporo-occipital cortex for the high-calorie versus low-calorie contrast in patients with AN compared with control subjects.

CONCLUSIONS

Our finding of elevated rCBF within bilateral medial temporal lobes is similar to published results in patients with psychotic disorders and may be related to the body image distortion common to AN. The high-calorie food phobia exhibited by patients with AN appears to be associated with exaggerated responses in visual association cortex, as has been previously observed in studies of specific phobias.

Eating disorders: 1. anorexia nervosa

Although many of the factors that contribute to anorexia nervosa are not within the physician's control, early detection and prompt initiation of treatment may improve patient outcome. A high level of suspicion and a willingness to address the issue can serve our patients well.