Hyperactivity in anorexia nervosa: warming up not just burning-off calories

Anorexia nervosa: a rogue hibernation?

Anorexia nervosa is a puzzling and often tragic disorder which causes the individual to self starve and hyper-exercise. We present a speculative analysis of the disorder which begins by acknowledging and accepting the adaptation to flee famine theory. This theory holds that anorexia nervosa results from activation of an archaic pathway that functioned well during human's nomadic past. We advance this idea by suggesting that the faulty signal indicating there is a famine, arises from misalignment of the circadian/circannual oscillations. Entry and exit from hibernation is dependent on these cycles, and we draw an analogy between hibernation and anorexia nervosa. We offer ideas for testing the hypothesis, and targeting these faulty signals.

The association between malnutrition and psychological distress in patients with advanced head-and-neck cancer

OBJECTIVE

Malnutrition and psychological distress are often seen in patients with head-and-neck cancer, but little is known about the interrelationships between those two symptoms. The present study examined the relationship between malnutrition and psychological distress in patients with advanced head-and-neck cancer.

METHODS

Using the Patient-Generated Subjective Global Assessment, 99 patients with advanced-stage head-and-neck cancer were screened for nutrition status. The patients were also screened for psychosocial distress (using the Distress Thermometer) and for psychosocial issues (using the Problem Checklist). Any relationship between malnutrition and psychosocial distress was determined by regression and correlation analysis. We also used t-tests to compare distress levels for patients with and without specific nutrition-related symptoms.

RESULTS

The study group included 80 men and 19 women [mean age: 58.4 ± 10.9 years (range: 23-85 years)]. The correlation between poorer nutrition status and level of psychological distress was significant r = 0.37 (p < 0.001). Specifically, reduced food intake and symptoms were both positively associated with distress: r = 0.27 and r = 0.29 respectively, both significant at p < 0.01. After controlling for the effects of psychosocial problems and pain, nutrition status remained a significant predictor of distress, explaining 3.8% of the variance in the distress scores of the patients (p < 0.05).

CONCLUSIONS

Malnutrition and symptoms were strongly related to distress in patients with advanced head-and-neck cancer. Our results suggest the need for further research into the complex relationship between nutrition status and distress and into the management of both nutrition and distress in cancer care.

Advances in the neurobiology of eating disorders

PURPOSE OF REVIEW

To systematize new neurobiological findings on the cause and treatment of eating disorders.

RECENT FINDINGS

The conceptual framework of the cause of eating disorders has undergone great changes in the past decades. Recently, the National Institute of Mental Health proposed a new set of criteria for research purposes--the Research Domain Criteria (RDoC). We aim to structure this study as much as possible using these constructs across biological units of analysis, summarizing new findings. Brain imaging techniques have become sophisticated in identifying brain circuits related to illness behaviour and to fundamental traits such as reward and social processing. Genetic studies have moved from candidate gene studies onto genome-wide association studies; however, the field needs to cooperate to collect larger samples in order to benefit from this approach. Hormonal changes as the results of starvation or as underlying factors for behavioural changes still receive attention in both animal and human studies. Advances made in neuropsychology show problems in cognition (set shifting and central coherence) and in other RDoC domains. Some of these findings have been translated into treatment.

SUMMARY

New biological models are being developed which explain causal and maintaining factors. The RDoC construct may be used to systematize these findings.

Longitudinal changes in the physical activity of adolescents with anorexia nervosa and their influence on body composition and leptin serum levels after recovery

Objective

Patients with anorexia nervosa (AN) are often observed to have high levels of physical activity, which do not necessarily diminish after a successful therapy. Previous studies have shown that body fat tissue recovery in these patients is associated with a disproportional restoration of the adipocyte hormone, leptin. Therefore, we wondered whether the individual variation in physical activity in AN patients prior to treatment may be related to body fat percentage and plasma leptin level outcome.

Method

Body fat percentage, leptin serum, and physical activity levels (accelerometer) were measured in adolescents with an (n=37, age 13 to 17.5 years) at initial assessment, at the end of study participation (median 12 months), and at one-year follow-up.

Results

Accelerometer data were used to split the patients in two groups: those with low (n=26) and those with high levels of physical activity (HLPA, n=11). These groups did not differ in terms of age, IQ, presence of menses, BMI and season of admission. The HLPA group was characterized by a longer total duration of illness. Physical activity levels during therapy decreased for the group with initially HLPA and increased for the group with low levels of physical activity (to comparable levels). Physical activity remained stable after one year. The increase in body fat percentage and leptin levels were dependent on the recovery status; however, recovered patients with initially HLPA had significantly higher fat mass during the follow-up.

Discussion

HLPA, an important modulator of AN progression in adolescents, can be successfully diminished by therapeutic intervention. Among recovered patients, those with initially HLPA had higher fat mass levels than those with low levels of physical activity. This finding suggests that HLPA are an important modulator of the body composition recovery mechanism.

Irisin: what promise does it hold?

PURPOSE OF REVIEW

The recently identified myokine, irisin has raised great expectations as a potential target in the conservative treatment of obesity. This review focuses on studies exploring the effects of irisin in humans.

RECENT FINDINGS

Peroxisome proliferator-activated receptor γ coactivator-1 α expression in skeletal muscles is induced by exercise followed by expression of the membrane protein fibronectin type III domain containing 5. After cleavage from fibronectin type III domain containing 5, irisin is secreted into blood increasing thermogenesis by browning of subcutaneous white/beige adipose tissue. Although clear-cut data have been reported in rodents, the thermogenic effect of irisin in humans remains controversial. The initially reported exercise-dependent increase of irisin in humans could not be confirmed in most studies. However, a robust finding in human studies is the association of irisin with BMI.

SUMMARY

The discovery of irisin provides more insight into exercise-induced browning of adipose tissue, and therefore leads to a better understanding of mechanisms underlying body weight regulation and further down the road possibly may lead to treatment strategies of diseases with greatly altered body weight such as obesity or anorexia nervosa.

Climate might be considered as a risk factor for anorexia nervosa? A hypothesis worth another look

Environmental factors, such as ambient temperature m(AT), may have a causal role in the development of anorexia nervosa (AN), in addition to factors like the idealization of thinness. We present the literature and a bibliographic analysis that associate AN and a temperate climate.

A rat in the labyrinth of anorexia nervosa: contributions of the activity-based anorexia rodent model to the understanding of anorexia nervosa

Activity-based anorexia (ABA) is an analogous animal model of anorexia nervosa where food-restricted rats develop excessive running activity when given free access to a running wheel; their body weight sharply decreases, and finally self-starvation and death ensue unless animals are removed from the experimental conditions. The parallel of this animal model with major signs in the human disorder has been the focus of much attention from researchers and clinicians as a platform for translational research. The paper reviews the historical antecedents of ABA, research characterizing its occurrence, and its main limitations and strengths as a model of AN. As a symptomatic model of AN, the ABA model can provide clinicians with innovative and alternative routes for improving the treatment of AN.

Eating problems and overlap with ADHD and autism spectrum disorders in a nationwide twin study of 9- and 12-year-old children

Aim. To establish the prevalence of restrictive eating problems, the overlap and association with attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorders (ASD) and to estimate the heritability of eating problems in a general population sample of twins aged 9 and 12. Methods. Parents of all Swedish 9- and 12-year-old twin pairs born between 1993 and 1998 (n = 12,366) were interviewed regarding symptoms of ADHD, ASD, and eating problems (EAT-P). Intraclass correlations and structural equation modelling were used for evaluating the influence of genetic and environmental factors. Cross-twin, cross-trait correlations were used to indicate a possible overlap between conditions. Results. The prevalence of eating problems was 0.6% in the study population and was significantly higher in children with ADHD and/or ASD. Among children with eating problems, 40% were screened positive for ADHD and/or ASD. Social interaction problems were strongly associated with EAT-P in girls, and impulsivity and activity problems with EAT-P in boys. The cross-twin, cross-trait correlations suggested low correlations between EAT-P and ADHD or EAT-P and ASD. Genetic effects accounted for 44% of the variation in liability for eating problems. Conclusions. In the group with eating problems, there was a clear overrepresentation of individuals with ADHD and/or ASD symptoms.