Time Course of Leptin in Patients with Anorexia Nervosa during Inpatient Treatment: Longitudinal Relationships to BMI and Psychological Factors

<div><p>Background</p><p>Leptin, a hormone secreted by adipose tissue, appears to play a major role in the homeostasis of body weight and psychobiological processes associated with anorexia nervosa (AN). However, there is scarce data on its exact influence on this disorder, in particular data over time.</p><p>Objective</p><p>The present study addresses whether leptin changes during inpatient treatment play a role for treatment outcome and psychological factors in underweight AN patients.</p><p>Methods</p><p>In order to understand whether leptin’s role differs in relation to AN severity, data were assessed from 11 patients with a very low BMI and a higher chronicity (high severity group; HSS; mean BMI at the beginning of the study = 13.6; mean duration of illness = 5.1 years) vs. nine with less severe symptoms (LSS; mean BMI = 16.2; mean duration of illness = 3.7 years). During the course of treatment, serum leptin concentrations were assessed weekly while weight (BMI) was assessed twice per week. Concomitantly, psychological variables were obtained by means of electronic diaries. Unconditional linear growth models were calculated to evaluate the temporal course of leptin in relation to BMI. For HSS patients, two phases of treatment (BMI < 16 and BMI ≥ 16 kg/m²) were investigated.</p><p>Results</p><p>Leptin increased significantly with BMI in both groups of patients. For HSS patients, the increase of leptin in the first treatment phase did not predict later increases in BMI. Furthermore, the relationship of leptin and psychological factors was modulated by symptom severity. In HSS patients, higher leptin levels were associated with greater feelings of depression, anxiety, and stress whereas in LSS patients a higher leptin level showed the trend to be associated with lower psychological symptom burden.</p><p>Conclusions</p><p>Our results suggest that leptin changes are differently associated with weight gain and psychological symptoms depending on the severity of starvation.</p></div

Significant linear time trends of longitudinal regressions during inpatient treatment

<p>Significant linear time trends of longitudinal regressions during inpatient treatment</p

Lagged dependencies between emotional intolerance and AN symptom variables.

<p>Lagged dependencies between emotional intolerance and AN symptom variables.</p

Plots of significant Granger causal relations combined with information from the electronic diaries as well as corresponding impulse response functions.

<p>Analysed time windows are shadowed in grey; family therapy sessions are marked with a black triangle; special notes from the diary are marked with *. Impulse response function (IRF) / orthogonalised IRF (OIRF): responses are considered significant if their error bands do not include 0. Confidence bounds are computed employing Hall bootstrap method. For a detailed description of IRF / OIRF see explanations in the text.</p

Characteristics of the analyzed sample

<p>Characteristics of the analyzed sample</p

Average leptin serum concentrations (mean values) plotted against the BMI status of HSS and LSS patients (in increasing order).

<p>HSS = patient group with high symptom severity; LSS = patient group with less severe symptoms. Leptin was measured in μg/ l. Standard deviations (sd) are plotted in grey, number of measurements are plotted as black dots. Note that statistical analyses in the LSS group were performed starting with BMI = 16 kg/m².</p

Linear time trends (standardised coefficients from time series regressions) in emotional intolerance and AN symptom variables during inpatient stay (in all patients).

<p>Linear time trends (standardised coefficients from time series regressions) in emotional intolerance and AN symptom variables during inpatient stay (in all patients).</p

Items implemented in the electronic diary.

<p>Items implemented in the electronic diary.</p

Characteristics of the analysed diary sample.

<p>Characteristics of the analysed diary sample.</p

Time course of adiponectin and its relationship to psychological aspects in patients with anorexia nervosa during inpatient treatment

<div><p>Objective</p><p>The protein hormone adiponectin promotes metabolic and psychological health. The aim of the study was to track changes in adiponectin levels in response to weight gain and to assess associations between adiponectin and psychological aspects in patients with anorexia nervosa (AN).</p><p>Methods</p><p>To investigate if adiponectin levels depend on AN severity, data were assessed from 11 inpatients with a very low body mass index (BMI) and a high chronicity (high severity group; HSS), and nine with less severe symptoms (LSS). During the course of treatment, serum adiponectin concentrations were assessed on a weekly basis along with BMI. Psychological variables (i.e., depression, anxiety, stress, and AN-specific symptoms) were obtained by means of electronic diaries. Longitudinal regressions and correlations were calculated to evaluate the temporal course of adiponectin and its relationship with psychological self-ratings.</p><p>Results</p><p>At the beginning adiponectin was not increased in HSS patients (p = .56), and only marginally elevated in LSS patients (p = 0.07) compared with controls. In HSS patients, adiponectin increased along with BMI during the first treatment phase (i.e., when the BMI of patients was below 16 kg/m²) and thereafter decreased with further weight gain. In LSS patients, adiponectin was not associated with BMI increase. Furthermore, adiponectin was strongly negatively correlated with psychological self-ratings when the BMI of patients was above 16 kg/m², i.e., higher levels of adiponectin were related to lower ratings of depression, anxiety, and AN-specific symptoms.</p><p>Discussion</p><p>The study connects previous varying results by indicating that the course of adiponectin is dependent on BMI and symptom severity. Similarly, associations of adiponectin and psychological health depended on BMI.</p></div