Temporal relationships between awakening cortisol and psychosocial variables in inpatients with anorexia nervosa – A time series approach

Time course and reaction types of serum IGF-1 and its relationship to BMI and leptin regarding inpatients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a severe mental disorder that is characterized by restriction of energy intake, low weight, and endocrine abnormalities. One of the known endocrine changes in relation to underweight is in the GH/IGF-I axis. The aim of the study was (a) to investigate longitudinal characteristics of the IGF-I-change during therapy and weight gain in adult AN, (b) to determine relationships between IGF-I and leptin, (c) to characterize patients with weak and pronounced hormonal reactions to underweight.

DESIGN

Data was assessed from 19 AN patients. Over the first two months, serum IGF-I concentrations were assessed on a weekly basis; thereafter on a monthly basis. The trend of IGF-I values over time was analyzed using individual growth models.

RESULTS

In total, n = 177 IGF-I measurements were analyzed. IGF-I increased significantly dependent on BMI (slope = 20.81, p < 0.001), not modulated by duration of disease. The increase in IGF-I was significantly related to the increase in leptin concentrations over time (slope = 15.57, p < 0.001). Patients with a weaker hormonal reaction to underweight were significantly older compared to patients with a pronounced hormonal reaction (t(17) = 3.07, p = 0.007).

CONCLUSIONS

During treatment, IGF-I change is clearly related to BMI as well as to leptin. Age appears to be associated with the IGF-I response to underweight.

Time series analyses with psychometric data

Understanding of interactional dynamics between several processes is one of the most important challenges in psychology and psychosomatic medicine. Researchers exploring behavior or other psychological phenomena mostly deal with ordinal or interval data. Missing values and consequential non-equidistant measurements represent a general problem of longitudinal studies from this field. The majority of process-oriented methodologies was originally designed for equidistant data measured on ratio scales. Therefore, the goal of this article is to clarify the conditions for satisfactory performance of longitudinal methods with data typical in psychological and psychosomatic research. This study examines the performance of the Johansen test, a procedure incorporating a set of sophisticated time series techniques, in reference to data quality utilizing a Monte Carlo method. The main results of the conducted simulation studies are: (1) Time series analyses require samples of at least 70 observations for an accurate estimation and inference. (2) Discrete data and failing equidistance of measurements due to irregular missing values appear unproblematic. (3) Relevant characteristics of stationary processes can be adequately captured using 5- or 7-point ordinal scales. (4) For trending processes, at least 10-point scales are necessary to ensure an acceptable quality of estimation and inference.

Changes of BMI, steroid metabolome and psychopathology in patients with anorexia nervosa during hospitalization

Anorexia nervosa (AN) is associated with various alterations including the dysfunction of the HPA axis and consequently the hypercortisolemia and deficit in sex hormones but the comprehensive evaluation of changes in circulating steroids during the hospitalization of AN patients is lacking. We investigated the effect of realimentation of women with AN during hospitalization on 45 circulating steroids, the relationships between BMI, its change during hospitalization and physical activity, on one side and initial levels and their changes for two adipokines, circulating steroids, anorexia-specific (hunger, appetite and satiety), and anorexia non-specific symptoms (anxiety, depression fatigue, sleep, and body pain) on the other side. We included 33 women with anorexia who were hospitalized for 38(35, 44) days (median with quartiles). The increase of BMI from the initial value 15.2 (13.2, 16.6) kg/m² was 1.69 (1.37, 2.66) kg/m². The patients with more severe anorexia showed higher activity in 7β-, and 16α-hydroxylation of androgen precursors, which declined during hospitalization. Otherwise, the 7α-hydroxylation activity is higher in AN patients with less severe malnutrition and the ratio of 5-androstene-3β,7α,17β-triol to 5-androstene-3β,7β,17β-triol increased during the realimentation. Our data allow to speculate that the intensive 7β-, and 16α- and possibly also the 7α-hydroxylation of C19 Δ⁵ steroids participate in the pathophysiology of anorexia by additional catabolism of substrates available for synthesis of active androgens and estrogens. However, the question remains whether the synthetic analogues of 7α/β- and 16α-hydroxy-steroids prevent the catabolism of the sex steroid precursors, or further activate the "energy wasting" mitochondrial thermogenic metabolism.

Longitudinal study on novel neuropeptides phoenixin, spexin and kisspeptin in adolescent inpatients with anorexia nervosa - association with psychiatric symptoms

OBJECTIVES

It is hypothesized that novel neuropeptides such as phoenixin (PNX), spexin (SPX), and kisspeptin (KISS) are involved in the pathogenesis of eating disorders. The study presented here analyzed neuropeptide concentrations during the course of anorexia nervosa (AN) and aimed to correlate those values with anthropometric and psychometric measurements.

METHODS

A longitudinal study was carried outin 30 AN adolescent patients and 15 age-matched healthy female controls. Selected neuroprotein serum levels were analyzed in malnourished patients (accAN) and following partial weight recovery (norAN), and these values were compared with the control group.

RESULTS

In accAN patients, decreased serum PNX levels were detected while SPX serum concentrations were lower in the accAN and norAN patients. No differences were observed in KISS concentrations in all studied groups.

CONCLUSIONS

In malnourished adolescent inpatients with AN, serum PNX and SPX level were decreased. The partial weight recovery normalized PNX concentrations but failed to normalize SPX levels. Therefore these two neuropeptides might be crucial for the etiology and course of the AN. The KISS levels did not change in the course of AN. The PNX levels were associated with some symptoms of eating disorders which may indicate its potential contribution in the regulation of emotions and behaviors in AN.

How to Deal With Temporal Relationships Between Biopsychosocial Variables: A Practical Guide to Time Series Analysis

OBJECTIVE

Longitudinal data allow for conclusions about the temporal order of events and interactional dynamics between several processes. The aim of this article is to provide a concise and pragmatic description of time series analyses (TSAs) of patient samples with numerous (or daily) repeated biological, behavioral, or psychological measurements. In addition, the article demonstrates how to implement the described analyses with the software R.

METHODS

To illustrate the concrete application of the time series method, we use two case series of patients with anorexia nervosa. Upon awakening, the patients collected salivary cortisol on a daily basis and answered several questions on a handheld computer (electronic diary) regarding psychosocial variables at the time of salivary collection.

RESULTS

Basic concepts of time series analysis such as stationarity, auto- and cross-correlation, Granger causality, impulse response function, and variance decomposition are presented. In addition, we demonstrate vector autoregressive analyses with three variables. For Patient 1, we demonstrate how TSA is used to detect cortisol and anxiety decreases during inpatient treatment and also how TSA can be used to show that an increase in cortisol is followed by a next-day increase in anxiety. For Patient 2, TSA was used to show higher salivary cortisol upon awakening on the days the patient was weighed compared with other days. In addition, we show how interdependencies of depressive feelings, positive anticipations, and cortisol values can be quantified using TSA.

CONCLUSIONS

Time series designs enable modeling of temporal relationships and bidirectional associations between biopsychosocial variables within individuals. These individual patterns cannot be derived from traditional group-based statistical analyses. This article provides accessible research tools for conducting TSA relevant to psychosomatic and biobehavioral research.

Salivary cortisol in post-traumatic stress disorder: a systematic review and meta-analysis

BACKGROUND

Studies investigating salivary cortisol level as susceptibility marker for post-traumatic stress disorder (PTSD) produced inconsistent results. The aim of this study was to compare salivary cortisol concentration levels in PTSD patients with those in controls by synthesizing published data.

METHODS

We did a systematic review, meta-analysis and meta-regression of studies comparing concentrations of salivary cortisol between patients with PTSD and controls. The electronic databases of PubMed, Embase, Web of Science and Psyc-ARTICLES were searched for relevant articles. A random-effects model with restricted maximum-likelihood estimator is used to synthesize the effect size (assessed by standardized mean difference).

RESULTS

A total of 784 articles were identified of which 22 were included in the final analysis. A trend of lower salivary cortisol levels was found in PTSD patients when compared with the controls (SMD = - 0.28, 95% CI-0.53;-0.04, p = 0.022). Subgroup analysis showed that the salivary cortisol levels were lower in patients with PTSD than in controls in studies conducted after 2007 or in studies using saliva samples collected in the morning.

CONCLUSIONS

The evidence from this meta-analysis supports that salivary samples collected in the morning consistently showed a lower salivary cortisol level in patients with PTSD than in controls, although whether salivary cortisol could be used as a diagnostic tool requires further research.

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

OBJECTIVE

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).

METHODS

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.

RESULTS

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.

DISCUSSION

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.

Detection of AMA-M2 in human saliva: Potentials in diagnosis and monitoring of primary biliary cholangitis

Serum anti-mitochondrial antibody type 2 (AMA-M2) is considered as a pivotal biomarker for the diagnosis of primary biliary cholangitis (PBC). However, serological tests have many limitations, including inconvenience, invasiveness, and infection risks. Thus, a less invasive approach to detect AMA-M2 titer is desirable. We examined salivary AMA-M2 of potential PBC patients and found that AMA-M2 could be detected only in saliva of serum AMA-M2-positive PBC patients, but not in saliva of serum AMA-M2-negative PBC patients, oral lichen planus patients (OLP) patients, or healthy controls. Furthermore, the concentration of salivary AMA-M2 was positively correlated with the amount of serum AMA-M2 in patients. The salivary inflammatory cytokines were increased in the PBC, consistent with the results of serum test. These findings indicated that saliva might be a less invasive and cost-effective medium to accurately test for AMA-M2 levels and this is a promising development for the diagnosis and monitoring of PBC.

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

Background

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.

Objective

The present study addresses whether leptin changes during inpatient treatment play a role for treatment outcome and psychological factors in underweight AN patients.

Methods

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.

Results

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.

Conclusions

Our results suggest that leptin changes are differently associated with weight gain and psychological symptoms depending on the severity of starvation.