Exhaustion and cardiovascular risk factors: the role of vagally-mediated heart rate variability

PURPOSE

Exhaustion symptoms are known to be associated with cardiovascular disease (CVD) risk; however, the underlying mechanisms remain unclear. Autonomic imbalance, as indicated by reductions in vagally-mediated heart rate variability (vmHRV), appears to be a valid candidate for such a biological link, as it has been associated with both exhaustion symptoms and CVD risk and mortality.

METHODS

The present study examined a potential mediation of vmHRV on the association between exhaustion symptoms and self-reported CVD risk factors as well as the age dependency of this mediation in a large, heterogeneous sample of the Dresden Burnout Study (N = 388; 72.9% females; Mage = 42.61, SD = 11.67).

RESULTS

Results indicate that exhaustion symptoms were indirectly associated with CVD risk factors through vmHRV even after adjusting for well-known confounders (i.e., sex, body mass index, depressive symptoms). Moreover, this pattern was significant only among middle-aged (i.e., 54.27 years) and older individuals.

CONCLUSIONS

Our findings add to growing evidence that autonomic imbalance may be a key biological link between exhaustion symptoms and CVD risk in middle-aged and older individuals. Implications for public health are discussed.

Depressive symptoms are negatively associated with hair N-arachidonoylethanolamine (anandamide) levels: A cross-lagged panel analysis of four annual assessment waves examining hair endocannabinoids and cortisol

BACKGROUND

The endocannabinoid system (ECS) is increasingly being recognized as key regulatory system coupled with the glucocorticoid system implicated in the pathophysiology of major depressive disorder (MDD). However, prior studies examining the ECS in MDD have been inconclusive, of small sample size or of cross-sectional nature limiting interpretation of causal inferences or time-dependent effects.

METHODS

In a prospective community-based cohort study including 128 individuals (women: 108), depressive symptoms (PHQ-9) as well as hair cortisol and endocannabinoids were measured annually over four years (T1-T4). Cortisol, N-arachidonoylethanolamine (AEA), and 2-arachidonoyl-sn-glycerol/1-arachidonoyl-sn-glycerol (2-AG/1-AG) were extracted from 3 cm hair segments reflecting cumulative concentrations of the last three months prior sampling.

RESULTS

Cross-sectional group comparisons at baseline revealed reduced AEA and cortisol levels in the group with a positive MDD screening compared to individuals with low depressive symptomatology (both p < .05). Cross-lagged panel models showed that AEA levels at T2 were negatively associated with depressive symptoms at T3 (p < .05). Also, depressive symptoms at T3 were negatively associated with AEA levels at T4 (p < .01). The direction of association was reversed for 2-AG/1-AG, as 2-AG/1-AG levels at T1 were positively associated with depressive symptoms at T2 (p < .01).

CONCLUSIONS

While cross-sectional analyses suggest higher depressive symptomatology to be associated with reduced AEA and cortisol release, longitudinal analyses reveal that primarily AEA levels are negatively associated with depressive symptoms. These longitudinal associations elucidate time-dependent relationships between depressive symptomatology and the ECS and further highlight AEA as potential treatment target in MDD.

The moderating effect of cortisol and dehydroepiandrosterone on the relation between sleep and depression or burnout

For poor sleep quality (SQ) as well as major depressive disorder (MDD) and burnout, a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been identified. Although poor SQ is often reported as an early symptom of MDD or burnout, it is not clear whether HPA axis-related hormones can influence the association between SQ and MDD or burnout. This manuscript addresses this question by examining HPA axis-related hormones as potential moderators influencing the association between SQ and MDD or burnout.

In the fourth annual examination wave of the Dresden Burnout Study, we measured general SQ (including sleep duration and efficiency), depressive and burnout symptoms, and obtained hair samples for quantification of long-term integrated steroid concentrations (cortisol [hC], cortisone [hCn], dehydroepiandrosterone [hDHEA]) from 462 participants (67% female). Data on SQ, depressive and burnout symptoms were available from 342 participants from the preceding examination wave (average time span between examinations 13.2 months).

Cross-sectional analyses showed that the negative association between sleep duration and depressive symptoms was buffered by higher levels of hC, and hCn, whereas the negative association between sleep duration and burnout symptoms was buffered by higher levels of hDHEA. The negative association between sleep efficiency and burnout symptoms was intensified by higher levels of hC and hC/hCn ratio and the negative association between general SQ and burnout symptoms was intensified by higher levels of hC/hCn ratio. With regard to longitudinal data, a significant interaction effect between sleep duration and hC/hCn ratio could be detected for burnout symptoms.

Our results suggest opposed moderation effects of hair glucocorticoids on the association between SQ and depressive or burnout symptoms. This points toward opposed glucocorticoid receptor functioning in depression and burnout. To fully elucidate the negative consequences of poor SQ on MDD and burnout, the complex underlying mechanisms of action including HPA axis-related hormones need to be investigated in MDD and burnout separately.

•

hC and hDHEA are not directly related to depression, burnout, or sleep symptoms.

•

Higher hC levels buffer the relation between poor sleep quality (SQ) and depression.

•

Higher hC levels intensify the relation between poor SQ and burnout.

•

Higher hDHEA levels buffer the relation between poor SQ and burnout.

•

hC and hDHEA exhibit contrary effects on the relation between SQ and burnout.

Depressive symptoms are not associated with long-term integrated testosterone concentrations in hair

OBJECTIVES

The association between depressive symptomatology and endogenous testosterone levels is inconclusive. Large inter- and intra-individual testosterone differences suggest point measurements from saliva or serum to be inadequate to map basal testosterone concentrations highlighting the potential for long-term integrated testosterone levels from hair.

METHODS

Using data from a prospective cohort study, a total of 578 participants (74% female) provided complete data on depressive symptomatology, clinical features, and hair samples for quantification of testosterone concentrations at baseline. Available data of three annual follow-up examinations were used for longitudinal analyses.

RESULTS

Correlation analysis showed in both, men and women, hair testosterone across all the four time points not to be significantly related to depressive symptoms. Examined clinical features were not associated with testosterone levels, except for having a current diagnosis of a psychological disorder, which was associated with reduced testosterone levels in men, but not in women. Acceptable model fit for an autoregressive cross-lagged panel analysis emerged only for the female subsample suggesting inverse cross-relations for the prediction of testosterone by depressive symptomatology and vice versa.

CONCLUSIONS

Findings from this study add to the literature by showing no association between long-term integrated testosterone in hair and depressive symptomatology in men and women.

The Influence of Workload and Work Flexibility on Work-Life Conflict and the Role of Emotional Exhaustion

The purpose of this study is to examine the relationship between contextual work-related factors in terms of job demands (workload—WL) and job resources (work flexibility—WF), work–life conflict (WLC) and the burnout dimension emotional exhaustion (EE) in a large population-based sample. Building on the job demands resources model (JDRM), we have developed the hypothesis that WL has an indirect effect on EE that is mediated by WLC. We conducted a secondary analysis using data from the Dresden Burnout Study (DBS, N = 4246, mean age (SD) = 42.7 years (10.5); 36.4% male). Results from structural equation modelling revealed that EE is positively associated with WL (β = 0.15, p = 0.001) and negatively associated with WF (β = −0.13, p = 0.001), also after accounting for potential confounding variables (demography, depressive symptoms, and lifetime diagnosis of burnout). Both effects are mediated by WLC (β = 0.18; p = 0.001 and β = 0.08; p = 0.001, respectively) highlighting the important role of WLC in employee health. In summary, WF may help to reduce burnout symptoms in employees, whereas WL may increase them. Study results suggest that both associations depend on WLC levels.

Sleep disturbances in major depressive and burnout syndrome: A longitudinal analysis

Sleep quality (SQ) is considered to be a critical variable in major depressive syndrome (MD) as well as in burnout syndrome (B). Thus far, no study examined the differential influence of these syndromes on SQ. MD and B have been assessed in 4,415 participants at baseline and in 1,396 participants at follow-up based on the Patient Health Questionnaire-9 (PHQ-9) and the Maslach Burnout Inventory-General Survey (MBI-GS). The Pittsburgh Sleep Quality Index was used to measure SQ. Based on the PHQ-9 and MBI-GS at baseline assessment, participants were divided into four groups: a control group, a MD group, a B group, and a comorbid group suffering from MD and B. Multiple regression analyses showed that all groups demonstrate significantly worse SQ than the control group, while individuals with MD showed a lower SQ compared to individuals with B. The comorbid group showed the lowest SQ. Longitudinal analyses showed a significant bidirectional association between major depressive symptoms and SQ, whereas burnout symptoms were predictive for SQ but not vice versa. The study indicates differences between MD and B with regard to SQ, suggesting worse SQ in more severely burdened groups. Major depressive symptoms are bidirectionally linked to SQ, whereas burnout symptoms are only suggested a risk factor for impaired SQ.

Effort-reward imbalance at work is associated with hair cortisol concentrations: Prospective evidence from the Dresden Burnout Study

Chronic stress experienced at work is considered a major health challenge for modern societies. In fact there is ample evidence that deleterious work environments, based on high efforts in relation to few rewards, substantially augment the risk for a number of highly prevalent diseases (e.g. ischemic heart disease, stroke). One potential pathway mediating these associations involves the stress-related activation of the hypothalamus-pituitary-adrenocortical (HPA) axis with proceeding alterations in the secretion of its main effector hormone cortisol. In this study we assessed a prospective, two-year effect of effort-reward imbalance (ERI) on cortisol secretion, based on a sub sample (N = 150; mean ± SD age: 42.4 ± 11.1; 84.0% female) of the ongoing Dresden Burnout Study (DBS). The provided ERI measures were collected as part of the online baseline and first follow up assessment. Further, cortisol secretion patterns over prolonged periods of time were evaluated in three consecutive years of laboratory baseline and follow up visits. Our findings suggest prospective associations between ERI and cortisol, indicating a blunted cortisol secretion in response to long-term work stress (p < 0.001). Given the regulatory properties of cortisol on various central and peripheral target tissues (e.g. cardiovascular system, liver, adipose tissue), a long-term decrease of cortisol availability can be hypothesized to cause multiple health-challenging consequences. Based on our findings, providing work environments where high efforts are always linked with high rewards have to be considered an important issue for employees health.

Conservation of DNA methylation in dipteran insects

DNA methylation is a central mechanism of epigenetic regulation. Whereas vertebrate DNA methylation requires at least four different DNA methyltransferases, Drosophila melanogaster only utilizes a single, Dnmt2-like enzyme. This profound difference has raised the question of the evolutionary significance of the Drosophila methylation system. We have now identified Dnmt2-like open reading frames in the genome sequences of Drosophila pseudoobscura and Anopheles gambiae. These genes represent the only candidate DNA methyltransferases in their respective genomes. Consistent with a catalytic activity of Dnmt2 proteins, we could also demonstrate low but significant levels of DNA methylation in genomic DNA from these species. Lastly, we were also able to detect highly conserved Dnmt2-like open reading frames and concomitant DNA methylation in several additional Drosophila species, which suggests that Dnmt2-mediated DNA methylation has been conserved over a considerable evolutionary distance.

[The pH-dependent solubility of heavy metals from sewage sludge of different compositions]

Sludge suspensions of anaerobically digested sewage sludge, limed anaerobically digested sewage sludge, precipitation sludge of the tertiary waste water treatment and limed precipitation sludge were incubated for 8 days with continuous rotation at nine defined pH-values (pH 1, 3-10). After membrane filtration (0.45 micron) solution concentrations of Zn, Cd, Cu, Pb and Cr were determined by atomic absorption spectroscopy. Results show that solubilities of Cd, Zn and Cu depend not only on pH-value but also in a high degree on the sludge type. The solubility is by far the lowest in the anaerobically digested sludge. Most obvious differences can be found for Cd: While the concentrations of soluble Cd in anaerobically digested sludge only increase at pH values lower than pH 4, the solubility of Cd in precipitation sludge and limed sludges already show rapid increases at pH values lower than 7. The solubility of Pb and Cr remains low in all sludges at all pH-values ranging from pH 3 to pH 10. These results show that when judging ecological effects of heavy metals from sewage sludges the physical and chemical composition of these sludges should be considered.