Measures of adiposity predict interleukin-6 responses to repeated psychosocial stress

Interleukin-6 Family of Cytokines in Cancers

Nine soluble ligands [interleukin-6 (IL-6), interleukin-11 (IL-11), leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine, interleukin-27 (IL-27), and interleukin-31] share the ubiquitously expressed transmembrane protein-glycoprotein-130 beta-subunit (gp130) and thus form IL-6 family cytokines. Proteins that may be important for cancerogenesis, CT-1, IL-11, IL-27, LIF, OSM, and CNTF, belong to the superfamily of IL-6. Cytokines such as IL-6, IL-11, and IL-27 are better investigated in comparison with other members of the same family of cytokines, eg, CT-1. Gp130 is one of the main receptors through which these cytokines exert their effects. The clinical implication of understanding the pathways of these cytokines in oncology is that targeted therapy to inhibit or potentiate cytokine activity may lead to remission in some cases.

How Loneliness Gets Under the Skin: Inflammation Mediates the Relationship Between Loneliness and Gait Speed

OBJECTIVE

Loneliness is linked to interleukin 6 (IL-6), a marker of systemic inflammation, which chronically has deleterious effects on physical and mental health across the adult life span. This study investigated cross-sectional relationships among loneliness, IL-6, demographics, multimorbidity, depression, obesity, friendship quantity, and slowed gait.

METHODS

Data from the Midlife Development in the United States Biomarker Project, a national adult sample ( N = 822; age range, 26-78 years) was used for this study. The PROCESS macro tested the hypothesis that IL-6 would mediate the relationship between loneliness and gait, after adjusting for demographic and health risk factors.

RESULTS

Age ( β = 0.292, p < .001), sex ( β = 0.197, p < .001), body mass index (BMI, β = 0.374, p < .001), waist-hip ratio ( β = 0.242, p < .001), and loneliness ( β = 0.089, p = .025) but not multimorbidity ( β = 0.043, p = .20), depression history ( β = 0.022, p = .47), depression symptoms ( β = 0.036, p = .28), and number of friends ( β = 0.022, p = .46) contributed to the variance in IL-6. Serial mediation analyses supported the chained effect of loneliness on walking time through BMI and IL-6. Results also showed specific indirect effects of BMI and IL-6 on walking time, suggesting more than one pathway by which loneliness influences health.

CONCLUSIONS

These results suggest that loneliness may increase the risk of systemic inflammation, leading to slowed gait and adverse health outcomes. Psychosocial interventions that address loneliness may provide an optimal treatment target for reducing inflammation and preventing declines in health.

Stress-induced brain responses are associated with BMI in women

Overweight and obesity are associated with altered stress reactivity and increased inflammation. However, it is not known whether stress-induced changes in brain function scale with BMI and if such associations are driven by peripheral cytokines. Here, we investigate multimodal stress responses in a large transdiagnostic sample using predictive modeling based on spatio-temporal profiles of stress-induced changes in activation and functional connectivity. BMI is associated with increased brain responses as well as greater negative affect after stress and individual response profiles are associated with BMI in females (pperm < 0.001), but not males. Although stress-induced changes reflecting BMI are associated with baseline cortisol, there is no robust association with peripheral cytokines. To conclude, alterations in body weight and energy metabolism might scale acute brain responses to stress more strongly in females compared to males, echoing observational studies. Our findings highlight sex-dependent associations of stress with differences in endocrine markers, largely independent of peripheral inflammation.

Longitudinal analysis for the risk of depression according to the consumption of sugar-sweetened carbonated beverage in non-diabetic and diabetic population

Studies have presented that high intake of sugar-sweetened carbonated beverage (SSCB) was more associated with the prevalence of depression. However, longitudinal evidence is still insufficient to identify whether the effect of SSCB on incident depression is independent of metabolic factors. Therefore, to evaluate the effect of SSCB consumption on the risk of depression, we analyzed the risk of depression according to the consumption of SSCB in 87,115 working aged Koreans who responded to Center for Epidemiologic Studies Depression (CES-D) scale. They were categorized into 5 groups by SSCB consumption based on one serving dose (200 ml) with never/almost never, < 1 serving/week, 1 ≤ serving/week < 3, 3 ≤ serving/week < 5, and 5 ≤ serving/week. During follow-up, CES-D ≥ 16 was determined as incident depressive symptom. Cox proportional hazards model was used to calculate the multivariable-adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptom. In analysis for all study participants, the risk of depressive symptom significantly increased proportionally to SSCB consumption (never/almost never: reference, < 1 serving/week: 1.12 [1.07-1.17], 1 ≤  ~  < 3 serving/week: 1.26 [1.19-1.33], 3 ≤  ~  < 5 serving/week: 1.32 [1.23-1.42], and ≥ 5 serving/week: 1.45 [1.33-1.59]). This association was identically observed in men, women, normal glycemic subgroup and prediabetes subgroup.

Predicting depressive symptom by cardiometabolic indicators in mid-aged and older adults in China: a population-based cross-sectional study

Objective

Depressive symptom is a serious mental illness often accompanied by physical and emotional problems. The prevalence of depressive symptom in older adults has become an increasingly important public health priority. Our study used cardiometabolic indicators to predict depressive symptom in middle-aged and older adults in China.

Methods

The data came from the China Health and Retirement Longitudinal Study 2011 (CHARLS2011), which was a cross-sectional study. The analytic sample included 8,942 participants aged 45 years or above. The study evaluated the relationship between cardiometabolic indicators and depression by measuring 13 indicators, including body mass index (BMI), waist circumference, waist-height ratio (WHtR), conicity index, visceral adiposity index (VAI), Chinese visceral adiposity index (CVAI), lipid accumulation product (LAP), a body shape index (ABSI), body roundness index (BRI), triglyceride glucose index (TyG-index) and its correlation index (TyG-BMI, TyG-waist circumference, TyG-WHtR). Binary logistic regression analysis was used to examine the association between thirteen cardiometabolic indicators and depressive symptom. In addition, the receiver operating characteristic (ROC) curve analysis and area under curve (AUC) were used to evaluate the predictive anthropometric index and to determine the optimum cut-off value.

Results

The study included 8,942 participants, of whom 4,146 (46.37%) and 4,796 (53.63%) were male and female. The prevalence of depressive symptom in mid-aged and older adults in China was 41.12% in males and 55.05% in females. The results revealed that BMI [AUC = 0.440, 95%CI: 0.422-0.457], waist circumference [AUC = 0.443, 95%CI: 0.425-0.460], WHtR [AUC = 0.459, 95%CI: 0.441-0.476], LAP [AUC = 0.455, 95%CI: 0.437-0.472], BRI [AUC = 0.459, 95%CI: 0.441-0.476], CVAI [AUC = 0.449, 95%CI: 0.432-0.467], TyG-BMI [AUC = 0.447, 95%CI: 0.429-0.465], and TyG-waist circumference [AUC =0.452, 95%CI: 0.434-0.470] were weak predictors of depressive symptom (p < 0.05) in males. In females, BMI [AUC = 0.470, 95%CI: 0.453-0.486], LAP [AUC = 0.484, 95%CI: 0.467-0.500], TyG-BMI [AUC = 0.470, 95%CI: 0.454-0.487], and TyG-waist circumference [AUC =0.481, 95%CI: 0.465-0.498] were weak predictors of depressive symptom (p < 0.05). On the other side, VAI, ABSI, conicity index and TyG index could not predict depressive symptom in middle-aged and older adults.

Conclusion

Most cardiometabolic indicators have important value in predicting depressive symptom. Our results can provide measures for the early identification of depressive symptom in middle-aged and older adults in China to reduce the prevalence of depressive symptom and improve health.

Cytokine alterations in pediatric internalizing disorders: Systematic review and exploratory multi-variate meta-analysis

Pediatric internalizing disorders are prevalent and characterized by a maladaptive cognitive, emotional response to a perceived stressor. The hypothesized effect of this response is observable changes in behavior mediated by homeostatic inflammatory cytokines. The aim of this study was to synthesize the literature and analyze the effect of cytokines on pediatric internalizing disorders. Influential moderating variables, including mean body mass index, fasting status at blood collection, participant sex, cytokine type, mean age, percentage of sample medicated, and diagnosis, were also assessed. A systematic literature search was performed in electronic databases (Medline, PubMed, and PsycINFO) from January 1, 1980 to June 15, 2022. Case-control studies of pediatric internalizing disorders, specifically anxiety and depression, were reviewed for their association with peripheral cytokine levels. Meta-analyses were performed using a random effects multi-variate model and effect sizes were calculated using Hedge's g for IL-2, CRP, IL-6, TNF-α, IL-1β, IFN-γ, and IL-10. Thirty-three studies were reviewed and 28 studies were included in the meta-analysis (n = 1322 cases and n = 3617 controls). Peripheral cytokine levels were elevated in pediatric internalizing disorders compared to controls (Hedge's g = 0.19, p < 0.001). In the moderator analyses, depression diagnosis (Hedge's g = 0.18, p = 0.009) and non-fasting blood collection (Hedge's g = 0.20, p = 0.006) were significant. The meta-analytic findings are limited by methodological variation between studies, high heterogeneity, and low statistical power. Despite this, the findings suggest that elevated peripheral cytokine levels may play a role in the etiology and/or symptom maintenance of pediatric internalizing disorders.

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Depression diagnosis and non-fasting blood collection were observed to significantly influenced peripheral cytokine levels.

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No individual peripheral cytokines tested were associated with pediatric internalizing disorders.

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Overall, elevated peripheral cytokines were observed in pediatric internalizing disorders compared to controls.

Baseline anxiety-sensitivity to estradiol fluctuations predicts anxiety symptom response to transdermal estradiol treatment in perimenopausal women - A randomized clinical trial

BACKGROUND

The menopausal transition (perimenopause) is associated with an increased risk of major depression, characterized by anxiety and anhedonia phenotypes. Greater estradiol (E2) variability predicts the development of perimenopausal depression, especially within the context of stressful life events (SLEs). While transdermal E2 (TE2) reduces perimenopausal depressive symptoms, the mechanisms underlying TE2 efficacy and predictors of TE2 treatment response remain unknown. This study aimed at determining relationships between E2 fluctuations, mood symptoms, and physiologic stress-reactivity (cortisol and interleukin-6) and whether differences in mood-sensitivity to E2 fluctuations predict mood responses to TE2 treatment.

METHODS

This randomized, double-blind, placebo-controlled trial investigated medically healthy women (46-60 years) in the early or late menopause transition. Baseline E2-sensitivity strength was calculated from eight weekly individual correlations between week-to-week E2 change and index week anxiety (State-Trait Anxiety Inventory) and anhedonia (Snaith-Hamilton Pleasure Scale). Women then received eight weeks of TE2 or transdermal placebo.

RESULTS

Analyses included 73 women (active TE2 n = 35). Greater baseline E2 fluctuations predicted greater anhedonia (p = .002), particularly in women with more SLEs. Greater E2 fluctuations also predicted higher cortisol (p = .012) and blunted interleukin-6 (p = .02) stress-responses. Controlling for baseline symptoms, TE2 was associated with lower post-treatment anxiety (p < .001) and anhedonia (p < .001) versus placebo. However, the efficacy of TE2 for anxiety (p = .007) and also for somatic complaints (p = .05) was strongest in women with greater baseline E2 sensitivity strength.

CONCLUSIONS

TE2 treatment reduced perimenopausal anxiety and anhedonia. The ability of baseline mood-sensitivity to E2 fluctuations to predict greater TE2 efficacy has implications for individualized treatment of perimenopausal anxiety disorders.

Changes in appetite during quarantine and their association with pre-COVID-19 mental and physical health

BACKGROUND

The COVID-19 Pandemic resulted in high levels of fear, anxiety, and stress. People with pre-existing physical and mental health conditions may have been more affected by the sudden changes in daily habits during the initial months of global quarantine imposed during the COVID-19 pandemic.

METHODS

We designed the Quarantine, Anxiety, and Diet (QUAD) Survey to investigate the effect of pre-existing health conditions on the relationship of COVID-19 stress and food behavior. The anonymous survey was distributed online and only adults were eligible to participate.

RESULTS

The results showed that responders with pre-existing health conditions differed from healthy participants in eating behavior during this time of stress. Compared to those classified as healthy, fewer people with pre-existing physical illness showed an increase in appetite with stress during the COVID-19 pandemic. Responders with pre-existing psychiatric illness were more likely to show increases or decreases in appetite with stress compared to healthy responders. Furthermore, higher BMI was associated with higher rate of increased appetite, whereas low BMI showed a higher rate of decreased appetite, both compared to normal BMI.

CONCLUSION

The QUAD Survey demonstrated that individuals with pre-COVID-19 psychiatric conditions are at a higher risk of maladaptive food behavior under stress. Since pre-existing psychiatric illnesses and acute stressors are known risk factors for eating disorders, special attention should be placed on those at risk to mediate the psychological and physical effects of stress and anxiety.

The longitudinal connection between depressive symptoms and inflammation: Mediation by sleep quality

Although there is a strong association between depressive symptoms and markers of inflammation, it remains unclear whether depressive symptoms at one point in life may predict inflammation later in life. Moreover, despite extant literature linking sleep with both depressive symptoms and inflammation, there is little research investigating poor sleep as a mechanism linking depressive symptoms with later inflammation. The links between depression and physical health can also vary by gender. In longitudinal analyses with data from the Midlife in the United States (MIDUS) study, we examined whether depressive symptoms were associated with inflammatory markers 11 years later and whether these associations were mediated by sleep disturbances or moderated by gender. Participants reported depressive symptoms and demographic information at baseline. At 11-year follow-up, the same participants (n = 968) reported depressive symptoms, sleep quality and duration using validated scale items, and provided a blood sample from which inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) were quantified. Actigraphy assessment of sleep was obtained in a subsample (n = 276). After adjusting for concurrent depressive symptoms and other relevant covariates, baseline depressive symptoms were associated with CRP 11 years later in the full sample, and with IL-6 among women. Subjective sleep quality mediated the association between depressive symptoms and CRP. Results suggest that depressive symptoms may be longitudinally associated with inflammation; however, directionality issues cannot be determined from the present work, particularly as inflammation markers (which might have been associated with baseline depressive symptoms) were not available at baseline. Findings further suggest that longitudinal associations between depressive symptoms and inflammation may potentially be explained by sleep and may reflect gender specific patterns.

The Dose-Response Associations of Sugar-Sweetened Beverage Intake with the Risk of Stroke, Depression, Cancer, and Cause-Specific Mortality: A Systematic Review and Meta-Analysis of Prospective Studies

The associations between sugar-sweetened beverage (SSB) consumption and the risk of stroke, depression, cancer, and cause-specific mortality have not been determined, and the quantitative aspects of this link remain unclear. This meta-analysis therefore conducted a systematic review and dose-response analysis to determine their causal links. The database searches were conducted in PubMed, Cochrane library, Embase, Web of Science up to 10 November 2021. The intervention effects were evaluated by relative risk (RR) with 95% confidences (CI). Thirty-two articles met the inclusion criteria. Higher levels of SSB consumption significantly increased the risk of stroke (RR 1.12, 95% CI 1.03–1.23), depression (1.25, 1.11–1.41), cancer (1.10, 1.03–1.17), and all-cause mortality (1.08, 1.05–1.11) compared with none or lower SSB intake. The associations were dose-dependent, with per 250 mL increment of SSB intake daily increasing the risk of stroke, depression, cancer, and all-cause mortality by RR 1.09 (1.03–1.15), 1.08 (1.06–1.10), 1.17 (1.04–1.32), and 1.07 (1.03–1.11), respectively. The link was curved for depression and cancer risk (p_non-linear < 0.05). Subgroup analysis suggested that higher SSB intake increased ischemic stroke by 10%, CVD-caused mortality by 13%, and cancer-caused mortality by 6.0% than none or lower SSB consumption. It is suggested that SSB accounts for a leading risk factor of stroke, depression, cancer, and mortality, and that the risk rises in parallel with the increment of SSB intake (and is affected by participant characteristics).

Physiological stress in response to multitasking and work interruptions: Study protocol

BACKGROUND

The biopsychological response patterns to digital stress have been sparsely investigated so far. Important potential stressors in modern working environments due to increased digitalization are multitasking and work interruptions. In this study protocol, we present a protocol for a laboratory experiment, in which we will investigate the biopsychological stress response patterns to multitasking and work interruptions.

METHODS

In total, N = 192 healthy, adult participants will be assigned to six experimental conditions in a randomized order (one single-task, three dual-task (two in parallel and one as interruption), one multitasking, and one passive control condition). Salivary alpha-amylase as well as heart rate as markers for Sympathetic Nervous System Activity, heart rate variability as measure for Parasympathetic Nervous System (PNS) activity, and cortisol as measure for activity of the hypothalamic-pituitary adrenal (HPA) axis will be assessed at six time points throughout the experimental session. Furthermore, inflammatory markers (i.e., IL-6, C-reactive protein (CRP), and secretory immunoglobulin-A) will be assessed before and after the task as well as 24 hours after it (IL-6 and CRP only). Main outcomes will be the time course of these physiological stress markers. Reactivity of these measures will be compared between the experimental conditions (dual-tasking, work interruptions, and multitasking) with the control conditions (single-tasking and passive control).

DISCUSSION

With this study protocol, we present a comprehensive experiment, which will enable an extensive investigation of physiological stress-responses to multitasking and work interruptions. Our planned study will contribute to a better understanding of physiological response patterns to modern (digital) stressors. Potential risks and limitations are discussed. The findings will have important implications, especially in the context of digital health in modern working and living environments.

Differences in acute stress responses depending on first or second language in a Hispanic-American sample

Using a second language is a daily experience for many people today, among them many migrants. To determine whether speaking a second language induces a stronger cortisol or alpha-amylase (sAA) response than first language, we tested a Hispanic-American sample in two Trier Social Stress Test (TSST) conditions: First (Spanish) and second (German) language. Thirty-two participants (64.5% female) between the age of 19 and 53 years (mean = 30.68) from Latin America were tested (15 in Spanish, 17 in German). Participants were randomized to a German or Spanish version of the TSST, gave six saliva samples and completed questionnaires on perceived threat and stress, positive and negative affect as well as state-anxiety. A significantly higher stress response was found in the German condition for salivary cortisol, but not for sAA. Self-report showed significantly higher perceived threat and negative affect after the TSST for the German compared to the first language condition. Speaking a second compared to first language in a challenging situation appeared to be more stressful and threatening for participants. Further, reported increases in state-anxiety appeared to be higher in the German condition, even though group differences did not reach significance. A more detailed investigation of underlying, stress inducing mechanisms should be considered in future studies as well as associations with language proficiency and improvements over time.

Role of dietary factors in the prevention and treatment for depression: an umbrella review of meta-analyses of prospective studies

The role of diet in depression is becoming increasingly acknowledged. This umbrella review aimed to summarize comprehensively the current evidence reporting the effects of dietary factors on the prevention and treatment of depression. PubMed, Embase, and the Cochrane Library were searched up to June 2021 to identify relevant meta-analyses of prospective studies. Twenty-eight meta-analyses, with 40 summary estimates on dietary patterns (n = 8), food and beverages (n = 19), and nutrients (n = 13) were eligible. The methodological quality of most meta-analyses was low (50.0%) or very low (25.0%). Quality of evidence was moderate for inverse associations for depression incidence with healthy diet [risk ratio (RR): 0.74, 95% confidential interval (CI), 0.48-0.99, I² = 89.8%], fish (RR: 0.88, 95% CI, 0.79-0.97, I²= 0.0%), coffee (RR: 0.89, 95% CI, 0.84-0.94, I²= 32.9%), dietary zinc (RR: 0.66, 95% CI 0.50-0.82, I²= 13.9%), light to moderate alcohol (<40 g/day, RR: 0.77, 95% CI, 0.74-0.83, I²= 20.5%), as well as for positive association with sugar-sweetened beverages (RR: 1.05, 95% CI, 1.01-1.09, I²= 0.0%). For depression treatment, moderate-quality evidence was identified for the effects of probiotic [standardized mean difference (SMD): -0.31, 95% CI, -0.56 to -0.07, I²= 48.2%], omega-3 polyunsaturated fatty acid (SMD: -0.28, 95% CI, -0.47 to -0.09, I² = 75.0%) and acetyl-L-carnitine (SMD: -1.10, 95% CI, -1.65 to -0.56, I² = 86.0%) supplementations. Overall, the associations between dietary factors and depression had been extensively evaluated, but none of them were rated as high quality of evidence, suggesting further studies are likely to change the summary estimates. Thus, more well-designed research investigating more detailed dietary factors in association with depression is warranted.

Integrating anthropometric and cardiometabolic health methods in stress, early experiences, and development (SEED) science

Within Stress, Early Experiences, and Development (SEED) science, there is a growing body of research demonstrating complex associations not only between stress, development, and psychopathology, but also with chronic disease risk factors. We argue that it is important for SEED researchers to consider including child anthropometric and physical health measures to more comprehensively capture processes of risk and resilience. Broader adoption of harmonized anthropometry and health measures in SEED research will facilitate collaborations, yielding larger datasets for research in high-risk populations, and greater opportunity to replicate existing findings. In this review, we identify optimal anthropometric and cardiometabolic health measurement methods used from infancy through adolescence, including those that are low-burden and inexpensive. Methods covered include: waist, hip, and head circumference, height, length, weight, pubertal development, body composition, blood pressure, arterial stiffness, carotid intima media thickness, and serum measures of cardiometabolic risk and inflammation. We provide resources for SEED researchers to integrate these methods into projects or to better understand these methods when reading the literature as well as where to find collaborators for more in-depth studies incorporating these measures. With broader integration of psychological and physical health measures in SEED research, we can better inform theory and interventions to promote health and resilience in individuals who have experienced early stress.

To stress or not to stress: Brain-behavior-immune interaction may weaken or promote the immune response to SARS-CoV-2

The COVID-19 pandemic continues to strongly affect people with health disadvantages, creating a heavy burden on medical systems and societies worldwide. Research is growing rapidly and recently revealed that stress-related factors such as socio-economic status, may also play a pivotal role. However, stress research investigating the underlying psychoneuroimmune interactions is missing. Here we address the question whether stress-associated neuroendocrine-immune mechanisms can possibly contribute to an increase in SARS-CoV-2 infections and influence the course of COVID-19 disease. Additionally, we discuss that not all forms of stress (e.g. acute versus chronic) are detrimental and that some types of stress could attenuate infection-risk and -progression. The overall aim of this review is to motivate future research efforts to clarify whether psychosocial interventions have the potential to optimize neuroendocrine-immune responses against respiratory viral infections during and beyond the COVID-19 pandemic. The current state of research on different types of stress is summarized in a comprehensive narrative review to promote a psychoneuroimmune understanding of how stress and its mediators cortisol, (nor)adrenaline, neuropeptides and neurotrophins can shape the immune defense against viral diseases. Based on this understanding, we describe how people with high psychosocial stress can be identified, which behaviors and psychosocial interventions may contribute to optimal stress management, and how psychoneuroimmune knowledge can be used to improve adequate care for COVID-19 and other patients with viral infections.

[Can Stress Interact with SARS-CoV-2? A Narrative Review with a Focus on Stress-Reducing Interventions that may Improve Defence against COVID-19]

OBJECTIVE

The COVID-19 pandemic is on the rise and causes many concerns and fears in the population as well as among medical care givers. This raises the question as to how psychosocial stress associated with the pandemic can be managed, and also if certain forms of stress can contribute to an increase in infections and critical illnesses.

METHODS

Against the background of the current state of research on stress and the immune response, we provide a narrative review of studies addressing the question as to how stress can influence the immune defence against viral diseases.

RESULTS

Excessive stress can compromise the barrier function of the airways and alter neuroendocrine control of immune function, which can create a virus-permissive immune response.

DISCUSSION

Because certain forms of stress can play a role in the successful immune defence against viral respiratory disease, it is important to identify people with high psychosocial stress and to help them manage their stress. Conclusion Psychosocial measures that contribute to improved stress management may have a positive effect on the immune response against viral respiratory infections.

The Impact of Stressful Life Events on the Incidence of Type 2 Diabetes in U.S. Adults From the Health and Retirement Study

OBJECTIVES

We evaluated the association between cumulative stressful life events (SLE) and type of stress (lifetime vs recent) and incident diabetes (Type 2 diabetes mellitus [T2DM]) in middle-aged U.S. adults.

METHODS

Data from the 2006-2014 waves of the Health and Retirement Study (HRS) were analyzed (n = 7,956). Stress-related differences in age at T2DM diagnosis were estimated using Cox proportional hazards models.

RESULTS

The adjusted risk of T2DM significantly increased by 6% per unit increase in cumulative SLE (95% confidence interval [CI] = 1.03, 1.11), by 5% per unit increase in lifetime stress (95% CI = 1.00, 1.09), and by 23% per unit increase in recent stress (95% CI = 1.12, 1.36). Each level of cumulative SLE (1, 2, 3, and ≥4 events) and recent stress (1 and ≥2 events) compared to no stress was significantly associated with an increased risk of T2DM. Each level of lifetime stress compared to no stress was significantly associated with an elevated risk of T2DM except for 3 events.

DISCUSSION

Cumulative SLE and type of stress were associated with incident T2DM in middle-aged adults. Reducing the direct effect of stress with management interventions may reduce the indirect effect of developing T2DM and warrants further investigation.

A systematic review of the Trier Social Stress Test methodology: Issues in promoting study comparison and replicable research

Since its development in 1993, the Trier Social Stress Test (TSST) has been used widely as a psychosocial stress paradigm to activate the sympathetic nervous system and hypothalamic-pituitary-adrenal axis (HPAA) stress systems, stimulating physiological functions (e.g. heart rate) and cortisol secretion. Several methodological variations introduced over the years have led the scientific community to question replication between studies. In this systematic review, we used the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) to synthesize procedure-related data available about the TSST protocol to highlight commonalities and differences across studies. We noted significant discrepancies across studies in how researchers applied the TSST protocol. In particular, we highlight variations in testing procedures (e.g., number of judges, initial number in the arithmetic task, time of the collected saliva samples for cortisol) and discuss possible misinterpretation in comparing findings from studies failing to control for variables or using a modified version from the original protocol. Further, we recommend that researchers use a standardized background questionnaire when using the TSST to identify factors that may influence physiological measurements in tandem with a summary of this review as a protocol guide. More systematic implementation and detailed reporting of TSST methodology will promote study replication, optimize comparison of findings, and foster an informed understanding of factors affecting responses to social stressors in healthy people and those with pathological conditions.

Physiological stressor impact on peripheral facial temperature, Il-6 and mean arterial pressure, in young people

Nowadays, stress is part of everyday life, whose long-term effects can trigger health risks. Among the main alterations that occur in the human body we can find the variation of inflammatory activity, blood pressure, and facial peripheral temperature. The objective of this work is to show the facial thermal behavior for men and women, as well as the differences in vascular and inflammatory responses induced by the effect of acute social stress. The Trier Social Stress Test was applied to 15 women and 15 men, free of disease, with an average age of 23.8 years and a standard deviation of 5.52. After capturing the baseline state, and at the end of the test, the inflammatory activity was measured through salivary interleukin-6; the mean blood pressure, and the capture of facial thermographic images. For the thermal images, six regions of interest (biothermomarkers) were analyzed: forehead, right cheek, left cheek, chin, nose, and corrugator muscle. The results obtained after analyzing the information were: an increase in inflammatory activity, an increase in mean blood pressure, and significant temperature changes in different areas of interest of the face, depending on gender. For men, it only appeared in the region of the nose and women's forehead, cheeks, and nose. Furthermore, the correlation between the three variables (il-6, blood pressure, and temperature) was performed and no significant values were found. Regarding the relationship between genders, only significant values were found for il-6.

Happiness and Inflammatory Responses to Acute Stress in People With Type 2 Diabetes

Background

Positive psychological characteristics in people with type 2 diabetes (T2D) are associated with better health and longevity, and one plausible physiological mechanism involves lower markers of inflammation. Positive affect is related to lower basal inflammatory markers and smaller inflammatory responses to acute stress, but this association in people with T2D remains to be examined.

Purpose

To examine the relationship between happiness and inflammatory markers at baseline and in response to acute stress in people with T2D.

Methods

One hundred forty people with T2D took part in laboratory-based stress testing. We aggregated daily happiness ratings over 7 days before stress testing. During the laboratory session, participants underwent two mental stress tasks—the mirror tracing and the Stroop task. Blood was sampled at baseline and post-stress (up to 75 min post-stress) to detect plasma interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1Ra), and monocyte chemoattractant protein-1 (MCP-1). Associations between happiness and inflammatory markers and responses were analyzed using multivariable linear regressions.

Results

Greater daily happiness significantly predicted lower baseline and post-stress IL-6 concentrations, and lower baseline MCP-1, after adjusting for covariates. The association between happiness and reduced basal IL-6 maintained after further controlling for daily sadness. We did not find significant associations between daily happiness and inflammatory responses to acute stress. No associations were detected for IL-1Ra.

Conclusions

Happier individuals with T2D have lower inflammatory markers before and after acute stress, albeit independent of stress responsivity. Findings could provide a protective physiological pathway linking daily happiness with better health in people with T2D.

Sex Differences in Interleukin-6 Responses Over Time Following Laboratory Pain Testing Among Patients With Knee Osteoarthritis

Epidemiological studies suggest that women are not only at a higher risk for developing knee osteoarthritis (KOA), but also report greater symptom severity compared to men. One potential underlying mechanism of these sex differences may be exaggerated inflammatory responses to pain among women compared to men. The present study examined sex differences in interleukin-6 (IL-6) response over time following experimental pain testing. We hypothesized that women, when compared to men, would show greater IL-6 reactivity when exposed to acute pain in a human laboratory setting. Eighty-four participants (36 men and 48 women) with KOA scheduled for total knee arthroplasty underwent a quantitative sensory testing (QST) battery. A total of seven IL-6 measurements were taken, twice at baseline, once immediately after QST, and every 30 minutes up to 2 hours after QST. Consistent with our hypothesis, women, when compared to men, showed accelerated increases in IL-6 levels following laboratory-evoked pain, even after controlling for body mass index, marital status, clinical pain, evoked pain sensitivity, and situational pain catastrophizing. Given that KOA is a chronic condition, and individuals with KOA frequently experience pain, these sex differences in IL-6 reactivity may contribute to the maintenance and/or exacerbation of KOA symptoms. PERSPECTIVES: The present study demonstrates that women, when compared to men, exhibit greater IL-6 reactivity after exposure to laboratory-evoked pain. Such sex differences may explain the mechanisms underlying women's higher chronic pain risk and pain perception, as well as provide further insight in developing personalized pain interventions.

Activation of the hypothalamic-pituitary adrenal axis in response to a verbal fluency task and associations with task performance

Speech fluency can be impaired in stressful situations. In this study, it was investigated whether a verbal fluency task by itself, i.e. without the presence of any further stressors, induces responses of the hypothalamic-pituitary adrenal (HPA) axis and of the sympathetic nervous system (SNS). The sample consisted of n = 85 participants (68.2% female; 33.3 ± 15.2 years) who performed two consecutive verbal fluency tasks for two minutes each. The categories were either ‘stress’ or ‘disease’ and ‘animals’ or ‘foods’ which were presented in a randomized order. Three saliva samples were collected, prior to the task (t₀), immediately after (t₁), and ten minutes after it (t₂). Salivary α-amylase and cortisol were assessed. Furthermore, blood pressure, heart rate, and ratings of actual stress perception, level of effort, and tiredness were measured. The verbal fluency task induced a HPA axis response with a maximum cortisol level at t₂ which was independent of task performance. Furthermore, perceived stress and effort, as well as tiredness increased after the task. Moreover, tiredness immediately after the task was negatively correlated with task performance. No α-amylase, blood pressure, or heart rate, and therefore SNS, responses were found. Implications for the integrated specificity model are discussed. We conclude that a verbal fluency task acts like an acute stressor that induces a cortisol and a perceived stress response without the need for further (e.g., social-evaluative) stress components. Therefore, it is a less time-consuming alternative to other stress tasks that can be used in field studies with little effort.

Evaluation of the socially evaluated cold-pressor group test (SECPT-G) in the general population

Background

In stress research, economic instruments for introducing acute stress responses are needed. In this study, we investigated whether the socially evaluated cold-pressor group test (SECPT-G) induces salivary alpha-amylase (sAA) and/or cortisol responses in the general population and whether this is associated with anthropometric, experimental, and lifestyle factors.

Methods

A sample of 91 participants from the general population was recruited. Salivary cortisol and sAA levels were assessed prior to (t₀), immediately after (t₁), and 10 min after the SECPT-G (t₂).

Results

A robust cortisol increase was found immediately after the SECPT-G, which further increased between t₁ and t₂. This was independent of most of the control variables. However, men showed a trend toward higher cortisol increases than women (p = 0.005). No sAA responses were found at all. However, sAA levels were dependent on measurement time point with highest levels between 9 pm and 9:30 pm. Participants who immersed their hands into the ice water for the maximally allowed time of 3 min showed higher sAA levels at all time points than participants who removed their hands from the water earlier.

Conclusions

We conclude that the SECPT-G is a good means of an acute stress test when cortisol—but not necessarily sAA—responses are intended.

Stress and inflammation - The need to address the gap in the transition between acute and chronic stress effects

Stress responses help us navigate our environment and respond appropriately to threats. Stress systems communicate threats to the entire organism, and as such, also stimulate inflammatory mechanisms. This modulation might serve protective functions in the short term, but sustained low-grade inflammation has severe long-term health consequences. While we have reached a reasonable level of understanding of acute, as well as chronic stress effects on inflammatory mechanisms, there is a significant gap in our understanding of the transitional phase between acute and chronic stress. The purpose of this review is to first summarize current knowledge of our understanding of acute stress effects on inflammation, as well as of chronic stress effects on inflammation, and to then analyze the state of knowledge about the transitional phase between acute and chronic stress. Research discussed here shows that we are beginning to understand the early phase of repeated acute stress, but lack information on longer term exposure to repeated acute stress experiences. More research is needed to bridge this important gap und our conceptualization and understanding of the stress and health relationship.

Higher trait reappraisal predicts stronger HPA axis habituation to repeated stress

Undergoing stress can be advantageous when it leads to adaptation and growth; however, failure of the hypothalamic-pituitary-adrenal (HPA) axis to habituate (i.e., nonhabituation) involves continuing to become highly activated in response to repeated exposure of the same stimulus and is considered maladaptive. Although 50-75% of individuals assessed in a laboratory exhibit adaptive habituation to repeated stress, variability in habituation suggests psychological processes used in response to stress may play a role, such as emotion regulation (ER). Nonetheless, no research to date has investigated whether ER strategies affect HPA axis habituation. We investigated whether tendency to use two ER strategies, reappraisal and suppression, influenced HPA axis habituation among 84 healthy young adults (60.7% female; M_age = 24.8 years, SD = 6.0) exposed to a standardized experimental stress paradigm on two consecutive days. HPA axis stress responses were assessed using salivary cortisol concentrations. We also examined whether non-manipulated state ER strategies (i.e., those used by the participant during and following the stressor on the first day) modulated HPA axis habituation over and above trait-use in a subsample (N = 60). Trait, but not state, reappraisal was associated with stronger HPA axis habituation. Neither trait nor state suppression were significantly associated with HPA axis habituation. These findings expand our current understanding of how ER can affect stress-related health outcomes and suggest habitual reappraisal plays an important role in adaption of the HPA axis to stress.

Socioeconomic status and central adiposity as determinants of stress-related biological responses relevant to cardiovascular disease risk

Stress-related processes have been implicated in the associations between lower socioeconomic status (SES), central adiposity, and cardiovascular disease risk. This study analysed the impact of SES and central adiposity on cardiovascular, inflammatory and neuroendocrine stress responses, and associations with cytomegalovirus (CMV) infection in a sample of 537 men and women aged 53-76 years (mean 62.89 years). SES was defined by grade of employment (higher, intermediate, and lower categories), and central adiposity was indexed by waist-hip ratio (WHR). Cardiovascular, inflammatory and cortisol responses were monitored during administration of a standardized mental stress testing protocol and salivary cortisol was measured repeatedly over the day. Lower SES was associated with raised systolic and diastolic blood pressure (BP), plasma interleukin (IL-6), fibrinogen, C-reactive protein, and salivary cortisol, and a large WHR accentuated SES differences in fibrinogen, C-reactive protein, and likelihood of CMV seropositivity, independently of general adiposity indexed by body mass index. During mental stress testing, return to resting levels (recovery) following behavioural challenge in systolic and diastolic BP and heart rate was impaired among lower SES participants, particularly those with large WHR. Lower SES participants had greater cortisol concentrations across the day, but this pattern did not vary with WHR. These findings extend the evidence relating lower SES to stress-related biological risk factors for cardiovascular disease, and indicate that central adiposity may augment these effects.

Sugar-sweetened beverages consumption and the risk of depression: A meta-analysis of observational studies

BACKGROUND

It remains inconsistent whether sugar-sweetened beverages (SSBs) consumption increases the risk of depression. Thus, we carried out a meta-analysis to evaluate the association between SSBs consumption and the risk of depression.

METHODS

PubMed and Web of Science were searched for relevant articles published up to June 2018. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated by the fixed-effects model or random effect model based on heterogeneity test.

RESULTS

10 observational studies involving 37,131 depression cases among 365,289 participants were included. The combined risk of depression for the highest versus lowest consumption of SSBs was 1.31 (95% CI 1.24-1.39). The findings were consistent in the cross-sectional studies (RR = 1.38; 95% CI 1.26-1.52) as well as in the cohort studies (RR = 1.30; 95% CI 1.19-1.41) A nonlinear dose-response relationship was found (P_nonlinearity = 0.0103) for depression risk and SSBs consumption. Compared with SSBs nondrinkers, those who drank the equivalent of 2 cups/day of cola might increase the risk of depression by 5% (RR = 1.05; 95% CI 1.01-1.09). And the equivalent of 3cans/day of cola might have approximately 25% higher risk of depression.

LIMITATIONS

10 studies were included in this meta-analysis, of which only 4 were cohort studies, and more cohort studies need to be performed in the future.

CONCLUSIONS

This meta-analysis indicates that SSBs consumption might be associated with a modestly higher risk of depression. The results need to be further confirmed in the future.

Old Friends, immunoregulation, and stress resilience

There is a considerable body of evidence indicating that chronic adverse experience, especially chronic psychosocial stress/trauma, represents a major risk factor for the development of many somatic and affective disorders, including inflammatory bowel disease (IBD) and posttraumatic stress disorder (PTSD). However, the mechanisms underlying the development of chronic stress-associated disorders are still in large part unknown, and current treatment and prevention strategies lack efficacy and reliability. A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this review, we provide evidence indicating that increases in immune (re-)activity and inflammation, potentially promoted by a reduced exposure to immunoregulatory microorganisms ("Old Friends") in today's modern society, may be causal factors in mediating the vulnerability to development and persistence of stress-related pathologies. Moreover, we discuss strategies to increase immunoregulatory processes and attenuate inflammation, as for instance contact with immunoregulatory Old Friends, which appears to be a promising strategy to promote stress resilience and to prevent/treat chronic stress-related disorders.

Sex differences in interleukin-6 stress responses in people with Type 2 diabetes

People with Type 2 diabetes (T2D) show dysregulated inflammatory responses to acute stress, but the effect of sex on inflammatory responses in T2D remains unclear. The purpose of this study was to investigate differences in interleukin (IL)-6 stress responses between older men and women with T2D. One hundred and twenty-one people (76 men; mean age = 64.09, SD = 7.35, 45 women; mean age = 63.20, SD = 6.70) with doctor-verified T2D took part in this laboratory-based stress testing study. Participants carried out acute mental stress tasks, and blood was sampled at baseline, immediately poststress, 45 min poststress, and 75 min poststress to detect plasma IL-6 concentrations. IL-6 change scores were computed as the difference between the baseline measurement and the three time points poststress. Main effects and interactions were tested using mixed model analysis of covariance. We found a significant main effect of time on IL-6 levels, and a significant Sex × Time interaction. In adjusted analyses including the three change scores and all the covariates, the significant Sex × Time interaction was maintained; IL-6 responses were greater in women at 45 and 75 min poststress compared with men, adjusting for age, body mass index, smoking, household income, glycated hemoglobin, oral antidiabetic medication, insulin/other injectable antidiabetic medication, depressive symptoms, and time of day of testing. Different inflammatory stress response pathways are present in men and women with T2D, with women producing larger IL-6 increases. The long-term implications of these differences need to be elucidated in future studies.

Childhood adversity impact on gut microbiota and inflammatory response to stress during pregnancy

BACKGROUND

Adverse childhood experiences (ACEs), such as abuse or chronic stress, program an exaggerated adult inflammatory response to stress. Emerging rodent research suggests that the gut microbiome may be a key mediator in the association between early life stress and dysregulated glucocorticoid-immune response. However, ACE impact on inflammatory response to stress, or on the gut microbiome, have not been studied in human pregnancy, when inflammation increases risk of poor outcomes. The aim of this study was to assess the relationships among ACE, the gut microbiome, and cytokine response to stress in pregnant women.

METHODS

Physically and psychiatrically healthy adult pregnant women completed the Adverse Childhood Experiences Questionnaire (ACE-Q) and gave a single stool sample between 20 and 26 weeks gestation. Stool DNA was isolated and 16S sequencing was performed. Three 24-hour food recalls were administered to assess dietary nutrient intake. A subset of women completed the Trier Social Stress Test (TSST) at 22-34 weeks gestation; plasma interleukin-6 (IL-6), interleukin-1β (IL-1β), high sensitivity C-reactive protein (hsCRP), tumor necrosis factor α (TNF-α), and cortisol were measured at four timepoints pre and post stressor, and area under the curve (AUC) was calculated.

RESULTS

Forty-eight women completed the ACE-Q and provided stool; 19 women completed the TSST. Women reporting 2 or more ACEs (high ACE) had greater differential abundance of gut Prevotella than low ACE participants (q = 5.7 × 10^-13). Abundance of several gut taxa were significantly associated with cortisol, IL-6, TNF-α and CRP AUCs regardless of ACE status. IL-6 response to stress was buffered among high ACE women with high intake of docosahexaenoic acid (DHA) (p = 0.03) and eicosapentaenoic acid (EPA) (p = 0.05).

DISCUSSION

Our findings suggest that multiple childhood adversities are associated with changes in gut microbiota composition during pregnancy, and such changes may contribute to altered inflammatory and glucocorticoid response to stress. While preliminary, this is the first study to demonstrate an association between gut microbiota and acute glucocorticoid-immune response to stress in a clinical sample. Finally, exploratory analyses suggested that high ACE women with high dietary intake of ω-3 polyunsaturated fatty acids (PUFAs) had a dampened inflammatory response to acute stress, suggesting potentially protective effects of ω-3s in this high-risk population. Given the adverse effects of inflammation on pregnancy and the developing fetus, mechanisms by which childhood adversity influence the gut-brain axis and potential protective factors such as diet should be further explored.

Biopsychosocial approach to understanding resilience: Stress habituation and where to intervene

BACKGROUND

Resilience in the face of adversity is a human experience that leads to better health, both mentally and physically. We briefly review its historical origins rooted in ecological biology and its adoption into health care. Resilience is the common response to adversity or potential traumatic events. Individual differences in emotion regulation and coping skills as well as social capital and one's physical environment influence a person's ability to achieve resilience.

PROPOSED MECHANISM

One potential biopsychosocial measure of resilience includes stress habituation to repeated stress as demonstrated in the laboratory, possibly providing a tool to observe mastery of resilience training in the clinic. Evidence-based interventions at the individual and small group level (eg, family, classroom) have successfully shown development of resilient behaviours and improved mental and physical health outcomes. However, the role of social context and public policy clearly influence an individual's ability to be resilient.

CONCLUSIONS

Despite the current limited evidence of the effectiveness of resilience building interventions, clinicians, researchers, and other health care professions have an obligation to become advocates for laws and policies that support the most vulnerable, and least resilient, in our society to attain resilience for their health. This salutary effect will enable them to become socially as well as economically productive members of the community at large. It is not possible to remove stress or adversity from life, but we can influence the development of regulatory flexibility and decrease the sociocultural factors linked to the nonresilient experience, thus mitigating adversity's long-term effects on health.

Inflammation-Nature's Way to Efficiently Respond to All Types of Challenges: Implications for Understanding and Managing "the Epidemic" of Chronic Diseases

Siloed or singular system approach to disease management is common practice, developing out of traditional medical school education. Textbooks of medicine describe a huge number of discrete diseases, usually in a systematic fashion following headings like etiology, pathology, investigations, differential diagnoses, and management. This approach suggests that the body has a multitude of ways to respond to harmful incidences. However, physiology and systems biology provide evidence that there is a simple mechanism behind this phenotypical variability. Regardless if an injury or change was caused by trauma, infection, non-communicable disease, autoimmune disorders, or stress, the typical physiological response is: an increase in blood supply to the area, an increase in white cells into the affected tissue, an increase in phagocytic activity to remove the offending agent, followed by a down-regulation of these mechanisms resulting in healing. The cascade of inflammation is the body's unique mechanism to maintain its integrity in response to macroscopic as well as microscopic injuries. We hypothesize that chronic disease development and progression are linked to uncontrolled or dysfunctional inflammation to injuries regardless of their nature, physical, environmental, or psychological. Thus, we aim to reframe the prevailing approach of management of individual diseases into a more integrated systemic approach of treating the "person as a whole," enhancing the patient experience, ability to a make necessary changes, and maximize overall health and well-being. The first part of the paper reviews the local immune cascades of pro- and anti-inflammatory regulation and the interconnected feedback loops with neural and psychological pathways. The second part emphasizes one of nature's principles at work-system design and efficiency. Continually overwhelming this finely tuned system will result in systemic inflammation allowing chronic diseases to emerge; the pathways of several common conditions are described in detail. The final part of the paper considers the implications of these understandings for clinical care and explore how this lens could shape the physician-patient encounter and health system redesign. We conclude that healthcare professionals must advocate for an anti-inflammatory lifestyle at the patient level as well as at the local and national levels to enhance population health and well-being.

Perceived discrimination is associated with the inflammatory response to acute laboratory stress in women at risk for cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death in the United States and exacts a disproportionate toll on minorities. Growing evidence demonstrates that perceived discrimination is a significant contributing factor to psychological distress, chronic low-grade inflammation, and cardiovascular health. However, little is known regarding the extent to which perceived discrimination contributes to the inflammatory response to acute stress. Therefore, the purpose of this study was to examine the influence of perceived discrimination on the inflammatory response to a laboratory acute stress paradigm in women at risk for CVD. A cross-sectional sample of 99 postmenopausal women (50 African American and 49 non-Hispanic White) (mean age 60.2 years) with at least two risk factors for CVD underwent the Trier Social Stress Test (TSST). Subjects completed the Detroit Area Study Discrimination Scale (DAS-DS) Everyday Discrimination subscale and provided blood and saliva samples prior to the TSST and every 15 min up to 90 min post-TSST to measure a pro-inflammatory cytokine, interleukin-6 (IL-6). Perceived discrimination was significantly associated with the salivary IL-6 response to the TSST (b = 0.49, SE = 0.13, p = <0.001) controlling for age, race, marital status, household income, BMI, statin use, childhood maltreatment, depressive symptoms, and subjective social status. Women who reported higher levels of perceived discrimination had higher levels of salivary IL-6 at baseline and following the TSST as compared to women who reported lower levels of perceived discrimination. Results suggest that higher levels of perceived discrimination, regardless of race and socioeconomic status, may heighten levels of inflammation, prior to and following an acute stress exposure. The circulating Il-6 response was associated with BMI only and did not correlate with salivary IL-6. These data suggest that perceived discrimination may contribute to the salivary-IL-6 acute stress response. However, more research is needed to help clarify the complex relationships among stress and salivary proinflammatory cytokines.

Anhedonia as a clinical correlate of inflammation in adolescents across psychiatric conditions

Objectives: Peripheral inflammation has been associated with multiple psychiatric disorders, particularly with depression. However, findings remain inconsistent and unreproducible, most likely due to the disorder's heterogeneity in phenotypic presentation. Therefore, in the present study, in an effort to account for inter-individual differences in symptom severity, we utilised a dimensional approach to assess the relationships between a broad panel of inflammatory cytokines and key psychiatric symptoms (i.e. depression, anhedonia, anxiety, fatigue and suicidality) in adolescents across psychiatric disorders. We hypothesised that only anhedonia (reflecting deficits of reward function) will be associated with inflammation.Methods: Participants were 54 psychotropic medication-free adolescents with diverse psychiatric conditions and 22 healthy control (HC) adolescents, aged 12-20. We measured 41 cytokines after in vitro lipopolysaccharide stimulation. Mann-Whitney U and Spearman correlation tests examined group comparison and associations, respectively, while accounting for multiple comparisons and confounds, including depression severity adolescent.Results: There were no group differences in cytokine levels. However, as hypothesised, within the psychiatric group, only anhedonia was associated with 19 cytokines, including haematopoietic growth factors, chemokines, pro-inflammatory cytokines, and anti-inflammatory cytokines.Conclusions: Our findings suggest that general inflammation may induce reward dysfunction, which plays a salient role across psychiatric conditions, rather than be specific to one categorical psychiatric disorder.

Less immune activation following social stress in rural vs. urban participants raised with regular or no animal contact, respectively

Our results show that a standardized laboratory psychosocial stressor causes a greater inflammatory response in young healthy participants with an urban upbringing in the absence of pets, relative to young healthy participants with a rural upbringing in the presence of farm animals. In view of the known links between persistent inflammatory states and psychiatric disturbances, and considering that many stress-associated physical and mental disorders are more prevalent in environments offering a narrow range of microbial exposures, we feel that our findings are of general interest and significance. Moreover, we feel our study is timely, as urbanization and the associated socioeconomic consequences are increasing.

Urbanization is on the rise, and environments offering a narrow range of microbial exposures are linked to an increased prevalence of both physical and mental disorders. Human and animal studies suggest that an overreactive immune system not only accompanies stress-associated disorders but might even be causally involved in their pathogenesis. Here, we show in young [mean age, years (SD): rural, 25.1 (0.78); urban, 24.5 (0.88)] healthy human volunteers that urban upbringing in the absence of pets (n = 20), relative to rural upbringing in the presence of farm animals (n = 20), was associated with a more pronounced increase in the number of peripheral blood mononuclear cells (PBMCs) and plasma interleukin 6 (IL-6) concentrations following acute psychosocial stress induced by the Trier social stress test (TSST). Moreover, ex vivo-cultured PBMCs from urban participants raised in the absence of animals secreted more IL-6 in response to the T cell-specific mitogen Con A. In turn, antiinflammatory IL-10 secretion was suppressed following TSST in urban participants raised in the absence of animals, suggesting immunoregulatory deficits, relative to rural participants raised in the presence of animals. Questionnaires, plasma cortisol, and salivary α-amylase, however, indicated the experimental protocol was more stressful and anxiogenic for rural participants raised in the presence of animals. Together, our findings support the hypothesis that urban vs. rural upbringing in the absence or presence of animals, respectively, increases vulnerability to stress-associated physical and mental disorders by compromising adequate resolution of systemic immune activation following social stress and, in turn, aggravating stress-associated systemic immune activation.

Early life socioeconomic status associates with interleukin-6 responses to acute laboratory stress in adulthood

It is proposed that environmental exposures in early life influence immune programming. Specifically, socioeconomic disadvantage is thought to program an immune phenotype that is prone to inflammation and associated with increased risk for inflammatory disease later in life. Existing literature shows an inverse association of early childhood socioeconomic status (SES) with adult levels of systemic inflammation. Here, we extend that literature to examine whether early childhood SES also relates to the magnitude of inflammatory response to acute psychological stress in adulthood. Healthy volunteers (N = 110; 40-58 years; 59% female; 90% white) performed a laboratory stress protocol, with blood samples drawn at the end of a 30-min baseline, a 5-min speech task, and a 30-min recovery to assess interleukin (IL)-6 stress responses. An early childhood SES index was derived from reports of parental home and vehicle ownership, and number of bedrooms per child in the home across ages 1-2, 3-4, and 5-6. Regressions adjusted for current age, sex, race, and BMI showed that lower SES at age 1-2 was associated with larger IL-6 stress responses in adulthood (ΔR² = 0.05, β = -0.24, p = .03). This association was independent of adult SES and task-evoked affective responses. No association was found between SES at ages 3-4 or 5-6 and IL-6 responses. These results provide initial evidence for a link between disadvantage in the first 2 years of life and heightened inflammatory response to stress in adulthood; this link may contribute to the increased disease risk that accompanies being raised in disadvantaged socioeconomic circumstances.

Cortisol Stress Reactivity to the Trier Social Stress Test in Obese Adults

OBJECTIVE

Approximately 600 million adults worldwide suffer from obesity. In addition to individual's eating behavior and lack of physical activity in the development of obesity and overweight, psychosocial stress as well as hormonal stress reactivity must also be considered as important contributing factors. In the current study we compared the cortisol stress response pathway in a psychosocial stress induction (Trier Social Stress Test; TSST) with obese individuals and normal-weight controls.

METHOD

32 obese individuals (17 females; mean age = 33.94 years, SD = 11.31 years) and 32 normal-weight controls (17 females; mean age = 29.09 years, SD = 10.46 years) underwent the TSST. The salivary cortisol responses and three appraisal questionnaires (Primary Appraisal Secondary Appraisal, Visual Analogue Scale, Trier Inventory for Chronic Stress) were measured.

RESULTS

After stress induction, there was a significant main group difference between the obese individuals and the normal-weight controls for cortisol, with lower baseline and post-stress cortisol levels in the obese individuals. Nevertheless, the obese individuals as well as the normal-weight controls showed no significant difference in the self-reported assessment of the stress condition but some significant differences in the cognitive appraisal of the TSST.

CONCLUSION

In conclusion, the induction of psychosocial stress showed differences in the cortisol patterns between the obese individuals and the normal-weight controls. Furthermore, the present data suggest that obesity leads to lower cortisol activity, which may indicate alterations in the Hypothalamic-pituitary-adrencortical (HPA) axis.

Added sugars and sugar-sweetened beverage consumption, dietary carbohydrate index and depression risk in the Seguimiento Universidad de Navarra (SUN) Project

The association between added sugars or sugar-sweetened beverage consumption and the risk of depression, as well as the role of carbohydrate quality in depression risk, remains unclear. Among 15 546 Spanish university graduates from the Seguimiento Universidad de Navarra (SUN) prospective cohort study, diet was assessed with a validated 136-item semi-quantitative FFQ at baseline and at 10-year follow-up. Cumulative average consumption of added sugars, sweetened drinks and an overall carbohydrate quality index (CQI) were calculated. A better CQI was associated with higher whole-grain consumption and fibre intake and lower glycaemic index and consumption of solid (instead of liquid) carbohydrates. Clinical diagnoses of depression during follow-up were classified as incident cases. Multivariable time-dependent Cox regression models were used to estimate hazard ratios (HR) of depression according to consumption of added sugars, sweetened drinks and CQI. We observed 769 incident cases of depression. Participants in the highest quartile of added sugars consumption showed a significant increment in the risk of depression (HR=1·35; 95 % CI 1·09, 1·67, P=0·034), whereas those in the highest quartile of CQI (upper quartile of the CQI) showed a relative risk reduction of 30 % compared with those in the lowest quartile of the CQI (HR=0·70; 95 % CI 0·56, 0·88). No significant association between sugar-sweetened beverage consumption and depression risk was found. Higher added sugars and lower quality of carbohydrate consumption were associated with depression risk in the SUN Cohort. Further studies are necessary to confirm the reported results.

Adiposity moderates links from early adversity and depressive symptoms to inflammatory reactivity to acute stress during late adolescence

Both early adversity and depression are associated with heightened inflammation. However, few studies have focused on inflammatory reactivity to psychosocial stress and examined adiposity as a potential moderator. Yet, repeated heightened inflammatory reactivity over time is thought to contribute to low-grade chronic inflammation and adipose tissue is a key source of pro-inflammatory cytokines. The purpose of the present study was to examine whether early adversity and depressive symptoms were related to stress-induced inflammation and whether these associations varied by total body and abdominal adiposity as measured by body mass index (BMI) and waist circumference (WC) in a sample of late adolescents. Participants reported on their early family environment and current depressive symptoms, had their height, weight, and WC assessed for adiposity markers, and provided blood samples for IL-6 assessment before and after a standardized laboratory stress task. No main effect of early adversity on IL-6 reactivity to acute stress was observed. However, significant interactions between early adversity and BMI and WC emerged. Greater exposure to early adversity was associated with greater IL-6 responses only among adolescents with higher BMI or WC. The same pattern of findings was observed for depressive symptoms. Additionally, moderated mediation analyses indicated that among adolescents with greater adiposity, early adversity indirectly influenced IL-6 reactivity via current depressive symptoms. These findings contribute to our understanding of vulnerability factors that may amplify the associations between early adversity and depressive symptoms and inflammation during relatively early stages of life.

The Dietary Inflammatory Index, shift work, and depression: Results from NHANES

OBJECTIVES

Abnormal physiology (e.g., inflammation), brought on by environmental exposures (e.g., diet or shift work [SW]), can affect numerous bodily systems, including the brain, and may be associated with depressive symptomatology. The study examined the associations between SW and depressive symptoms and diet-related inflammation (estimated by the Dietary Inflammatory Index [DII]) and depressive symptoms. Additionally, diet was examined as a mediator between SW and depressive symptoms.

METHOD

Data were obtained from the U.S. National Health and Nutrition Examination Survey (Centers for Disease Control and Prevention, 2013). SW data were based on self-report. Dietary data were collected using 24-hr dietary recalls for DII calculation. Depressive symptoms were defined using a cut-point of 10 (moderate) on the Patient Health Questionnaire-9 (PHQ-9). Logistic regression was used to estimate odds ratios and 95% confidence intervals (95% CI) for depressive symptoms by SW and DII quartiles.

RESULTS

DII scores were associated with depressive symptoms among women. Women in DII quartile 4 were 30% more likely to report depressive symptoms than women in quartile 1 (95% CI [1.00-1.68]). There was no association between symptoms and SW when using a PHQ-9 cut-point of 10. When using a cut-point of 5 (mild depressive symptoms), those working any form of SW were more likely to suffer from mild symptoms than day workers (odds ratio = 1.22; 95% CI [1.04-1.43]). There was some evidence for mediation by the DII between SW and depressive symptoms.

CONCLUSIONS

Future longitudinal studies should examine effects of reductions in inflammation through diet on depressive symptoms, especially among shift workers, to elucidate the role of diet on depression among these groups. (PsycINFO Database Record

The Relationship between Stress and Severe Obesity: A Case-Control Study

Background

Several etiological factors for obesity have been identified, whereas other factors related to obesity, such as stress, remain poorly understood. This study used psychiatric methods to examine the relationship between stress and obesity.

Methods

Matched study and control groups were established, and the female and male control subjects were selected separately by random sampling. The control subjects were matched with the case subjects with respect to place of residence, sex, age, date that a pension was granted, and occupation. Psychiatric and psychological methods were assessed using a questionnaire and statistical analyses.

Results

Psychiatric interviews indicated that stress was more prevalent in the study group than in the control group. Separation from parents was nearly significantly more frequently in the study group than in the control group. The questionnaire on coping mechanisms revealed that case subjects tended to resolve their problems in an active manner.

Conclusions

The aim of this case-control study was to examine the relationship between stress and obesity in individuals receiving a disability pension. We identified stress factors that affect the development of obesity. We believe our study is both necessary and important, as these findings provide valuable insight into the relationship between severe obesity and stress.

Stronger hypothalamus-pituitary-adrenal axis habituation predicts lesser sensitization of inflammatory response to repeated acute stress exposures in healthy young adults

Effective adjustment of the stress systems to repeated stress is regarded as an adaptive response of the organism facing environmental threats. Given the intertwined relationship between the stress systems and the inflammatory system, it could be expected that inflammatory processes should adapt to repeated stress as well. However, only little is known about adaptational processes of the different components of the immune system in response to repeated stress, and how these might be related to adaptational processes of the hypothalamus-pituitary-adrenal (HPA) axis. We here examined N=22 healthy participants (mean age 23years, 50% female) and exposed them to a standardized laboratory stressor twice, 24h apart. Plasma interleukin 6 (IL-6), salivary cortisol and psychometric parameters were assessed repeatedly up to 120min post stress. Results revealed a significant day by time interaction for cortisol (F=5.06; p=0.013) and IL-6 (F=4.42; p=0.041), indicating habituation of HPA axis and sensitization of inflammatory stress responses. Cortisol habituation and inflammatory sensitization were inversely related when controlling for sex (r=-0.44; p=0.044). Explorative analyses revealed significant associations between the IL-6 response on the second exposure with perceived stress (r=0.58; p=0.004), vital exhaustion (r=0.57; p=0.009), depression (r=0.47; p=0.026) and purpose in life (r=-0.50; p=0.04). These findings may help to increase understanding of the still only rudimentary understood interplay of adaptational processes of endocrine and immune responses to repeated stress and might indicate a link between inflammatory disinhibition and psychological indicators of well-being.

A Functional Interleukin-18 Haplotype Predicts Depression and Anxiety through Increased Threat-Related Amygdala Reactivity in Women but Not Men

Common functional polymorphisms in the gene encoding interleukin-18 (IL18), a cytokine belonging to the IL-1 superfamily that can induce synthesis of several other cytokines, have been associated with major depressive episodes following the experience of stressful life events. The neural mechanisms underlying these associations remain unexamined. Here we use an imaging genetics strategy to examine the effects of risk-related IL18 haplotypes comprising rs187238 and rs1946518 on threat-related amygdala reactivity and, through an indirect effect, stress-related symptoms of depression and anxiety in 448 non-Hispanic Caucasian university students. Analyses indicated that women but not men possessing an IL18 haplotype comprising both risk-related alleles evidenced increased threat-related left centromedial amygdala reactivity relative to other haplotype groups. Moreover, in women only, increased threat-related left centromedial amygdala reactivity predicted increased symptoms of depression and anxiety in individuals also reporting higher levels of life stress. Path analyses revealed a significant indirect effect of IL18 risk haplotype on symptoms of depression and anxiety through increased threat-related amygdala reactivity. These results suggest that a common functional IL18 haplotype associated with heightened proinflammatory responses confers susceptibility to stress-related depression and anxiety through effects on threat-related amygdala function, a risk pathway specific to women. If replicated, these patterns can inform the search for personalized interventions targeting neurobiological pathways of risk associated with inflammation.

Role of inflammatory cytokines in depression: Focus on interleukin-1β

According to the World Health Organization, major depression will become the leading cause of disability worldwide by the year 2030. Despite extensive research into the mechanisms underlying this disease, the rate, prevalence and disease burden has been on the rise, particularly in the industrialized world. Epidemiological studies have shown biological and biochemical differences in disease characteristics and treatment responses in different age groups. Notable differences have been observed in the clinical presentation, co-prevalence with other diseases, interaction with the immune system and even in the outcome. Thus, there is an increased interest in characterizing these differences, particularly in terms of contribution of different factors, including age, cytokines and immunotherapy. Research into the possible mechanisms of these interactions may reveal novel opportunities for future pharmacotherapy. The aim of the present review is to document recent literature regarding the impact of inflammatory mechanisms on the pathophysiology of the depressive disorder.

Sex differences in the association between stressor-evoked interleukin-6 reactivity and C-reactive protein

Individuals differ consistently in the magnitude of their inflammatory responses to acute stressors, with females often showing larger responses than males. While the clinical significance of these individual differences remains unclear, it may be that greater inflammatory responses relate to increased systemic inflammation and thereby risk for chronic inflammatory disease. Here, we examined whether acute stressor-evoked interleukin (IL)-6 responses associate with resting levels of C-reactive protein (CRP), a marker of systemic inflammation, and whether this association differs by sex. Subjects were 57 healthy midlife adults (30-51years; 33% female; 68% white). Blood was drawn before and 30-min after two mental stress tasks: a multisource interference task and a Stroop color word task. Hierarchical regressions controlling for age, sex, race, and BMI tested whether stressor-evoked IL-6 responses were associated with resting CRP and whether this association differed by sex. Results indicated that sex and stressor-evoked IL-6 responses interacted to predict CRP (ΔR²=0.08, B=-1.33, β=-0.39, p=0.02). In males, larger stressor-evoked IL-6 responses associated with higher CRP, whereas in females, stressor-evoked IL-6 responses showed a non-significant negative association with CRP. These findings indicate that inflammatory responses to acute stressors associate with resting levels of CRP; however, this association differs by sex. Previous literature suggests that there are sex differences in stressor-evoked IL-6 responses, but this is the first study to show sex differences in the relationship between acute inflammatory responses and systemic inflammation. The contribution of these sex differences to inflammatory disease risk warrants further investigation.

Post-menopausal Women Exhibit Greater Interleukin-6 Responses to Mental Stress Than Older Men

BACKGROUND

Acute stress triggers innate immune responses and elevation in circulating cytokines including interleukin-6 (IL-6). The effect of sex on IL-6 responses remains unclear due to important limitations of previous studies.

PURPOSE

The purpose of this study was to examine sex differences in IL-6 responses to mental stress in a healthy, older (post-menopausal) sample accounting for several moderating factors.

METHODS

Five hundred six participants (62.9 ± 5.60 years, 55 % male) underwent 10 min of mental stress consisting of mirror tracing and Stroop task. Blood was sampled at baseline, after stress, and 45 and 75 min post-stress, and assayed using a high sensitivity kit. IL-6 reactivity was computed as the mean difference between baseline and 45 min and between baseline and 75 min post-stress. Main effects and interactions were examined using ANCOVA models.

RESULTS

There was a main effect of time for the IL-6 response (F 3,1512 = 201.57, p = <.0001) and a sex by time interaction (F 3,1512 = 17.07, p = <.001). In multivariate adjusted analyses, IL-6 reactivity was significantly greater in females at 45 min (M = 0.37 ± 0.04 vs. 0.20 ± 0.03 pg/mL, p = .01) and at 75 min (M = 0.57 ± 0.05 vs. 0.31 ± 0.05 pg/mL, p = .004) post-stress compared to males. Results were independent of age, adiposity, socioeconomic position, depression, smoking and alcohol consumption, physical activity, statin use, testing time, task appraisals, hormone replacement, and baseline IL-6. Other significant predictors of IL-6 reactivity were lower household wealth, afternoon testing, and baseline IL-6.

CONCLUSIONS

Healthy, post-menopausal females exhibit substantially greater IL-6 responses to acute stress. Inflammatory responses if sustained over time may have clinical implications for the development and maintenance of inflammatory-related conditions prevalent in older women.

Glucocorticoid mediated regulation of inflammation in human monocytes is associated with depressive mood and obesity

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is observed in various conditions, including depression and obesity, which are also often related. Glucocorticoid (GC) resistance and desensitization of peripheral GC receptors (GRs) are often the case in HPA dysregulation seen in depression, and GC plays a critical role in regulation of inflammation. Given the growing evidence that inflammation is a central feature of some depression cases and obesity, we aimed to investigate the immune-regulatory role of GC-GR in relation to depressive mood and obesity in 35 healthy men and women. Depressive mood and level of obesity were assessed, using Beck Depression Inventory (BDI-Ia) and body mass index (BMI), respectively. We measured plasma cortisol levels via enzyme-linked immunosorbent assay and lipopolysaccharide-stimulated intracellular tumor necrosis factor (TNF) production by monocytes, using flow cytometry. Cortisol sensitivity was determined by the difference in monocytic TNF production between the conditions of 1 and 0 μM cortisol incubation ("cortisol-mediated inflammation regulation, CoMIR"). GR vs. mineralocorticoid receptor (MR) antagonism for CoMIR was examined by using mifepristone and spironolactone. A series of multiple regression analyses were performed to investigate independent contribution of depressive mood vs. obesity after controlling for age, gender, systolic blood pressure (SBP), and plasma cortisol in predicting CoMIR. CoMIR was explained by somatic subcomponents of depressive mood (BDI-S: β=-0.499, p=0.001), or BMI (β=-0.466, p<0.01) in separate models. The effects of BMI disappeared when BDI-S was controlled for in the model, while BDI-S remained a significant independent predictor for CoMIR (β=-0.369, p<0.05). However, BMI remained the only independent predictor when BDI-T or BDI-C were controlled for in the model. Mediation analyses also revealed that the relationship between BMI and CoMIR was mediated by BDI-S. The exploratory findings of the relative GR vs. MR roles in CoMIR, using GR and MR blockers, indicated that CoMIR in our cellular model was predominantly mediated by GRs at the higher cortisol dose (1 μM). There was initial indication that greater obesity and somatic depressive symptoms were associated with smaller efficacy of the blockers, which warrants further investigation. Our findings, although in a preclinical sample, signify the shared pathophysiology of immune dysregulation in depression and obesity and warrant further mechanistic investigation.

Neuro-oncology family caregivers are at risk for systemic inflammation

Prolonged periods of family caregiving can induce stress levels that may negatively influence caregiver health. However, the physiologic effect of psychological distress in oncology family caregivers has received little attention. Therefore we aimed to determine longitudinal profiles of inflammatory cytokines (IL-6 and IL-1ra) in neuro-oncology caregivers and identify associations between psychological distress and cytokine levels. Depressive symptoms, anxiety, caregiver burden and blood were collected from 108 adult caregivers at adult patients' diagnosis, 4-, 8-, and 12-months. Trajectory analyses of log transformed cytokine levels were performed. Multiple logistic regression analyses evaluated the impact of psychological distress on cytokine levels. For both cytokines, two distinct populations were identified, neither of which changed over time. High IL-1ra was associated with male caregivers with anxiety (OR = 1.7; 95 %CI 1.06-2.83) and obese caregivers (BMI = 40) who felt burdened due to disrupted schedules (OR = 1.3; 95 %CI 1.02-1.77). Conversely, caregivers with a healthy weight (BMI = 25) who felt burdened due to disrupted schedules were less likely to have high IL-1ra (OR = 0.71; 95 %CI 0.54-0.92). Caregivers ≤30 years old with lower self-esteem from caregiving were 1.16 times (95 %CI 1.04-1.30) more likely to have high IL-6. Analysis demonstrated groups of family caregivers with high and low levels of systemic inflammation and these levels did not change longitudinally over the care trajectory. Poor physical health in family caregivers may have a negative impact on the burden placed on the healthcare system in general and on the well-being of neuro-oncology patients in particular.

Inflammation: depression fans the flames and feasts on the heat

Depression and inflammation fuel one another. Inflammation plays a key role in depression's pathogenesis for a subset of depressed individuals; depression also primes larger cytokine responses to stressors and pathogens that do not appear to habituate. Accordingly, treatment decisions may be informed by attention to questions of how (pathways) and for whom (predispositions) these links exist, which are the focus of this article. When combined with predisposing factors (moderators such as childhood adversity and obesity), stressors and pathogens can lead to exaggerated or prolonged inflammatory responses. The resulting sickness behaviors (e.g., pain, disturbed sleep), depressive symptoms, and negative health behaviors (e.g., poor diet, a sedentary lifestyle) may act as mediating pathways that lead to further, unrestrained inflammation and depression. Depression, childhood adversity, stressors, and diet can all influence the gut microbiome and promote intestinal permeability, another pathway to enhanced inflammatory responses. Larger, more frequent, or more prolonged inflammatory responses could have negative mental and physical health consequences. In clinical practice, inflammation provides a guide to potential targets for symptom management by signaling responsiveness to certain therapeutic strategies. For example, a theme across research with cytokine antagonists, omega-3 fatty acids, celecoxib, and exercise is that anti-inflammatory interventions have a substantially greater impact on mood in individuals with heightened inflammation. Thus, when inflammation and depression co-occur, treating them in tandem may enhance recovery and reduce the risk of recurrence. The bidirectional links between depression, inflammation, and disease suggest that effective depression treatments could have a far-reaching impact on mood, inflammation, and health.