Understanding the impact of exposure to adverse socioeconomic conditions on chronic stress from a complexity science perspective

Exploring the mechanisms underlying increased risk of depressive disorder in ethnic minority populations in Europe: A causal loop diagram

BACKGROUND

Multiple ethnic minority populations in Europe show high risk of major depressive disorder (MDD), with ethnic discrimination and low socioeconomic position (SEP) as established risk factors. How this risk is shaped by the interactions between these, and other social factors, remains to be elucidated. We aimed to develop a causal-loop diagram (CLD) to gain a better understanding of how factors at the intersection of ethnic discrimination and SEP dynamically interact to drive MDD risk.

METHODS

We iteratively mapped the interactions and feedback loops between factors at the intersection of ethnic discrimination and SEP, drawing input from (i) a series of two interviews with a range of MDD domain experts, (ii) an existing CLD mapping the onset of MDD across psychological, biological, and social dimensions at the level of the individual, and (iii) other relevant literature.

RESULTS

Through tracing the feedback loops in the resulting CLD, we identified ten driving mechanisms for MDD onset in ethnic minorities (two related to ethnic discrimination, SEP, social network and support, and acculturation, as well as one relating to the living environment and self-stigma towards MDD); and four factors that modulate these mechanisms (recent migration, religious affiliation, neighborhood social environment, and public stigma towards MDD). The intersecting nature of ethnic discrimination and SEP, combined with the reinforcing dynamics of the identified driving mechanisms across time- and spatial scales, underscores the excess exposure to circumstances that increase MDD risk in ethnic minorities.

CONCLUSIONS

While this CLD requires validation through future studies, the intersecting and reinforcing nature of the identified driving mechanisms highlights that tackling the high risk of MDD in ethnic minorities may require intervening at multiple targets, from the individual (e.g., psychological interventions targeting negative beliefs or reducing stress) to the societal level (e.g., addressing labor market discrimination).

Socioeconomic inequalities in pandemic-induced psychosocial stress in different life domains among the working-age population

BACKGROUND

Psychosocial stress is considered a risk factor for physical and mental ill-health. Evidence on socioeconomic inequalities with regard to the psychosocial consequences of the COVID-19 pandemic in Germany is still limited. We aimed to investigate how pandemic-induced psychosocial stress (PIPS) in different life domains differed between socioeconomic groups.

METHODS

Data came from the German Corona-Monitoring nationwide study - wave 2 (RKI-SOEP-2, November 2021-February 2022). PIPS was assessed using 4-point Likert scales with reference to the following life domains: family, partnership, own financial situation, psychological well-being, leisure activity, social life and work/school situation. Responses were dichotomised into "not stressed/slightly stressed/rather stressed" (0) versus "highly stressed" (1). The sample was restricted to the working-age population in Germany (age = 18-67 years, n = 8,402). Prevalence estimates of high PIPS were calculated by sex, age, education and income. Adjusted prevalence ratios (PRs) were estimated using Poisson regression to investigate the association between education/income and PIPS; high education and income were the reference groups.

RESULTS

The highest stress levels were reported in the domains social life and leisure activity. Women and younger participants reported high stress levels more frequently. The highest inequalities were found regarding people's own financial situation, and PIPS was higher in low vs. high income groups (PR 5.54, 95% CI 3.61-8.52). Inequalities were also found regarding partnerships with higher PIPS in low vs. high education groups (PR 1.68, 95% CI 1.13-2.49) - and psychological well-being with higher PIPS in low vs. high income groups (PR 1.52, 95% CI 1.14-2.04).

CONCLUSION

Socioeconomic inequalities in PIPS were found for different life domains. Generally, psychosocial support and preventive interventions to help people cope with stress in a pandemic context should be target-group-specific, addressing the particular needs and circumstances of certain socioeconomic groups.

Efficacy of resilience-related psychological interventions in patients with long-term diseases: A meta-analysis of randomised controlled trials

Patients with long-term disease experience low resilience, emphasising the importance of psychological interventions to improve resilience. However, there is no comprehensive evidence on the efficacy of resilience-related psychological interventions (RRPIs) in this population. Therefore, we performed a meta-analysis to evaluate and extend knowledge from previous meta-analyses on the efficacy of RRPIs on resilience, stress, anxiety, depression and quality of life among patients with long-term disease. Cochrane Library, Embase, Ovid-MEDLINE, PubMed, Scopus, Web of Science and CINAHL electronic databases were searched until 3 February 2023. The pooled effect size of the efficacy of RRPIs was calculated using the Hedges' g (g) with random-effects model, while Cochrane Q-statistics and I2 tests assessed heterogeneity in Comprehensive Meta-Analysis 3.0 software. The Cochrane Risk of Bias 2.0 tool evaluated the quality of studies. Moderator analysis was used to explore sources of heterogeneity. Twenty randomised controlled trial studies were identified, representing a total of 1388 individuals with long-term disease. RRPIs significantly enhance resilience (g = 0.79), alleviate stress (g = -0.78), decrease anxiety (g = -1.14), mitigate depression (g = -0.96) and improve quality of life (g = 0.48). Positive psychology, mindfulness, cognitive behavioural therapy, acceptance and commitment-based intervention exhibited medium effects in strengthening resilience. Short-term effects of RRPIs on enhancing resilience were observed at 3-month follow-up period (g = 0.50). The incorporation of RRPIs into the management of patients with long-term disease shows a positive impact on their resilience, stress, anxiety, depression and quality of life. The results offer an evidence-based foundation for nurses in promoting resilience among patients with long-term disease.

"Emotional stress is more detrimental than the virus itself": A qualitative study to understand HIV testing and pre-exposure prophylaxis (PrEP) use among internal migrant men in South Africa

INTRODUCTION

South Africa has one of the highest rates of internal migration on the continent, largely comprised of men seeking labour in urban centres. South African men who move within the country (internal migrants) are at higher risk than non-migrant men of acquiring HIV yet are less likely to test or use pre-exposure prophylaxis (PrEP). However, little is known about the mechanisms that link internal migration and challenges engaging in HIV services.

METHODS

We recruited 30 internal migrant men (born outside Gauteng Province) during August 2022 for in-depth qualitative interviews at two sites in Johannesburg (Gauteng) where migrants may gather, a factories workplace and a homeless shelter. Interviewers used open-ended questions, based in the Theory of Triadic Influence, to explore experiences and challenges with HIV testing and/or PrEP. A mixed deductive inductive content analytic approach was used to review data and explain why participants may or may not use these services.

RESULTS

Migrant men come to Johannesburg to find work, but unreliable income, daily stress and time constraints limit their availability to seek health services. While awareness of HIV testing is high, the fear of a positive diagnosis often overshadows the benefits. In addition, many men lack knowledge about the opportunity for PrEP should they test negative, though they express interest in the medication after learning about it. Additionally, these men struggle with adjusting to urban life, lack of social support and fear of potential stigma. Finally, the necessity to prioritize work combined with long wait times at clinics further restricts their access to HIV services. Despite these challenges, Johannesburg also presents opportunities for HIV services for migrant men, such as greater anonymity and availability of HIV information and services in the city as compared to their rural homes of origin.

CONCLUSIONS

Bringing HIV services to migrant men at community sites may ease the burden of accessing these services. Including PrEP counselling and services alongside HIV testing may further encourage men to test, particularly if integrated into counselling for livelihood and coping strategies, as well as support for navigating health services in Johannesburg.

The current state of complex systems research on socioeconomic inequalities in health and health behavior-a systematic scoping review

BACKGROUND

Interest in applying a complex systems approach to understanding socioeconomic inequalities in health is growing, but an overview of existing research on this topic is lacking. In this systematic scoping review, we summarize the current state of the literature, identify shared drivers of multiple health and health behavior outcomes, and highlight areas ripe for future research.

METHODS

SCOPUS, Web of Science, and PubMed databases were searched in April 2023 for peer-reviewed, English-language studies in high-income OECD countries containing a conceptual systems model or simulation model of socioeconomic inequalities in health or health behavior in the adult general population. Two independent reviewers screened abstracts and full texts. Data on study aim, type of model, all model elements, and all relationships were extracted. Model elements were categorized based on the Commission on Social Determinants of Health framework, and relationships between grouped elements were visualized in a summary conceptual systems map.

RESULTS

A total of 42 publications were included; 18 only contained a simulation model, 20 only contained a conceptual model, and 4 contained both types of models. General health outcomes (e.g., health status, well-being) were modeled more often than specific outcomes like obesity. Dietary behavior and physical activity were by far the most commonly modeled health behaviors. Intermediary determinants of health (e.g., material circumstances, social cohesion) were included in nearly all models, whereas structural determinants (e.g., policies, societal values) were included in about a third of models. Using the summary conceptual systems map, we identified 15 shared drivers of socioeconomic inequalities in multiple health and health behavior outcomes.

CONCLUSIONS

The interconnectedness of socioeconomic position, multiple health and health behavior outcomes, and determinants of socioeconomic inequalities in health is clear from this review. Factors central to the complex system as it is currently understood in the literature (e.g., financial strain) may be both efficient and effective policy levers, and factors less well represented in the literature (e.g., sleep, structural determinants) may warrant more research. Our systematic, comprehensive synthesis of the literature may serve as a basis for, among other things, a complex systems framework for socioeconomic inequalities in health.

Do financial constraint and perceived stress modify the effects of food tax schemes on food purchases: moderation analyses in a virtual supermarket experiment

OBJECTIVE

To investigate whether financial constraint and perceived stress modify the effects of food-related taxes on the healthiness of food purchases.

DESIGN

Moderation analyses were conducted with data from a trial where participants were randomly exposed to: a control condition with regular food prices, an sugar-sweetened beverage (SSB) tax condition with a two-tiered levy on the sugar content in SSB (5-8 g/100 ml: €0·21 per l and ≥8 g/100 ml: €0·28 per l) or a nutrient profiling tax condition where products with Nutri-Score D or E were taxed at a 20 percent level. Outcome measures were overall healthiness of food purchases (%), energy content (kcal) and SSB purchases (litres). Effect modification was analysed by adding interaction terms between conditions and self-reported financial constraint or perceived stress in regression models. Outcomes for each combination of condition and level of effect modifier were visualised.

SETTING

Virtual supermarket.

PARTICIPANTS

Dutch adults (n 386).

RESULTS

Financial constraint or perceived stress did not significantly modify the effects of food-related taxes on the outcomes. Descriptive analyses suggest that in the control condition, the overall healthiness of food purchases was lowest, and SSB purchases were highest among those with moderate/high levels of financial constraint. Compared with the control condition, in a nutrient profiling tax condition, the overall healthiness of food purchases was higher and SSB purchases were lower, especially among those with moderate/high levels of financial constraint. Such patterns were not observed for perceived stress.

CONCLUSION

Further studies with larger samples are recommended to assess whether food-related taxes differentially affect food purchases of subgroups.

Using network analysis to identify leverage points based on causal loop diagrams leads to false inference

Network analysis is gaining momentum as an accepted practice to identify which factors in causal loop diagrams (CLDs)-mental models that graphically represent causal relationships between a system's factors-are most likely to shift system-level behaviour, known as leverage points. This application of network analysis, employed to quantitatively identify leverage points without having to use computational modelling approaches that translate CLDs into sets of mathematical equations, has however not been duly reflected upon. We evaluate whether using commonly applied network analysis metrics to identify leverage points is justified, focusing on betweenness- and closeness centrality. First, we assess whether the metrics identify the same leverage points based on CLDs that represent the same system but differ in inferred causal structure-finding that they provide unreliable results. Second, we consider conflicts between assumptions underlying the metrics and CLDs. We recognise six conflicts suggesting that the metrics are not equipped to take key information captured in CLDs into account. In conclusion, using betweenness- and closeness centrality to identify leverage points based on CLDs is at best premature and at worst incorrect-possibly causing erroneous identification of leverage points. This is problematic as, in current practice, the results can inform policy recommendations. Other quantitative or qualitative approaches that better correspond with the system dynamics perspective must be explored.

Chronic Stress and Latent Virus Reactivation: Effects on Immune Aging, Chronic Disease Morbidity, and Mortality

OBJECTIVES

Social stress has been shown to affect immune functioning. Past research has found that chronic social stress and latent viral infections accelerate immune aging, leading to chronic disease morbidity and mortality. Chronic stress may also reactivate latent viral infections, like cytomegalovirus (CMV), accelerating the aging of the immune system.

METHOD

Utilizing panel survey data from 8,995 U.S. adults aged 56 or older from the Health and Retirement Study, this study investigates whether chronic stress interacts with CMV positivity to drive aging of the immune system, multimorbidity, and mortality.

RESULTS

Results of moderated mediation analysis indicate that the effect of CMV positivity on morbidity and mortality as mediated by immune aging indicators is amplified by chronic stress.

DISCUSSION

These findings suggest that immune aging is a biological pathway underlying the stress process and help explain past findings in the literature on stress and health.

Chronic stress-induced immune dysregulation in breast cancer: Implications of psychosocial factors

Chronic stress refers to continuous emotional changes and psychological pressure that individuals experience when they are unable to adjust and stabilize the internal environment over an extended period. It can increase the pressure on endocrine mediators and cytokines in the circulation, as well as tissues throughout the hypothalamic-pituitary-adrenaline (HPA) axis and sympathetic nervous system (SNS); thus, evolving the internal environment of the tumor. This review assesses several key issues, involving psychosocial factors, and integrates clinical, cellular, and molecular studies-as well as the latest research progress-to provide a mechanistic understanding regarding breast oncopsychology. We propose that chronic stress contributes to large individual diferences in the prognosis of breast cancer survivors because they change the basic physiological processes of the endocrine and immune systems, which in turn regulate tumor growth. The study of psychological and physiological reactions of breast cancer patients suggests a new idea for psychological intervention and clinical treatment for breast cancer patients.

Unequally Unequal? Contextual-level status inequality and social cohesion moderating the association between individual-level socioeconomic position and systemic chronic inflammation

BACKGROUND

Status inequality is hypothesised to increase socioeconomic inequalities in health by creating an environment in which social cohesion erodes and social comparisons intensify. Such an environment may cause systemic chronic inflammation. Although these are often-used explanations in social epidemiology, empirical tests remain rare.

METHODS

We analysed data from the West of Scotland Twenty-07 Study. Our sample consisted of 1977 participants in 499 small residential areas. Systemic chronic inflammation was measured by high-sensitivity C-reactive protein (hs-CRP; <10 mg/L). An area-level measurement of status inequality was created using census data and contextual-level social cohesion was measured applying ecometrics. We estimated linear multilevel models with cross-level interactions between socioeconomic position (SEP), status inequality, and social cohesion adjusted for age and gender. Our main analysis on postcode sector-level was re-estimated on three smaller spatial levels.

RESULTS

The difference in hs-CRP between disadvantaged and advantaged SEPs (0.806 mg/L; p = 0.063; [95%CI: -0.044; 1.656]) was highest among participants living in areas where most residents were in advantaged SEPs. In these status distributions, high social cohesion was associated with a shallower socioeconomic gradient in hs-CRP and low social cohesion was associated with a steeper gradient. In areas with an equal mix of SEPs or most residents in disadvantaged SEPs, the estimated difference in hs-CRP between disadvantaged and advantaged SEPs was -0.039 mg/L (p = 0.898; [95%CI: 0.644; 0.566]) and -0.257 mg/L (p = 0.568; [95%CI: 1.139; 0.625]) respectively. In these status distributions, the gradient in hs-CRP appeared steeper when social cohesion was high and potentially reversed when social cohesion was low. Results were broadly consistent when using area-levels smaller than postcode sectors.

CONCLUSIONS

Inequalities in hs-CRP were greatest among participants living in areas wherein a majority of residents were in advantaged SEPs and social cohesion was low. In other combinations of these contextual characteristics, inequalities in systemic chronic inflammation were not detectable or potentially even reversed.

Mediating role of learned helplessness' components in the association between health literacy/social support and self-management among maintenance haemodialysis patients in Changsha, China: a cross-sectional study

OBJECTIVES

To explore the multiple mediating roles of the learned helplessness's core system in the relationship between health literacy/social support and self-management.

DESIGN

Cross-sectional survey design.

SETTING

Changsha, China.

PARTICIPANTS

239 Chinese maintenance haemodialysis (MHD) patients.

METHODS

Two multiple mediator models were constructed based on the COM-B (Capacity, Opportunity, Motivation - Behaviour) model. A total of 239 Chinese MHD patients participated in a cross-sectional study, which included surveys on the Learned Helplessness Scale for MHD patients, Dialysis Knowledge Questionnaire, Social Support Scale and Self-Management Scale for Haemodialysis. The PROCESS macro in SPSS was used for mediated effects analysis.

RESULTS

Helplessness and internality partially mediated the relationship between health literacy/social support and self-management ((β=-0.212, p<0.01; β=0.240, p<0.01)/(β=-0.331, p<0.001; β=0.376, p<0.001)). The mediation effect size was 0.780 (95% CI (0.373 to 1.218)) in the health literacy model, accounting for 45.29% of the total effect, and 0.286 (95% CI (0.207 to 0.377)) in the social support model, accounting for 57.88% of the total effect. The differences in effect sizes for helplessness and internality in the two models were -0.080 (95% CI (-0.374 to 0.216)) and -0.041 (95% CI (-0.127 to 0.043)), respectively.

CONCLUSION

Health literacy/social support directly affects MHD patients' self-management and indirectly affects it by changing learned helplessness, such as increasing internality while reducing helplessness.

Adverse childhood and adulthood experiences and risk of new-onset cardiovascular disease with consideration of social support: a prospective cohort study

BACKGROUND

The relationship between adverse childhood experiences (ACEs) and adverse adulthood experiences (AAEs) and their association with incident cardiovascular disease (CVD) have not been extensively studied. Considering social support, we evaluated the complex relations of ACEs and AAEs with incident CVD.

METHODS

This prospective cohort study used data from the 2014 life course survey and the 2015 and 2018 surveys of the China Health and Retirement Longitudinal Study, a national survey of Chinese adults aged ≥ 45 years from 28 provinces across China. The study population included 5836 individuals (mean [SD] age, 59.59 [8.22] years, 49.7% were males). Information on ACEs, AAEs, young adulthood social support, health behavior factors, health status factors, and demographics was measured. Cox regression models, the difference method to estimate the mediation proportion, and the additive and multiplicative interactions were performed. Subgroup and sensitivity analyses were also conducted.

RESULTS

During follow-up, 789 incident cases of CVD occurred. The fully adjusted model, including demographics, health behaviors, health status factors (e.g., depressive symptoms), and social support as control variables, demonstrated that the overall number of ACEs (Hazard ratio [HR]: 1.11, 95% CI: 1.08 to 1.14) and AAEs (HR: 1.19, 95% CI: 1.16 to 1.22) were associated with an increased risk of incident CVD. A dose-response relationship existed between the number of ACEs or AAEs and incident CVD risk. The overall AAEs were found to mediate 17.7% (95% CI: 8.2 to 34.2%) of the association between ACEs and incident CVD. Moreover, a significant additive interaction between ACEs and AAEs was detected (RERI [95% CI]: 0.32 [0.09 to 0.56]). Compared with adults without exposure to both ACE and AAE, those with exposure to both at least one ACE and one AAE indicator had the highest risk of incident CVD (HR: 1.96, 95% CI: 1.72 to 2.23).

CONCLUSIONS

Exposure to ACEs or AAEs was independently associated with an increased risk of incident CVD among Chinese middle-aged and older adults in a dose-response manner, and the overall AAEs partially mediated the association between ACEs and incident CVD. Preventive measures aimed at addressing either ACEs or AAEs alone may not significantly reduce the risk of CVD later in life. The necessity of a comprehensive life-course health strategy targeting the prevention of adversity merits increased attention.

Applying systems thinking to unravel the mechanisms underlying orthostatic hypotension related fall risk

Orthostatic hypotension (OH) is an established and common cardiovascular risk factor for falls. An in-depth understanding of the various interacting pathophysiological pathways contributing to OH-related falls is essential to guide improvements in diagnostic and treatment opportunities. We applied systems thinking to multidisciplinary map out causal mechanisms and risk factors. For this, we used group model building (GMB) to develop a causal loop diagram (CLD). The GMB was based on the input of experts from multiple domains related to OH and falls and all proposed mechanisms were supported by scientific literature. Our CLD is a conceptual representation of factors involved in OH-related falls, and their interrelatedness. Network analysis and feedback loops were applied to analyze and interpret the CLD, and quantitatively summarize the function and relative importance of the variables. Our CLD contains 50 variables distributed over three intrinsic domains (cerebral, cardiovascular, and musculoskeletal), and an extrinsic domain (e.g., medications). Between the variables, 181 connections and 65 feedback loops were identified. Decreased cerebral blood flow, low blood pressure, impaired baroreflex activity, and physical inactivity were identified as key factors involved in OH-related falls, based on their high centralities. Our CLD reflects the multifactorial pathophysiology of OH-related falls. It enables us to identify key elements, suggesting their potential for new diagnostic and treatment approaches in fall prevention. The interactive online CLD renders it suitable for both research and educational purposes and this CLD is the first step in the development of a computational model for simulating the effects of risk factors on falls.

Complexity in Epidemiology and Public Health. Addressing Complex Health Problems Through a Mix of Epidemiologic Methods and Data

Public health and the underlying disease processes are complex, often involving the interaction of biologic, social, psychologic, economic, and other processes that may be nonlinear and adaptive and have other features of complex systems. There is therefore a need to push the boundaries of public health beyond single-factor data analysis and expand the capacity of research methodology to tackle real-world complexities. This article sets out a way to operationalize complex systems thinking in public health, with a particular focus on how epidemiologic methods and data can contribute towards this end. Our proposed framework comprises three core dimensions-patterns, mechanisms, and dynamics-along which complex systems may be conceptualized. These dimensions cover seven key features of complex systems-emergence, interactions, nonlinearity, interference, feedback loops, adaptation, and evolution. We relate this framework to examples of methods and data traditionally used in epidemiology. We conclude that systematic production of knowledge on complex health issues may benefit from: formulation of research questions and programs in terms of the core dimensions we identify, as a comprehensive way to capture crucial features of complex systems; integration of traditional epidemiologic methods with systems methodology such as computational simulation modeling; interdisciplinary work; and continued investment in a wide range of data types. We believe that the proposed framework can support the systematic production of knowledge on complex health problems, with the use of epidemiology and other disciplines. This will help us understand emergent health phenomena, identify vulnerable population groups, and detect leverage points for promoting public health.

Understanding the system dynamics of obesity-related behaviours in 10- to 14-year-old adolescents in Amsterdam from a multi-actor perspective

Introduction and Methods

To develop an understanding of the dynamics driving obesity-related behaviours in adolescents, we conducted systems-based analysis on a causal loop diagram (CLD) created from a multi-actor perspective, including academic researchers, adolescents and local stakeholders.

Results

The CLD contained 121 factors and 31 feedback loops. We identified six subsystems with their goals: (1) interaction between adolescents and the food environment, with profit maximisation as goal, (2) interaction between adolescents and the physical activity environment, with utility maximisation of outdoor spaces as goal, (3) interaction between adolescents and the online environment, with profit maximisation from technology use as goal, (4) interaction between adolescents, parenting and the wider socioeconomic environment, with a goal focused on individual parental responsibility, (5) interaction between healthcare professionals and families, with the goal resulting in treating obesity as an isolated problem, and (6) transition from childhood to adolescence, with the goal centring around adolescents' susceptibility to an environment that stimulates obesity-related behaviours.

Discussion

Analysis showed that inclusion of the researchers' and stakeholders' perspectives contributed to an understanding of how the system structure of an environment works. Integration of the adolescents' perspective enriched insights on how adolescents interact with that environment. The analysis further showed that the dynamics driving obesity-related behaviours are geared towards further reinforcing such behaviours.

Socioeconomic inequalities in self-assessed health and food consumption: the mediating roles of daily hassles and the perceived importance of health

BACKGROUND

Urgent daily hassles, which are more common among people with a lower socioeconomic position (SEP), might limit one's ability to address less pressing goals, such as goals related to health promotion. Consequently, health goals may be viewed as less focal, which could jeopardize one's health. This study examined an understudied pathway: whether a higher severity of daily hassles resulted in a lower perceived importance of health and whether these two factors sequentially mediate socioeconomic inequalities in self-assessed health (SAH) and food consumption.

METHODS

A cross-sectional survey among 1,330 Dutch adults was conducted in 2019. Participants self-reported SEP (household income, educational level), the severity of eleven daily hassles (e.g., financial hassles, legal hassles), the perceived importance of health (not being ill, living a long life), SAH, and food consumption. Structural equation modeling was used to examine whether daily hassles and the perceived importance of health sequentially mediated income and educational inequalities in SAH, fruit and vegetable consumption (FVC) and snack consumption.

RESULTS

No evidence of sequential mediation through daily hassles and the perceived importance of health was found. Daily hassles individually mediated income inequalities in SAH (indirect effect: 0.04, total effect: 0.06) and in FVC (indirect effect: 0.02, total effect: 0.09). The perceived importance of not being ill and living a long life both individually mediated educational inequalities in SAH (indirect effects: 0.01 and -0.01, respectively, total effect: 0.07).

CONCLUSIONS

Income inequalities in SAH and FVC were explained by daily hassles, and educational inequalities in SAH were explained by the perceived importance of health. Socioeconomic inequalities may not be sequentially explained by a more severe experience of daily hassles and a lower perceived importance of health. Interventions and policies addressing challenging circumstances associated with a low income may improve SAH and healthy food consumption among lower-income groups.

Understanding the relationships between physiological and psychosocial stress, cortisol and cognition

Stress is viewed as a state of real or perceived threat to homeostasis, the management of which involves the endocrine, nervous, and immune systems. These systems work independently and interactively as part of the stress response. The scientific stress literature, which spans both animal and human studies, contains heterogeneous findings about the effects of stress on the brain and the body. This review seeks to summarise and integrate literature on the relationships between these systems, examining particularly the roles of physiological and psychosocial stress, the stress hormone cortisol, as controlled by the hypothalamic-pituitary-adrenal (HPA) axis, and the effects of stress on cognitive functioning. Health conditions related to impaired HPA axis functioning and their associated neuropsychiatric symptoms will also be considered. Lastly, this review will provide suggestions of clinical applicability for endocrinologists who are uniquely placed to measure outcomes related to endocrine, nervous and immune system functioning and identify areas of intervention.

Exploring experiences with stressors and coping resources among Dutch socioeconomic groups during the COVID-19 pandemic

The COVID-19 crisis impacts populations globally. This impact seems to differ for groups with low- and high-socioeconomic status (SES). We conducted a qualitative study in the Netherlands using a salutogenic perspective to examine experiences with stressors and coping resources during the pandemic among both SES groups to gain insight on how to promote the health and well-being of these groups. We conducted 10 focus group discussions and 20 interviews to explore the experiences, including resources and stressors, of respondents from low- (N = 37) and high-SES (N = 38) groups (25-55 years, Dutch speaking). We analyzed the findings at individual, community, and national levels. The results show that coping depends on government-imposed measures and the way individuals handle these measures; restriction to the home context with positive and negative consequences for work and leisure; psychological negative consequences and resourcefulness; and social effects related to unity (e.g. social cohesion or support) and division (including polarization). Respondents with lower SES expressed more problems with COVID-19 measures and experienced more social impact in their neighborhood than those with higher SES. Where low-SES groups especially mentioned the effects of staying at home on family life, high-SES groups mentioned effects on work life. At last, psychological consequences seem to differ somewhat across SES groups. Recommendations include consistent government-imposed measures and government communication, support for home schooling children, and strengthening the social fabric of neighborhoods.

Brain-gut-liver axis: Chronic psychological stress promotes liver injury and fibrosis via gut in rats

Background

The effect of chronic psychological stress on hepatitis and liver fibrosis is concerned. However, its mechanism remains unclear. We investigated the effect and mechanism of chronic psychological stress in promoting liver injury and fibrosis through gut.

Methods

Sixty male SD rats were randomly assigned to 6 groups. Rat models of chronic psychological stress (4 weeks) and liver fibrosis (8 weeks) were established. The diversity of gut microbiota in intestinal feces, permeability of intestinal mucosa, pathologies of intestinal and liver tissues, collagen fibers, protein expressions of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor kappa β (NF-κβ), tumor necrosis factor α (TNF-α) and interleukin 1 (IL-1) in liver tissue, liver function and coagulation function in blood and lipopolysaccharide (LPS) in portal vein blood were detected and analyzed.

Results

The diversities and abundances of gut microbiota were significant differences in rats among each group. The pathological lesions of intestinal and liver tissues, decreased expression of occludin protein in intestinal mucosa, deposition of collagen fibers and increased protein expression of TLR4, MyD88, NF-κβ, TNF-α and IL-1 in liver tissue, increased LPS level in portal vein blood, and abnormalities of liver function and coagulation function, were observed in rats exposed to chronic psychological stress or liver fibrosis. There were significant differences with normal rats. When the dual intervention factors of chronic psychological stress and liver fibrosis were superimposed, the above indicators were further aggravated.

Conclusion

Chronic psychological stress promotes liver injury and fibrosis, depending on changes in the diversity of gut microbiota and increased intestinal permeability caused by psychological stress, LPS that enters liver and acts on TLR4, and active LPS-TLR4 pathway depend on MyD88. It demonstrates the possibility of existence of brain-gut-liver axis.

How theory can help to understand the potential impact of food environment policies on socioeconomic inequalities in diet: an application of Bourdieu's capital theory and the scarcity theory

Government policies that promote healthy food environments are considered promising to reduce socioeconomic inequalities in diet. Empirical evidence of effects on these inequalities, however, is relatively scarce and, with a few exceptions, tends to be inconclusive. We use two contemporary theories that help to understand socioeconomic inequalities in health and health-related behaviours (Bourdieu's capital theory and Mullainathan and Shafir's scarcity theory) to reason how policies influencing food environments may differentially impact lower and higher socioeconomic groups. In essence, these theories enable us to understand how specific elements of broader daily living conditions (e.g. social practices that lead to habitus formation, material conditions that shape experiences of scarcity) may lead to a greater benefit of certain food environment policies for the healthfulness of diets of lower or higher socioeconomic groups. We conclude that the application of theories on the mechanisms underlying socioeconomic inequalities in health can help to guide future empirical studies in testing theory-based hypotheses on differential effects of policies, and thereby enhance the development of effective policies tackling socioeconomic inequalities in dietary intakes.

Individual Workplace Well-Being Captured into a Literature- and Stakeholders-Based Causal Loop Diagram

This study demonstrates an innovative approach to capture the complexity of individual workplace well-being, improving our understanding of multicausal relationships and feedback loops involved. The literature shows that a high number of interacting factors are related to individual workplace well-being. However, many studies focus on subsets of factors, and causal loops are seldomly studied. The aim of the current study was, therefore, to capture individual workplace well-being in a comprehensive conceptual causal loop diagram (CLD). We followed an iterative, qualitative, and transdisciplinary systems-thinking approach including literature search, group model building sessions, retrospective in-depth interviews with employees, and group sessions with human resource professionals, managers, job coaches, and management consultants. The results were discussed with HR and well-being officers of twelve organizations for their critical reflection on the recognizability and potential of the developed CLD. The final result, a conceptual individual workplace well-being CLD, provides a comprehensive overview of multiple, measurable key factors relating to individual workplace well-being and of the way these factors may causally interact over time, either improving or deteriorating workplace well-being. In future studies, the CLD can be translated to a quantitative system dynamics model for simulating workplace well-being scenarios. Ultimately, these simulations could be used to design effective workplace well-being interventions.

Lower Socioeconomic Position Is Associated with Greater Activity in and Integration within an Allostatic-Interoceptive Brain Network in Response to Affective Stimuli

Socioeconomic inequities shape physical health and emotional well-being. As such, recent work has examined the neural mechanisms through which socioeconomic position (SEP) may influence health. However, there remain critical gaps in knowledge regarding the relationships between SEP and brain function. These gaps include a lack of research on: (1) the association between SEP and brain functioning in later life, (2) relationships between SEP and functioning of the whole brain beyond specific regions of interest, and (3) how neural responses to positive affective stimuli differ by SEP. The current study addressed these gaps by examining the association between SEP (i.e., education, income) and neural responses to affective stimuli among 122 mid- to late-life adults. During MRI scanning, participants viewed 30 positive, 30 negative, and 30 neutral images; activation and network connectivity analyses explored associations between SEP and neural responses to these affective stimuli. Analyses revealed that those with lower SEP showed greater neural activity to both positive and negative images in regions within the allostatic-interoceptive network, a system of regions implicated in representing and regulating physiological states of the body and the external environment. There were no positive associations between SEP and neural responses to negative or positive images. In addition, graph-theory network analyses showed that individuals with lower SEP demonstrated greater global efficiency within the allostatic-interoceptive network and executive control network, across all task conditions. The findings suggest that lower SEP is associated with enhanced neural sensitivity to affective cues that may be metabolically costly to maintain over time and suggest a mechanism by which SEP might get "under the skull" to influence mental and physical well-being.