Does income inequality have lasting effects on health and trust?

Causal Assessment of Income Inequality on Self-Rated Health and All-Cause Mortality: A Systematic Review and Meta-Analysis

Policy Points Income is thought to impact a broad range of health outcomes. However, whether income inequality (how unequal the distribution of income is in a population) has an additional impact on health is extensively debated. Studies that use multilevel data, which have recently increased in popularity, are necessary to separate the contextual effects of income inequality on health from the effects of individual income on health. Our systematic review found only small associations between income inequality and poor self-rated health and all-cause mortality. The available evidence does not suggest causality, although it remains methodologically flawed and limited, with very few studies using natural experimental approaches or examining income inequality at the national level.

CONTEXT

Whether income inequality has a direct effect on health or is only associated because of the effect of individual income has long been debated. We aimed to understand the association between income inequality and self-rated health (SRH) and all-cause mortality (mortality) and assess if these relationships are likely to be causal.

METHODS

We searched Medline, ISI Web of Science, Embase, and EconLit (PROSPERO: CRD42021252791) for studies considering income inequality and SRH or mortality using multilevel data and adjusting for individual-level socioeconomic position. We calculated pooled odds ratios (ORs) for poor SRH and relative risk ratios (RRs) for mortality from random-effects meta-analyses. We critically appraised included studies using the Risk of Bias in Nonrandomized Studies - of Interventions tool. We assessed certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework and causality using Bradford Hill (BH) viewpoints.

FINDINGS

The primary meta-analyses included 2,916,576 participants in 38 cross-sectional studies assessing SRH and 10,727,470 participants in 14 cohort studies of mortality. Per 0.05-unit increase in the Gini coefficient, a measure of income inequality, the ORs and RRs (95% confidence intervals) for SRH and mortality were 1.06 (1.03-1.08) and 1.02 (1.00-1.04), respectively. A total of 63.2% of SRH and 50.0% of mortality studies were at serious risk of bias (RoB), resulting in very low and low certainty ratings, respectively. For SRH and mortality, we did not identify relevant evidence to assess the specificity or, for SRH only, the experiment BH viewpoints; evidence for strength of association and dose-response gradient was inconclusive because of the high RoB; we found evidence in support of temporality and plausibility.

CONCLUSIONS

Increased income inequality is only marginally associated with SRH and mortality, but the current evidence base is too methodologically limited to support a causal relationship. To address the gaps we identified, future research should focus on income inequality measured at the national level and addressing confounding with natural experiment approaches.

Income Inequality and Bullying Victimization and Perpetration: Evidence From Adolescents in the COMPASS Study

Previous research indicates that the disproportionate distribution of income within society is associated with aggression and violence. Although research has been conducted identifying the relationship between income inequality and bullying victimization and perpetration, little is known about possible mediators. We investigated the association between income inequality and bullying perpetration and victimization among adolescents participating in the Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking, and Sedentary behavior (COMPASS) study. We identified whether school connectedness and psychosocial well-being mediated the relationship between income inequality and bullying behavior. This study used pooled cross-sectional data from 147,748 adolescents aged 13 to 18 from three waves (2015–2016, 2016–2017, 2017–2018) of the COMPASS study from 157 secondary schools in British Columbia, Alberta, Ontario, and Quebec (Canada). The Gini coefficient was calculated based on the school Census Divisions (CD) using the Canada 2016 Census and linked with student data. We used multilevel modeling to investigate the relationship between income inequality and self-reported bullying victimization and perpetration, while controlling for individual-, school-, and CD-level characteristics. A standard deviation increase in Gini coefficient was associated with increased odds for bullying victimization and perpetration. Findings were observed among girls; however, inequality was only associated with perpetration among boys. We identified social cohesion and psychosocial well-being as potential mediators. To counter the adverse effects of income inequality, school-based interventions designed to increase school connectedness and student psychosocial well-being should be implemented to protect against bullying.

Integrating and differentiating personality and psychopathology: A psychodynamic perspective

Several strands of research converge to suggest that personality and psychopathology can be integrated in the form of a hierarchical model of individual differences. The notion that personality and psychopathology are intrinsically linked has a long tradition within psychodynamic approaches. In this article, we first summarize empirical evidence supporting two related key assumptions of psychodynamic approaches to personality and psychology: that a developmental, person-centered approach is needed to complement a static, disorder-centered approach in the conceptualization and treatment of psychopathology; and that personality and psychopathology are best conceptualized as dynamic attempts at adaptation. Research in each of these areas supports the notion that personality and psychopathology are difficult to separate and may be moderated by severity (i.e., general psychopathology) such that increasing levels of severity result in increased intrinsic coupling between the two. We then discuss these findings in the context of a newly emerging social-communicative approach to human development that suggests that personality and psychopathology are better conceptualized in terms of a disorder of social communication, and that the purported rigidity and stability typically attributed to them are largely explained by the stability of the environmental mechanisms that underpin them, rather than by stable intrapersonal traits. The implications of these new views for the future of the science of personality and psychopathology, and for treatment strategies, are discussed.

The Mentalizing Approach to Psychopathology: State of the Art and Future Directions

Mentalizing is the capacity to understand others and oneself in terms of internal mental states. It is assumed to be underpinned by four dimensions: automatic–controlled, internally–externally focused, self–other, and cognitive–affective. Research suggests that mental disorders are associated with different imbalances in these dimensions. Addressing the quality of mentalizing as part of psychosocial treatments may benefit individuals with various mental disorders. We suggest that mentalizing is a helpful transtheoretical and transdiagnostic concept to explain vulnerability to psychopathology and its treatment. This review summarizes the mentalizing approach to psychopathology from a developmental socioecological evolutionary perspective. We then focus on the application of the mentalizing approach to personality disorders, and we review studies that have extended this approach to other types of psychopathology, including depression, anxiety, and eating disorders. We summarize core principles of mentalization-based treatments and preventive interventions and the evidence for their effectiveness. We conclude with recommendations for future research.

The greater the economic inequality, the later people have children: The association between economic inequality and reproductive timing

Economic inequality is associated with a series of social outcomes, including health, social trust, and crime rates. However, little is known about the role of economic inequality as a characteristic of the socioecological environment in individuals' reproductive behavior. According to embodied capital theory, this research explored how individuals calibrate their reproductive timing to maximize payoffs to investment in embodied capital in an environment of high economic inequality. Five studies were conducted to test the hypothesis that higher economic inequality leads people to delay reproduction. Across nations (Study 1), we found that the average reproductive age is higher in nations with greater economic inequality. Study 2 found that people living in more economically unequal U.S. states tend to marry later. In Study 3, individuals who perceived higher levels of inequality in a given society planned to have their children later. Finally, in Study 4, the priming of high inequality led to a greater preference for delaying reproduction, which represented a desire to pursue one's development rather than to build a family (Study 4a and 4b). These results expand the literature regarding the effect of economic inequality on human behavior.

Socio-economic status, self-rated health and mental health: the mediation effect of social participation on early-late midlife and older adults

Background

Socioeconomic status (SES) is a major determinant of diverse health outcomes, among these are self-rated-health and mental health. Yet the mechanisms underlying the SES—health relation are not fully explored. Socioeconomic inequalities in health and mental health may form along several pathways. One is social participation which is linked to better self-rated-health and mental health. We examined (1) whether various social participation practices, including the usage of information and communication technology, relate to a unidimensional or multidimensional phenomenon (2) the relationship among SES, social participation, self-rated-health and mental health; (3) whether social participation and mental health mediates the association between SES and self-rated-health; (4) whether social participation and self-rated-health mediates the links between SES and mental health.

Method

Cross-sectional data for individuals aged 35 and older were taken from the Israeli Social Survey for 2016 (N = 4848). Social participation practices included connection with family and friends, self-perceived-support, self-perceived trust, volunteering, civic and political involvement, and information and communication technology usage. An exploratory factor analysis was conducted for all social participation practices. We then constructed structural Equation Modeling (SEM) to explore paths of relations among SES, social participation, self-rated-health and mental health.

Results

We found disparities in self-rated health and mental health across SES. Social participation practice, ‘frequency of meeting with friends’, mediated the links between SES-self-rated health and SES-mental health. Formal social participation practices along with internet usage mediated the SES- self-rated health link. Informal social participation practices and self-perceived trust mediated the SES-mental health link. Mental health mediated the SES- self-rated health link and self-rated health mediated the SES-mental health link.

Conclusion

The links between SES and the two health constructs were enhanced by common and distinct social participation practices. Enhancement of social participation practices among low SES individuals is recommended. Social participation should be a prominent aspect of preventive medicine practice and health promotion interventions. Policy makers are called to support such programs as an important way to promote public health.

Chronic stress, structural exposures and neurobiological mechanisms: A stimulation, discrepancy and deprivation model of psychosis

Chronic stress exposure has been established as a key vulnerability factor for developing psychotic disorders, including schizophrenia. A structural, or systems level perspective, has often been lacking in conceptualizations of chronic stress for psychotic disorders. The current review thus identified three subtypes of structural exposures. Stimulation exposures included urban environments, population density and crime exposure, with intermediary mechanisms of lack of safety and high attentional demands. Underlying neural mechanisms included threat neural circuits. Discrepancy exposures included environmental ethnic density, income inequality, and social fragmentation, with intermediary mechanisms of lack of belonging and social exclusion, and neural mechanisms including the oxytocin system. Deprivation exposures included environments lacking socioeconomic, educational, or material resources, with intermediary mechanisms of lack of needed environmental enrichment, and underlying neural mechanisms of over-pruning and protracted PFC development. Delineating stressor etiology at the systems level is a necessary step in reducing barriers to effective interventions and health policy.

A "Swiss paradox" in the United States? Level of spatial aggregation changes the association between income inequality and morbidity for older Americans

Although a preponderance of research indicates that increased income inequality negatively impacts population health, several international studies found that a greater income inequality was associated with better population health when measured on a fine geographic level of aggregation. This finding is known as a “Swiss paradox”. To date, no studies have examined variability in the associations between income inequality and health outcomes by spatial aggregation level in the US. Therefore, this study examined associations between income inequality (Gini index, GI) and population health by geographic level using a large, nationally representative dataset of older adults. We geographically linked respondents’ county data from the 2012 Behavioral Risk Factor Surveillance System to 2012 American Community Survey data. Using generalized linear models, we estimated the association between GI decile on the state and county levels and five population health outcomes (diabetes, obesity, smoking, sedentary lifestyle and self-rated health), accounting for confounders and complex sampling. Although state-level GI was not significantly associated with obesity rates (b = − 0.245, 95% CI − 0.497, 0.008), there was a significant, negative association between county-level GI and obesity rates (b = − 0.416, 95% CI − 0.629, − 0.202). State-level GI also associated with an increased diabetes rate (b = 0.304, 95% CI 0.063, 0.546), but the association was not significant for county-level GI and diabetes rate (b = − 0.101, 95% CI − 0.305, 0.104). Associations between both county-level GI and state-level GI and current smoking status were also not significant. These findings show the associations between income inequality and health vary by spatial aggregation level and challenge the preponderance of evidence suggesting that income inequality is consistently associated with worse health. Further research is needed to understand the nuances behind these observed associations to design informed policies and programs designed to reduce socioeconomic health inequities among older adults.

Effect of Income Inequality on Health in Quebec: New Insights from Panel Data

We investigated the relationship between income inequality and all-cause mortality in 87 regional county municipalities (RCMs) of Quebec (Canada) while accounting for time lags and effects of other socioeconomic variables. We presumed to be true that income inequality entails stress and depression. Thus, these phenomena were tested as mediating factors. The data used consist of eight (8) area-based chronological variables: mortality rate, Gini index, disposable income, criminality rate, number of physicians, density of population, and the proportion of people reporting feeling stressed or depressed. The association between income inequality and mortality was analyzed using the generalized method of moments (GMM) approach with local fixed effects to control unobservable characteristics. Our results show that higher income inequality led to a significant increase of mortality rate with a time lag of 5 years when socioeconomic characteristics were held constant. As expected, households’ disposable income and mortality rate were negatively associated. Moreover, mortality rate was positively associated with population density and negatively associated with the number of physicians. Finally, only depression showed the potential to act as a mediating factor. Based on our findings, we suggest that, over time, income inequality, by amplifying depression phenomena, increases the mortality rate in Quebec’s RCMs.

Do comprehensive school reforms impact the health of early school leavers? Results of a comparative difference-in-difference design

In the current article, we examine whether and how reforms in tracking age affect educational inequalities in health among people between the ages of 25-75 years. Particular attention is paid to the health consequences for early school leavers. The study combines data from the European Social Survey (2002-2016) on 21 countries with country-cohort information on education policies. Moreover, a difference-in-difference design is used, which takes advantage of both the cross-national and cross-temporal variability in the implementation of comprehensive schooling reforms. The results reveal statistically significant, but very small effects of de-tracking policies on people's health. That is, comprehensive education leads to slight improvements in health among people who have attained upper secondary or tertiary education, but these improvements are achieved at the expense of the health of those with the lowest levels of education. Our study should encourage future research to further explore the institutional impact of educational systems on the health of individuals.

Development of a richer measure of health outcomes incorporating the impacts of income inequality, ethnic diversity, and ICT development on health

BACKGROUND

In the literature, measuring health outcomes usually entails examining one dependent variable using cross-sectional data. Using a combination of mortality and morbidity variables, this study developed a new, richer measure of health outcome. Using the health outcome index, this study investigated the impacts of income inequality, levels of ethnic diversity and information and communication technology (ICT) development on health using panel data.

METHODS

Partial least squares regression based on a structural equation model is used to construct a health outcome index for 30 OECD countries over the period of 2004 to 2015 using SmartPLS software. Then, panel corrected standard errors estimation and pooled ordinary least square regression with Driscoll and Kraay standard errors approaches were used to investigate the key determinants of health outcomes. Both methods are efficient when the panel data is heteroscedastic and the errors are cross-sectional dependent.

RESULTS

Income inequality, level of ethnic diversity and development in ICT access and use have an adverse effect on health outcomes, however, development in ICT skills has a significant positive impact. Moreover, OECD countries with a higher percentage of publicly funded healthcare showed better public health compared to countries where the percentage is smaller. Finally, rising incomes, development of technologies and tertiary education are key determinants for improving health outcomes.

CONCLUSIONS

The results indicate that countries with higher levels of income inequality and more ethnically diverse populations have lower levels of health outcomes. Policymakers also need to recognise the adverse effect of ICT use on public health and the benefits of public healthcare expenditure.

Effects of Relative Deprivation on Intention to Rebel: A Multiple Mediation Model

This study examined the mediating effects of future social expectations and interpersonal distrust on the relationship between individual relative deprivation and intention to rebel. Data were gathered from 807 people from multiple occupational backgrounds in a municipality in southwest China. Structural equation modelling showed that individual relative deprivation predicted intention to rebel directly and also that it predicted intention to rebel indirectly via negative future social expectations, interpersonal distrust, and a chain mediating effect of negative future social expectations and interpersonal distrust. These results highlight the importance of the associations between future social expectations and interpersonal distrust with intention to rebel in people who report relative deprivation. The findings also indicate that prevention and intervention programs related to relative deprivation and intention to rebel in China are worthy of further research.

Self-rated health, generalized trust, and the Affordable Care Act: A US panel study, 2006-2014

Previous research shows that generalized trust, the belief that most people can be trusted, is conducive to people's health. However, only recently have longitudinal studies suggested an additional reciprocal pathway from health back to trust. Drawing on a diverse body of literature that shows how egalitarian social policy contributes to the promotion of generalized trust, we hypothesize that this other 'reverse' pathway could be sensitive to health insurance context. Drawing on nationally representative US panel data from the General Social Survey, we examine whether the Affordable Care Act of 2010 could have had influence on the deteriorating impact of worsening self-rated health (SRH) on generalized trust. Firstly, using two-wave panel data (2008-2010, N = 1403) and employing random effects regression models, we show that a lack of health insurance coverage negatively determines generalized trust in the United States. However, this association is attenuated when additionally controlling for (perceived) income inequality. Secondly, utilizing data from two separate three-wave panel studies from the US General Social Survey (2006-10; N = 1652; 2010-2014; N = 1187), we employ fixed-effects linear regression analyses to control for unobserved heterogeneity from time-invariant factors. We demonstrate that worsening SRH was a stronger predictor for a decrease in generalized trust prior (2006-2010) to the implementation of the Affordable Care Act. Further, the negative effect of fair/poor SRH seen in the 2006-2010 data becomes attenuated in the 2010-2014 panel data. We thus find evidence for a substantial weakening of the previously established negative impact of decreasing SRH on generalized trust, coinciding with the most significant US healthcare reforms in decades. Social policy and healthcare policy implications are discussed.

Exploring pathways for building trust in vaccination and strengthening health system resilience

Background

Trust is critical to generate and maintain demand for vaccines in low and middle income countries. However, there is little documentation on how health system insufficiencies affect trust in vaccination and the process of re-building trust once it has been compromised. We reflect on how disruptions to immunizations systems can affect trust in vaccination and can compromise vaccine utilization. We then explore key pathways for overcoming system vulnerabilities in order to restore trust, to strengthen the resilience of health systems and communities, and to promote vaccine utilization.

Methods

Utilizing secondary data and a review of the literature, we developed a causal loop diagram (CLD) to map the determinants of building trust in immunizations. Using the CLD, we devised three scenarios to illustrate common vulnerabilities that compromise trust and pathways to strengthen trust and utilization of vaccines, specifically looking at weak health systems, harmful communication channels, and role of social capital. Spill-over effects, interactions and other dynamics in the CLD were then examined to assess leverage points to counter these vulnerabilities.

Results

Trust in vaccination arises from the interactions among experiences with the health system, the various forms of communication and social capital – both external and internal to communities. When experiencing system-wide shocks such as the case in Ebola-affected countries, distrust is reinforced by feedback between the health and immunization systems where distrust often lingers even after systems are restored and spills over beyond vaccination in the broader health system. Vaccine myths or anti-vaccine movements reinforce distrust. Social capital – the collective value of social networks of community members – plays a central role in increasing levels of trust.

Conclusions

Trust is important, yet underexplored, in the context of vaccine utilization. Using a CLD to illustrate various scenarios helped to explore how common health and vaccine vulnerabilities can reinforce and spill over distrust through vicious, reinforcing feedback. Restoring trust requires a careful balance between eliminating vulnerabilities and strengthening social capital and interactions among communication channels.

Early-life income inequality and adolescent health and well-being

A prevailing hypothesis about the association between income inequality and poor health is that inequality intensifies social hierarchies, increases stress, erodes social and material resources that support health, and subsequently harms health. However, the evidence in support of this hypothesis is limited by cross-sectional, ecological studies and a scarcity of developmental studies. To address this limitation, we used pooled, multilevel data from the Health Behaviour in School-aged Children study to examine lagged, cumulative, and trajectory associations between early-life income inequality and adolescent health and well-being. Psychosomatic symptoms and life satisfaction were assessed in surveys of 11- to 15-year-olds in 40 countries between 1994 and 2014. We linked these data to national Gini indices of income inequality for every life year from 1979 to 2014. The results showed that exposure to income inequality from 0 to 4 years predicted psychosomatic symptoms and lower life satisfaction in females after controlling lifetime mean income inequality, national per capita income, family affluence, age, and cohort and period effects. The cumulative income inequality exposure in infancy and childhood (i.e., average Gini index from birth to age 10) related to lower life satisfaction in female adolescents but not to symptoms. Finally, individual trajectories in early-life inequality (i.e., linear slopes in Gini indices from birth to 10 years) related to fewer symptoms and higher life satisfaction in females, indicating that earlier exposures mattered more to predicting health and wellbeing. No such associations with early-life income inequality were found in males. These results help to establish the antecedent-consequence conditions in the association between income inequality and health and suggest that both the magnitude and timing of income inequality in early life have developmental consequences that manifest in reduced health and well-being in adolescent girls.