The impact of income inequality on individual and societal health: absolute income, relative income and statistical artefacts

Contextual effects of social integration and disintegration on health status: evidence from South Korea

BACKGROUND

Many studies have shown that various social integration variables represented by social capital are beneficial to communities, including collective health. However, the rapid decline in fertility rates and the breakup of familyism in developed countries require a new approach to social disintegration, but the literature is insufficient. Here, we explored the contextual effects of social integration and social disintegration on the health of individuals.

METHODS

The research data consist of merged datasets of 6909 respondents who were quota-sampled by approximately 30 people from 229 local governments in Korea. The individual-level independent variable is a social integration measure consisting of 26 questions in four areas. The community-level independent variables are five integral and aggregate variables extracted from 81 indicators. The dependent variable is self-rated health status. Potential confounders are gender, age, annual income, educational attainment, district type, and the number of beds in medical institutions per 1000 people.

RESULTS

The results showed that at the individual level, the higher the inclusive attitude of in- and out-of-networks, after adjusting for potential confounders, the less likely the respondent belongs to the unhealthy group (p < 0.001). At the community level, the higher the proportion of single-person households in a community after adjusting for potential confounders, the less likely the respondent belongs to the unhealthy group (p < 0.05). The effect size was 0.22.

CONCLUSION

Thus far, social integration has been preferred, with the positive aspects of social capital being emphasized. However, this study shows that in some cases, social disintegration can instead positively influence an individual's health. Therefore, further studies of the various conditions of social context effects on health are necessary.

Socioeconomic status, health inequalities and non-communicable diseases: a systematic review

AIM

A comprehensive approach to health highlights its close relationship with the social and economic conditions, physical environment and individual lifestyles. However, this relationship is not exempt from methodological problems that may bias the establishment of direct effects between the variables studied. Thus, further research is necessary to investigate the role of socioeconomic variables, their composition and distribution according to health status, particularly on non-communicable diseases.

SUBJECTS AND METHODS

To shed light on this field, here a systematic review is performed using PubMed, the Cochrane Library and Web of Science. A 7-year retrospective horizon was considered until 21 July 2017.

RESULTS

Twenty-six papers were obtained from the database search. Additionally, results from "hand searching" were also included, where a wider horizon was considered. Five of the 26 studies analyzed used aggregated data compared to 21 using individual data. Eleven considered income as a study variable, while 17 analyzed the effect of income inequality on health status (2 of the studies considered both the absolute level and distribution of income). The most used indicator of inequality in the literature was the Gini index.

CONCLUSION

Although different types of analysis produce very different results concerning the role of health determinants, the general conclusion is that income distribution is related to health where it represents a measure of the differences in social class in the society. The effect of income inequality is to increase the gap between social classes or to widen differences in status.

A short note on economic development and socioeconomic inequality in female body weight

The origin of the obesity epidemic in developing countries is still poorly understood. It has been prominently argued that economic development provides a natural interpretation of the growth in obesity. This paper tests the main aggregated predictions of the theoretical framework to analyze obesity. Average body weight and health inequality should be associated with economic development. Both hypotheses are confirmed: we find higher average female body weight in economically more advanced countries. In relatively nondeveloped countries, obesity is a phenomenon of the socioeconomic elite. With economic development, obesity shifts toward individuals with lower socioeconomic status.

Income inequality as a moderator of the relationship between psychological job demands and sickness absence, in particular in men: an international comparison of 23 countries

OBJECTIVES

The aim of this study was to investigate whether more sickness absence is reported in countries with higher income inequality than elsewhere, and whether the level of income inequality moderates the association between psycho-social job demands and sickness absence.

METHODS

Our analysis is based on the Fifth European Working Conditions Survey that compared 23 European countries. We performed multi-level regression analysis. On the macro-level of analysis we included the Gini-Index as measure of inequality. On the micro-level of analysis we followed the Karasek-Theorell model and included three scales for psychological job demands, physical job demands, and decision latitude in the model. The model was stratified by sex.

RESULTS

We found that, in countries with high income inequality, workers report significantly more sickness absence than workers in countries with low income inequality. In addition we found that the level of income inequality moderates the relationship between psychological job demands and sickness absence. High psychological job demands are significantly more strongly related to more days of sickness absence in countries with low income inequality than in countries with high income inequality.

CONCLUSIONS

As the nature and causal pathways of cross-level interaction effects still cannot be fully explained, we argue that future research should aim to explore such causal pathways. In accordance with WHO recommendations we argue that inequalities should be reduced. In addition we state that, particularly in countries with low levels of income inequality, policies should aim to reduce psychological job demands.

Where wealth matters more for health: the wealth-health gradient in 16 countries

Researchers have long demonstrated that persons of high economic status are likely to be healthier than persons of low socioeconomic standing. Cross-national studies have also demonstrated that health of the population tends to increase with country's level of economic development and to decline with level of economic inequality. The present research utilizes data for 16 national samples (of populations fifty years of age and over) to examine whether the relationship between wealth and health at the individual-level is systematically associated with country's level of economic development and country's level of income inequality. The analysis reveals that in all countries rich persons tend to be healthier than poor persons. Furthermore, in all countries the positive association between wealth and health holds even after controlling for socio-demographic attributes and household income. Hierarchical regression analysis leads to two major conclusions: first, country's economic resources increase average health of the population but do not weaken the tie between wealth and health; second, a more equal distribution of economic resources (greater egalitarianism) does not raise health levels of the population but weakens the tie between wealth and health. The latter findings can be mostly attributed to the uniqueness of the US case. The findings and their significance are discussed in light of previous research and theory.

Relative income inequality and selected health outcomes in urban Chinese youth

Self reported cross-sectional data gathered in 2002 from 12,449 middle and high school students from seven major cities in China were examined to explore the association of self-perceived relative income inequality (SPRII) with general health status, depression, stress, and cigarette smoking. Two types of self-perceived relative income were evaluated: household income relative to peers (SPRII-S) and relative to their own past (SPRII-P). SPRII-S and SPRII-P were coded as three-level categorical variables: lower, equal, and higher. As hypothesized, the youth in the "Lower" SPRII-S or SPRII-P groups reported the worst general health and the highest levels of depression and stress; the youth in the "Higher" groups reported the best general health. Unexpectedly, the youth in the "Higher" groups did not report the lowest levels of depression and stress, and the relationship between SPRII and cigarette smoking was even less straightforward. The expected positive relationship between SPRII and the general health status is consistent with previous research, but the relationships between SPRII and depression, stress, and cigarette smoking behavior are not. Further studies are needed to elucidate the complex associations between SPRII and health outcomes in rapidly transforming economies such as China.

Long-term employment and health inequalities in Canadian communities

OBJECTIVES

This study examines the long-term unemployment rate and various health outcomes across Canadian communities to estimate employment-related health inequalities in these communities.

METHODS

The study uses cross-sectional community-level health data along with data on the long-term employment rate for various communities across Canada to quantify health inequalities among these communities. The health outcomes that are considered in this study include total and disease specific mortality rates; health conditions such as high blood pressure, diabetes, injuries, and self rated health; and life expectancies at birth and at age 65. Health inequalities are estimated using the concentration index, which is used to measure health inequalities along socioeconomic dimensions. The concentration index is estimated by a regression of weighted relative health (ill health) over weighted cumulative relative rank of the populations. All the estimates are provided separately for males and females.

RESULTS

The findings of the study support the existence of inequalities in community health outcomes as related to the long-term employment rates in those communities. Communities with lower long term employment rates (higher unemployment rates) have poorer health outcomes in terms of higher mortality rates, worse health conditions, and shorter life expectancies.

CONCLUSION

Health inequalities related to long-term employment have important policy implications. They call for policies that would increase and maintain long term employment rates as part of a broader socioeconomic approach to health. Long term employment ensures income security and prevents the psychosocial experiences leading to mental and physical ill health.

Is democracy good for health?

Studies of health have recognized the influence of socioeconomic position on health outcomes. People with higher socioeconomic ranking, in general, tend to be healthier than those with lower socioeconomic rankings. The effect of political environment on population health has not been adequately researched, however. This study investigates the effect of democracy (or lack thereof) along with socioeconomic factors on population health. It is maintained that democracy may have an impact on health independent of the effects of socioeconomic factors. Such impact is considered as the direct effect of democracy on health. Democracy may also affect population health indirectly by affecting socioeconomic position. To investigate these theoretical links, some broad measures of population health (e.g., mortality rates and life expectancies) are empirically examined across a spectrum of countries categorized as autocratic, incoherent, and democratic polities. The regression findings support the positive influence of democracy on population health. Incoherent polities, however, do not seem to have any significant health advantage over autocratic polities as the reference category. More rigorous tests of the links between democracy and health should await data from multi-country population health surveys that include specific measures of mental and physical morbidity.

The causal effect of income on health: evidence from German reunification

We investigate whether there was a causal effect of income changes on the health satisfaction of East and West Germans in the years following reunification. Our data source is the German Socio-Economic Panel (GSOEP) between 1984 and 2002, and we fit a recently proposed fixed-effects ordinal estimator to our health measures and use a causal decomposition technique to account for panel attrition. We find evidence of a significant positive effect of income changes on health satisfaction, but the quantitative size of this effect is small. This is the case with respect to current income and a measure of 'permanent' income.

Income inequality and self-rated health in US metropolitan areas: A multi-level analysis

Income inequality has been found to affect health in a number of international and cross-national studies. Using data from a telephone survey of adults in the United States, this study analyzed the effect of metropolitan level income inequality on self-rated health. It combined individual data from the 2000 Behavioral Risk Factor Surveillance System with metropolitan level income data from the 2000 Census. After controlling for smoking, age, education, Black race, Hispanic ethnicity, sex, household income, and metropolitan area per capita income, this study found that for each 1 point rise in the GINI index (on a hundred point scale) the risk of reporting Fair or Poor self-rated health increased by 4.0% (95% confidence interval 1.6-6.5%). Given that self-rated health is a good predictor of morbidity and mortality, this suggests that metropolitan area income inequality is affecting the health of US adults.

Income, Income Inequality, and Cardiovascular Disease Mortality: Relations Among County Populations of the United States, 1985 to 1994

OBJECTIVES

Despite the major contribution of cardiovascular disease (CVD) to total mortality, and reports demonstrating strong relations between income and CVD, the joint relations of population-level income and income inequality with CVD mortality are not well described. This study was undertaken to describe relations among population-level income, income equality, and mortality due to cardiovascular disease, coronary heart disease, and stroke.

METHODS

County income distributions were determined from 1990 census data, and CVD mortality rates were obtained from the Compressed Mortality File. Relations among income, income inequality, and CVD mortality were examined in stratified and Poisson regression analyses.

RESULTS

County income was inversely related and income inequality was directly related to CVD, coronary heart disease, and stroke mortality. Relations were strongest for stroke. Relations of stroke mortality with income inequality were strongest in low-income populations.

CONCLUSIONS

The CVD mortality experiences of county populations are related to both income and income distribution in a complex, disease-dependent manner. The authors' findings are especially relevant to the Southeast, a region of high income inequality, low income, and high stroke mortality.

Excess winter mortality in Europe: a cross country analysis identifying key risk factors

OBJECTIVE

Much debate remains regarding why certain countries experience dramatically higher winter mortality. Potential causative factors other than cold exposure have rarely been analysed. Comparatively less research exists on excess winter deaths in southern Europe. Multiple time series data on a variety of risk factors are analysed against seasonal-mortality patterns in 14 European countries to identify key relations Subjects and setting: Excess winter deaths (all causes), 1988-97, EU-14.

DESIGN

Coefficients of seasonal variation in mortality are calculated for EU-14 using monthly mortality data. Comparable, longitudinal datasets on risk factors pertaining to climate, macroeconomy, health care, lifestyle, socioeconomics, and housing were also obtained. Poisson regression identifies seasonality relations over time.

RESULTS

Portugal suffers from the highest rates of excess winter mortality (28%, CI=25% to 31%) followed jointly by Spain (21%, CI=19% to 23%), and Ireland (21%, CI=18% to 24%). Cross country variations in mean winter environmental temperature (regression coefficient (beta)=0.27), mean winter relative humidity (beta=0.54), parity adjusted per capita national income (beta=1.08), per capita health expenditure (beta=-1.19), rates of income poverty (beta=-0.47), inequality (beta=0.97), deprivation (beta=0.11), and fuel poverty (beta=0.44), and several indicators of residential thermal standards are found to be significantly related to variations in relative excess winter mortality at the 5% level. The strong, positive relation with environmental temperature and strong negative relation with thermal efficiency indicate that housing standards in southern and western Europe play strong parts in such seasonality.

CONCLUSIONS

High seasonal mortality in southern and western Europe could be reduced through improved protection from the cold indoors, increased public spending on health care, and improved socioeconomic circumstances resulting in more equitable income distribution.

Does an increase of low income families affect child health inequalities? A Swedish case study

STUDY OBJECTIVE

Reduction of health inequalities is a primary public health target in many countries. A change of proportion of low income families might affect child health inequalities. Yet, the importance of family incomes in high income welfare states is not well established. The aim of this study was to investigate the effect of increased percentage of low income families on child health inequalities during an economic recession in Sweden, 1991-1996.

DESIGN

Health inequalities for six health indicators were assessed during the period 1991-1996 and during adjacent periods. Relative inequality indices were estimated according to Pamuk and Mackenback. Appraisal of a child's socioeconomic situation was based on social data for the child's residency area.

SETTING

The total population of children and adolescents 0-<19 years old living in Stockholm County, Sweden, was studied. Each one year cohort comprised 20 470-25 420 people.

MAIN OUTCOME MEASURES

Mortality; rate of low birth weight; days of hospital care for infections, asthma/allergic disorders, and unintentional injuries; and rate of abortions.

MAIN RESULTS

Mortality decreased annually by 6.9%. The average relative inequality index for mortality before the recession was 1.40 and was lower during the recession, 1.14. The remaining five health indicators, and the relative inequality index for these indicators, did not differ significantly between the recession years (1991-1996) and adjacent periods.

CONCLUSIONS

Relative health inequalities did not change, or decreased, during the recession years. The findings indicate that the connection was weak between child health inequalities and family incomes, within the frame of time and the range of income changes that occurred during the study period.

Income inequality, household income, and health status in Canada: a prospective cohort study

OBJECTIVES

This study sought to determine whether income inequality, household income, and their interaction are associated with health status.

METHODS

Income inequality and area income measures were linked to data on household income and individual characteristics from the 1994 Canadian National Population Health Survey and to data on self-reported health status from the 1994, 1996, and 1998 survey waves.

RESULTS

Income inequality was not associated with health status. Low household income was consistently associated with poor health. The combination of low household income and residence in a metropolitan area with less income inequality was associated with poorer health status than was residence in an area with more income inequality.

CONCLUSIONS

Household income, but not income inequality, appears to explain some of the differences in health status among Canadians.

Modelling health, income and income inequality: the impact of income inequality on health and health inequality

A framework is developed to analyse the impact of the distribution of income on individual health and health inequality, with individual health modelled as a function of income and the distribution of income. It is demonstrated that the impact of income inequality can generate non-concave health production functions resulting in a non-concave health production possibility frontier. In this context, the impact of different health policies are considered and it is argued that if the distribution of income affects individual health, any policy aimed at equalising health, which does not account for income inequality, will lead to unequal distributions of health. This is an important development given current UK government attention to reducing health inequality.

Income related inequalities in mental health in Great Britain: analysing the causes of health inequality over time

Using regression techniques this paper estimates the level of income related health inequality in GB in 1992 and 1998. Inequality is decomposed to investigate which socio-demographic factors are important contributors to health differences. The paper includes a range of measured and subjective income variables to control for absolute income. A relative deprivation measure is included to test the impact of income inequality on health inequality. It is found that subjective financial status is a major determinant of ill-health and makes a major contribution to income related inequalities in health. Relative deprivation is an important contributor for women but not for men.