Economic transition and changing relation between income inequality and mortality in Taiwan: regression analysis

Does Democracy Matter for Public Health?

This study examines the effect of democracy on public health by using panel data of 188 countries over the period 1972-2019. We use various regression methods, such as pooled ordinary least squares, fixed effects, dynamic generalized method of moments (GMM), a split-sample method, and a quadratic model to address econometric issues. The pooled regression supports the positive effect on health, but it does not exist in low-income countries, which can be explained by the threshold effect. The fixed effects regression confirms the positive impact on infant mortality but not on life expectancy, which illustrates the historical and cumulative effect of democracy on life expectancy. The non-linear regression finds a U-shaped relationship between democracy and infant mortality, which is consistent with the fixed effects regression result of the positive effect on mortality in the low-income group. The dynamic GMM regression shows the expected strong relationship between previous health and current health status. Overall, the regression analysis supports the positive effect of democracy on public health.

Precarious Suicide Behavior According to Housing Price Gap: A Case Study on South Korea

In 2018, the suicide rate in South Korea was the highest among the Organisation for Economic Co-operation and Development countries, and socioeconomic inequality has intensified. This study analyzes the impact relationship between suicidal impulses and economic inequality in South Korea. This study measures suicidal impulses thoughts National Health Survey Data and economic inequality based on the housing prices gap in the country. The primary analysis results were as follows: First, suicidal impulses were positively associated with the high index of housing price inequality; this correlation has become tight in recent years. Second, it was confirmed that the higher the income level, the higher the correlation between suicidal impulses with the index of housing price inequality. Third, the correlation between housing price inequality with suicidal impulse increased consistently in highly urbanized areas, but the statistical significance was low in non-urban areas.

Social policies and change in education-related disparities in mortality in Japan, 2000-2010

Persistent socioeconomic disparity in mortality is a widely observed phenomenon despite improvements in the economic standard of living and the prevailing universal healthcare coverage policy. In this study, we selected Japan as a case in which public universal coverage has maintained horizontal equity in healthcare access while demographic and economic challenges have affected the life chances of vulnerable subpopulations over the past decade. We assessed the changing trends in the education-related disparity in mortality over a decade across demographic subpopulations for different causes of death, with the goal of generating social policy lessons to contribute to closing the mortality gap. Using a deterministic data merge between nationwide census and death records, we estimated age- and sex-specific mortality rates for 14 causes and their education-related gradients with absolute and relative indices of inequality in 2000 and 2010 via Poisson regression. Estimation parameters were standardized to the age structure of the sub-population of high school graduates in 2000 as the reference. The results demonstrated that the relative gaps in all-cause mortality persisted despite a decrease in the average mortality rate over the study period. The absolute gaps in mortality increased for preventable causes of death associated with lifestyle behavior choices. The average mortality worsened among socioeconomically vulnerable populations such as youth and women, who were left behind in the existing social/economic policy. External causes of death such as suicide and traffic accidents showed decreasing absolute gaps in a subpopulation targeted by universal social and labor policy measures. These change patterns indicate that, compared with a high-risk approach, a universal policy approach to dealing with societal and fundamental causes of health inequality seems more effective in reducing the education-related mortality gap in both absolute and relative terms.

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Socioeconomic gaps in mortality persist despite extended healthcare coverage.

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Education-related mortality gaps were confirmed in 2000 and 2010 in Japan.

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Relative inequality in preventable diseases increased under checkup-for-all policy.

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Youth and women, left behind in the current social policy, faced worsened gaps.

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Mortality gaps decreased when a universal policy on societal causes was adopted.

Investigating the relationship between district-level socioeconomic status and individual obesity in Taiwanese adolescents: A large-scale cross-sectional analysis

The current study aimed to assess the prevalence of obesity and to explore the relationship between socioeconomic status and obesity among adolescents in Taiwan, a transitioning country. Data from the Taiwan School Physical Fitness Database on 1,875,627 Taiwanese adolescents aged 10-18 years were analyzed. The average family income per household in each district was collected from the national statistical institutional database. Descriptive statistics, Chi-square tests, Pearson correlation analysis, and mixed model analyses were used. The overall prevalence of combined overweight and obesity was 28.1%. The prevalence of overweight/obesity significantly differed according to gender and age. Furthermore, the average family income per household was negatively associated with the district-level prevalence of obesity. Additionally, when controlling for physical fitness, the average family income per household remained negatively associated with adolescent obesity. In addition, multilevel analysis was also applied to explore the relationship between district-level socioeconomic status and individual-level obesity to prevent the nested data structure from affecting the results. The results revealed that the average family income per household negatively correlated with individual obesity. These findings provide insight for public health officials into preventing and managing adolescent obesity.

Double disadvantage: income inequality, spatial polarization and mortality rates in Taiwan

Background

Previous studies have suggested that social and economic spatial polarization is associated with various health outcomes. However, few studies have examined the joint effect of income inequality and spatial polarization on health.

Methods

Data on mortality in 2008-12 were from the Ministry of Health and Welfare. We constructed economic spatial polarization using the Index of Concentration at the Extremes (ICE) by tax data from the Ministry of Finance. The Gini coefficient was from the Family Income and Expenditure Survey. Using multilevel datasets of 352 townships nested within 20 cities in Taiwan, we examined the association between township-level ICE and mortality, and further examined whether city-level income inequality moderate this association.

Results

In 2008-12, the average age-standardized mortality in Taiwan was 470.5 per 100 000 populations. As compared to the highest income-based ICE quintile, the lowest ICE quintile was associated with an excess 171.7 deaths per 100 000 people (95% CI = 116.1, 227.3) after controlling for income inequality and population size. One unit rise in the Gini coefficient further increased 29.9 deaths (95% CI = 12.4, 47.5) for the lowest ICE quintile, as compared to the highest.

Conclusion

The joint effect of income inequality and small-scale economic polarization may shed light on how inequalities increase mortality.

Household income, income inequality, and health-related quality of life measured by the EQ-5D in Shaanxi, China: a cross-sectional study

Background

In advanced economies, economic factors have been found to be associated with many health outcomes, including health-related quality of life (HRQL), and people’s health is affected more by income inequality than by absolute income. However, few studies have examined the association of income inequality and absolute income with HRQL in transitional economies using individual data. This paper focuses on the effects of county or district income inequality and absolute income on the HRQL measured by EQ-5D and the differences between rural and urban regions in Shaanxi province, China.

Methods

Data were collected from the 2008 National Health Service Survey conducted in Shaanxi, China. The EQ-5D index based on Japanese weights was employed as a health indicator. The income inequality was calculated on the basis of self-reported income. The special requirements for complex survey data analysis were considered in the bivariate analysis and linear regression models.

Results

The mean of the EQ-5D index was 94.6. The EQ-5D index of people with low income was lower than that in the high-income group (for people in the rural region: 93.2 v 96.1, P < 0.01; for people in the urban region: 95.5 v 96.8, P < 0.01). Compared with people with moderate inequality, the EQ-5D index of those with high inequality was relatively lower (for people living in the rural region: 91.1 v 95.8, P < 0.01; for people living in the urban region: 95.6 v 97.3, P < 0.01). Adjusted by age, gender, education, marital status, employment, medical insurance, and chronic disease, all the coefficients of the low-income group and high income inequality were significantly negative. After stratifying by income group, all the effects of high income inequality remained negative in both income groups. However, the coefficients of the models in the high income group were not statistically significant.

Conclusion

Income inequality has damaging effects on HRQL in Shaanxi, China, especially for people with low income. In addition, people living in rural regions were more vulnerable to economic factors.

GENES AND GINI: WHAT INEQUALITY MEANS FOR HERITABILITY

Research has established that genetic differences among people explain a greater or smaller proportion of the variation in life outcomes in different environmental conditions. This review evaluates the results of recent educationally relevant behavioural genetic studies and meta-analyses in the context of recent trends in income and wealth distribution. The pattern of results suggests that inequality and social policies can have profound effects on the heritability of educational attainment and achievement in a population (Gene–Gini interplay). For example, heritability is generally higher at greater equality levels, suggesting that inequality stifles the expression of educationally relevant genetic propensities. The review concludes with a discussion of the mechanisms of Gene–Gini interplay and what the findings mean for efforts to optimize education for all people.

The association between relative deprivation and self-rated health, depressive symptoms, and smoking behavior in Taiwan

Relative deprivation has been hypothesized as one explanation for the association between income inequality and health. However, few studies have examined the effect of relative deprivation on psychosocial and behavioral outcomes. Using a cross-sectional data from the National Survey on Knowledge, Attitude, and Practice of Health Promotion in Taiwan, this study examined the relationship between relative deprivation and physical health (self-rated health), psychosocial health (depressive symptoms), and behavioral health (smoking) among working-age Taiwanese men and women. We found that higher relative deprivation (measured by the Yitzhaki Index) is significantly associated with a higher prevalence of poor self-rated health, depressive symptoms, and current smoking in both genders. After controlling for demographic variables and absolute income, the prevalence ratios (PRs) of reporting poor health for each 10,000 NT-dollars higher in the Yitzhaki Index are between 1.25 and 1.57, depending on the reference groups. The PRs were between 1.33 and 1.77 for depressive symptoms, and between 1.04 and 1.46 for smoking. Additionally, the depressive symptoms attenuated the association between relative deprivation and self-rated health. The results were consistent with various definitions of reference groups. In conclusion, this study suggests that the psychosocial process of relative deprivation is a crucial mechanism linking income inequality to health. Narrowing the income gap between rich and poor may protect the physical and mental well-being of the population and reduce the prevalence of smoking.

Redistributive effects of the National Health Insurance on physicians in Taiwan: a natural experiment time series study

BACKGROUND

Previous studies have evaluated the effects of various health manpower policies but did not include full consideration of the effect of universal health insurance on physician re-distribution. This study examines the effects of implementing National Health Insurance (NHI) on the problem of geographic mal-distribution of health providers in Taiwan.

METHODS

Data on health providers and population between 1971 and 2001 are obtained from relevant governmental publications in Taiwan. Gini coefficients derived from the Lorenz curve are used under a spline regression model to examine the impact of the NHI on the geographic distribution of health providers.

RESULTS

The geographic distribution equality of the three key health providers has improved significantly after the implementation of NHI program. After accounting for the influences of other confounding factors, Gini coefficients of the three key providers have a net reduction of 1.248% for dentists, 0.365% for western medicine physicians, and 0.311% for Chinese medicine physicians. Overall, the absolute values of the three key providers' Gini coefficients also become close to one another.

CONCLUSIONS

This study found that NHI's offering universal health coverage to all citizens and with proper financial incentives have resulted in more equal geographic distributions among the key health care providers in Taiwan.

Income inequality and cause-specific mortality during economic development

PURPOSE

Life expectancy is strongly related to national income, whether there is an additional contribution of income inequality is unclear.

METHODS

We used negative binomial regression to examine the association of neighborhood-level Gini, adjusted for age, sex, and income, with mortality rates in Hong Kong from 1976 to 2006.

RESULTS

The association of neighborhood Gini with all-cause mortality varied over time (p-value for interaction < .01). Neighborhood Gini was positively associated with nonmedical mortality in 1976 to 1986; incident rate ratio (IRR) 1.09, 95% confidence interval (95% CI) 1.02-1.16 per 0.1 change and in 1991 to 2006, IRR 1.24, 95% CI 1.13-1.36, adjusted for age, sex and absolute income. Similarly adjusted, Gini was not associated with all-cause mortality in 1976 to 1986 (IRR 0.96, 95% CI 0.93-1.00) but was in 1991 to 2006 (IRR 1.25, 95% CI 1.20-1.29), when Gini was also positively associated with death from cardiovascular diseases, respiratory diseases and some cancers.

CONCLUSIONS

Independent of income, income inequality was positively associated with nonmedical mortality rates at a low level of spatial aggregation, indicating the consistent harms of social disharmony. However, the impact on medical mortality was less consistent, suggesting the relevance of contextual factors.

Do people die from income inequality of a decade ago?

The long-term impact of income inequality on health has not been fully explored in the current literature. Until now, 4 studies have examined the lagged effect on population/group mortality rate at the aggregate level, and 7 studies have investigated the effect of income inequality on subsequent individual mortality risk within a restricted time period. These 11 studies suffer from the same limitation: they do not simultaneously control for a series of preceding income inequalities. The results of these studies are also mixed. Using the U.S. National Health Interview Survey data 1986-2004 with mortality follow-up data 1986-2006 (n = 701,179), this study investigates the lagged effects of national-level income inequality on individual mortality risk. These effects are tested by using a discrete-time hazard model where contemporaneous and preceding income inequalities are treated as time-varying person-specific covariates, which then track a series of income inequalities that a respondent faces from the survey year until s/he dies or is censored. Findings suggest that income inequality did not have an instantaneous detrimental effect on individual mortality risk, but began exerting its influence 5 years later. This effect peaked at 7 years, and then diminished after 12 years. This pattern generally held for three measures of income inequality: the Gini coefficient, the Atkinson index, and the Theil entropy index. The findings suggest that income inequality has a long-term detrimental impact on individual mortality risk. This study also explains discrepancies in the existant literature.

Socioeconomic determinants of disability in Chile

BACKGROUND

Disability is a worldwide public health priority. A shift from a biomedical perspective of dysfunction to a broader social understanding of disability has been proposed. Among many different social factors described in the past, socioeconomic position remains as a key multidimensional determinant of health. The study goal was to analyze the relationship between disability and different domains of socioeconomic position in Chile.

METHODS

Cross-sectional analysis of an anonymized population-based survey conducted in Chile in 2006. Any disability (dichotomous variable) and 6 different types of disability were analyzed on the bases of their relationship with income quintiles, occupational status, educational level, and material living standards (quality of the housing, overcrowding rate and sanitary conditions). Confounding and interaction effects were explored using R statistical program.

RESULTS

Income, education, occupation, and material measures of socioeconomic position, along with some sociodemographic characteristics of the population, were independently associated with the chance of being disabled in Chile. Interestingly, classic measures of socioeconomic position (income, education, and occupation) were consistently associated with any disability in Chile, whereas material living conditions were partially confounded by these classic measures. In addition to this, each type of disability showed a particular pattern of related social determinants, which also varied by age group.

CONCLUSIONS

This study contributed to the understanding of disability in Chile and how different domains of socioeconomic position might be associated with this prevalent condition. Disability remains a complex multidimensional public health problem in Chile that requires the inclusion of a wide range of risk factors, of which socioeconomic position is particularly relevant.

A multilevel analysis of the effects of neighbourhood income inequality on individual self-rated health in Hong Kong

We examined the effect on self-rated health of neighbourhood-level income inequality in Hong Kong, which has a high and growing Gini coefficient. Data were derived from two population household surveys in 2002 and 2005 of 25,623 and 24,610 non-institutional residents aged 15 or over. We estimated neighbourhood-level Gini coefficients in each of 287 Government Planning Department Tertiary Planning Units. We used multilevel regression analysis to assess the association of neighbourhood income inequality with individual self-perceived health status. After adjustment for both individual- and household-level predictors, there was no association between neighbourhood income inequality, median household income or household-level income and self-rated health. We tested for but did not find any statistical interaction between these three income-related exposures. These findings suggest that neighbourhood income inequality is not an important predictor of individual health status in Hong Kong.

The global impact of income inequality on health by age: an observational study

OBJECTIVES

To explore whether the apparent impact of income inequality on health, which has been shown for wealthier nations, is replicated worldwide, and whether the impact varies by age.

DESIGN

Observational study.

SETTING

126 countries of the world for which complete data on income inequality and mortality by age and sex were available around the year 2002 (including 94.4% of world human population).

DATA SOURCES

Data on mortality were from the World Health Organization and income data were taken from the annual reports of the United Nations Development Programme.

MAIN OUTCOME MEASURES

Mortality in 5-year age bands for each sex by income inequality and income level.

RESULTS

At ages 15-29 and 25-39 variations in income inequality seem more closely correlated with mortality worldwide than do variations in material wealth. This relation is especially strong among the poorest countries in Africa. Mortality is higher for a given level of overall income in more unequal nations.

CONCLUSIONS

Income inequality seems to have an influence worldwide, especially for younger adults. Social inequality seems to have a universal negative impact on health.

A multilevel analysis of neighborhood and individual effects on individual smoking and drinking in Taiwan

Background

We assessed direct effects of neighborhood-level characteristics and interactive effects of neighborhood-level characteristics and individual socioeconomic position on adult smoking and drinking, after consideration of individual-level characteristics in Taiwan.

Methods

Data on individual sociodemographic characteristics, smoking, and drinking were obtained from Taiwan Social Change Survey conducted in 1990, 1995, and 2000. The overall response rate was 67%. A total of 5883 women and men aged over 20 living in 434 neighborhoods were interviewed. Participants' addresses were geocoded and linked with Taiwan census data for measuring neighborhood-level characteristics including neighborhood education, neighborhood concentration of elderly people, and neighborhood social disorganization. The data were analyzed with multilevel binomial regression models.

Results

Several interaction effects between neighborhood characteristics and individual socioeconomic status (SES) were found in multilevel analyses. Our results indicated that different neighborhood characteristics led to different interaction patterns. For example, neighborhood education had a positive effect on smoking for low SES women, in contrast to a negative effect on smoking for high SES women. This result supports the hypothesis of "relative deprivation," suggesting that poor people living in affluent neighborhoods suffer from relative deprivation and relative standing. On the other hand, neighborhood social disorganization has positive effects on drinking for low SES individuals, but not for high SES individuals. These interactive effects support the hypothesis of the double jeopardy theory, suggesting that living in neighborhoods with high social disorganization will intensify the effects of individual low SES.

Conclusion

The findings of this study show new evidence for the effects of neighborhood characteristics on individual smoking and drinking in Taiwan, suggesting that more studies are needed to understand neighborhood effects in Asian societies.

Socioeconomic determinants of infant mortality: a worldwide study of 152 low-, middle-, and high-income countries

BACKGROUND

To reach the Millennium Development Goals for health, influential international bodies advocate for more resources to be directed to the health sector, in particular medical treatment. Yet, health has many determinants beyond the health sector that are less evident than proximate predictors.

AIM

To assess the relative importance of major socioeconomic determinants of population health, measured as infant mortality rate (IMR), at country level.

METHODS

National-level data from 152 countries based on World Development Indicators 2003 were used for multivariate linear regression analyses of five socioeconomic predictors of IMR: public spending on health, GNI/capita, poverty rate, income equality (Gini index), and young female illiteracy rate. Analyses were performed on a global level and stratified for low-, middle-, and high-income countries.

RESULTS

In order of importance, GNI/capita, young female illiteracy, and income equality predicted 92% of the variation in national IMR whereas public spending on health and poverty rate were non-significant determinants when adjusted for confounding. In low-income countries, female illiteracy was more important than GNI/capita. Income equality (Gini index) was an independent predictor of IMR in middle-income countries only. In high-income countries none of these predictors was significant.

CONCLUSIONS

The relative importance of major health determinants varies between income levels, thus extrapolating health policies from high- to low-income countries is problematic. Since the size, per se, of public health spending does not independently predict health outcomes, functioning health systems are necessary to make health investments efficient. Potential health gains from improved female education and economic growth should be considered in low- and middle-income countries.

Variation of socioeconomic gradients in children's developmental health across advanced Capitalist societies: analysis of 22 OECD nations

Within societies, there is a well-established relation between socioeconomic position and a wide range of outcomes related to well-being, and this relation is known to vary in magnitude across countries. Using a large sample of nations, the authors explored whether differences in social policies explain differences in socioeconomic gradients across nations. Analyses were conducted on reading literacy in 15-year-olds, as an outcome related to cognitive development and to a host of factors that contribute to future well-being, including educational attainment and health. The results show a systematic variation in socioeconomic gradients and average scores across countries. Scores were favorable in countries with a long history of welfare state regimes, but countries where institutional change unfolded more recently and rapidly, or where welfare states are less well developed, clustered at the bottom of the rankings. Strong support was found for the "flattening up" hypothesis, which suggests that nations with higher average scores have less socioeconomic inequality in scores (or flatter gradients). Potential explanations for the observed patterns include differences between nations in the extent and distribution of income and social goods important for children's development.

Income inequality and population health: A review and explanation of the evidence

Whether or not the scale of a society's income inequality is a determinant of population health is still regarded as a controversial issue. We decided to review the evidence and see if we could find a consistent interpretation of both the positive and negative findings. We identified 168 analyses in 155 papers reporting research findings on the association between income distribution and population health, and classified them according to how far their findings supported the hypothesis that greater income differences are associated with lower standards of population health. Analyses in which all adjusted associations between greater income equality and higher standards of population health were statistically significant and positive were classified as "wholly supportive"; if none were significant and positive they were classified as "unsupportive"; and if some but not all were significant and supportive they were classified as "partially supportive". Of those classified as either wholly supportive or unsupportive, a large majority (70 per cent) suggest that health is less good in societies where income differences are bigger. There were substantial differences in the proportion of supportive findings according to whether inequality was measured in large or small areas. We suggest that the studies of income inequality are more supportive in large areas because in that context income inequality serves as a measure of the scale of social stratification, or how hierarchical a society is. We suggest three explanations for the unsupportive findings reported by a minority of studies. First, many studies measured inequality in areas too small to reflect the scale of social class differences in a society; second, a number of studies controlled for factors which, rather than being genuine confounders, are likely either to mediate between class and health or to be other reflections of the scale of social stratification; and third, the international relationship was temporarily lost (in all but the youngest age groups) during the decade from the mid-1980s when income differences were widening particularly rapidly in a number of countries. We finish by discussing possible objections to our interpretation of the findings.

Income inequality and mortality in Italy

BACKGROUND

The relationship between income inequality and health remains controversial in terms of whether or not it exists and, if so, its extent and the mechanisms involved. This study examines the relationship between income inequality, as indicated by the Gini coefficient, and mortality in Italy.

METHODS

Cross-sectional ecological study on the 57,138,489 inhabitants living in the 95 provinces existing in Italy in 1994. Multivariate weighted regression analysis of total and age-specific mortality, income inequality, gender, and interaction between income inequality and median income or geographical area.

RESULTS

A positive association between income inequality and total mortality was observed for both genders in provinces with a low per capita income and in Southern and Central Italy. The effect was present for infants and for persons over 24 years of age; it was marked for the elderly, particularly women. A negative association with mortality was observed for males living in the North-west. Interactions between income inequality and median income, and between income inequality and geographical area were found.

CONCLUSION

In Italy, the relationship between income inequality and health is mixed and not universal, in so far as a positive association was observed only in provinces with lower absolute income. Elderly persons living in Southern Italy represent the population subgroup most vulnerable to unequal income distribution. Income inequality can, in part, explain the historically higher mortality among women in Southern Italy compared to women in the North. These results indicate that income inequality affects the health of population subgroups differentially.

Income inequality and health in Ontario: a multilevel analysis

OBJECTIVE

To examine the association of income inequality at the public health unit level with individual health status in Ontario.

METHODS

Cross-sectional multilevel study carried out among subjects aged 25 years or older residing in 42 public health units in Ontario. Individual-level data drawn from 30,939 respondents in 1996-97 Ontario Health Survey. Median area income and income inequality (Gini coefficient) calculated from 1996 census. Self-rated health status (SRH) and Health Utilities Index (HUI-3) scores were used as main outcomes.

RESULTS

Controlling for individual-level factors including income, respondents living in public health units in the highest tercile of income inequality had odds ratios of 1.20 (95% CI 1.04 - 1.38) for fair/poor self-rated health, and 1.11 (95% CI 1.01 - 1.22) for HUI score below the median, compared with people living in public health units in the lowest tercile. Controlling further for median area income had little effect on the association.

CONCLUSION

Income inequality was significantly associated with individual self-reported health status at public health unit level in Ontario, independent of individual income.

Geographical inequalities of mortality by income in two developed island countries: a cross-national comparison of Britain and Japan

In this paper we examine the ecological relations between household income distribution and age-grouped mortality in Britain and Japan. Comparable datasets were prepared in terms of age intervals of mortality, household income intervals and geographical units for years around 1990. Then we conducted a series of regression analyses to associate absolute and relative income indices with age and sex-specific standardized mortality ratios (SMRs). The results are as follows: (1) In Britain mortality is lower where inequalities in income are lower, while in Japan there is no obvious relationship. It is, however, apparent that-just as in the case of the USA and Canada-Britain and Japan appear to merge and appear part of a greater pattern when considered as a series of city regions. Thus an overall global relationship between income inequality and mortality may exist. To assess such global relationship, further studies using cross-national regional datasets covering a wide rage of rich nations are desirable. (2) Income-mortality relations are consistent among different age-sex groups in Britain, but there are substantial differences in the relationships as revealed between different demographic groups in Japan. In particular, while absolute income levels are correlated negatively with mortality of working-age men in both countries, mortality of elderly people in Japan is higher where absolute income is higher. This indicates the different historical contexts to the health divides these two different geographical contexts, but further consideration of a more historically nuanced understanding of income-mortality relations is required.

Changes in mortality after the recent economic crisis in South Korea

PURPOSE

To examine the changes in all cause mortality and cause-specific mortality after the economic crisis in South Korea.

METHODS

Monthly mortality data for an entire country was used and intervention analysis applied to compare mortality after the crisis with mortality which would have occurred if the trends before the crisis had continued.

RESULTS

All cause mortality began to increase about 1 year after the crisis, while cardiovascular increased immediately. Transport accidents decreased significantly during the year following the crisis and then regressed towards the pre-economic crisis level. Suicides increased rapidly and maintained an upward trend but subsequently reduced towards the pre-economic crisis level.

CONCLUSIONS

This study has shown an evidence of a relationship between economic crisis and mortality.

Does income inequality harm health? New cross-national evidence

The provocative hypothesis that income inequality harms population health has sparked a large body of research, some of which has reported strong associations between income inequality and population health. Cross-national evidence is frequently cited in support of this important hypothesis, but the hypothesis remains controversial, and the cross-national work has been criticized for several methodological shortcomings. This study replicates previous work using a larger sample (692 observations from 115 countries over the 1947-1996 period), a wider range of statistical controls, and fixed-effects models that address heterogeneity bias. The relationship between health and inequality shrinks when controls are included. In fixed-effects models that capture unmeasured heterogeneity, the association between income inequality and health disappears. The null findings hold for two measures of income inequality: the Gini coefficient and the share of income received by the poorest quintile of the population. Analysis of a sample of wealthy countries also fails to support the hypothesis.

Social inequality and ethnic differences in smoking in New Zealand

This study tests a generalisation of the 'Wilkinson' thesis that the greater a nation's income inequality, the poorer the average national health status. We consider the effect of socio-economic inequality upon ethnic variations in smoking in New Zealand. Analysis of Maori and Pakeha (New Zealanders of European descent) smoking rates from the 1996 Census is conducted for 73 Territorial Local Authority areas in New Zealand, disaggregated by gender and rural-urban location. Partial correlation is used to control for absolute levels of deprivation and examine the independent effect of ethnic social inequality upon smoking rates. The level of social inequality between Maori and Pakeha has an independent effect on Maori smoking rates. Pakeha smoking rates by contrast are more sensitive to variations in absolute rather than relative deprivation. The effect of inequality is greatest for Maori women, especially among urban residents. By contrast, among Maori men the effects are greatest in rural areas. The results provide some qualified support for the Wilkinson thesis and suggest that policies which address fundamental issues of social inequality will play a small, but significant, role in helping to reduce high smoking rates amongst Maori.

Income inequality and health: a critical review of the literature

This article critically reviews published literature on the relationship between income inequality and health outcomes. Studies are systematically assessed in terms of design, data quality, measures, health outcomes, and covariates analyzed. At least 33 studies indicate a significant association between income inequality and health outcomes, while at least 12 studies do not find such an association. Inconsistencies include the following: (1) the model of health determinants is different in nearly every study, (2) income inequality measures and data are inconsistent, (3) studies are performed on different combinations of countries and/or states, (4) the time period in which studies are conducted is not consistent, and (5) health outcome measures differ. The relationship between income inequality and health is unclear. Future studies will require a more comprehensive model of health production that includes health system covariates, sufficient sample size, and adjustment for inconsistencies in income inequality data.

Is income inequality a determinant of population health? Part 1. A systematic review

This article reviews 98 aggregate and multilevel studies examining the associations between income inequality and health. Overall, there seems to be little support for the idea that income inequality is a major, generalizable determinant of population health differences within or between rich countries. Income inequality may, however, directly influence some health outcomes, such as homicide in some contexts. The strongest evidence for direct health effects is among states in the United States, but even that is somewhat mixed. Despite little support for a direct effect of income inequality on health per se, reducing income inequality by raising the incomes of the most disadvantaged will improve their health, help reduce health inequalities, and generally improve population health.

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.

Trends in the association between average income, poverty and income inequality and life expectancy in Spain

In this paper, we study the relation between life expectancy and both average income and measures of income inequality in 1980 and 1990, using the 17 Spanish regions as units of analysis. Average income was measured as average total income per household. The indicators of income inequality used were three measures of relative poverty-the percentage of households with total income less than 25%, 40% and 50% of the average total household income-the Gini index and the Atkinson indices with parameters alpha=1, 1.5 and 2. Pearson and partial correlation coefficients were used to evaluate the association between average income and measures of income inequality and life expectancy. None of the correlation coefficients for the association between life expectancy and average household income was significant for men. The association between life expectancy and average household income in women, adjusted for any of the measures of income inequality, was significant in 1980, although this association decreased or disappeared in 1990 after adjusting for measures of poverty. In both men and women, the partial correlation coefficients between life expectancy and the measures of relative income adjusted for average income were positive in 1980 and negative in 1990, although none of them was significant. The results with regard to women confirm the hypothesis that life expectancy in the developed countries has become more dissociated from average income level and more associated with income inequality. The absence of a relation in men in 1990 may be due to the large impact of premature mortality from AIDS in regions with the highest average total income per household and/or smallest income inequality.

Income inequality, residential poverty clustering and infant mortality: a study in Rio de Janeiro, Brazil

In this paper, we propose an approach to investigate the hypothesis that the residential concentration of poverty affects health status more deeply than when poverty is randomly scattered in a given geographical area. To characterize the geographic pattern of poverty in the city of Rio de Janeiro, Brazil, an index that measures the heterogeneity of poverty concentration among sub-areas was proposed. We used census data and defined poverty by means of the household head monthly income. The 153 neighborhoods that compose the city were used as the geographic units, and the census tracts as the sub-areas. The proposed index measures differences of poverty concentration across census tracts within a neighborhood. The effects of geographic poverty clustering on infant mortality related variables (early neonatal mortality rate; post-neonatal mortality rate; proportion of adolescent mothers; and fertility rate among adolescents) were estimated by partial correlation coefficients, controlling for the neighborhood poverty rate. Our study revealed that intra-city variations of the post-neonatal mortality rate are associated with geographic patterns of poverty, and that pregnancy in adolescence is strongly and contextually correlated with intra-neighborhood poverty clustering, even after adjustment for the poverty rate. The evidence of relevant health differences associated with the spatial concentration of poverty supports the hypothesis that properties of the environment of residence contextually influence health. Our findings suggest that prevention of some infant mortality related problems has to be focused directly on features of communities, considering their physical, cultural and psychosocial characteristics, being of particular concern the health of communities segregated from the society at large by extreme poverty.

The macroeconomic determinants of health

Why are some societies healthier than others? The consensus in development economics is that the health achievement of nations has to do with their levels of economic development. Higher per capita incomes, through steady and stable economic growth, increase a nation's capacity to purchase the necessary economic goods and services that promote health. In this paper, we review the conceptual and empirical linkages between poverty and poor health in both developing and developed countries. The empirical evidence is overwhelming that poverty, measured at the level of societies as well as individuals, is causally related to poor health of societies and individuals, respectively. Recent macroeconomic research has also drawn attention to the role of health as a form of human capital that is vital for achieving economic stability. In particular, attention has been drawn toward the ways in which unhealthy societies impede the process of economic development. However, the reciprocal connection between economic prosperity and improved health is neither automatic nor universal. Other features of society, such as the equality in the distribution of the national wealth, seem to matter as well for improving average population health and especially for reducing inequalities in health. We conclude by arguing for a need to reexamine the way in which health is conceptualized within the macroeconomic development framework.

Income inequality and self rated health in Britain

STUDY OBJECTIVE

Several studies have reported an association between income inequality and increased mortality, but few have used net income data, controlled for individual income, or evaluated sensitivity to the choice of inequality measure. The study tested the hypotheses that people in regions of Britain with the greatest income inequality would report worse health than those in other regions, after adjusting for individual socioeconomic circumstances.

DESIGN

Cross sectional survey.

SETTING

England, Wales, and Scotland.

PARTICIPANTS

8366 people living in private households.

MAIN RESULTS

Regional income inequality, measured using the Gini index, was associated with worse self rated health, especially among those with the lowest incomes (adjusted OR 1.55, 95% CI 1.24 to 1.92) (p<0.001). This association was not robust to the choice of income inequality measure, being maximal for the Gini coefficient and weakest when using indices that are more sensitive to income differences among those at the top or bottom of the income distribution.

CONCLUSIONS

The study found limited evidence of an association between income inequality and worse self rated health in Britain, which was greatest among those with the lowest individual income levels. As regions with the highest income inequality were also the most urban, these findings may be attributable to characteristics of cities rather than income inequality. The variation in this association with the choice of income inequality measure also highlights the difficulty of studying income distributions using summary measures of income inequality.

Income, income inequality and health: what can we learn from aggregate data?

It has been suggested that, especially in countries with high per capita income, there is an independent effect of income distribution on the health of individuals. One source of evidence in support of this relative income hypothesis is the analysis of aggregate cross-section data on population health, per capita income and income inequality. We examine the empirical robustness of cross-section analyses by using a new data set to replicate and extend the methodology in a frequently cited paper. The estimated relationship between income inequality and population health is not significant in any of our estimated models. We also argue there are serious conceptual difficulties in using aggregate cross-sections as a means of testing hypotheses about the effect of income, and its distribution, on the health of individuals.

Individual income, income distribution, and self rated health in Japan: cross sectional analysis of nationally representative sample

OBJECTIVE

To assess the effects on self rated health of individual income and income distribution in Japan.

DESIGN

Cross sectional analysis. Data collected on household income, self rated health, and other sociodemographic characteristics at the individual level from comprehensive survey of the living conditions of people on health and welfare in a nationally representative sample from each prefecture.

SETTING

Prefectures in Japan.

PARTICIPANTS

80 899 people aged >15 years with full records in survey.

MAIN OUTCOME MEASURES

Dichotomous variable for self rated health of each respondent (0 if excellent, very good or good; 1 if fair or poor).

RESULTS

Inequality in income at the prefecture level measured by the Gini coefficient was comparable with that in other industrialised countries. Unadjusted odds ratios show a 14% increased risk (odds ratio 1.14, 95% confidence interval 1.02 to 1.27) in reporting poor or fair health for individuals living in prefectures with higher inequality in income. After adjustment, individual income was more strongly associated with self rated health than income inequality. Additional inclusion of regional effects showed that median income at the prefecture level was inversely related to self rated health.

CONCLUSIONS

Individual income, probably relative to the median prefecture income, has a stronger association with self rated health than income inequality at the prefecture level.

Economic growth, income equality, and population health among the Asian Tigers

The "Tiger" economies of Southeast Asia provide examples of developing nations where economic growth and increasing income equality are compatible and, when occurring together, are associated with superior health trends over time. The degree of income inequality in the Asian Tigers declined during the period of rapid economic growth. Traditionally, economists have viewed economic growth and relative parity in income distribution as incompatible, or trade-offs. This poses a public policy dilemma, since a reasonable propensity to increase a nation's overall economic well-being would mean forsaking measures that increase income parity. The Asian Tigers, however, have shown that this need not be viewed as a trade-off. Economic growth and a simultaneous increase in income equality are possible and, with respect to health outcomes, desirable. The authors propose a variety of mechanisms through which income inequality can enhance economic growth, and discuss policies in education, agricultural land reform, and housing that influence the simultaneous attainment of income equality and economic growth.

Health and rapid economic change in the late twentieth century

Rapidly expanding economies, such as the post-war Tiger Economies, are associated with increasing health and rapidly contracting economies, such as Central and Eastern Europe in the early 1990s, are associated with declining health. In Central and Eastern Europe health decline in association with economic contraction has been mediated by changes in income distribution and, also, by health-determining aspects of civil society. The nations of Central and Eastern Europe are an example of swift economic and political transformation occurring concurrently with economic decline; with increasing disparity in income distributions; and with high levels of distrust in civil institutions. Concurrent with these declines was a marked reduction in health status, described here in terms of life expectancy. Conversely, the nations of Southeast Asia experienced rapid economic growth and increasing life expectancies. Though data are scarce, the experience of the Tiger Economies appears to be one of economic growth; a virtuous cycle of increased investment in education and housing; and increasing parity in income distribution based upon a relatively equitable distribution of returns on education.