Income inequality and child mortality in wealthy nations

BACKGROUND: Relationships between income inequality and various health indicators have been the subject of much study and some controversy. We investigated associations between child mortality and income inequality amongst the wealthier OECD countries as well as changes in their relative child mortality rankings over time. METHODS: Data were drawn from the 2003-2006 'State of the World's Children' reports published by UNICEF; Gini coefficients on income inequality were also used. Pearson correlation coefficients were calculated to investigate associations. Longitudinal child mortality data was used to compare rankings. RESULTS: We discovered very strong associations between child mortality and income inequality. In contrast to earlier results, these associations persist when the USA is excluded from the analysis. The countries with the worst child mortality figures were previously singled out in a 1993 UNICEF study on child neglect in rich nations. We also report their worsening child mortality rankings, since 1960, relative to the other OECD countries. CONCLUSIONS: The results strengthen the existing evidence linking child mortality with income inequality in wealthy nations, and add to the evidence that sociopolitical factors are important in this regard.     

Wage inequality, the health system, and infant mortality in wealthy industrialized countries, 1970-1996

This pooled, cross-sectional, time-series study assesses the impact of health system variables on the relationship between wage inequality and infant mortality in 19 OECD countries over the period 1970-1996. Data are derived from the OECD, World Value Surveys, Luxembourg Income Study, and political economy databases. Analyses include Pearson correlation and fixed-effects multivariate regression. In year-specific and time-series analyses, the Theil measure of wage inequality (based on industrial sector wages) is positively and statistically significantly associated with infant mortality rates--even while controlling for GDP per capita. Health system variables--in particular the method of healthcare financing and the supply of physicians--significantly attenuated the effect of wage inequality on infant mortality. In fixed effects multivariate regression models controlling for GDP per capita and wage inequality, variables generally associated with better health include income per capita, the method of healthcare financing, and physicians per 1000 population. Alcohol consumption, the proportion of the population in unions, and government expenditures on health were associated with poorer health outcomes. Ambiguous effects were seen for the consumer price index, unemployment rates, the openness of the economy, and voting rates. This study provides international evidence for the impact of wage inequalities on infant mortality. Results suggest that improving aspects of the healthcare system may be one way to partially compensate for the negative effects of social inequalities on population health.     

Social capital, income inequality, and mortality.

OBJECTIVES: Recent studies have demonstrated that income inequality is related to mortality rates. It was hypothesized, in this study, that income inequality is related to reduction in social cohesion and that disinvestment in social capital is in turn associated with increased mortality. METHODS: In this cross-sectional ecologic study based on data from 39 states, social capital was measured by weighted responses to two items from the General Social Survey: per capita density of membership in voluntary groups in each state and level of social trust, as gauged by the proportion of residents in each state who believed that people could be trusted. Age-standardized total and cause-specific mortality rates in 1990 were obtained for each state. RESULTS: Income inequality was strongly correlated with both per capita group membership (r = -.46) and lack of social trust (r = .76). In turn, both social trust and group membership were associated with total mortality, as well as rates of death from coronary heart disease, malignant neoplasms, and infant mortality. CONCLUSIONS: These data support the notion that income inequality leads to increased mortality via disinvestment in social capital.     

Income, inequality and mortality in 14 developed countries

The tendency for more egalitarian societies to have lower mortality rates has been identified in international data and subsequently confirmed in analyses of areas within countries, particularly within the USA. However, recent reports using data on OECD countries from the Luxembourg Income Study (LIS) suggest this relation no longer exists. We investigated whether the shift in relative poverty from elderly people (with high death rates) to young families (low death rates) may have affected the associations. Using age- and sex-specific mortality among 14 OECD countries in relation to income inequality, median income and absolute and relative poverty, we found that wider income distribution is related to higher premature mortality, and higher age-specific mortality rates below, but not above, age 65 years. Absolute income levels showed no consistent relation to mortality. The changing age distribution of relative poverty may have affected the way income inequality impacts on mortality measured across all ages.     

Cultural capital and social inequality in health

Economic and social resources are known to contribute to the unequal distribution of health outcomes. Culture-related factors such as normative beliefs, knowledge and behaviours have also been shown to be associated with health status. The role and function of cultural resources in the unequal distribution of health is addressed. Drawing on the work of French Sociologist Pierre Bourdieu, the concept of cultural capital for its contribution to the current understanding of social inequalities in health is explored. It is suggested that class related cultural resources interact with economic and social capital in the social structuring of people's health chances and choices. It is concluded that cultural capital is a key element in the behavioural transformation of social inequality into health inequality. New directions for empirical research on the interplay between economic, social and cultural capital are outlined.     

Social capital, income inequality, and self-rated health in 45 countries

There has been growing interest in the relationship between the social environment and health. Among the concepts that have emerged over the past decade to examine this relationship are socio-economic inequality and social capital. Using data from the World Values Survey and the World Bank, we tested the hypothesis that self-rated health is affected by social capital and income inequality cross-nationally. The merit of our approach was that we used multilevel methods in a larger and more diverse sample of countries than used previously. Our results indicated that, for a large number of diverse countries, commonly used measures of social capital and income inequality had strong compositional effects on self-rated health, but inconsistent contextual effects, depending on the countries included. Cross-level interactions suggested that contextual measures can moderate the effect of compositional measures on self-rated health. Sensitivity tests indicated that effects varied in different subsets of countries. Future research should examine country-specific characteristics, such as differences in cultural values or norms, which may influence the relationships between social capital, income inequality, and health.     

The associations between US state and local social spending,income inequality,and individual all-cause and cause-specific mortality: The National Longitudinal Mortality Study

ObjectiveTo investigate government state and local spending on public goods and income inequality as predictors of the risks of dying.MethodsData on 431,637 adults aged 30–74 and 375,354 adults aged 20–44 in the 48 contiguous US states were used from the National Longitudinal Mortality Study to estimate the impacts of state and local spending and income inequality on individual risks of all-cause and cause-specific mortality for leading causes of death in younger and middle-aged adults and older adults. To reduce bias, models incorporated state fixed effects and instrumental variables.ResultsEach additional $250 per capita per year spent on welfare predicted a 3-percentage point (− 0.031, 95% CI: − 0.059, − 0.0027) lower probability of dying from any cause. Each additional $250 per capita spent on welfare and education predicted 1.6-percentage point (− 0.016, 95% CI: − 0.031, − 0.0011) and 0.8-percentage point (− 0.008, 95% CI: − 0.0156, − 0.00024) lower probabilities of dying from coronary heart disease (CHD), respectively. No associations were found for colon cancer or chronic obstructive pulmonary disease; for diabetes, external injury, and suicide, estimates were inverse but modest in magnitude. A 0.1 higher Gini coefficient (higher income inequality) predicted 1-percentage point (0.010, 95% CI: 0.0026, 0.0180) and 0.2-percentage point (0.002, 95% CI: 0.001, 0.002) higher probabilities of dying from CHD and suicide, respectively.ConclusionsEmpirical linkages were identified between state-level spending on welfare and education and lower individual risks of dying, particularly from CHD and all causes combined. State-level income inequality predicted higher risks of dying from CHD and suicide.     

Race, socioeconomic status, and cause-specific mortality

PURPOSE: Life expectancy for black Americans is five to eight years less than for Whites. The socioeconomic status (SES) of Blacks is also less than for Whites, and SES is associated with early mortality. This paper estimates the proportion of the racial difference in mortality attributable to SES by specific causes of death. METHODS: Data on 453,384 individuals in the National Longitudinal Mortality Study were used to estimate the hazard ratio associated with black race, with and without adjustment for income and education (measures of SES), in 38 strata defined by cause of death and age. RESULTS: For women, SES accounted for much (37-67%) of the black excess mortality for accidents, ischemic heart disease (ages 35-54), diabetes, and homicide; but not for hypertension, infections, and stomach cancers (11-17%). For men, SES accounted for much of the excess risk (30-55%) for accidents, lung cancer, stomach cancer, stroke, and homicide; but not for prostate cancer, pulmonary diseases, hypertension, and cardiomyopathy (0-17%). CONCLUSIONS: These results confirm those specific causes of death likely to underlie the overall excess mortality of Blacks, and identify those causes where SES may play a large role.     

Income inequality, social capital and self-rated health and dental status in older Japanese

The erosion of social capital in more unequal societies is one mechanism for the association between income inequality and health. However, there are relatively few multi-level studies on the relation between income inequality, social capital and health outcomes. Existing studies have not used different types of health outcomes, such as dental status, a life-course measure of dental disease reflecting physical function in older adults, and self-rated health, which reflects current health status. The objective of this study was to assess whether individual and community social capital attenuated the associations between income inequality and two disparate health outcomes, self-rated health and dental status in Japan. Self-administered questionnaires were mailed to subjects in an ongoing Japanese prospective cohort study, the Aichi Gerontological Evaluation Study Project in 2003. Responses in Aichi, Japan, obtained from 5715 subjects and 3451 were included in the final analysis. The Gini coefficient was used as a measure of income inequality. Trust and volunteering were used as cognitive and structural individual-level social capital measures. Rates of subjects reporting mistrust and non-volunteering in each local district were used as cognitive and structural community-level social capital variables respectively. The covariates were sex, age, marital status, education, individual- and community-level equivalent income and smoking status. Dichotomized responses of self-rated health and number of remaining teeth were used as outcomes in multi-level logistic regression models. Income inequality was significantly associated with poor dental status and marginally significantly associated with poor self-rated health. Community-level structural social capital attenuated the covariate-adjusted odds ratio of income inequality for self-rated health by 16% whereas the association between income inequality and dental status was not substantially changed by any social capital variables. Social capital partially accounted for the association between income inequality and self-rated health but did not affect the strong association of income inequality and dental status.     

Social inequality in fetal and perinatal mortality in the Nordic countries

AIM: The aim of this study is to review the epidemiological literature from the past 27 years on social inequality in fetal and perinatal mortality in the Nordic countries in order to examine whether social inequalities in fetal and perinatal mortality exist, and whether there are differences between the countries. METHODS: The databases MEDLINE and EMBASE were searched for Nordic epidemiological studies published between January 1980 and August 2007 about the association between social indicators and the outcomes spontaneous abortion, stillbirth or perinatal mortality. Thirty-five studies that fulfilled the inclusion criteria were identified for this review. RESULTS: Social differences in stillbirth and perinatal mortality were found in all of the identified Finnish and Norwegian studies and in the majority of studies from Denmark, whereas in the Swedish studies the findings were less consistent. As only a small number of studies on spontaneous abortion were identified (n=3), no conclusions were drawn with regard to this outcome. CONCLUSIONS: There seems to be a reasonable body of evidence that social inequality in stillbirth and perinatal mortality exists in Norway, Finland and Denmark, whereas the conclusions regarding Sweden are more uncertain. A number of methodological problems complicate the comparison of the findings. Nordic collaborative analyses of social gradients in spontaneous abortion, stillbirth and perinatal mortality, which take these methodological concerns into account, are needed in order to draw inferences across countries.     

Healthy and unhealthy migrant effect on the mortality of immigrants from wealthy countries residing in Spain

This study attempts to identify the possible existence of a healthy migrant effect and an unhealthy migrant effect on the mortality of immigrants from wealthy countries who move to Spain. Immigrants aged 35–64 years from France, Germany, Great Britain and 16 other wealthy OECD countries who resided in Spain were compared with respect to: (1) mortality from cancer, cardiovascular disease, and all other diseases and (2) employment status, duration of residence, and educational level, in two geographic areas: the “preferred destination area”—the Mediterranean coast, Balearic Islands and Canary Islands—and the rest of Spain. In general, cancer mortality was lower and mortality from cardiovascular disease was higher in immigrants who resided in the preferred destination area than in their countries of origin and than in immigrants who resided in the rest of Spain. Immigrants in the preferred destination area had a higher percentage of retired persons, longer time of residence and a lower percentage of persons with university education. The largest differences between the two areas in cardiovascular and all-disease mortality and in the frequency of the aforementioned sociodemographic characteristics were observed in British immigrants and those from the 16 OECD countries. Possible explanations for these findings are suggested which are compatible with the presence of an unhealthy and/or healthy immigrant bias in the two areas.     

Social inequality and health: the role of social capital

The aim of the article is to examine whether and to what degree the unequal distribution of social capital in the population explains the relationship between socioeconomic position and health in Norway. Theoretical insight and empirical evidence seem to suggest that social capital mediates the effect of socioeconomic position on health outcomes. However, only a few studies have addressed this question and those that have done so have used few and simple indicators of social capital. This study is based on a nationwide cross-sectional survey (N = 3190) commissioned by Statistics Norway. The survey was designed to cover a comprehensive set of variables measuring different aspects of the theoretical construct of social capital. Two health outcomes, self-perceived health and longstanding illness, were analysed. The results showed that the mediating role of social capital between socioeconomic position and health was negligible for both health outcomes. After controlling for socio-demographic variables and socioeconomic position, only neighbourhood satisfaction and generalised trust showed a significant association with self-perceived health, whereas none of the social capital variables had any significant association with longstanding illness. Some theoretical and methodological implications of the results are discussed.     

Neighborhood racial composition,social capital and black all-cause mortality in Philadelphia

Neighborhood characteristics such as racial composition and social capital have been widely linked to health outcomes, but the direction of the relationship between these characteristics and health of minority populations is controversial. Given this uncertainty, we examined the relationship between neighborhood racial composition, social capital, and black all-cause mortality between 1997 and 2000 in 68 Philadelphia neighborhoods. Data from the U.S. Census, the Philadelphia Health Management Corporation's 2004 Southeast Pennsylvania Community Health Survey, and city vital statistics were linked by census tract and then aggregated into neighborhoods, which served as the unit of analysis. Neighborhood social capital was measured by a summative score of respondent assessments of: the livability of their community, the likelihood of neighbors helping one another, their sense of belonging, and the trustworthiness of their neighbors. After adjustment for the sociodemographic characteristics of neighborhood residents, black age-adjusted all-cause mortality was significantly higher in neighborhoods that had lower proportion of black residents. Neighborhood social capital was also associated with lower black mortality, with the strongest relationship seen for neighborhoods in the top half of social capital scores. There was a significant interaction between racial composition and social capital, so that the effect of social capital on mortality was greatest in neighborhoods with a higher proportion of black residents and the effect of racial composition was greatest in neighborhoods with high social capital. These results demonstrate that age-adjusted all-cause black mortality is lowest in mostly black neighborhoods with high levels of social capital in Philadelphia.     

Differences in cause-specific infant mortality among Chinese, Japanese, and white Americans.

Although black-white differences in infant mortality have received much attention, information is limited about mortality differentials among Asian Americans. This study investigated racial differences in infant mortality in a sample of 21,288 Chinese, 11,882 Japanese, and 65,818 white resident singleton livebirths obtained from the National Center for Health Statistics 1983 and 1984 linked birth/infant death files. The crude infant mortality rates were 8.03, 6.56, and 8.46 per 1,000 livebirths for Chinese, Japanese, and white births, respectively. Cause-specific mortality varied considerably among the three racial groups. While the Japanese had lower rates of infant deaths and deaths from perinatal conditions for firstborn infants, they had higher rates of sudden infant death syndrome, as did Chinese females. The results of a logistic regression analysis indicate that the racial differences in total and cause-specific mortality persist when adjustment is made for demographic factors, use of prenatal care, infant sex, and birth weight. The effect of these latter variables on infant mortality varied by causes of death. The relations between infant mortality and variables such as marital status, maternal education, and birth interval appear indirect, operating partially through birth weight. While birth weight was the single strongest determinant of infant mortality, its relative importance varied by cause of death. The study findings suggest that policy decisions surrounding racial differences in infant mortality should not only be considered in light of specific races, but also with regard to cause-specific mortality. Moreover, additional research is needed to understand the cultural, biological, and behavioral factors that give rise to the racial differences.     

Air pollution and cause-specific mortality in Milan, Italy, 1980-1989.

In several studies, investigators have reported associations among air pollution, weather, and daily deaths, usually from all causes. In the current study, we focused on the difference in lag time between exposure to total suspended particulates or extreme weather and cause-specific mortality in an effort to understand the potential underlying mechanism. We used a robust Poisson regression in a generalized additive model to investigate the association between air pollution and daily mortality. We used a loess smooth function to model season, weather, and humidity; indicator variables for hot days were also used. To examine the relationship in a currently meaningful range, we excluded all days with a total suspended particulate concentration higher than 200 microg/m3. We found a significant association on the concurrent day, both for respiratory infection deaths (11% increase/100 microg/m3 increase in total suspended particulate; 95% confidence interval = 5, 17) and for heart-failure deaths (7% increase; 95% confidence interval = 3, 11). The associations with myocardial infarction (i.e., 10% increase; 95% confidence interval = 3, 18) and chronic obstructive pulmonary disease (12% increase, 95% confidence interval = 6, 17) were found for the means of 3 and 4 d prior to death. We observed an effect of cold weather at lag 1 for respiratory infections and an effect of hot weather at lag 0 for heart failure and myocardial infarctions. The association for all causes and cause-specific deaths was almost identical to that noted previously in Philadelphia, Pennsylvania. Smoothed functions of total suspended particulates suggested a higher slope at lower concentrations, and this finding may account for differences noted between European and U.S. studies. Given that both the dependence between weather and daily mortality and the lag between exposure and death varies by cause of death, analyses by specific causes of death would be very useful in the future.     

Maternal social capital and child nutritional status in four developing countries

Social capital has been shown to be positively associated with a range of health outcomes, yet no studies have explored the association between maternal social capital and child nutritional status. Using data from the Young Lives study comprising 7242 1-year-old children from Peru, Ethiopia, Vietnam and the state of Andhra Pradesh in India, we find significant differences in the levels of, in particular, structural social capital (group membership and citizenship) between countries. While few associations were found between structural measures of social capital, support from individuals and cognitive social capital (e.g. trust, social harmony) displayed fairly consistent positive associations with child nutritional status across countries.     

Measuring social inequalities in cause-specific mortality in France: Comparison between linked and unlinked approaches

BackgroundMonitoring the time trends in socioeconomic inequalities in mortality by cause is a key public health issue. The aim of this study was to compare methods to measure social inequalities in cause-specific mortality in the French population aged 25–55 years. More specifically, it compares bias and precision related to the use of occupational class declared at the last census (linked data) to the one declared at the time of death on the death certificate (unlinked data).MethodsWe used a representative sample of 1% of the French population. Causes of death were obtained by direct linkage with the French national death registry. Occupational class was classified into eight categories. Taking professionals and managers as the reference, relative risks of mortality by cause and their 95% confidence intervals were estimated using Poisson models for the 1983–1989, 1991–1997, and 2000–2006 periods. The relative risks were calculated with both linked data and exhaustive unlinked data.ResultsOver the 2000–2006 period, occupational classes declared at census and on the death certificate were consistent for half of the deaths. Relative risks for manual workers were found to be similar between the two approaches over the 1983–1989 and 1991–1997 periods, and higher for the unlinked approach over the 2000–2006 period. Over the latter period, the order and magnitude of relative risks varied similarly by occupational class and cause of death for both approaches. Confidence intervals obtained from linked data were wide.ConclusionOccupational class derived from the death certificate must be used with caution as a measure for epidemiological purposes and the available linked data do not allow accurate estimates of social inequalities in cause-specific mortality. Other solutions should be considered in order to improve the follow-up of social inequalities in mortality. This would require the collection of educational level on the death certificate or the linkage of the cause of death database with other exhaustive and informative databases.