Some mechanisms linking economic inequality and infant mortality

Ethnic inequality and public health

We examine the association between ethnic inequality and various key health outcomes for a global set of developed and developing countries. Our results show that higher ethnic inequality is associated with a poor state of public health, such as higher child and maternal mortality, increased stillbirths and child stunting, and reduced life expectancy at birth. This set of effects is found to be predominant mainly in developing countries, and Sub-Saharan African countries. Results remain robust to the inclusion of various other measures of inequality, ethnic composition indices, geographic endowments, and other relevant controls. We argue that lower contraceptive usage and poor vaccination rates are potential mechanisms through which ethnic inequality affects health outcomes. Policies targeted at improving public health may need to focus more on these key intermediate channels in ethnic minority regions.

Public Health Services, Health Human Capital, and Relative Poverty of Rural Families

With the successful completion of the battle against poverty, after 2020, the focus and difficulty of China's poverty governance will change from solving absolute poverty to alleviating relative poverty. Analyzing and studying the alleviation of relative poverty from the perspective of public health services is in line with the current needs of consolidating and expanding poverty alleviation in China, and it is also of great significance to building a long-term solution mechanism for relative poverty. In this study, basic panel data were constructed by using the data of five CFPS surveys in 2010, 2012, 2014, 2016, and 2018 and matched with the macro data. The correlation between public health services and rural households' relative poverty was also analyzed by using logit regression analysis and the KHB mediation effect decomposition method. The results show that (1) public health services play a significant role in promoting the accumulation of health human capital, improving individual feasible ability, and alleviating the relative poverty of rural families; (2) the improvement of public health services is conducive to the alleviation of the relative poverty of rural families; (3) we should continue to increase investment in public health care in underdeveloped areas and strive to promote the balanced development of public health services, so as to further consolidate and expand the achievements of poverty eradication.

Health Outcomes, Income and Income Inequality: Revisiting the Empirical Relationship

In this paper we revisit the relationship between health outcomes, income, and income inequality by applying alternative panel methodologies to a dataset of high-income countries spanning the time period 1980-2017. In this direction, we adopt alternative methodological frameworks in order to provide a) meaningful results by taking into account standard errors that alleviate problems of cross-sectional (spatial) and temporal dependence, and b) insights into the underlying relationships at several points of the conditional distribution of the health outcomes dependent variables. The evidence strongly supports the significant role that income plays in determining health outcomes. The findings relating to income inequality and nonlinear terms are more fragmented in that their significance and sign-direction depend on the functional form and the respective quantiles of the distribution the relationships are evaluated.

How Does Deprivation Affect Early-Age Mortality? Patterns of Socioeconomic Determinants of Neonatal and Postneonatal Mortality in Bolivia

Three mechanisms related to household living standards might affect early-age mortality: the absolute level of deprivation, its level relative to the average of the community, and the inequality in the distribution of deprivation within communities. A large body of literature has explored the effect of the absolute level of deprivation, but little research has examined the association between relative deprivation and early-age mortality, and findings related to deprivation inequality are inconsistent. Using 2008 Bolivian Demographic and Health Survey data, this study explores patterns of association between the three factors and mortality occurring in the neonatal and postneonatal periods. Because household-level deprivation might capture some unmeasured characteristics at the community level, such as area-specific investments, this study decomposes household-level deprivation into its between- and within-community components. The results show that after possible confounders are controlled for, community-level absolute deprivation is a significant predictor of neonatal and postneonatal mortality. Relative deprivation and deprivation inequality are not associated with early-age mortality. These findings are specific to a context of widespread deprivation and low inequality within communities; the role of the distribution of deprivation might be more important in countries in which basic needs are met within a bigger proportion of the population. This study helps identify crucial sectors of development related to living standards and deprivation inequality in order to tackle neonatal and postneonatal mortality.

Health expenditure, human capital, and economic growth: an empirical study of developing countries

Social security systems were successively established in most developing countries in the 1980s and 1990s. To ensure the long-term sustainability of these newly established systems it is essential to carefully monitor the economic impact. Based on the panel data of 21 developing countries from 2000 to 2016, this paper is the first to apply the panel threshold model to empirically analyze the relationship between national health expenditures and economic growth under different levels of human capital. The results show that health expenditure and economic growth have significant interval effects because of the different levels of human capital. Specifically, when human capital levels are low, health expenditure is significantly negatively correlated with economic growth. When human capital is at a medium level, health expenditure has a positive but not significant impact on economic growth. When the level of human capital is high, the positive economic impact of the health expenditure is significantly enhanced. In addition, subgroup analyses indicate that population aging and low fertility aggravate the negative impact of health expenditures on economic growth. This study provides reliable analysis and can be used by developing countries to maintain a long-term sustainable social security system.

State- and county-level income inequality and infant mortality in the USA in 2010: a cohort study

OBJECTIVES

We examined the relationship between income inequality and the risk for infant/neonatal mortality at the state and county level and tested possible mediators of this relationship.

METHODS

We first linked state and county Gini coefficients to US Vital Statistics 2010 Cohort Linked Birth and Infant Death records (n = 3,954,325). We then fit multilevel models to test whether income inequality was associated with infant/neonatal mortality. County-level factors were tested as potential mediators.

RESULTS

Adjusted analyses indicated that income inequality at the county level-but not at the state level-was associated with increased odds of infant mortality (OR 1.14, 95% CI 1.10, 1.18) and neonatal death (OR 1.17, 95% CI 1.12, 1.23). Our mediators explained most of this variation. Bivariate analyses revealed associations between 3 county-level measures-patient-to-physician ratio, the violent crime rate, and sexually transmitted infection rate-and infant and neonatal mortality. Proportion of college-educated adults was associated with decreased odds for neonatal mortality.

CONCLUSIONS

Local variations in access to care, the rate of sexually transmitted disease, and crime are associated with infant mortality, while variations in college education in addition to these mediators explain neonatal mortality. To reduce infant and neonatal mortality, experiments are needed to examine the effectiveness of policies targeted at reducing income inequality and improving healthcare access, policing, and educational opportunities.

Structural Racism and Odds for Infant Mortality Among Infants Born in the United States 2010

OBJECTIVES

While ecological studies indicate that high levels of structural racism within US states are associated with elevated infant mortality rates, studies using individual-level data are needed. To determine whether indicators of structural racism are associated with the individual odds for infant mortality among white and black infants in the US.

METHODS

We used data on 2,163,096 white and 590,081 black infants from the 2010 US Cohort Linked Birth/Infant Death Data Files. Structural racism indicators were ratios of relative proportions of blacks to whites for these domains: electoral (registered to vote and voted; state legislature representation), employment (civilian labor force; employed; in management; with a bachelor's degree), and justice system (sentenced to death; incarcerated). Multilevel logistic regression was used to determine whether structural racism indicators were risk factors of infant mortality.

RESULTS

Compared to the lowest tertile ratio of relative proportions of blacks to whites with a bachelor's degree or higher-indicative of low structural racism-black infants, but not whites, in states with moderate (OR = 1.12, 95% CI = 0.94, 1.32) and high tertiles (OR = 1.25, 95% CI = 1.03, 1.51) had higher odds of infant mortality.

CONCLUSIONS

Educational and judicial indicators of structural racism were associated with infant mortality among blacks. Decreasing structural racism could prevent black infant deaths.

Income inequality and social gradients in children's height: a comparison of cohort studies from five high-income countries

BACKGROUND

Health and well-being are better, on average, in countries that are more equal, but less is known about how this benefit is distributed across society. Height is a widely used, objective indicator of child health and predictor of lifelong well-being. We compared the level and slope of social gradients in children's height in high-income countries with different levels of income inequality, in order to investigate whether children growing up in all socioeconomic circumstances are healthier in more equal countries.

METHODS

We conducted a coordinated analysis of data from five cohort studies from countries selected to represent different levels of income inequality (the USA, UK, Australia, the Netherlands and Sweden). We used standardised methods to compare social gradients in children's height at age 4-6 years, by parent education status and household income. We used linear regression models and predicted height for children with the same age, sex and socioeconomic circumstances in each cohort.

RESULTS

The total analytic sample was 37 063 children aged 4-6 years. Gradients by parent education and household income varied between cohorts and outcomes. After adjusting for differences in age and sex, children in more equal countries (Sweden, the Netherlands) were taller at all levels of parent education and household income than children in less equal countries (USA, UK and Australia), with the greatest between-country differences among children with less educated parents and lowest household incomes.

CONCLUSIONS

The study provides preliminary evidence that children across society do better in more equal countries, with greatest benefit among children from the most disadvantaged socioeconomic groups.

State-level income inequality and mortality among infants born in the United States 2007-2010: A Cohort Study

BACKGROUND

United States state-level income inequality is positively associated with infant mortality in ecological studies. We exploit spatiotemporal variations in a large dataset containing individual-level data to conduct a cohort study and to investigate whether current income inequality and increases in income inequality are associated with infant and neonatal mortality risk over the period of the 2007-2010 Great Recession in the United States.

METHODS

We used data on 16,145,716 infants and their mothers from the 2007-2010 United States Statistics Linked Infant Birth and Death Records. Multilevel logistic regression was used to determine whether 1) US state-level income inequality, as measured by Z-transformed Gini coefficients in the year of birth and 2) change in Gini coefficient between 1990 and year of birth (2007-2010), predicted infant or neonatal mortality. Our analyses adjusted for both individual and state-level covariates.

RESULTS

From 2007 to 2010 there were 98,002 infant deaths: an infant mortality rate of 6.07 infant deaths per 1000 live births. When controlling for state and individual level characteristics, there was no significant relationship between Gini Z-score and infant mortality risk. However, the observed increase in the Gini Z-score was associated with a small but significant increase likelihood of infant mortality (AOR = 1.03 to 1.06 from 2007 to 2010). Similar findings were observed when the neonatal mortality was the outcome (AOR = 1.05 to 1.13 from 2007 to 2010).

CONCLUSIONS

Infants born in states with greater changes in income inequality between 1990 and 2007 to 2010 experienced a greater likelihood of infant and neonatal mortality.

Differential relationship between state-level minimum wage and infant mortality risk among US infants born to white and black mothers

BACKGROUND

Compared to other Organisation for Economic Co-operation and Development (OECD) nations, US infant mortality rates (IMRs) are particularly high. These differences are partially driven by racial disparities, with non-Hispanic black having IMRs that are twice those of non-Hispanic white. Income inequality (the gap between rich and poor) is associated with infant mortality. One proposed way to decrease income inequality (and possibly to improve birth outcomes) is to increase the minimum wage. We aimed to elucidate the relationship between state-level minimum wage and infant mortality risk using individual-level and state-level data. We also determined whether observed associations were heterogeneous across racial groups.

METHODS

Data were from US Vital Statistics 2010 Cohort Linked Birth and Infant Death records and the 2010 US Bureau of Labor Statistics. We fit multilevel logistic models to test whether state minimum wage was associated with infant mortality. Minimum wage was standardised using the z-transformation and was dichotomised (high vs low) at the 75th percentile. Analyses were stratified by mother's race (non-Hispanic black vs non-Hispanic white).

RESULTS

High minimum wage (adjusted OR (AOR)=0.93, 95% CI 0.83 to 1.03) was associated with decreased odds of infant mortality but was not statistically significant. High minimum wage was significantly associated with reduced infant mortality among non-Hispanic black infants (AOR=0.80, 95% CI 0.68 to 0.94) but not among non-Hispanic white infants (AOR=1.04, 95% CI 0.92 to 1.17).

CONCLUSIONS

Increasing the minimum wage might be beneficial to infant health, especially among non-Hispanic black infants, and thus might decrease the racial disparity in infant mortality.

Does Quality of Government Matter in Public Health?: Comparing the Role of Quality and Quantity of Government at the National Level

This study aims to examine the degree of direct or indirect impact of quality and quantity of government on public health. It is a very important topic in that previous studies did not consider the role of government; they focused on the impact of national economic, social, and political factors on public health, therefore, disregarding the governmental factors. We measured the quantity of government by public expenditure on heath (i.e., rate of share of government budget to gross domestic product (GDP)) and the quality of government by five variables such as corruption control, government effectiveness, regulatory quality, voice and accountability, and rule of law. Based on national-level panel data (three waves) that covered 148–194 countries, we examined how quality and quantity of government has an impact on four kinds of public health, i.e., infant mortality, under-five mortality, maternal mortality, and life expectancy. Results show that both the quality and quantity of government had a significant impact on public health. In the quality of government, government effectiveness has a positive impact on life expectancy and a negative influence on infant deaths. Moreover, the quality of government has a greater impact on public health than the quantity of government. Lastly, the quality of government plays a role in moderating the relationships between quantity of government and the predicted variables.

Political Economy of Infant Mortality Rate: Role of Democracy Versus Good Governance

Despite numerous studies on whether democracy reduces the infant mortality rate (IMR), the empirical results remain mixed at best. In this article, I perform several theoretical and empirical exercises that help explain why and under what conditions we should expect politics to matter most for a decrease in IMR. First, I capitalize on the epidemiological view that IMR – the most commonly used indicator of health in social sciences – is better suited to reflect public health micromanagement than overall social development. Second, I theorize that autocrats have incentives to invest in health up to a certain point, which could lead to a reduction in IMR. Third, I introduce an omitted variable – good governance – that trumps the importance of a political regime for IMR: (1) it directly affects public health micromanagement, and (2) many autocrats made inroads in achieving good governance. Finally, for the first time in such research, I use a disaggregated IMR approach to corroborate my hypotheses.

Preterm Birth in the Context of Increasing Income Inequality

OBJECTIVE

Preterm birth is a leading cause of infant morbidity and mortality. Little is known about the contextual effect of U.S. income inequality on preterm birth, an issue of increasing concern given that the current economic divide is the largest since 1928.

METHODS

We examined changes in inequality over time in relation to preterm birth among singleton deliveries from an electronic medical record-based cohort (n = 223,512) conducted in 11 U.S. states and the District of Columbia from 2002 to 2008. Increasing income inequality was defined as a positive change in state-level Gini coefficient from the year prior to birth. Multi-level models estimated the independent effect of increasing inequality on preterm birth (>22 and <37 weeks) controlling for maternal demographics, health behaviors, insurance status, chronic medical conditions, and state-level poverty and unemployment during the year of birth.

RESULTS

The preterm birth rate was 12.3% where inequality increased and 10.9% where it did not. After adjustment, increasing inequality remained significantly associated with preterm birth (adjusted odds ratio 1.07, 95% confidence interval 1.04, 1.11). We observed no significant interaction by insurance status or race, suggesting that increasing inequality had a broad effect across the population.

CONCLUSIONS

The contextual effect of increasing income inequality on preterm birth risk merits further study.

Do racial inequities in infant mortality correspond to variations in societal conditions? A study of state-level income inequality in the U.S., 1992-2007

BACKGROUND

Prior studies have examined the association between income inequality and overall infant mortality rates (IMR). We examine effects of income inequality on racial inequities in IMR over the period 1992-2007 in the U.S.

METHODS

Race-specific state IMR data were obtained from 1992 to 2007, from which absolute and relative IMR inequities were calculated. Fixed and random effects models, adjusted for state-level median income, percent poverty, percent high school graduates, and unemployment rate, were used to determine contemporaneous and lagged state-level associations between income inequality and racial IMR inequities.

RESULTS

Racial IMR inequities varied significantly across the U.S. Contemporaneous income inequality was negatively associated with white IMR only. Two-year lagged income inequality was negatively associated with black IMR and had the most pronounced effect on racial inequities in IMR.

DISCUSSION

Future studies should consider lagged effects of income inequality on IMR and other health outcomes, and should examine other potential societal conditions that may account for state-level variations in racial IMR inequities.

Louisiana implementation of the National Fetal and Infant Mortality Review (NFIMR) program model: successes and opportunities

Common features of successful, local-level, Fetal Infant Mortality Review (FIMR) Programs are identified by the National Fetal and Infant Mortality Review (NFIMR) Program, including medical records abstraction and home interviews, case reviews by a case review team (CRT), and community systems action recommendations implemented by a community action team (CAT). This paper presents Louisiana's FIMR program, an adaptation of NFIMR recommendations. In 2001, the Louisiana Maternal and Child Health Program began a statewide FIMR Network (LaFIMR) based on the NFIMR model. Geographic areas of focus, case identification, staffing, data collection methods, and CRT and CAT membership and activities include modifications of the NFIMR recommendations unique to LaFIMR implementation. Adaptations made to the NFIMR model were advantageous to LaFIMR's success. Specifically, LaFIMR geographic areas of interest cover multiple natural communities. Compared with independent FIMR programs elsewhere, LaFIMR represents a Title V Program-based coordinated network of regional LaFIMR teams offering opportunities for expanded partnerships. Primary sources for LaFIMR case identification include obituaries and hospital logs, with secondary identification available through vital records. Improvements in vital records data systems are expected to enhance future LaFIMR case identification. LaFIMR-identified records that are linked with vital event certificates provide enhanced contextual findings for reviews and support continuous quality improvement processes. These differences in the LaFIMR implementation reinforce the NFIMR-supported uniqueness of FIMR programs across the United States, and may encourage other FIMR programs to consider how adaptations to NFIMR recommendations could benefit their programs.

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.

What is driving the black-white difference in low birthweight in the US?

This is a first effort to quantify the contribution of different factors in explaining racial difference in low birthweight rate (LBW). Mother's health, child characteristics, prenatal care, socioeconomic status (SES), and the socioeconomic and healthcare environment of mother's community are important inputs into the birthweight production function, and a vast literature has delved into obtaining causal estimates of their effect on infant health. What is unknown is how much of the racial gap in LBW is explained by all these inputs together. We apply a nonlinear extension of the Oaxaca-Blinder method proposed by Fairlie to decompose this gap into the portion explained by differences in observed characteristics and the portion that remains unexplained. Data are obtained from several sources in order to capture as many observables as possible, although the primary data source is the Natality Detail Files. Results show that of the 6.8 percentage point racial gap in LBW, only 0.9-1.9 points are explained by white-black differences in endowments across those measures, and of those endowments, most of the gap in LBW is explained by the differences in SES. The unexplained difference is attributed to racial differences in the returns to or the marginal product of investments in infant health.

Regional socioeconomic indicators and ethnicity as predictors of regional infant mortality rate in Slovakia

OBJECTIVE

Exploring the associations of regional differences in infant mortality with selected socioeconomic indicators and ethnicity could offer important clues for designing public health policy measures.

METHODS

Data included perinatal and infant mortality in the 79 districts of the Slovak population in 2004. Linear regression was used to analyse the contribution of education, unemployment, income and proportion of Roma population on regional differences in perinatal and infant mortality rates.

RESULTS

All the explored socioeconomic indicators and ethnicity individually contributed significantly to both perinatal and infant mortality, with the exception of income. In the model exploring the influence of all these variables together on perinatal and infant mortality, only the effect of the proportion of Roma population remained significant. This model explained 34.9% of the variance for perinatal and 36.4% of the variance for infant mortality.

CONCLUSIONS

Living in Roma settlements indicates an accumulation of socioeconomic disadvantage. Health literacy, health-related behaviour and many other factors might contribute to the explanation of the differences in infant mortality, and a better understanding of these processes might help us to design tailored interventions.

Asociación de los tipos de carencia y grado de desarrollo humano con la mortalidad infantil en México, 2008

El objetivo del artículo fue conocer la asociación entre los diferentes tipos de carencia social y económica y los niveles de mortalidad infantil reportados durante el 2008 en México. Se realizó un estudio ecológico, analizando la correlación y el riesgo relativo entre el índice de desarrollo humano y distintos niveles de carencias sociales y económicas con las tasas de mortalidad infantil reportadas a nivel nacional y estatal. Existe una fuerte correlación entre un mayor nivel de desarrollo humano con una menor tasa de mortalidad. La carencia educativa y el atraso en la calidad y espacio de la vivienda se asocian con una mayor tasa de mortalidad infantil. Si bien la mortalidad infantil en México ha disminuido notablemente en los últimos 28 años, su reducción no ha sido homogénea y se mantienen inequidades que determinan las tasas de mortalidad en relación a los niveles diferenciados de pobreza. Es necesario el diseño de programas con una visión transdisciplinaria que permitan disminuir las tasas de mortalidad con el pleno desarrollo de los individuos y sus familias

Poverty, sprawl, and restaurant types influence body mass index of residents in California counties

OBJECTIVES

This article examines the relationships between structural poverty (the proportion of people in a county living at < or =130% of the federal poverty level [FPL]), urban sprawl, and three types of restaurants (grouped as fast food, chain full service, and independent full service) in explaining body mass index (BMI) of individuals.

METHODS

Relationships were tested with two-tiered hierarchical models. Individual-level data, including the outcome variable of calculated BMI, were from the 2005, 2006, and 2007 California Behavioral Risk Factor Surveillance Survey (n = 14,205). County-level data (n = 33) were compiled from three sources. The 2000 U.S. Census provided the proportion of county residents living at < or = 130% of FPL and county demographic descriptors. The sprawl index used came from the Smart Growth America Project. Fast-food, full-service chain, and full-service independently owned restaurants as proportions of the total retail food environment were constructed from a commercially available market research database from 2004.

RESULTS

In the analysis, county-level demographic characteristics lost significance and poverty had a consistent, robust association on BMI (p < 0.001). Sprawl demonstrated an additional, complementary association to county poverty (p < 0.001). Independent restaurants had a large, negative association to BMI (p < 0.001). The coefficients for chain and fast-food restaurants were large and positive (p < or = 0.001), indicating that as the proportion of these restaurants in a county increases, so does BMI.

CONCLUSIONS

This study demonstrates the important role of county poverty and urban sprawl toward understanding environmental influences on BMI. Using three categories of restaurants demonstrates different associations of full-service chain and independent restaurants, which are often combined in other research.

The relationship between levels of income inequality and dental caries and periodontal diseases

The objective of this study was to evaluate the association between income inequality at a lagged time of 2 and 11 years with two short latency outcomes (untreated dental caries and gingivitis) and two long latency outcomes (edentulism and periodontal attachment loss > 8mm). We used data from the Brazilian oral health survey in 2002-2003. Our analysis included 13,405 subjects aged 35-44 years. Different lagged Gini at municipal level were fitted using logistic and negative binomial multilevel analyses. Covariates included municipal per capita income, equivalized income, age, sex, time since last dental visit and place of residence (rural versus urban). Crude estimates showed that only untreated dental caries was associated with current and lagged Gini, but in adjusted models only current Gini remained significant with a ratio of 1.19 (95%CI: 1.09-1.30) for every ten-point increase in the Gini coefficient. We conclude that lagged Gini showed no association with oral health; and current income Gini was associated with current dental caries but not with periodontal disease.

Creating opportunities for training California's public health workforce

INTRODUCTION

Today there are significant challenges to public health, and effective responses to them will require complex approaches and strategies implemented by a qualified workforce. An adequately prepared workforce requires long-term development; however, local health departments have limited financial and staff resources. Schools and programs accredited by the Council for Education on Public Health (CEPH) are required to provide continuing education but are constrained by the lack of resources, limited time, and geography.

METHOD

To meet these challenges, a statewide university/community collaborative model for delivering continuing education programs was developed. A needs assessment of California's public health workforce was conducted to identify areas of interest, and two continuing education trainings were developed and implemented using innovative distance education technology.

RESULTS

Thirty-six percent of the participants completed electronic evaluations of learning outcomes and use of the digital technology platform. Participants indicated a significant increase in knowledge, reported that the trainings were cost effective and convenient, and said that they would participate in future online trainings. Collaborative partners found that this model provides a cost-effective, environmentally sound, and institutionally sustainable method for providing continuing education to public health professionals.

DISCUSSION

Offering continuing education via distance technology requires substantial institutional infrastructure and resources that are often beyond what many public institutions can provide alone. This project provides a model for collaborating with community partners to provide trainings, using a digital technology platform that requires minimal training and allows presenters and participants to log on from anywhere there is Internet access.

Income inequality and income segregation

This article investigates how the growth in income inequality from 1970 to 2000 affected patterns of income segregation along three dimensions: the spatial segregation of poverty and affluence, race-specific patterns of income segregation, and the geographic scale of income segregation. The evidence reveals a robust relationship between income inequality and income segregation, an effect that is larger for black families than for white families. In addition, income inequality affects income segregation primarily through its effect on the large-scale spatial segregation of affluence rather than by affecting the spatial segregation of poverty or by altering small-scale patterns of income segregation.

Impact of income and income inequality on infant health outcomes in the United States

OBJECTIVES

The goal was to investigate the relationships of income and income inequality with neonatal and infant health outcomes in the United States.

METHODS

The 2000-2004 state data were extracted from the Kids Count Data Center. Health indicators included proportion of preterm births (PTBs), proportion of infants with low birth weight (LBW), proportion of infants with very low birth weight (VLBW), and infant mortality rate (IMR). Income was evaluated on the basis of median family income and proportion of federal poverty levels; income inequality was measured by using the Gini coefficient. Pearson correlations evaluated associations between the proportion of children living in poverty and the health indicators. Linear regression evaluated predictive relationships between median household income, proportion of children living in poverty, and income inequality for the 4 health indicators.

RESULTS

Median family income was negatively correlated with all birth outcomes (PTB, r = -0.481; LBW, r = -0.295; VLBW, r = -0.133; IMR, r = -0.432), and the Gini coefficient was positively correlated (PTB, r = 0.339; LBW, r = 0.398; VLBW, r = 0.460; IMR, r = 0.114). The Gini coefficient explained a significant proportion of the variance in rate for each outcome in linear regression models with median family income. Among children living in poverty, the role of income decreased as the degree of poverty decreased, whereas the role of income inequality increased.

CONCLUSIONS

Both income and income inequality affect infant health outcomes in the United States. The health of the poorest infants was affected more by absolute wealth than relative wealth.

Income inequality, mortality, and self rated health: meta-analysis of multilevel studies

OBJECTIVE

To provide quantitative evaluations on the association between income inequality and health.

DESIGN

Random effects meta-analyses, calculating the overall relative risk for subsequent mortality among prospective cohort studies and the overall odds ratio for poor self rated health among cross sectional studies.

DATA SOURCES

PubMed, the ISI Web of Science, and the National Bureau for Economic Research database. Review methods Peer reviewed papers with multilevel data. Results The meta-analysis included 59 509 857 subjects in nine cohort studies and 1 280 211 subjects in 19 cross sectional studies. The overall cohort relative risk and cross sectional odds ratio (95% confidence intervals) per 0.05 unit increase in Gini coefficient, a measure of income inequality, was 1.08 (1.06 to 1.10) and 1.04 (1.02 to 1.06), respectively. Meta-regressions showed stronger associations between income inequality and the health outcomes among studies with higher Gini (>or=0.3), conducted with data after 1990, with longer duration of follow-up (>7 years), and incorporating time lags between income inequality and outcomes. By contrast, analyses accounting for unmeasured regional characteristics showed a weaker association between income inequality and health. Conclusions The results suggest a modest adverse effect of income inequality on health, although the population impact might be larger if the association is truly causal. The results also support the threshold effect hypothesis, which posits the existence of a threshold of income inequality beyond which adverse impacts on health begin to emerge. The findings need to be interpreted with caution given the heterogeneity between studies, as well as the attenuation of the risk estimates in analyses that attempted to control for the unmeasured characteristics of areas with high levels of income inequality.

The individual and contextual pathways between oral health and income inequality in Brazilian adolescents and adults

We evaluate the association between income inequality (Gini index) and oral health and in particular the role of alternative models in explaining this association. We also studied whether or not income at the individual level modifies the Gini effect. We used data from an oral health survey in Brazil in 2002-2003. Our analysis included 23,568 15-19 and 22,839 35-44 year-olds nested in 330 municipalities. Different models were fitted using multilevel analysis. The outcomes analysed were the number of untreated dental caries (count), having at least one missing tooth (dichotomous) and being edentulous (dichotomous). To assess interaction as a departure from additivity we used the Synergy Index. For this, we dichotomized the Gini coefficient (high vs low inequality) by the median value across municipalities and the individual income in the point beyond which it showed roughly no association with oral health. Adjusted rate ratio of mean untreated dental caries, respectively for the 15-19 and 35-44 age groups, was 1.12 and 1.16 for each 10 points increase in Gini scale. Adjusted odds ratio of a 15-19 year-old having at least one missing tooth or a 35-44 year-old being edentulous was, respectively, 1.19 and 1.01. High income inequality had no statistically significant synergistic effect with being poor or living in a poor municipality. Higher levels of income inequality at the municipal level were associated with worse oral health and there was an unexplained residual effect after controlling for potential confoundings and mediators. Municipal level income inequality had a similar, detrimental effect, among individuals with lower or higher income.

Does government provision of healthcare explain the relationship between income inequality and low birthweight?

This paper estimates the relationship between state and county income inequality and low birthweight (LBW) in the U.S. It examines whether more unequal societies are also less healthy because such societies have lower investment in population health. The model includes an extensive list of community and individual controls and community fixed-effects. Results show that unequal states in fact have greater social investments, and absent these investments children born in such states would be more likely to be LBW. Using alternate measures of inequality reveals that income inequality in the upper tail of the income distribution is not related to LBW; but inequality in the lower tail of the income distribution is associated with increased LBW where the supply of healthcare mitigates the effect of income inequality. Consistent with prior findings, county income inequality is not significantly related to LBW.

Place matters: variation in the black/white very preterm birth rate across U.S. metropolitan areas, 2002-2004

OBJECTIVE

We reported on the distribution of very preterm (VPT) birth rates by race across metropolitan statistical areas (MSAs).

METHODS

Rates of singleton VPT birth for non-Hispanic white, non-Hispanic black, and Hispanic women were calculated with National Center for Health Statistics 2002-2004 natality files for infants in 168 MSAs. Subanalysis included stratification by parity, age, smoking, maternal education, metropolitan size, region, proportion of MSA that was black, proportion of black population living below the poverty line, and indices of residential segregation.

RESULTS

The mean metropolitan-level VPT birth rate was 12.3, 34.8, and 15.7 per 1,000 live births for white, black, and Hispanic women, respectively. There was virtually no overlap in the white and black distributions. The variation in mean risk across cities was three times greater for black women compared with white women. The threefold disparity in mean rate, and two- to threefold increased variation as indicated by standard deviation, was maintained in all subanalyses.

CONCLUSION

Compared with white women, black women have three times the mean VPT birth risk, as well as three times the variance in city-level rates. The racial disparity in VPT birth rates was composed of characteristics that were constant across MSAs, as well as factors that varied by MSA. The increased sensitivity to place for black women was unexplained by measured maternal and metropolitan factors. Understanding determinants of differences in both the mean risk and the variation of risk among black and white women may contribute to reducing the disparity in risk between races.

Lower early neonatal mortality among singletons in transnational marriage families: Taiwan Birth Registry

The nativity composition of the Taiwan population has changed substantially since 1980, which resulted in one in six children being born to foreign-born mothers in 2004. The purpose of this study was to compare the early neonatal mortality rates among babies of foreign-born and Taiwan-born mothers. Data was obtained from the Taiwan Birth Registry Database in 2004 by the Bureau of Health Promotion, Department of Health, Taiwan. Multivariate analysis was used to examine the influence of the different maternal nationalities on early neonatal mortality after adjusting for important maternal and infant variables. Infants born to foreign-born mothers had a lower early neonatal mortality rate (5.6 per thousand) compared to those born to Taiwan-born mothers (9.4 per thousand). Even after adjusting for important maternal and infant variables, newborns of foreign-born mothers still had a lower risk of early neonatal death compared to newborns of Taiwan-born mothers (odds ratio = 0.68, 95% CI = 0.57-0.80). Foreign-born status may serve as an important index of differentiation in early neonatal mortality among the current Taiwan population. Selection, economic and non-economic aspects may explain the paradox of favorable early neonatal mortality outcomes.

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.