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.     

An exploratory multilevel analysis of income,income inequality and self-rated health of the elderly in China

In the last three decades, China has experienced rapid economic development and growing economic inequality, such that economic disparities between rural and urban areas, as well as coastal and interior areas have deepened. Since the late 1990s China has also experienced an ageing population which has attracted attention to the wellbeing of the rapidly growing number of elderly. This research aims to characterise province differences in health and to explore the effects of individual income and economic disparity in the form of income inequality on health outcomes of the elderly. The study is based on the Chinese Longitudinal Healthy Longevity Survey data collected in 2008 for 23 provinces. Multilevel logistic models are employed to investigate the relationship between income, income inequality and self-rated health for the elderly using both individual and province-level variables. Results are presented as relative odds ratios, and for province differentials as Median Odds Ratios. The analysis is deliberately exploratory so as to find evidence of income effects if they exist and particular attention is placed on how province-level inequality (contemporaneous and lagged) may moderate individual relationships. The results show that the health of the elderly is not only affected by individual income (the odds of poor health are 3 times greater for the elderly with the lowest income compared to those at the upper quartile) but also by a small main effect for province-level income inequality (odds ratio of 1.019). There are significant cross-level interactions such that where inequality is high there are greater differences between those with and without formal education, and between men and women with the latter experiencing poorer health.     

Individual social capital, neighbourhood deprivation, and self-rated health in England

Individual social capital is increasingly considered to be an important determinant of an individual's health. This study examines the extent to which individual social capital is associated with self-rated health and the extent to which individual social capital mediates t.he relationship between neighbourhood deprivation and self-rated health in an English sample. Individual social capital was conceptualized and operationalized in both the social cohesion- and network resource tradition, using measures of generalized trust, social participation and social network resources. Network resources were measured with the position generator. Multilevel analyses were applied to wave 2 and 3 of the Taking Part Surveys of England, which consist of face-to-face interviews among the adult population in England (N(i) = 25,366 respondents, N(j) = 12,388 neighbourhoods). The results indicate that generalized trust, participation with friends and relatives and having network members from the salariat class are positively associated with self-rated health. Having network members from the working class is, however, negatively related to self-rated health. Moreover, these social capital elements are partly mediating the negative relationship between neighbourhood deprivation and self-rated health.     

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.     

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.     

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.     

Metropolitan area income inequality and self-rated health--a multi-level study

We examined the association of income inequality measured at the metropolitan area (MA) and county levels with individual self-rated health. Individual-level data were drawn from 259,762 respondents to the March Current Population Survey in 1996 and 1998. Income inequality and average income were calculated from 1990 census data, the former using Gini coefficients. Multi-level logistic regression models were used. Controlling for sex, age, race, and individual-level household income, respondents living in high, medium-high, and medium-low income inequality MAs had odds ratios of fair/poor self-rated health of 1.20 (95% confidence interval 1.04-1.38), 1.07 (0.95-1.21), and 1.02 (0.91-1.15), respectively, compared to people living in the MAs with the lowest income inequality. However, we found only a small association of MA-level income inequality with fair/poor health when controlling further for average MA household income: odds ratios were 1.10 (0.95-1.28), 1.01 (0.89-1.14), and 1.00 (0.89-1.12), respectively. Likewise, we found only a small association of county-level income inequality with self-rated health although only 40.7% of the sample had an identified county on CPS data. Regarding the association of state-level income inequality with fair/poor health, we found the association to be considerably stronger among non-metropolitan (i.e. rural) compared to metropolitan residents.     

Socioeconomic inequality in voting participation and self-rated health

OBJECTIVES: This study tested the hypothesis that disparities in political participation across socioeconomic status affect health. Specifically, the association of voting inequality at the state level with individual self-rated health was examined. METHODS: A multilevel study of 279,066 respondents to the Current Population Survey (CPS) was conducted. State-level inequality in voting turnout by socioeconomic status (family income and educational attainment) was derived from November CPS data for 1990, 1992, 1994, and 1996. RESULTS: Individuals living in the states with the highest voting inequality had an odds ratio of fair/poor self-rated health of 1.43 (95% confidence interval [CI] = 1.22, 1.68) compared with individuals living in the states with the lowest voting inequality. This odds ratio decreased to 1.34 (95% CI = 1.14, 1.56) when state income inequality was added and to 1.27 (95% CI = 1.10, 1.45) when state median income was included. The deleterious effect of low individual household income on self-rated health was most pronounced among states with the greatest voting and income inequality. CONCLUSIONS: Socioeconomic inequality in political participation (as measured by voter turnout) is associated with poor self-rated health, independently of both income inequality and state median household income.     

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

The relative income hypothesis, that relative income has a direct effect on individual health, has become an important part of the literature on health inequalities. This paper presents a four-quadrant diagram, which shows the effect of income, relative income and aggregation bias on individual and societal health. The model predicts that increased income inequality reduces average health regardless of whether relative income affects individual health. If relative income does have a direct effect then societal health will decrease further.     

Primary care, income inequality, and self-rated health in the United States: a mixed-level analysis.

Using the 1996 Community Tracking Study household survey, the authors examined whether income inequality and primary care, measured at the state level, predict individual morbidity as measured by self-rated health status, while adjusting for potentially confounding individual variables. Their results indicate that distributions of income and primary care within states are significantly associated with individuals' self-rated health; that there is a gradient effect of income inequality on self-rated health; and that individuals living in states with a higher ratio of primary care physician to population are more likely to report good health than those living in states with a lower such ratio. From a policy perspective, improvement in individuals' health is likely to require a multi-pronged approach that addresses individual socioeconomic determinants of health, social and economic policies that affect income distribution, and a strengthening of the primary care aspects of health services.     

我国居民与收入相关的健康不平等实证研究

本文利用中国健康与营养调查（CHNS）2006年的调查数据，从定量的角度对我国居民与收入相关的健康不平等进行了分析。本文利用有序Probit模型获得了自评健康数据背后的实际健康得分，在此基础上计算健康集中指数衡量我国居民与收入相关的健康不平等程度。结果表明，我国居民的健康不平等问题较为严重，健康不平等问题在城乡之间和不同经济发展水平地区之间存在着较大的差别。     

Exploring the generalisability of the association between income inequality and self-assessed health

A growing between- and within-country literature suggests that the association between income inequality and health reflects individual- or area-level characteristics with which income inequality is associated, rather than the effects of income inequality per se. These studies also suggest that the association between income inequality and health is country-specific. Unresolved methodological issues include the geographical level at which to model the effects of income inequality, and the appropriate statistical methods to use. This study compares the results of single-level and multi-level logistic regression models estimating the association between income inequality and self-assessed health in local authorities in Scotland. The results suggest that there is a significant positive association between income inequality and health across local authorities in Scotland, even after adjusting for individual-level socio-economic status. They also suggest that there is significant local authority-level variation in self-assessed health, but this is small compared to the variation at the individual level. Income and other measures of individuals' socio-economic status are more strongly associated with self-assessed health than income inequality. This study provides further evidence that the income inequality:health association is place-specific. It also suggests that methodological choices regarding the ways of estimating the association between self-assessed health, individual-level socio-economic status and area-level income inequality may not make a substantive difference to the results when contextual effects are small. Further work is required to test the sensitivity of these conclusions to alternative levels of geographical aggregation.     

Neo-materialist theory and the temporal relationship between income inequality and longevity change

This study uses a neo-materialist perspective to develop theoretical predictions regarding temporal ties between income inequality and change in population health. The argument focuses on the relationship between income inequality and adoption of longevity-enhancing innovations. It asserts that longevity change should be influenced by preexisting levels of income inequality and that, consequently, income inequality can cause differential longevity improvement across jurisdictions even if inequality levels remain unchanged. State-level U.S. data from 1970 to 2000 are used to jointly model the effects of initial levels and change in income inequality on 10-year life expectancy change. Results confirm that states with higher levels of inequality experienced less subsequent improvement in life expectancy. Contrary to findings from prior research, analyses also reveal a strong negative association between change in inequality and change in longevity once initial levels of inequality and other state characteristics are controlled. Finally, direct tests of the relationship between income inequality and the adoption of innovations in quality of medical care indicate that the two are highly related and that differences in the average quality of care can account for the negative cross-sectional association between income inequality and life expectancy.     

The predictors of self-rated health and the relationship between self-rated health and health service needs are similar across socioeconomic groups in Canada

ObjectiveTo examine if there are systematic differences in the predictors of self-rated health (SRH) and to examine the relationship between SRH and health care utilization across socioeconomic groups.Study Design and SettingWe used cross-sectional data from the Canadian Community Health Survey linked to the Ontario Health Insurance Plan (N = 17,109). We examined relative differences in the factors associated with different levels of SRH across socioeconomic groups (as assessed by education and household income) using probit models separately for men and women. We then examined differences in expected health care costs, as assessed by adjusted clinical group weights using administrative health care records, between socioeconomic groups within the same level of SRH.ResultsWe found limited differences across the predictive ability of a broad range of physical, mental, health service/care utilization, and health behavior variables on SRH across socioeconomic groups. In addition, no differences were found in the expected health care utilization costs across socioeconomic groups within the same level of SRH.ConclusionsThe results of this study suggest that SRH assesses a broad variety of factors, including physical health status, mental health status, health service/care utilization, and health behaviors, relatively equally across socioeconomic groups, measured as either education or income.     

Neighbourhood inequality, neighbourhood affluence and population health

While there is now considerable evidence that the neighbourhood income levels (poverty/affluence) exert an independent effect on health, there is little evidence that neighbourhood income inequality is consequential, net of individual-level socio-economic resources. We show that the usual explanation for the absence of an independent effect of neighbourhood inequality--the assumption of economic homogeneity at the neighbourhood level--cannot account for this result. The authors use hierarchical models that combine individual micro-data from Statistics Canada's 1996/97 National Population Health Survey (NPHS) with neighbourhood and city-level socio-economic characteristics from the 1996 Census of Canada to estimate the effects of neighbourhood affluence and income inequality on self-reported health status. The findings indicate that the negative "ecological" correlation between average neighbourhood health and neighbourhood income inequality is the result not only of compositional differences among individuals but also of contextual neighbourhood effects associated with low and high inequality neighbourhoods.     

Relative deprivation in income and self-rated health in the United States

Absolute income is robustly associated with health status. Few studies have, however, examined if relative income is independently associated with health. We examined if, over and above the effects of absolute income, individual relative deprivation in income as well as position in the income hierarchy is associated with individual poor health in the U.S. Using three rounds of the Current Population Surveys (CPS), we analyzed the association between self-rated health (1 = fair/poor, 0 = otherwise) and the Yitzhaki index of relative deprivation in income and percentile position in the income hierarchy across 17 reference groups. Over and above the effects of absolute income, the odds ratio for reporting poor health among individuals in the highest quintile of relative deprivation compared to the lowest quintile ranged between 2.18 and 3.30, depending on the reference groups used. A 10 percentile increase in income position within reference groups was associated with an odds ratio of poor health of 0.89. Relative deprivation appeared to explain between 33 and 94% of the association between individual income and self-rated health. Relative deprivation in income is independently associated with poor health over and above the well established effects of absolute income on health. Relative deprivation may partly explain the association between income inequality and worse population health status.     

Further examination of the cross-country association between income inequality and population health

Several scholars have put forward the view that the estimates by Rodgers [(1979). Income and inequality as determinants of mortality: An international cross-section analysis. Population Studies, 33 (2), 343-351], Flegg [(1982). Inequality of income, illiteracy and medical care as determinants of infant mortality in underdeveloped countries. Population Studies, 36 (3), 441-458] and Waldmann [(1992). Income distribution and infant mortality. Quarterly Journal of Economics, 107 (4), 1283-1302] showing a negative cross-country association between income inequality and population health, cannot be replicated from recent data. In view of the importance of this matter, the present study further examines the issue from the most recent, and probably more accurate, data for the largest cross-country sample used in this line of research. The main conclusion is that the negative cross-country association between income inequality and good health, reported by Rodgers, Flegg, and Waldmann, is replicated very well. The different findings indicated by some scholars may have been due to their samples or the models being unusual. Therefore, the recent skepticism about the existence of such a negative association needs to be reconsidered. Several additional points are also noted. First, income inequality shows significance even after an index of ethnic heterogeneity is included. Second, ethnic heterogeneity itself has a negative association with population health. Third, income inequality retains significance in the presence of a measure of social capital. Fourth, however, the association between the measure of social capital and population health appears weak. Fifth, a simple analysis does not support the view that the positive association between income inequality and infant mortality in less developed countries (LDCs) may just be a reflection of the role of poverty. Finally, there is some support for the proposition that while income may be relatively more important for health in LDCs, the role of income inequality may be stronger in developed economies.     

Changes in income inequality and the health of immigrants

Research suggests that income inequality is inversely associated with health. This association has been documented in studies that utilize variation in income inequality across countries or across time from a single country. The primary criticism of these approaches is their inability to account for potential confounders that are associated with income inequality. This paper uses variation in individual experiences of income inequality among immigrants within the United States (U.S.) to evaluate whether individuals who moved from countries with greater income inequality than the U.S. have better health than those who migrated from countries with less income in equality than the U.S. Utilizing individual-level (March Current Population Survey) and country-level data (the United Nations Human Development Reports), we show that among immigrants who have resided in the U.S. between 6 and 20 years, self-reported health is more favorable for the immigrants in the former category (i.e., greater income inequality) than those in the latter (i.e., lower income inequality). Results also show that self-reported health is better among immigrants from more developed countries and those who have more years of education, are male, and are married.