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标题：Income Inequality and Mortality: Results From a Longitudinal Study of Older Residents of São Paulo, Brazil
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作者：Roman Pabayo ; Alexandre D. P. Chiavegatto Filho ; Maria Lúcia Lebrão 等
期刊名称：American journal of public health
印刷版ISSN：0090-0036
出版年度：2013
卷号：103
期号：9
页码：e43-e49
DOI：10.2105/AJPH.2013.301496
语种：English
出版社：American Public Health Association
摘要：Objectives. We determined whether community-level income inequality was associated with mortality among a cohort of older adults in São Paulo, Brazil. Methods. We analyzed the Health, Well-Being, and Aging (SABE) survey, a sample of community-dwelling older adults in São Paulo (2000–2007). We used survival analysis to examine the relationship between income inequality and risk for mortality among older individuals living in 49 districts of São Paulo. Results. Compared with individuals living in the most equal districts (lowest Gini quintile), rates of mortality were higher for those living in the second (adjusted hazard ratio [AHR] = 1.44, 95% confidence interval [CI] = 0.87, 2.41), third (AHR = 1.96, 95% CI = 1.20, 3.20), fourth (AHR = 1.34, 95% CI = 0.81, 2.20), and fifth quintile (AHR = 1.74, 95% CI = 1.10, 2.74). When we imputed missing data and used poststratification weights, the adjusted hazard ratios for quintiles 2 through 5 were 1.72 (95% CI = 1.13, 2.63), 1.41 (95% CI = 0.99, 2.05), 1.13 (95% = 0.75, 1.70) and 1.30 (95% CI = 0.90, 1.89), respectively. Conclusions. We did not find a dose–response relationship between area-level income inequality and mortality. Our findings could be consistent with either a threshold association of income inequality and mortality or little overall association. The distribution of incomes in society has been hypothesized to influence a population’s health status. 1 Unequal societies tend to have a greater number of people in poverty who lack access to resources (e.g., health care and preventive measures) to achieve good health. Unequal conditions are also more apt to generate invidious social comparisons that lead to frustration and stress. 2 A more contentious claim made by a growing number of researchers is that unequal societies are damaging to the health of everybody—the poor as well as the comfortably well-off. 1 The putative mechanism for this effect is that income inequality erodes social solidarity. Reduced social cohesion in turn hampers a society’s ability to provide for many kinds of public goods, such as education, health care, and public health infrastructure. 3 For example, when the wealthiest members of society begin to purchase education for their children through private means, or purchase their health care through private channels, there is a corresponding clamor to cut taxes on the rich (since they are no longer benefiting from subscribing to the publicly financed system). Falling tax revenues eventually lead to reduced social spending and declining quality of public institutions for the rest of society. Although the detailed mechanisms through which growing inequality harms society need to be sketched out more fully, considerable evidence has accumulated on the association between income inequality and the health of individuals. Multilevel analyses have demonstrated that there is an excess risk of morbidity and mortality associated with living in a society with high levels of income inequality, even after adjustment for the confounding effects of individual income. 4 In other words, there appears to be a contextual influence of income inequality on the health of individuals, over and above their personal socioeconomic circumstances. Kondo et al. 5 conducted a meta-analysis of all multilevel studies linking income distribution to health, which included 9 longitudinal studies and 18 cross-sectional studies. In the pooled analysis of the prospective cohort studies, the authors reported that each 0.05-unit increment in the Gini index (a summary measure of income inequality) was associated with a 7.8% excess risk of all-cause mortality. Nonetheless, data remain sparse from Latin America, where the degree of income inequality is among the highest in the world. Previous studies have looked at the association between income inequality and health in Chile 6 and Brazil, 7,8 but these have been cross-sectional or ecological. In addition, debate continues concerning what kinds of individuals are most vulnerable to the harmful effects of income inequality. In the US National Longitudinal Mortality Study, 9 the association between higher income inequality and increased mortality risk was shown only among working-age individuals; among older individuals (> 65 years), there was no such association. We address 2 gaps in the literature. We provide a longitudinal test of the association between community-level income inequality and mortality in São Paulo, Brazil, a country with one of the highest degrees of income inequality in the world. We also provide a test of the income inequality hypothesis in a predominantly elderly population.