收入不平等与个体健康 基于2005年中国综合社会调查的实证分析

Income Inequality and Individual Health:An Empirical Analysis of the 2005 Chinese General Social Survey

文章利用2005年中国综合社会调查(CGSS2005)数据与县级社会统计资料,通过拟合多层Logistic回归模型,分析了地区收入不平等程度对个体健康状况的影响,系统检验了绝对收入理论和收入不平等理论。结果表明,即使在控制了个体收入对健康的凹陷效应之后,县级收入不平等程度仍对个体自评健康具有显著的负面影响。对收入不平等影响健康的作用机制的进一步分析表明,社会心理机制仅能部分解释不平等对健康的负面效应,而新唯物主义机制未能得到经验支持。

Health is not only one of the ultimate goals of human development, but also a key element of human capital. Health plays significant roles in determining individual＇s life quality and facilitating social development. With the general improvement of people＇ s living standards in the past several decades in China, health issues have attracted more and more attention from social researchers and policy makers. Although China has sustained rapid economic growth in recent years, the problem of social inequality has aggravated and the income gap between the rich and the poor has widened substantially. To date, empirical investigation of the impact of income inequality on health in China is still very limited. In contrast, more and more studies in other countries since the 1970 ＇s have suggested that income inequality is negatively associated with population health at the aggregate level. Two competing hypotheses have been proposed to explain the relationship between income inequality and population health. One is the absolute income hypothesis, which claims that the aggregate relationship between income inequality and population health is an instance of ecological fallacy and that it simply reflects the nonlinear effect of individual income on health; the other is the income inequality hypothesis, which insists that income inequality have a genuine, detrimental effect on individual health, proposing psychosocial and neo-materialist mechanisms for the harm of income inequality to individual health. In this study, drawing data from the 2005 Chinese General Social Survey （CGSS2005） and county-level social statistics, we examined the relationships between individual income, county income inequality and individual health in China, and systematically tested the absolute income hypothesis and the income inequality hypothesis empirically. Although the results showed the existence of marginally diminishing returns in the effects of income on health, the urban-to-rural income ratio at the county level was still negatively associated with individual self-rated general health even after controlling for the concave effect of the absolute income on health. This finding empirically supported the income inequality hypothesis, evidencing that income inequality did pollute individual health independently. We further explored the potential mechanisms through which income inequality affected individual health, and tested the explanatory power of the social psychological mechanism and the neo-materialist mechanism, respectively. The results gave some support to the former in partially accounting for the negative association of income inequality to individual health but not for the latter.