Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan.
J Public Health (Oxf). 2018 Sep 1;40(3):e228-e234. doi: 10.1093/pubmed/fdx179.
Previous studies have suggested that social and economic spatial polarization is associated with various health outcomes. However, few studies have examined the joint effect of income inequality and spatial polarization on health.
Data on mortality in 2008-12 were from the Ministry of Health and Welfare. We constructed economic spatial polarization using the Index of Concentration at the Extremes (ICE) by tax data from the Ministry of Finance. The Gini coefficient was from the Family Income and Expenditure Survey. Using multilevel datasets of 352 townships nested within 20 cities in Taiwan, we examined the association between township-level ICE and mortality, and further examined whether city-level income inequality moderate this association.
In 2008-12, the average age-standardized mortality in Taiwan was 470.5 per 100 000 populations. As compared to the highest income-based ICE quintile, the lowest ICE quintile was associated with an excess 171.7 deaths per 100 000 people (95% CI = 116.1, 227.3) after controlling for income inequality and population size. One unit rise in the Gini coefficient further increased 29.9 deaths (95% CI = 12.4, 47.5) for the lowest ICE quintile, as compared to the highest.
The joint effect of income inequality and small-scale economic polarization may shed light on how inequalities increase mortality.
先前的研究表明，社会和经济空间极化与各种健康结果有关。然而，很少有研究调查收入不平等和空间极化对健康的联合影响。
2008-12 年的死亡率数据来自卫生部。我们利用财政部税收数据构建经济空间极化的极值集中指数（ICE）。基尼系数来自家庭收入和支出调查。利用台湾 20 个城市中嵌套的 352 个乡镇的多层次数据集，我们检验了乡镇级 ICE 与死亡率之间的关联，并进一步检验了城市级收入不平等是否调节了这种关联。
在 2008-12 年，台湾的平均年龄标准化死亡率为每 10 万人 470.5 人。与收入最高的 ICE 五分位数相比，收入最低的 ICE 五分位数与每 10 万人中多余的 171.7 例死亡有关（95%CI=116.1，227.3），在控制了收入不平等和人口规模后。与收入最高的 ICE 五分位数相比，基尼系数每增加一个单位，收入最低的 ICE 五分位数的死亡人数将进一步增加 29.9 人（95%CI=12.4，47.5）。
收入不平等和小规模经济极化的联合效应可能揭示了不平等如何增加死亡率。
