Yang Tse-Chuan, Matthews Stephen A, Park Kiwoong
Department of Sociology, Center for Social and Demographic Analysis, University at Albany, State University of New York, 315 AS, 1400 Washington Avenue, Albany, NY 12222, Tel: 518-442-4647,
Departments of Sociology and Anthropology, Population Research Institute, Pennsylvania State University, 507 Oswald Tower, University Park, PA 16802.
Appl Geogr. 2017 Sep;86:139-151. doi: 10.1016/j.apgeog.2017.07.006. Epub 2017 Jul 18.
Two areas still need further examination in the ecological study of inequality and mortality. First, the evidence for the relationship between income inequality and mortality remains inconclusive, particularly when the analytic unit is small (e.g., county in the U.S.). Second, most previous studies are cross-sectional and are unable to address the recent diverging patterns whereby mortality has decreased and income inequality increased. This study aims to contribute to both topic areas by studying the relationship between inequality and mortality via a spatiotemporal approach that simultaneously considers the spatial structure and the temporal trends of inequality and mortality using county panel data between 1990 and 2010 for the conterminous U.S. Using both spatial panel random effect model and spatial panel fixed effect models, we found that (a) income inequality was not a significant factor for mortality after taking into account the spatiotemporal structure and the most salient factors for mortality (e.g., socioeconomic status); (b) the spatial panel fixed effect model indicated that income inequality was negatively associated with mortality over the time, a relationship mirroring the diverging patterns; and (c) the significant spatial and temporal fixed effects suggested that both dimensions are critical factors in understanding the inequality-mortality relationship in the U.S. Our findings extend support to the argument that income inequality does not affect mortality and suggest that the cross-sectional findings may be a consequence of ignoring the temporal trends.
在不平等与死亡率的生态学研究中，仍有两个领域需要进一步探讨。首先，收入不平等与死亡率之间关系的证据仍然不明确，特别是当分析单位较小时（例如美国的县）。其次，以前的大多数研究都是横断面研究，无法解决近期出现的死亡率下降而收入不平等加剧的分化模式。本研究旨在通过时空方法研究不平等与死亡率之间的关系，为这两个领域做出贡献，该方法使用1990年至2010年美国本土的县面板数据，同时考虑不平等和死亡率的空间结构和时间趋势。使用空间面板随机效应模型和空间面板固定效应模型，我们发现：（a）在考虑时空结构和死亡率的最显著因素（如社会经济地位）后，收入不平等不是死亡率的显著因素；（b）空间面板固定效应模型表明，随着时间的推移，收入不平等与死亡率呈负相关，这种关系反映了分化模式；（c）显著的空间和时间固定效应表明，这两个维度都是理解美国不平等与死亡率关系的关键因素。我们的研究结果支持了收入不平等不影响死亡率的观点，并表明横断面研究结果可能是忽略时间趋势的结果。
