Willis Alette, Krewski Daniel, Jerrett Michael, Goldberg Mark S, Burnett Richard T
Department of Geography and Environmental Studies, Carleton University, Ottawa, Ontario, Canada.
J Toxicol Environ Health A. 2003;66(16-19):1563-89. doi: 10.1080/15287390306425.
The American Cancer Society (ACS) Study of the effects of long-term exposure to ambient air pollution on mortality used metropolitan areas to assign exposures to individual cohort members (Pope et al., 1995); these authors did not, however, control for any other place-specific variables in their analysis. Consequently, the study has been criticized on the basis that the association observed between air pollution and mortality may be confounded by other unmeasured ecologic covariates. To address this criticism, the reanalysis team selected a set of place-specific variables that measured determinants of health ranging from the biophysical environment to the social environment and the healthcare system. This article outlines the process by which place-specific ecologic covariates were selected; data measuring these variables were obtained and geographic boundaries for places were delineated. Issues involved in obtaining and using geographically based ecological data are examined within the context of the reanalysis of the ACS study. Both the ecological fallacy and the atomistic fallacy are addressed and an argument is made for the importance of studying the effects of place-specific variables that are integral or contextual in nature. Issues relating to the Modifiable Areal Unit Problem (MAUP) are explored with reference to using ZIP codes and data from a variety of sources. It is argued that differences in the geographical scale of variability for various pollutants may prove to be the key to distinguishing between their relative impacts on health and that multilevel analyses are essential for understanding the impact of social and environmental determinants of health. A number of determinants of health are then briefly examined in terms of their association with mortality, the appropriateness of their being measured at the metropolitan scale, and the availability of data for the 1980s from U.S. sources. Finally, the article presents the database of place-specific ecologic covariates that was incorporated into the ACS models during the reanalysis in order to account for the influence that place may have above and beyond ambient air pollution.
美国癌症协会（ACS）关于长期暴露于环境空气污染对死亡率影响的研究，利用大都市区来确定各个队列成员的暴露情况（Pope等人，1995年）；然而，这些作者在分析中并未控制任何其他特定地点的变量。因此，该研究受到了批评，理由是空气污染与死亡率之间观察到的关联可能被其他未测量的生态协变量所混淆。为回应这一批评，重新分析团队选择了一组特定地点的变量，这些变量测量了从生物物理环境到社会环境以及医疗保健系统等健康决定因素。本文概述了选择特定地点生态协变量的过程；获取了测量这些变量的数据，并划定了地点的地理边界。在对ACS研究的重新分析背景下，探讨了获取和使用基于地理的生态数据所涉及的问题。讨论了生态谬误和原子主义谬误，并论证了研究本质上是整体或背景性的特定地点变量影响的重要性。参考使用邮政编码和来自各种来源的数据，探讨了与可变面积单元问题（MAUP）相关的问题。有人认为，各种污染物变异性地理尺度的差异可能是区分它们对健康相对影响的关键，多层次分析对于理解健康的社会和环境决定因素的影响至关重要。然后简要考察了一些健康决定因素与死亡率的关联、在大都市区尺度上测量它们的适宜性以及20世纪80年代美国来源数据的可得性。最后，本文展示了在重新分析期间纳入ACS模型的特定地点生态协变量数据库，以说明地点可能对环境空气污染之外的因素产生的影响。
