ABSTRACT

We used a transparent systematic review framework based on best practices for evaluating study quality and integrating evidence to conduct a review of the available epidemiology studies evaluating associations between long-term exposure to ambient concentrations of PM_2.5 and mortality (all-cause and non-accidental) conducted in North America. We found that while there is some consistency across studies for reporting positive associations, these associations are weak and several important methodological issues have led to uncertainties with regard to the evidence from these studies, including potential confounding by measured and unmeasured factors, exposue measurement error, and model misspecification. These uncertainties provide a plausible, alternative explanation to causality for the weakly positive findings across studies. Using a causality framework that incorporates best practices for making causal determinations, we concluded that the evidence for a causal relationship between long-term exposure to ambient PM_2.5 concentrations and mortality from these studies is inadequate.

摘要

我们使用了一个透明的系统审查框架，该框架基于评估研究质量和整合证据的最佳实践，以对现有的流行病学研究进行审查，评估长期暴露于环境浓度 PM _{2.5之间的关联}在北美进行的死亡率（全因和非意外）。我们发现，虽然报告正相关的研究之间存在一定的一致性，但这些相关性很弱，并且一些重要的方法问题导致这些研究的证据存在不确定性，包括测量和未测量因素的潜在混淆、暴露测量误差、和型号错误。这些不确定性为跨研究的弱阳性结果的因果关系提供了一种似是而非的替代解释。使用包含最佳实践的因果关系框架来确定因果关系，我们得出结论，长期暴露于环境 PM _{2.5之间存在因果关系的证据}这些研究的浓度和死亡率是不充分的。