Public Health Ontario, Toronto, ON, Canada.
ICES, Toronto, ON, Canada.
Int J Epidemiol. 2021 May 17;50(2):589-601. doi: 10.1093/ije/dyaa230.
Exposure to fine particulate (PM2.5) air pollution is associated with increased cardiovascular disease (CVD), but less is known about its specific components, such as metals originating from non-tailpipe emissions. We investigated the associations of long-term exposure to metal components [iron (Fe) and copper (Cu)] in PM2.5 with CVD incidence.
We conducted a population-based cohort study in Toronto, Canada. Exposures to Fe and Cu in PM2.5 and their combined impact on the concentration of reactive oxygen species (ROS) in lung fluid were estimated using land use regression models. Incidence of acute myocardial infarction (AMI), congestive heart failure (CHF) and CVD death was ascertained using health administrative datasets. We used mixed-effects Cox regression models to examine the associations between the exposures and health outcomes. A series of sensitivity analyses were conducted, including indirect adjustment for individual-level cardiovascular risk factors (e.g. smoking), and adjustment for PM2.5 and nitrogen dioxide (NO2).
In single-pollutant models, we found positive associations between the three exposures and all three outcomes, with the strongest associations detected for the estimated ROS. The associations of AMI and CHF were sensitive to indirect adjustment, but remained robust for CVD death in all sensitivity analyses. In multi-pollutant models, the associations of the three exposures generally remained unaltered. Interestingly, adjustment for ROS did not substantially change the associations between PM2.5 and CVD, but attenuated the associations of NO2.
Long-term exposure to Fe and Cu in PM2.5 and their combined impact on ROS were consistently associated with increased CVD death.
细颗粒物（PM2.5）空气污染暴露与心血管疾病（CVD）增加有关，但对于其特定成分（如非尾气排放来源的金属）的了解较少。我们研究了 PM2.5 中金属成分（铁[Fe]和铜[Cu]）的长期暴露与 CVD 发病之间的关系。
我们在加拿大多伦多进行了一项基于人群的队列研究。使用土地利用回归模型估计 PM2.5 中 Fe 和 Cu 的暴露情况及其对肺液中活性氧（ROS）浓度的综合影响。使用健康管理数据集确定急性心肌梗死（AMI）、充血性心力衰竭（CHF）和 CVD 死亡的发病情况。我们使用混合效应 Cox 回归模型来检验暴露与健康结果之间的关联。进行了一系列敏感性分析，包括对个体心血管风险因素（如吸烟）的间接调整，以及对 PM2.5 和二氧化氮（NO2）的调整。
在单污染物模型中，我们发现三种暴露与所有三种结果之间存在正相关，其中与估计的 ROS 之间的相关性最强。AMI 和 CHF 的关联对间接调整敏感，但在所有敏感性分析中，CVD 死亡的关联仍然稳健。在多污染物模型中，三种暴露的关联通常保持不变。有趣的是，ROS 的调整并未显著改变 PM2.5 与 CVD 之间的关联，但减弱了 NO2 的关联。
长期暴露于 PM2.5 中的 Fe 和 Cu 及其对 ROS 的综合影响与 CVD 死亡风险增加有关。
