在评估长期暴露于空气污染与新冠病毒肺炎死亡率之间的关联时潜在碰撞器偏倚的调查。

Investigation of potential collider bias in estimating the association between long-term exposure to air pollution and COVID-19 mortality.

作者信息

Zhang Jiawei, Andersen Zorana Jovanovic, Napolitano George Maria, Lim Youn-Hee

机构信息

Section of Environmental Health, Department of Public Health, University of Copenhagen, Copenhagen, Denmark.

出版信息

Environ Epidemiol. 2025 Apr 28;9(3):e394. doi: 10.1097/EE9.0000000000000394. eCollection 2025 Jun.

DOI:10.1097/EE9.0000000000000394

PMID:40304009

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC12040017/

Abstract

BACKGROUND

Patient-based cohorts were frequently used to investigate air pollution-related coronavirus disease 2019 (COVID-19) evidence, which can be subject to collider bias. However, this bias has not been explored. We aimed to quantify and adjust the collider bias by limiting study population to patients with COVID-19 when estimating the association between long-term exposure to air pollution (LTAP) and COVID-19 mortality.

METHODS

In a register-based cohort study including 3,721,813 residents aged 30 or older in Denmark, we followed them from 1 March 2020 to 26 April 2021. We estimated the hazard ratios of COVID-19 mortality associated with LTAP. We calculated the relative hazard ratios (RHR) by comparing the hazard ratios of COVID-19 mortality among the general population and patients (infected or hospitalized) to quantify the impact of collider bias, and further applied inverse probability weighting (IPW) to adjust the potential collider bias.

RESULT

We detected 138,742 positive for SARS-CoV-2, 11,270 COVID-19 hospitalizations, and 2557 deaths from COVID-19 during the study period. Although the demographic and socioeconomic characteristics differed among the three populations (general population, infected individuals, and hospitalized patients), infected and hospitalized patients experienced higher air pollution exposure compared with the general population. We observed greater associations of exposure to air pollution with COVID-19 mortality in the general population compared with the COVID-19 infected and hospitalized patients, with RHR of 0.88 (0.82, 0.95) and 0.85 (0.74, 0.97) per 0.55 µg/m increase in fine particulate matter (PM) when we limited to infected and hospitalized patients, respectively. Similar association was also observed with nitrogen dioxide exposure. After applying IPW, we observed moderate increase in the estimated association, with RHR altered to null.

CONCLUSION

Our findings suggest that associations between LTAP and COVID-19 mortality are likely underestimated in patient-based cohorts due to potential collider bias, while IPW could be a useful tool to adjust such bias.

摘要

背景

基于患者的队列研究经常被用于调查与空气污染相关的2019冠状病毒病（COVID-19）证据，但这类研究可能存在对撞机偏倚。然而，尚未对这种偏倚进行探讨。我们旨在通过在估计长期空气污染暴露（LTAP）与COVID-19死亡率之间的关联时将研究人群限制为COVID-19患者，来量化并调整对撞机偏倚。

方法

在一项基于登记的队列研究中，纳入了丹麦3721813名30岁及以上的居民，我们从2020年3月1日至2021年4月26日对他们进行随访。我们估计了与LTAP相关的COVID-19死亡率的风险比。通过比较普通人群和患者（感染或住院）中COVID-19死亡率的风险比来计算相对风险比（RHR），以量化对撞机偏倚的影响，并进一步应用逆概率加权（IPW）来调整潜在的对撞机偏倚。

结果

在研究期间，我们检测到138742例SARS-CoV-2阳性病例、11270例COVID-19住院病例以及2557例COVID-19死亡病例。虽然这三个人群（普通人群、感染个体和住院患者）的人口统计学和社会经济特征有所不同，但与普通人群相比，感染和住院患者暴露于更高的空气污染水平。与COVID-19感染和住院患者相比，我们观察到普通人群中空气污染暴露与COVID-19死亡率之间的关联更强，当我们将细颗粒物（PM）每增加0.55µg/m³限制在感染和住院患者中时，RHR分别为0.88（0.82，0.95）和0.85（0.74，0.97）。二氧化氮暴露也观察到类似的关联。应用IPW后，我们观察到估计的关联有适度增加，RHR变为无关联。