Research Group on Statistics, Econometrics and Health (GRECS), University of Girona, Girona, Spain; CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain.
Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Spain.
Environ Res. 2020 Dec;191:110177. doi: 10.1016/j.envres.2020.110177. Epub 2020 Sep 12.
The risk of infection and death by COVID-19 could be associated with a heterogeneous distribution at a small area level of environmental, socioeconomic and demographic factors. Our objective was to investigate, at a small area level, whether long-term exposure to air pollutants increased the risk of COVID-19 incidence and death in Catalonia, Spain, controlling for socioeconomic and demographic factors.
We used a mixed longitudinal ecological design with the study population consisting of small areas in Catalonia for the period February 25 to May 16, 2020. We estimated Generalized Linear Mixed models in which we controlled for a wide range of observed and unobserved confounders as well as spatial and temporal dependence.
We have found that long-term exposure to nitrogen dioxide (NO) and, to a lesser extent, to coarse particles (PM) have been independent predictors of the spatial spread of COVID-19. For every 1 μm/m above the mean the risk of a positive test case increased by 2.7% (95% credibility interval, ICr: 0.8%, 4.7%) for NO and 3.0% (95% ICr: -1.4%,7.44%) for PM. Regions with levels of NO exposure in the third and fourth quartile had 28.8% and 35.7% greater risk of a death, respectively, than regions located in the first two quartiles.
Although it is possible that there are biological mechanisms that explain, at least partially, the association between long-term exposure to air pollutants and COVID-19, we hypothesize that the spatial spread of COVID-19 in Catalonia is attributed to the different ease with which some people, the hosts of the virus, have infected others. That facility depends on the heterogeneous distribution at a small area level of variables such as population density, poor housing and the mobility of its residents, for which exposure to pollutants has been a surrogate.
感染 COVID-19 的风险和死亡风险可能与环境、社会经济和人口因素的小区域水平的异质分布有关。我们的目的是在小区域水平上研究，在控制社会经济和人口因素的情况下，长期暴露于空气污染物是否会增加 COVID-19 在加泰罗尼亚（西班牙）的发病率和死亡率。
我们使用混合纵向生态设计，研究人群由加泰罗尼亚的小区域组成，研究期间为 2020 年 2 月 25 日至 5 月 16 日。我们估计了广义线性混合模型，其中我们控制了广泛的观察和未观察到的混杂因素以及空间和时间依赖性。
我们发现，长期暴露于二氧化氮（NO）和，在较小程度上，粗颗粒物（PM）是 COVID-19 空间传播的独立预测因子。对于每个高于平均值的 1μm/m，阳性检测病例的风险增加 2.7%（95%置信区间，95%CrI：0.8%，4.7%），对于 NO 和 3.0%（95%CrI：-1.4%，7.44%），对于 PM。暴露于 NO 的第三和第四四分位数的区域的死亡风险分别比位于前两个四分位数的区域高 28.8%和 35.7%。
尽管长期暴露于空气污染物与 COVID-19 之间的关联可能至少部分是由生物学机制解释的，但我们假设加泰罗尼亚 COVID-19 的空间传播归因于某些人（病毒宿主）感染其他人的难易程度不同。这种便利性取决于人口密度、住房条件差和居民流动性等变量在小区域水平上的异质分布，这些变量的暴露是污染物的替代指标。
