Xu Ke, Hao Hua, Zhang Danlu, Wang Wenhao, Li Haomin, Deng Yanling, Ma Tszshan, Steenland Kyle, Chang Howard, Liu Yang
Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Environ Int. 2025 May;199:109513. doi: 10.1016/j.envint.2025.109513. Epub 2025 May 1.
Wildfire events in the US are becoming more frequent and more intensive due to climate change. Fire smoke can significantly contribute to ambient PM (PM, particles smaller than 2.5 µm in diameter) levels and alter its chemical composition. An emerging body of literature has linked COPD mortality and episodic wildfire smoke exposure, but studies on the effect of long-term fire smoke exposure is lacking. We aimed to evaluate how long-term exposure to smoke PM can affect COPD mortality among elderly people and to explore the spatial variability in this effect. We investigated all elderly people aged 65-100 years in the contiguous United States using Medicare and National Death Index data from 2008 to 2016. We identified three subregions based on wildfire smoke risk to indicate spatial differences in smoke exposure. We used time-varying Cox Proportional Hazards Models to explore the effect of smoke PM on COPD mortality. We found that smoke PM is strongly associated with COPD mortality. An increase of 1 µg/m in smoke PM was associated with a 9.2 % increase in COPD mortality among elderly people (95 % CI: 8.8 %-9.7 %). Specifically, A 1 µg/m increase in smoke PM may increase deaths by 40.4 %, 9.6 % and 3.9 % in low, moderate, and high wildfire risk areas, respectively. Our study reveals that long-term exposure to smoke PM significantly contributes to COPD mortality among elderly people. Notably, those living in regions with relatively lower wildfire risk appear vulnerable. Therefore, wildfire prevention should be emphasized in areas that are not typically wildfire active.
由于气候变化，美国的野火事件愈发频繁且愈发剧烈。火灾烟雾会显著增加环境空气中的细颗粒物（PM，直径小于2.5微米的颗粒物）水平，并改变其化学成分。越来越多的文献将慢性阻塞性肺疾病（COPD）死亡率与野火烟雾的间歇性暴露联系起来，但关于长期暴露于火灾烟雾影响的研究却很缺乏。我们旨在评估长期暴露于烟雾中的细颗粒物如何影响老年人的慢性阻塞性肺疾病死亡率，并探讨这种影响的空间变异性。我们利用2008年至2016年的医疗保险和国家死亡指数数据，对美国本土65至100岁的所有老年人进行了调查。我们根据野火烟雾风险确定了三个子区域，以表明烟雾暴露的空间差异。我们使用时变Cox比例风险模型来探究烟雾细颗粒物对慢性阻塞性肺疾病死亡率的影响。我们发现，烟雾细颗粒物与慢性阻塞性肺疾病死亡率密切相关。烟雾细颗粒物每增加1微克/立方米，老年人慢性阻塞性肺疾病死亡率就会增加9.2%（95%置信区间：8.8%-9.7%）。具体而言，在野火低、中、高风险地区，烟雾细颗粒物每增加1微克/立方米，死亡人数可能分别增加40.4%、9.6%和3.9%。我们的研究表明，长期暴露于烟雾细颗粒物会显著增加老年人慢性阻塞性肺疾病的死亡率。值得注意的是，生活在野火风险相对较低地区的人群似乎较为脆弱。因此，在通常并非野火高发的地区应强调预防野火。
