Gong Henry, Linn William S, Terrell Sheryl L, Anderson Karen R, Clark Kenneth W, Sioutas Costantinos, Cascio Wayne E, Alexis Neil, Devlin Robert B
Los Amigos Research and Education Institute, Downey, California 90242, USA.
Inhal Toxicol. 2004 Oct-Nov;16(11-12):731-44. doi: 10.1080/08958370490499906.
The elderly and individuals who have chronic obstructive pulmonary disease (COPD) may be sensitive to particulate matter (PM) air pollution. We evaluated short-term health responses of 13 elderly volunteers with COPD and 6 age-matched healthy adults to controlled exposures of ambient PM pollution in suburban Los Angeles. Using a Harvard particle concentrator and a whole-body chamber, we exposed each person on separate occasions to approximately 200 microg/m(3) concentrated ambient particles (CAP) less than 2.5 mum in diameter and to filtered air (FA). Each exposure lasted 2 h with intermittent mild exercise. We found no significant effects of CAP on symptoms, spirometry, or induced sputum. A significant negative effect of CAP on arterial oxygenation (measured by pulse oximetry) immediately postexposure was more pronounced in healthy subjects. Peripheral blood basophils increased after CAP in healthy but not in COPD subjects. In both groups, red cell counts increased slightly 1 day after exposure to FA but not to CAP. Preexposure ectopic heartbeats were infrequent in healthy subjects, but increased modestly during/after CAP exposure relative to FA. Ectopic beats were more frequent in COPD subjects, but decreased modestly during/after CAP relative to FA. Heart-rate variability over multi-hour intervals was lower after CAP than after FA in healthy elderly subjects but not in COPD subjects. Thus, in this initial small-scale study of older volunteers experimentally exposed to ambient PM, some acute cardiopulmonary responses were consistent with effects reported from epidemiologic studies. Unexpectedly, individuals with COPD appeared less susceptible than healthy elderly individuals. Further investigation of older adults is warranted to understand the pathophysiology and public health significance of these findings.
老年人以及患有慢性阻塞性肺疾病（COPD）的个体可能对颗粒物（PM）空气污染敏感。我们评估了13名患有COPD的老年志愿者和6名年龄匹配的健康成年人对洛杉矶郊区环境PM污染的受控暴露的短期健康反应。使用哈佛粒子浓缩器和全身舱，我们在不同时间分别让每个人暴露于直径小于2.5微米的约200微克/立方米的浓缩环境颗粒物（CAP）以及过滤空气（FA）中。每次暴露持续2小时并伴有间歇性轻度运动。我们发现CAP对症状、肺功能测定或诱导痰没有显著影响。暴露后立即通过脉搏血氧饱和度测量发现，CAP对健康受试者的动脉氧合有显著负面影响。健康受试者在接触CAP后外周血嗜碱性粒细胞增加，而COPD受试者没有。在两组中，暴露于FA后1天红细胞计数略有增加，但暴露于CAP后没有。健康受试者暴露前异位心跳很少见，但与FA相比，在接触CAP期间/之后适度增加。COPD受试者异位心跳更频繁，但与FA相比，在接触CAP期间/之后适度减少。在健康老年受试者中，接触CAP后多小时的心率变异性低于接触FA后，但COPD受试者没有。因此，在这项对实验性暴露于环境PM中的老年志愿者进行的初步小规模研究中，一些急性心肺反应与流行病学研究报告的结果一致。出乎意料的是，患有COPD的个体似乎比健康老年人更不易受影响。有必要对老年人进行进一步调查，以了解这些发现的病理生理学和公共卫生意义。
