Mar Therese F, Jansen Karen, Shepherd Kristen, Lumley Thomas, Larson Timothy V, Koenig Jane Q
Department of Environmental Health and Occupational Sciences, University of Washington, Seattle, Washington 98195-7234, USA.
Environ Health Perspect. 2005 Dec;113(12):1791-4. doi: 10.1289/ehp.7883.
The objective of this study was to evaluate associations between short-term (hourly) exposures to particulate matter with aerodynamic diameters < 2.5 microm (PM2.5) and the fractional concentration of nitric oxide in exhaled breath (FE(NO) in children with asthma participating in an intensive panel study in Seattle, Washington. The exposure data were collected with tapered element oscillation microbalance (TEOM) PM2.5 monitors operated by the local air agency at three sites in the Seattle area. FE(NO) is a marker of airway inflammation and is elevated in individuals with asthma. Previously, we reported that offline measurements of FE(NO) are associated with 24-hr average PM2.5 in a panel of 19 children with asthma in Seattle. In the present study using the same children, we used a polynomial distributed lag model to assess the association between hourly lags in PM2.5 exposure and FE(NO) levels. Our model controlled for age, ambient NO levels, temperature, relative humidity, and modification by use of inhaled corticosteroids. We found that FE(NO) was associated with hourly averages of PM2.5 up to 10-12 hr after exposure. The sum of the coefficients for the lag times associated with PM2.5 in the distributed lag model was 7.0 ppm FE(NO). The single-lag-model FE(NO) effect was 6.9 [95% confidence interval (CI), 3.4 to 10.6 ppb] for a 1-hr lag, 6.3 (95% CI, 2.6 to 9.9 ppb ) for a 4-hr lag, and 0.5 (95% CI, -1.1 to 2.1 ppb) for an 8-hr lag. These data provide new information concerning the lag structure between PM2.5 exposure and a respiratory health outcome in children with asthma.
本研究的目的是评估在华盛顿州西雅图市参与一项密集专题研究的哮喘儿童中，短期（每小时）暴露于空气动力学直径小于2.5微米的颗粒物（PM2.5）与呼出气中一氧化氮的分数浓度（FE(NO)）之间的关联。暴露数据是通过当地空气机构在西雅图地区三个地点操作的锥形元件振荡微天平（TEOM）PM2.5监测仪收集的。FE(NO)是气道炎症的一个标志物，在哮喘患者中会升高。此前，我们报告了在西雅图的19名哮喘儿童组成的小组中，FE(NO)的离线测量值与24小时平均PM2.5相关。在本研究中，我们使用相同的儿童，采用多项式分布滞后模型来评估PM2.5暴露的每小时滞后与FE(NO)水平之间的关联。我们的模型对年龄、环境NO水平、温度、相对湿度以及使用吸入性糖皮质激素进行的调整进行了控制。我们发现，FE(NO)与暴露后长达10 - 12小时的PM2.5每小时平均值相关。分布滞后模型中与PM2.5相关的滞后时间系数之和为7.0 ppm FE(NO)。单滞后模型中，1小时滞后时FE(NO)的效应为6.9 [95%置信区间（CI），3.4至10.6 ppb]，4小时滞后时为6.3（95% CI, 2.6至9.9 ppb），8小时滞后时为0.5（95% CI, -1.1至2.1 ppb）。这些数据提供了关于哮喘儿童中PM2.5暴露与呼吸健康结果之间滞后结构的新信息。
