Role of Diesel and Other Vehicular Exhaust in Exacerbation of Childhood Asthma

描述(申请人提供)：儿童哮喘的负担对生活在贫困和城市中心的儿童影响不成比例，其中许多是少数族裔群体。对于那些生活在交通密度高的城市环境中的人来说，人们越来越担心暴露在柴油和其他车辆废气中可能对呼吸系统健康造成不利影响。流行病学研究表明，暴露于高交通量，特别是高卡车交通--城市环境中柴油废气的主要来源--与哮喘症状、哮喘住院和肺功能下降之间存在关联。然而，由于柴油与火花点火废气以及一般车辆废气与其他污染源的分离所面临的挑战，接触柴油和其他车辆废气与不利的呼吸健康后果之间的定量联系尚未得到很好的表征。这项研究将描述与汽车尾气和其他特定空气污染源相关的环境暴露，并评估这些暴露与居住在底特律和密歇根州迪尔伯恩的儿童哮喘恶化的关系。我们将收集环境和室内空气质量数据，提供高时间和空间分辨率的污染浓度，并利用最先进的统计/地理空间模型来分配污染源包括柴油和其他车辆废气的暴露剂量，并制定针对个人的暴露剂量估计。我们将对210名哮喘儿童进行为期两年的纵向研究，每名儿童70人，分别居住在高流量/高卡车流量道路附近、靠近高流量/低卡车流量道路、远离高流量道路。将在八个季节的每个季节连续两周评估的日常健康措施将包括呼吸道症状、手持肺活量计评估的肺功能、用药情况和卫生服务利用情况。我们假设：1)与其他污染源相比，柴油和其他车辆废气对生活在高交通密度城市环境中的哮喘儿童的不良健康状况具有更强的预测作用；2)家庭中吸烟者的存在、家庭灰尘中高水平的常见过敏原或对此类过敏原的敏感，将在柴油和其他车辆废气和不良呼吸道健康结果之间产生更强的暴露-反应关系。

DESCRIPTION (provided by applicant): The burden of childhood asthma disproportionately affects children living in poverty and in urban centers, many of whom are minority ethnic groups. For those living in urban environments with high traffic densities, there is increasing concern about potential adverse respiratory health effects of exposure to diesel and other vehicular exhaust. Epidemiologic studies have shown associations between exposure to high traffic volumes, and especially to high truck traffic - the main source of diesel exhaust in urban settings - and increases in asthma symptoms, asthma hospitalizations, and decreased lung function. Yet, owing to the challenges of separating diesel from spark ignition exhaust, and vehicular exhaust in general from other sources of pollution, quantitative associations between exposure to diesel and other vehicular exhaust and adverse respiratory health outcomes have not been well-characterized. This study will characterize ambient exposures related to vehicular exhaust and other specific air pollutant sources, and evaluate the relationship of these exposures to the exacerbation of asthma among children living in Detroit and Dearborn, Michigan. We will collect ambient and indoor household air quality data which provides both high temporal and spatial resolution of pollution concentrations and utilize state-of-the-art statistical/geospatial models to apportion exposures among pollutant sources including diesel and other vehicular exhaust and to develop individual- specific exposure estimates. We will conduct a two-year longitudinal study involving 210 asthmatic children with 70 each living near high traffic/high truck volume roads, near high traffic/low truck volume roads, and distant from high traffic roads. Daily health measures to be assessed for two consecutive weeks in each of eight seasons will include respiratory symptoms, pulmonary function assessed by hand-held spirometers, medication use, and health services utilization. We hypothesize that: 1) exposures specific to diesel and other vehicular exhaust will be stronger predictors of adverse health status among children with asthma living in a high traffic density urban environment than other pollutant sources, and, 2) the presence of cigarette smokers in the household, high levels of common allergens in household dust, or sensitization to such allergens, will yield stronger exposure-response relationships between diesel and other vehicular exhaust and adverse respiratory health outcomes.